ANNUAL

FY 2008 REPORT

DOE Solar Energy

Technologies Program
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DOE Solar Energy Technologies Program 

It has been my pleasure to serve as the Program Manager in 2008. As you will see in this report, 

the U.S. Department of Energy (DOE) Solar Energy Technologies Program (SETP) plays a key 

role in accelerating the development of the U.S. solar industry and the advancement of solar 

technologies. 

The long-term objective of the program is to achieve high market penetration of solar energy 

technologies with an interim goal of achieving parity with conventional forms of electricity by 

2015. 

SETP is managed by a core group of technical and policy professionals at DOE and implemented 

through four separate subprograms: Photovoltaics (PV), Concentrating Solar Power (CSP), 

Systems Integration, and Market Transformation. The PV and CSP components focus on 

lowering the levelized cost of solar energy through a broad applied research and development 

(R&D) pipeline that covers device and process proof-of-concept, component and module 

prototyping, manufacturing scale-up, and system demonstration. Systems Integration and Market 

Transformation components address the diverse market and technical issues and challenges that 

must be surmounted to achieve high market penetration for solar technologies. All program 

efforts are conducted through an expansive set of partnerships with industry, government 

laboratories, universities, state and local governments, and other national organizations. 

During fiscal year (FY) 2008, SETP continued to make progress toward both long- and short-term 

goals. Highlights from the past year include the following: 

Photovoltaics 

•	 Made awards totaling more than $65 million for 62 industry projects spanning early-stage to 

market development. The awards addressed the challenges of scaling up novel, low-cost 

manufacturing across technologies including crystalline silicon, thin film, and concentrating 

PV. Success stories include: 

o	 SunPower achieved a production record of 23.6% efficiency on its all back-contacted 

crystalline silicon solar cell. 

o	 SoloPower moved its novel electroplating-based technology from a batch pilot operation 

in a development laboratory to a roll-to-roll processing line in a manufacturing facility. 

o	 MicroLink Devices developed an epitaxial lift-off process to manufacture solar cells for 

concentrator systems that reduce substrate costs while retaining high efficiency. 

•	 Achieved world-record efficiencies through applied research at the national laboratories. 

Successes include the new record of 20.0% for CIGS thin-film PV device and the recordsetting Inverted Metamorphic Multijunction solar cell with 40.8% efficiency at the National 

Renewable Energy Laboratory. 

Concentrating Solar Power 

•	 Established 15 partnerships with universities and CSP companies to support innovations in 

advanced high-temperature, heat-transfer fluids and thermal storage systems as important 

stepping stones for CSP to become cost-competitive with conventional energy sources. 

•	 Partnered with the Bureau of Land Management to initiate a Programmatic Environmental 

Impact Statement and conducted other joint activities necessary for the development of 

federal land in the Southwest for utility-scale solar projects. 

i 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Systems Integration 

•	 Awarded funds to 12 industry teams through the Solar Energy Grid Integration Systems 

project to develop new inverters and controllers with interfaces to energy-management 

systems. As much as $24 million in DOE investments is committed to completing these pilotproduction-phase projects. 

•	 Established monitoring of large-scale PV performance at high-penetration sites in California, 

Colorado, and Hawaii to better understand how high levels of PV impact the grid and reduce 

installation costs. 

Market Transformation 

•	 Strengthened the responsiveness, effectiveness, and accessibility of PV codes and 

standards through the Solar America Board for Codes and Standards. The board tracks key 

issues and released three studies on interconnection procedures for utility regulators, solar 

access laws, and external disconnect switches. 

•	 Expanded the Solar America Cities activity from 13 to 25 partnerships to further accelerate 

the adoption of solar energy technologies in a comprehensive citywide approach. 

In FY 2008, it was very encouraging for all in the solar industry to again see significant market 

growth and adoption of solar technologies both within and outside the United States. At both the 

state and federal level, solar technology was increasingly seen as a solution to long-term 

concerns about the environment, energy security, and price stability of energy sources. The 

industry, however, was not spared from the events and conditions that have impacted the global 

economy as whole. As we look toward the future, the DOE team will continue to structure 

program activities within a framework that can adjust to short-term industry and market conditions 

while also supporting long-term investments in research, development, and deployment. 

We look forward to working with all our stakeholders and partners to accomplish program goals 

and objectives in this important and exciting field, and we welcome your continued support and 

feedback. 

Sincerely, 

John Lushetsky 

Program Manager 

Solar Energy Technologies Program 

ii 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DOE Solar Program FY 2008 Annual Report Table of Contents 

Solar Energy Technologies Program........................................................................................................ i
 

Photovoltaic Subprogram Overview ........................................................................................................ 1
 

Applied Research
 

Exploratory Research
 

Silicon Center of Excellence..................................................................................................... 3
 

Next Generation Projects ......................................................................................................... 4
 

University and Exploratory Research ..................................................................................... 14
 

Industrial CRADAS .................................................................................................................. 16
 

Seed Fund Projects ................................................................................................................ 18
 

Electronic Materials and Devices 

Wafer Silicon........................................................................................................................... 21
 

Film Silicon .............................................................................................................................. 23
 

Copper Indium Gallium Diselenide Research ........................................................................ 26
 

Cadmium Telluride ................................................................................................................. 29
 

Concentrating Photovoltaics................................................................................................... 30
 

Organic Photovoltaics and Advanced Materials..................................................................... 33
 

Sensitized Solar Cells............................................................................................................. 37
 

Measurements and Characterization ........................................................................................ 39
 

Analytical Microscopy ............................................................................................................. 40
 

Electro-Optical Characterization............................................................................................. 43
 

Surface Analysis..................................................................................................................... 45
 

Cell and Module Performance................................................................................................ 47
 

PDIL Infrastructure, Engineering, and Integration .................................................................. 49
 

Systems and Component Development
 

Technology Pathway Partnerships......................................................................................... 51
 

University Partnerships........................................................................................................... 85
 

Photovoltaic Technology Incubator ........................................................................................ 90
 

Thin Film PV Partnership Program......................................................................................... 94
 

PV Manufacturing R&D .......................................................................................................... 96
 

Test and Evaluation
 

Modeling and Analysis
 

Systems Modeling .................................................................................................................. 99
 

Systems Analysis ................................................................................................................. 102
 

PV Grid Integration 

Grid Integration Support ....................................................................................................... 105
 

Inverter and Balance-of-Systems Project............................................................................. 107
 

Solar Energy Grid Integration Systems ................................................................................ 108
 

Reliability R&D 

Module Screening and Field Evaluation............................................................................... 112
 

Industry Reliability and Codes.............................................................................................. 115
 

Service Life Prediction.......................................................................................................... 116
 

Accelerated Lifetime Testing ................................................................................................ 117
 

Systems Engineering 

Module, Array, and System Test and Evaluation ................................................................. 120
 

PV Module Database............................................................................................................ 123
 

Energy Rating Method Validation......................................................................................... 124
 

Regional Experiment Stations .............................................................................................. 125
 

Resource and Safety Research 

Solar Radiometry and Modeling ........................................................................................... 128
 

Solar Resource Assessment and Characterization.............................................................. 129
 

Environmental Health and Safety......................................................................................... 130
 

iii 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Market Transformation 

Codes and Standards
 

Solar America Board of Codes and Standards .................................................................... 131
 

Training and Certification
 

Building Integration and Finance
 

Technical Partnerships
 

Technical Outreach
 

PV Installer Certification ....................................................................................................... 132
 

Solar Decathlon .................................................................................................................... 133
 

Solar America Showcases.................................................................................................... 137
 

Solar America Cities ............................................................................................................. 139
 

Government Solar Installation Program ............................................................................... 142
 

State and Stakeholder Outreach .......................................................................................... 143
 

State and Utility Outreach..................................................................................................... 145
 

Support Activities.................................................................................................................. 146
 

Solar Thermal Subprogram Overview.................................................................................................. 147
 

Concentrating Solar Power Subprogram Overview
 

Parabolic Trough Development
 

Dish/Stirling R&D
 

Thermal Storage R&D
 

Advanced CSP Concepts
 

CSP Market Transformation
 

Solar Heating and Lighting Overview
 

Parabolic Trough Research and Development .................................................................... 149
 

Industry Projects................................................................................................................... 153
 

Dish Engine Research and Development ............................................................................ 157
 

Industry Projects................................................................................................................... 159
 

Storage Components............................................................................................................ 162
 

Storage Systems .................................................................................................................. 163
 

Advanced Heat Transfer Fluid Development ....................................................................... 165
 

Industry Projects................................................................................................................... 167
 

Advanced Concepts R&D..................................................................................................... 169
 

Thermochemical Project....................................................................................................... 172
 

Industry Projects................................................................................................................... 174
 

Southwest Stakeholder Outreach......................................................................................... 180
 

CSP Resource Assessment ................................................................................................. 181
 

Market Analysis and Grid Integration ................................................................................... 182
 

Solar Advisor Support........................................................................................................... 183
 

Programmatic Environmental Impact Study ......................................................................... 184
 

SHC Systems Development and Market Transformation .................................................... 185
 

Systems Integration and Coordination
 

Program Management ................................................................................................................ 189
 

Equipment and Facilities............................................................................................................. 192
 

Communications ......................................................................................................................... 196
 

International Activities ............................................ ......................................................... 198
 

EERE Crosscutting Activities ...................................................................................................... 199
 

Small Business Innovation Research ......................................................................................... 201
 

Congressional Earmarks............................................................................................................. 204
 

Appendices
 

FY 2008 Budget Summary.......................................................................................................... 213
 

Acronyms and Abbreviations ...................................................................................................... 217
 

iv 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Photovoltaic Subprogram Overview 

After launching several new programs under the Solar America Initiative (SAI) in fiscal year (FY) 

2007, FY 2008 represents the first full-year implementation of SAI funding towards achieving grid 

parity by 2015. 

Funds were allocated among four key photovoltaic (PV) research and development areas (R&D): 

•	 Technology Pathway Partnerships (TPPs) are industry-led, public-private partnerships. 

The 11 awardees bring together key players across the supply chain to focus on 

innovations that reduce costs. 

•	 University PV Process and Product Development projects are leveraging the knowledge 

of universities to bring technology from laboratory to marketplace. 

•	 PV Technology Incubators are developing promising module technologies that have been 

successfully demonstrated on a small scale. 

•	 Next-Generation Research projects investigate high-risk/high-payoff PV device and 

process concepts. 

These subprograms areas comprise 62 projects that span early stage, applied R&D through 

market-oriented product and process development. In regards to the PV Technology Incubator 

awards, the second round of winners were announced with the selection of six new projects and 

seven of the original 10 projects proceeding to the second 9-month phase of their projects. 

In addition, the PV subprogram expanded efforts in technology transfer through an activity to 

bolster the efforts of lab staff who work with industry partners though cooperative research and 

development agreements (CRADAs) at the National Renewable Energy Laboratory. Through cost 

shared partnerships with industry, these projects seek to mature national lab research into 

marketable technologies. 

Other key efforts in PV reliability were expanded to help accelerate market acceptance of 

modules based on new materials. Internal “seed” research was funded to help bridge gaps 

between the traditional core research efforts at the national labs and to ensure that novel 

research topics are given an opportunity to demonstrate their promise. 

To improve system modeling and analysis, a new version of the Solar Advisory Model (SAM) has 

been developed by the national laboratories. Widely used within the solar industry, SAM provides 

a standardized tool for assessing PV system performance through a levelized cost of energy 

metric. 

Several projects also supported test and evaluation R&D. One example is the lab- and fieldtesting of industry-supplied products through the national labs. Products from more than 60 solar 

companies were tested for this purpose, and the testing data gathered was used to develop a 

better test database, test methods, and standards. 

Another key activity involved the development of new PV inverters, controllers, and energymanagement systems for distributed PV systems through the program’s Solar Energy Grid 

Integration Systems project. 

During FY 2008, several new market transformation activities begun in late FY 2007 were more 

fully developed. These activities included the Solar America Board for Codes and Standards, 25 

Solar America City partnerships, three state technical outreach partnerships, one utility technical 

outreach partnership, and seven Solar America Showcases. The market transformation activities 

served to reduce the barriers to widespread solar implementation nationwide. 

These and many more activities are detailed in the following reports. 

1 Photovoltaic
Photovoltaic 2
 

 

____________________________________________________________________________________ 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

Silicon Center of Excellence
 

University Crystalline Silicon Photovoltaics Research and Development
 

Performing Organization: Georgia Institute of Technology (GIT) 

Key Technical Contact: Carolyn Elam, (303) 275-4953, carolyn.elam@go.doe.gov 

DOE HQ Technology Manager: Scott Stephens, (202) 586-0565, Scott.Stephens@ee.doe.gov 

FY 2008 Budgets: $713K (DOE), $178K (GIT) 

Objectives 

•	 Advance state of crystalline silicon (Si) solar cell technology to make photovoltaics (PV) more 

competitive with conventional energy sources. 

•	 Emphasize fundamental and applied research to develop low-cost, high-efficiency cells on 

commercial silicon substrates. 

•	 Utilize strong PV industry involvement and support strong PV education program domestically. 

•	 Reduce c-Si module price to $1.25/W by 2020 with installed PV system cost of $3.30/W and 

levelized cost of energy (LCOE) of 9¢/kWh. 

Accomplishments 

•	 Developed cost model to show 18% to 20% efficient thin c-Si cells can reduce levelized cost of 

PV-generated electricity to 5–10¢/kWh. 

•	 Developed clear roadmap for 20% efficient cells that involves development of: 

o	 Narrow Silver (Ag) grid & improved contacts: +1%. 

o	 High sheet resistance emitter: +1%. 

o	 Dielectric passivation and reflective back contact: +1. 

•	 Developed new experimental method to measure amount of hydrogen injected into Si during 

firing of screen-printed contacts. 

•	 Developed Ag-colloid back surface reflector that enhances light trapping and improve short 

circuit current by 2.6%. 

•	 Achieved 18% efficient commercial-ready cells using high sheet resistance emitters. 

•	 Developed 19% efficient 4-cm2 cells with passivated Boron-Back Surface Field (B-BSF). 

•	 Developed 19%-efficient 4-cm2 cells with rear dielectric passivation without parasitic shunting. 

Future Directions 

•	 Ended on June 30, 2008, so no further work is planned for this award. 

1. Major FY 2008 Publications 

A. Das; D.S. Kim; V. Meemongkolkiat; A. 

Rohatgi. “19% efficient screen –printred cells 

using a passivated transparent boron back 

surface field.” 33rd IEEE PVSC Proceedings; 

2008, San Diego, California. 

D.S. Kim; M.H. Kang; B. Rounsaville; A. Ristow; 

A. Rohatgi; Y. Awad; G. Okoniewski; A. Moore; 

M. Davies; R. Smirani; M.A. El Khakani; J. 

Hong. “High performance solar cells with silicon 

carbon nitride (SiCxNy) antireflection coatings 

deposited from polymeric solid source.” 33rd 

IEEE PVSC Proceedings; 2008, San Diego, 

California. 

A. Ebong; D.S. Kim; A. Rohatgi; W. Zhang. 

“Understanding the mechanism of light induced 

plating of silver on screen printed contacts for 

high sheet resistance emitters with low surface 

phosphorus concentration.” 33rd IEEE PVSC 

Proceedings; 2008, San Diego, California. 

S. Ramanathan; V. Meemongkolkiat; A. Rohatgi. 

“Spin on based process for simultaneous 

diffusion and passivation for high efficiency 

LBSF solar cells.” 33rd IEEE PVSC Proceedings; 

2008, San Diego, California. 

3 Photovoltaic

Applied Research

Exploratory Research
 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

Next Generation Projects 

Performing Organizations:	 Arizona State University (ASU); California Institute of Technology (CIT); 

Massachusetts Institute of Technology (MIT); Mayaterials, Inc.; 

Pennsylvania State University (Penn State); Rochester Institute of 

Technology (RIT); Solasta, Inc.; Solexant Corporation; Soltaix LLC; 

Stanford University (Stanford); University of California, Davis (UC Davis); 

University of California, San Diego (UC San Diego); University of 

Colorado (CU); University of Delaware (UD); University of Florida (UF); 

University of Illinois; University of Michigan (U-M); University of South 

Florida (USF); University of Washington (UW); Voxtel, Inc.; Wakonda 

Technologies, Inc. 

Key Technical Contacts:	 Carolyn Elam (DOE/GO, Primary Contact), 303-275-4953, 

carolyn.elam@go.doe.gov 

Joe Lucas (DOE/GO), 303-275-4849, joe.lucas@go.doe.gov 

Jim Payne (DOE/GO), 303-275-4756, jim.payne@go.doe.gov 

Brad Ring (DOE/GO), 303-275-4930, brad.ring@go.doe.gov 

Holly Thomas (DOE/GO), 303-275-4818, holly.thomas@go.doe.gov 

DOE HQ Technology Manager:	 Marie Mapes, 202-586-000, marie.mapes@hq.doe.gov 

FY 2008 Budgets:	 $6,000K (DOE/GO) 

Objectives 

•	 Make solar electricity from photovoltaics (PV) cost-competitive with conventional forms. 

•	 Address long-term technological and scientific challenges for improved performance, lower cost, 

and improved reliability of PV components and systems. 

Accomplishments 

•	 Completed merit review of the applications 

•	 Selections announced March 2008 with 25 projects negotiated and awarded. 

Future Directions 

•	 Evaluate progress of critical milestones and decide at the end of the each project’s first phase, 

starting in fiscal year (FY) 2009 and extending into FY 2010. 

1. Introduction 

The Next Generation Photovoltaic (PV) Devices 

and Processes projects represent innovative, 

revolutionary, and highly disruptive nextgeneration PV technologies. These PV research 

and development (R&D) activities are expected to 

produce prototype PV cells and/or processes by 

2015, with full commercialization by 2030. 

2. Technical Approach 

The selected projects below each received $240K. 

Agreement Title 

ASU; John Kouvetakis 

(Advanced Semiconductor Materials for PV) 

CIT; Harry Atwater 

(Solar Cells from Earth-Abundant Semiconductors) 

MIT; Vladimir Bulovic 

(Colloidal Nanocrystal Quantum Dot PV Devices) 

MIT; Emanuel Sachs 

(Recrystallization of Silicon Wafers in Thin Film 

Capsules) 

Mayaterials, Inc.; Richard Laine 

(Solar Grade Silicon from Ag By-Products) 

Penn State; Joan Redwing 

(High Aspect Ratio Semiconductor Heterojunction Cell) 

Penn State; Harry Allcock 

(Improved Electrodes and Electrolytes for Dye-Based 

Solar Cells) 

Agreement Title 

ASU; Mark van Schilfgaarde 

(II-IV-V Based Thin Film Tandem PV Cell) 

Photovoltaic

Applied Research

Exploratory Research

4
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Agreement Title 

RIT; Seth M. Hubbard 

(High Efficiency Nanostructured III-V Cells for PV 

Concentrators) 

Solasta, Inc.; Michael Naughton 

(High Efficiency Power via Separated Photo and 

Voltaic Pathways) 

Solexant Corporation; Alison Breeze 

(High Efficiency Quantum Dot Cells Based on Multiple 

Exciton Generation) 

Soltaix LLC; Mehrdad Moslehi 

(Ultra-High-Efficiency, Thin-Film, Crystalline Silicon 

Solar Cells) 

Stanford; Yi Cui 

((Culn (Ga) Se2 (CIGS) Nanowire Solar Cells)) 

Stanford; Peter Peumans 

(Nanostructured Materials for Solution-Processed PV) 

UC-Davis; Adam Moule 

(Functional Multi-Layer Solution Processable Polymer 

Solar Cells) 

UC San Diego; Edward T. Yu 

(High-efficiency PV Based on Semiconductor 

Nanostructures) 

CU; Josef Michl 

(Exciton Fission for an Ultra-High Efficiency, Low Cost 

Solar Cell) 

UD; William Shafarman 

(Novel Approaches to Wide Bandgap CuInSe2 Based 

Absorbers) 

UF; Jiangeng Xue 

(High Efficiency Hybrid Organic-Inorganic PV Cells) 

University of Illinois; John Rogers 

(Transfer Printed Microcells with Micro-Optic 

Concentrators ) 

U-M; Stephen Forrest 

(Crystalline Organic PV Cells) 

USF; Christos Ferekides 

(Next Generation CdTe Technology: Substrate FoilBased Cells) 

UW; Alex Jen 

(Interfacial Engineering for p-Conjugated PolymerBased Heterojunction Devices) 

Voxtel, Inc.; David Schut 

(Optimization of Impact Ionization in Composite 

Nanocrystal Devices) 

Wakonda; Leslie Fritzemeier 

(Novel Manufacturing of Flexible III-V Thin Films) 

3. Results and Accomplishments 

3.1 II-IV-V Based Thin Film Tandem PV Cell 

(ASU-Schilfgaarde) 

Accomplishments 

•	 Developed methods to synthesize II-IV-V2 

targets for pulsed laser deposition and 

sputtering with a range of compositions. 

•	 Initiated systematic study of thin film ZnGeAs2 

growth using pulsed-laser deposition. 

•	 Carried out calculations for new II-IV-V 

candidates: MgGeAs2 and MgSnAs2. 

Future Directions 

•	 Optimize growth conditions of ZnGeAs2, 

ZnSnP2, and other II-IV-V2 compounds and 

alloys deemed to be useful for PV work for 

stoichiometry, defect density, and doping. 

•	 Perform density function calculations, 

including advanced technique to model bulk 

and defect properties of II-IV-V2 compounds 

and alloys, emphasis on low cost and low 

volatility elements. 

•	 Develop heterostructure and tandem PV 

devices and measure performance. 

3.2 Advanced Semiconductor Materials for PVs 

(ASU-Kouvetakis) 

Accomplishments 

•	 Completed scale-up of deposition chemistry to 

transition ASU Ge-on-Si technology from 

laboratory-scale substrates to 4” Si platforms. 

•	 Synthesized new families of SiGeSn alloys 

lattice-matched to Ge to serve as fourth 

junction in PV stack 

Si(100)/Ge/SiGeSn/InGaAs/InGaP. 

•	 Developed proof-of-concept materials growth 

of fully lattice matched 

Si(100)/Ge/SiGeSn/InGaAs structures en 

route to four-junction structure. 

•	 Determined optical properties for SiGeSn/Ge 

structures demonstrating independent tuning 

of band structure at a fixed lattice constant for 

the first time in group-IV materials. 

Future Directions 

•	 Complete scale-up of growth of Ge-on-Si to 

commercial-size large area wafers (4”≤ φ ≤ 

12”) in collaboration with industrial partners, 

ASM America and Epiworks, Inc. 

•	 Fabricate p- and n-doped GeSiSn layers and 

subsequent formation and measurements of 

GeSiSn PIN diodes to demonstrate integration 

in hybrid Group IV / III-V PV designs. 

•	 Complete ongoing characterizations of 

compositional dependence of bandgap in 

SiGeSn alloys for use in four-junction cells. 

•	 Fabricate p- and n-doped GeSn layers and 

measurements of GeSn PIN diodes en route 

to two junction prototypes. 

3.3 Solar Cells from Earth-Abundant 

Semiconductors (CIT–Atwater) 

This project has just begun, but objectives include: 

•	 Synthesize two-junction cells with top subcells 

composed of earth-abundant compound 

semiconductors including quantum dots (QD), 

earth-abundant Zn3P2 films, and bottom 

subcells composed of Si pn junction cells. 

5 Photovoltaic

Applied Research

Exploratory Research
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Exploit recent advances in plasmonics to 

realize high efficiency solar cells based on 

enhanced absorption and carrier collection in 

ultrathin film and QD absorber layers. 

•	 Design plasmonic structures to enhance solar 

light absorption in ultrathin film Si and wide 

bandgap earth-abundant Zn3P2 films and lowdimensional semiconductor structures. 

3.4 Colloidal Nanocrystal Quantum Dot PV 

Devices (MIT-Bulovic) 

Accomplishments 

•	 Demonstrated morphology of printed QD films 

can be improved with use of parylene-C 

coating, resulting in uniform QD surface 

coverage, enhanced short circuit current, open 

circuit voltage, and built-in potential. 

•	 Demonstrated high open circuit voltage can be 

achieved with stable and transparent indium 

tin oxide electrodes. 

•	 Demonstrated new synthesis of core-shell IR 

QDs of PbS. 

•	 Demonstrated scale-up of QD synthesis. 

•	 Applied chemical treatment of thin QD films to 

facilitate QD tight-packing. 

Future Directions 

•	 Discern which interface dominantly contributes 

to exciton dissociation processes in QD-PVs. 

•	 Fabricate All-Metal-Oxide PVs. 

•	 Incorporate IR QDs in the PV structures. 

•	 QD thin film process development to minimize 

pin-holes responsible for QD-PV device 

shunting. 

3.5 Recrystallization of Silicon Wafers in Thin Film 

Capsules (MIT-Sachs) 

Accomplishments 

•	 Scaled up size of wafers processed by almost 

a factor of four. 

•	 Improved thickness control of wafers. 

•	 Demonstrated low dislocation density in 

recrystallized wafers. 

•	 Initiate work on grain nucleation and modeling 

of crystal growth. 

Future Directions 

•	 Focus on attaining good electronic properties 

and making efficient solar cells. 

3.6 Solar Grade Silicon from Agricultural ByProducts (Mayaterials-Laine) 

Accomplishments 

•	 Developed extraction and purification 

technique that results in silica with dopant 

levels that meet target objectives. 

- Total silica impurities are at or below 10 

ppm total – 99.999% purity. 

- Process scaled to 500g batch sizes and 

testing procedures have been established 

to ensure fast turnaround resulting in 

faster program execution. 

Future Directions 

•	 Convert high-purity silica into solar grade 

silicon. 

•	 Remove as much of remaining impurities as 

possible from silica prior to conversion. 

•	 Investigate alternative paths to solar-grade 

silicon through silane-based process. 

3.7 High Aspect Ratio Semiconductor 

Heterojunction Cells (Penn State-Redwing) 

Accomplishments 

•	 Controlled growth of Si wires with diameters of 

700 nm using a gold catalyst contained within 

pores etched into SiO2/Si substrates. 

•	 Fabricated 25 μm long Si wires with diameters 

ranging from 1.5 – 2.5 μm by deep reactive ion 

etching (DRIE) to be used as a control. 

•	 Grew single crystal of an n-type coating on to 

p-type vapor-liquid-solid (VLS)-grown Si 

nanowires by low pressure chemical vapor 

deposition. 

•	 Intrinsic a-Si coating on VLS-grown Si 

nanowires and etched Si wires using PECVD. 

•	 Developed ITO coating of etched Si wires. 

•	 Fabricated radial junction using etched Si 

wires and gas phase dopant diffusion, 

resulting in diode like I-V characteristics. 

•	 Measured Voc of 320 mV measured on VLSgrown Si nanowires obtained from a redox 

couple using a non-aqueous solution of 

[Ru(bpy)3]2+. 

Future Directions 

•	 Improve VLS growth of Si wires to achieve 1:1 

relationship between wire and SiO2 pore 

diameters and increase density of Si wires to 

maximize absorption area. 

•	 Optimize radial junction solar cell fabricated 

using etched Si pillars and gas phase diffusion 

for use as control structure. 

•	 Fabricate and test radial junction wire devices 

formed, using doped VLS Si wires and LPCVD 

n-type coating process. 

•	 Fabricate and test radial junction devices 

formed using a-Si PECVD coating process. 

•	 Transfer patterning and growth process to 

glass substrates to reduce production costs. 

3.8 Improved Electrodes and Electrolytes for DyeBased Solar Cells (Penn State-Allcock) 

Photovoltaic

Applied Research

Exploratory Research

6
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Accomplishments	 QD cell, as compared to 12.8% for a baseline 

•	 Synthesized methoxyethoxyethoxy 

phosphazene oligomer and polymer materials 

as base for dye solar cell electrolytes. 

Formulated electrolytes with phosphazene and 

LiI / I2 components and performed 

electrochemical testing. 

•	 Fabricated TiO2 electrodes with microspherepatterned nanoporous type and 

nanorod/nanotube type structures, performed 

electrochemical testing under traditional dye 

solar cell conditions. 

•	 Performed test assembly of phosphazene 

electrolytes with nanoporous and nanotublar 

electrodes, obtained preliminary results. 

•	 Formulated gel electrolytes based on 

polymeric phosphazene and propylene 

carbonate. Preformed electrochemical 

experiments and assembled test cells for 

efficiency evaluation. 

•	 Developed characterization standard for 

electrolyte infusion into nanoporous substrated 

using SEM method. Identified ease or difficulty 

of penetration of polymeric compounds into 

various nanoporous electrodes. 

Future Directions 

•	 Optimize cell fabrication of existing electrolyte 

and electrode pairs. 

•	 Synthesize anion-conduction promoting 

phosphazene electrolyte materials and 

electrochemical/assembled cell testing. 

•	 Fabricate electrodes with alternate 

nanopatterns and assembly/testing of 

corresponding dye cells. 

•	 Fabricate procedures to improve electrolyte 

infiltration and viability of mass production. 

•	 Explore suitable additives for formulation of 

cost effective, thermally stable gel electrolytes. 

3.9 High Efficiency Nanostructured III-V Cells for 

PV Concentrators (RIT-Hubbard) 

Accomplishments 

•	 Completed growth and strain balancing of 5X, 

10X and 20X arrays of InAs QDs. Strain 

balancing was vital to reduction of 

nonradiative recombination in the QD stacks. 

•	 Grew, fabricated, and measured initial 

baseline p-i-n and 5-20X array QD enhanced 

GaAs solar cells. Correct strain balancing lead 

to an improved short circuit current value 

compared to cells without QD stacks. 

•	 Took high concentration measurements for 

baseline and 5X QD enhanced solar cell. An 

AM1.5d (low AOD) efficiency of 15.0% at 

100X concentration was measured for the 5X 

cell without QDs. 

•	 Measured thermal conductivity of solar cell 

structure with and without QDs and compared 

structure thermal resistance with that of bulk 

GaAs. The results are important for thermal 

management of the concentrator solar cells. 

Future Directions 

•	 Optimize concentrator and QD cell growth. 

Specifically QD enhanced cell design and QD 

material. Increased stacking of QD layers 

through use of high quality strain balancing 

approach. Demonstrate further enhancement 

of short circuit current and efficiency under 

concentration. 

•	 Investigate IB levels in InAs QD enhanced 

solar cells as well as other identified candidate 

materials (e.g., Sb based QDs). 

•	 Develop model and computer simulation of 

QD enhanced solar cells and intermediate 

band solar cells. 

•	 Continue experimental investigation of thermal 

properties of nanostructured solar cell 

structures to optimize heat removal from solar 

cells designed for concentrator applications. 

•	 Measure performance and spectral response 

of cells as function of atmospheric and 

environmental conditions. 

3.10 High Efficiency Power via Separated Photo 

and Voltaic Pathways (Solasta-Naughton) 

Accomplishments 

•	 Fabricated a-Si solar cells in Solasta 

architecture. 

•	 Demonstrated increased light collection in 

Solasta cells as compared to conventional, 

planar cells having same absorber thickness. 

•	 Demonstrated increased charge carrier 

collection and increased PV efficiency in 

Solasta cells as compared to conventional, 

planar cells having same absorber thickness. 

Future Directions 

•	 Improve absolute efficiency of a-Si cells, 

toward 15%-20%. 

•	 Increase cell area to 100 cm2. 

•	 Extend Solasta thin film solar cell architecture 

to other absorber media. 

•	 Incorporate third generation phenomena in 

Solasta architecture. 

3.11 High Efficiency QD Cells Based on Multiple 

Exciton Generation (Solexant-Breeze) 

Accomplishments 

•	 Developed layer-by-layer deposition technique 

for QD films with in-situ ligand exchange. 

7 Photovoltaic

Applied Research

Exploratory Research
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Demonstrated 79% estimated peak internal 

quantum efficiency for planar QD solar cell 

device (year one milestone). 

•	 Demonstrated improved near-IR performance 

for QD devices utilizing plasma and chemical 

processing of QD films. 

•	 Established equipment and process for atomic 

layer deposition (ALD) of metal sulfide thin 

films. 

•	 Created first QD/metal sulfide ALD hybrid 

devices. 

Future Directions 

•	 Finish development for complete coverage of 

high surface area substrates with QD 

sensitizers. 

•	 Expand selection of metal sulfide ALD 

materials and ALD film process treatment. 

•	 Advance QD/ALD devices from planar to 

nanostructured design. 

•	 Develop barrier layer films to increase device 

efficiency via reduction of interface 

recombination. 

3.12 Ultra-High-Efficiency, Thin-Film, Crystalline 

Silicon Solar Cells (Soltaix-Moslehi) 

Accomplishments 

•	 Confirmed improved mechanical integrity of 

Soletaix’s structure compared to conventional 

crystalline silicon structures and enabled 

characterization of geometrical parameters on 

mechanical integrity. 

•	 Obtained initial data from mechanical testing 

to establish integrity of starting material. 

•	 Developed short and full flow wafers to define 

substrate generation process at low cost. 

Future Directions 

•	 Continue electrical and optical simulations to 

further optimize Soletaix’s structure coupled 

with more mechanical experiments to 

determine a geometrical window which 

maximizes performance, lowers silicon 

consumption, and is mechanically robust. 

•	 Demonstrate ability to further utilize less 

silicon to improve cost reduction. 

•	 Complete process integration of working cell 

on Soletaix’s substrates. 

•	 Demonstrate 17% efficient cells. 

3.13 Culn (Ga) Se2 (CIGS) Nanowire Solar Cells 

(Stanford - Yi Cui) 

Accomplishments 

•	 Synthesized family of Cu-In-Ga-Se nanowire 

materials, including GaSe, In2Se3, In2­

xGaxSe3, CuInSe2. 

•	 Understood structure evolution during 

CuInSe2-CdS junction formation. 

Future Directions 

•	 Synthesize CuInGaSe2 nanowire materials. 

•	 Perform single nanowire solar cell study. 

3.14 Nanostructured Materials for SolutionProcessed PV (Stanford-Peumans) 

Accomplishments 

•	 Demonstrated solution-processed silver 

nanowire transparent electrode with sheet 

resistance <10Ohm/sq and solar-averaged 

transparency >85%. The materials cost is 

~$0.10/m2. 

•	 Demonstrated basic organic solar cell on silver 

nanowire electrodes. 

•	 Demonstrated solution-processed ZnO 

nanowire transparent electrode with sheet 

resistance ~1kOhm/sq. 

Future Directions 

•	 Improve performance of silver nanowire 

electrodes to sheet resistances <5hm/sq and 

transparencies>90%. 

•	 Improve sheet resistance of ZnO nanowire 

electrodes. Transparency assessment of 

these electrodes. 

•	 Integrate solution-processed transparent 

electrodes into single junction cells of various 

types to demonstrate technical viability. 

•	 Analyze industrial-scale manufacturing. 

3.15 Functional Multi-Layer Solution Processable 

Polymer Solar Cells (UC-Davis-Moule) 

Accomplishments 

•	 Prepared film samples and measurements 

using atomic force microscopy (topography, 

phase, conduction and Kelvin probe modes), 

neutron reflectometry, ultra-fast pump-probe 

optical laser spectroscopy, and scanning 

electron microscopy. 

•	 Set up optical and electrical modeling of multilayer films. First publication is in preparation. 

Future Directions 

•	 Develop multi-layer deposition method. 

•	 Develop multi-layer devices. 

•	 Develop predictive optical and electrical 

modeling tools. 

3.16 High-efficiency PV Based on Semiconductor 

Nanostructures (UC San Diego-Yu) 

Accomplishments 

•	 Demonstrated absorption over increased 

range of wavelength in lattice-matched 

GaInAsP/InP quantum-well solar cells, relative 

to InP homojunction solar cells. 

Photovoltaic

Applied Research

Exploratory Research

8
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Demonstrated increased power conversion 

efficiency in GaInAsP/InP quantum-well solar 

cells compared to InP homojunction solar cells 

(~5-7% increase in conversion efficiency). 

•	 Demonstrated plasmonic scattering by Au 

nanostructures of normally incident photons 

into lateral propagation paths associated with 

waveguide modes in quantum-well solar cells, 

and increase in photon absorption efficiency. 

•	 Demonstrated Mie scattering by dielectric 

nanoparticles of normally incident photons into 

lateral propagation paths associated with 

waveguide modes in quantum-well solar cells, 

and increase in photon absorption efficiency. 

•	 Demonstrated increased power conversion 

efficiency in quantum-well solar cells 

incorporating nanostructure scattering effects 

relative to quantum-well solar cells without 

nanostructured scatterers (~17% increase in 

power conversion efficiency). 

Future Directions 

•	 Design and demonstrate quantum-well solar 

cells with improved scattering-based coupling 

to quantum-well waveguide modes for further 

increases in photon absorption efficiency. 

•	 Explore semiconductor nanowire 

heterostructure growth for high-efficiency PV. 

•	 Fabricate and characterize semiconductor 

nanowire heterostructure PV devices. 

3.17 Exciton Fission for an Ultra-High Efficiency, 

Low Cost Solar Cell (CU-Michl) 

Accomplishments 

•	 Built instrumentation needed for singlet 

fission (SF) studies. 

•	 Discovered neat solid 1,3­

diphenylisobenzofuran, designed for SF using 

first principles, exhibits a significant yield of 

triplet by SF (over 10%). 

•	 Found dimers of 1,3-diphenylisobenzofuran 

only give significant SF when the constituent 

monomerichromophores are coupled very 

strongly (directly connected by a bond). 

•	 Prepared previously computed new SF 

chromophore of the p-benzoquinodimethane 

type and discovered that it suffers from nonradiative processes in the excited singlet state, 

now being modified to avoid this difficulty. 

•	 Discovered computationally two new families 

of promising SF chromophores. 

•	 Performed theoretical studies of SF dynamics 

in the coherent and the non-coherent limits. 

Future Directions 

•	 Discover new SF chromophore families. 

•	 Synthesize and photophysically characterize 

new SF chromophore family. 

•	 Examine coupling of SF chromophores into 

dimers and oligomers. 

•	 Develop procedures for SF chromophore 

nanocrystal formation and characterization. 

•	 Develop combined coherent/incoherent 

dynamics model for SF. 

3.18 Novel Approaches to Wide Bandgap 

CuInSe2 Based Absorbers (UD-Shafarman) 

Accomplishments 

•	 Developed source for controlled thermal 

evaporation of silver, and single phase 

(AgCu)(InGa)Se2 thin films were deposited 

with controlled composition over a wide range 

of compositions. 

•	 Demonstrated An (AgCu)(InGa)Se2-based 

solar cell with 17% conversion efficiency, 

demonstrating viability of this alloy material for 

high efficiency solar cells. 

•	 Fabricated An (AgCu)(InGa)Se2 cell with VOC 

= 0.86 V and efficiency >10%, indicating 

possible alloy to produce high voltage devices. 

•	 Showed (AgCu)(InGa)Se2 films sub-bandgap 

optical transmission above 90%, greater than 

typical Cu(InGa)Se2 films, which is necessary 

for use as top cell in tandem device. 

•	 Transient photocapacitance measurements of 

(AgCu)(InGa)Se2 showed low Urbach 

energies indicated by sharp optical bandtails, 

suggesting low alloy disorder and high quality 

material. 

•	 Modified laser system at IEC for annealing of 

CuInSe2-alloy thin films and conditions for 

controlled reaction of films were established. 

•	 Established anneal conditions for laser/film 

treatments to control Cu(InGa)Se2 surface 

modification and provide apparent melting or 

partial recrystallization of films. 

•	 Produced laser annealing experiments using 

low power density with improved current 

collection and higher efficiency compared to 

unannealed control samples. 

Future Directions 

•	 Quantify effects of evaporation process 

modifications and relative Ag content in wide 

bandgap (AgCu)(InGa)Se2 films with respect 

to materials properties and device behavior. 

•	 Analyze capacitance-based characterization of 

(AgCu)(InGa)Se2 devices to provide basis and 

guide for improvement of these devices. 

•	 Expand laser-based annealing to include 

surface characterization and control as well as 

different anneal conditions. 

9 Photovoltaic

Applied Research

Exploratory Research
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.19 Very High Efficiency Hybrid OrganicInorganic PV Cells (UF-Xue) 

Accomplishments 

•	 Developed two classes of ternary nanosphere 

systems: a ternary Zn1-xCdxSe nanosphere 

with molar zinc concentrations of x=17%, 25% 

and 75% with good monodispersity and sharp 

emission spectra, and a ternary-core/shell 

nanosphere Zn1-xCdxS/ZnSe with x=17% and 

1.8 eV band gap. 

•	 Developed two synthetic approaches to 

facilitate separate needs to (1) mimic oligomer 

functionalized to nanorod surface and (2) 

quantify physical and electro-optical 

characteristics of pristine ternary 

nanostructures. 

•	 Synthesized two main building blocks of 

mono-functionalized all-thiophene oligome, 

validating chosen synthetic route. A model 

compound bearing phosphonic acid functional 

group was synthesized, structurally 

characterized, and transferred to Holloway 

group for initial binding studies. 

•	 Prepared and characterized two different 

series of poly(phenylene ethynylene) 

polymers, one containing amino end caps and 

one containing phosphonate end caps. 

•	 Studied CdSe nanosphere size and postdeposition thermal annealing on device 

performance of P3HT/CdSe hybrid PV cells 

and achieved conversion efficiencies of 1.5%. 

Future Directions 

•	 Synthesize ternary nanorods with bandgap of 

1.5-1.8 eV. 

•	 Finalize synthesis of mono- and bi-functional 

oligomers and polymers and study effect of 

grafting oligomer/polymers onto CdSe or 

ZnCdSe nanocrystals on steady-state 

photoluminescence of materials. 

•	 Optimize morphology of hybrid thin films and 

align nanorods assisted by an external field. 

•	 Fabricate hybrid PV cells based on 

functionalized ologimer/polymers and ternary 

nanocrystals and study effect of ternary 

composition on Voc in these devices. 

•	 Design and fabricate tandem hybrid PV cells 

to broadly cover the solar spectrum. 

3.20 Transfer Printed Microcells with Micro-Optic 

Concentrators (University of Illinois-Rogers) 

Accomplishments 

•	 Perfected transfer printing of GaAs microcells 

from single source ink layers. 

•	 Designed and fabricated lenticular micro-lens 

arrays. 

•	 Developed new metallic inks for direct-write 

metallization of interconnects, advancing 

direct ink write design rules by ~100 times. 

•	 Demonstrated full fabrication protocol and high 

efficiency operation in test platform, based on 

single crystalline Si PV microcells. 

•	 Optimized printing tool for >99% assembly of 

medium-scale (900) GaAs microcell. 

•	 Achieved better than 5 micron large area 

placement accuracy for printed GaAs cells. 

Future Directions 

•	 Interconnect direct ink write of microcells in 

GaAs-based arrays. Geometrically expanded 

array of printed microcells and conductive 

landing pads will be delivered from Semprius 

for interconnection by DIW between landing 

pads and microcells to form module 

backplane. 

•	 Demonstrate effectiveness of a multilayer 

stack design that will significantly enhanced 

cost competitiveness of necessary wafer side 

processing of “III-IV” PV ink. 

•	 Integrate full III-V module subsystems. 

•	 Advance cell integration and printing 

strategies to embed new forms of 

performance. 

3.21 Crystalline Organic PV Cells (U-M-Forrest) 

Accomplishments 

•	 Devised new method for accurately and 

quickly measuring exciton diffusion length in 

organic crystalline and amorphous thin films. 

•	 Developed model for calculating efficiencies in 

organic PV cells. 

•	 Invented and demonstrated new organic PV 

cell based on dual heterojunction architecture. 

Future Directions 

•	 Design high efficiency organic tandem cell, 

using diffusion lengths and absorption 

characteristics of a range of crystalline and 

polycrystalline organic materials. 

•	 Determine growth conditions to achieve 

crystallinity of organic films in tandem cell. 

•	 Fabricate and characterize tandem cells, using 

optimized materials and growth conditions. 

•	 Begin reliability testing of tandem cells. 

3.22 Next Generation CdTe Technology: 

Substrate Foil-Based Cells (USF-Ferekides) 

Accomplishments 

•	 Investigated structural properties of 

semiconductor films deposited by CSS-in 

substrate configuration on foil substrates. 

Photovoltaic

Applied Research

Exploratory Research

10
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Established in-situ process for sequential 

deposition of substrate CdTe solar cells on foil 

substrates. 

•	 Introduced three potential back-contact 

materials into solar cell structures. 

•	 Initiated adhesion studies of solar cell stacks 

using tape and nano-indentation techniques. 

Future Directions 

•	 Continue adhesion studies of solar cell 

structures on foil substrates. 

•	 Continue development/investigation of back 

contact materials. 

•	 Optimize semiconductor deposition process 

(CSS and/or modified-CSS). 

•	 Optimize heat treatment process. 

•	 Optimize front transparent electrode 

configuration. 

3.23 Interfacial Engineering for p-Conjugated 

Polymer-Based Heterojunction Devices (UW-Jen) 

Accomplishments 

•	 Demonstrated highest power conversion 

efficiency (4.9%) and good stability in inverted 

structure bulk heterojunction OPV device with 

C60-SAM modified ZnO nanoparticles to 

improve electron collection. 

•	 Developed series of high-performance 

amorphous Pt-containing π-conjugated 

polymers with high hole-mobility (> 0.01 

cm2V-1s-1) and power conversion efficiency 

(> 4 %). Broad absorption and high mobility of 

these polymers are very promising for allsolution process based polymer solar cells. 

•	 Improved performance (35%) of inverted 

polymer solar cells with C60-SAM modified 

interface between TiO2 and P3HT:PCBM 

blend. 

•	 Developed simple and effective method to 

tune interface of cathode in polymer solar cells 

by inserting a layer of solution-processable, 

ZnO/self-assembled monolayer (SAM) 

between polymer film and cathode. High workfunction stable metals could be used as 

cathode to obtain high power conversion 

efficiencies that are comparable to state-ofthe-art OPVs. 

•	 Demonstrated nanopatterned surfaces could 

be used to guide phase separation in 

conjugated polymer/fullerene blends which 

result in both micro- and nano-scale changes 

in film morphology. 

•	 Used scanning Kelvin probe microscopy 

(SKPM) to study the catechol-modified ZnO 

surfaces in efficient OPV devices. 

•	 Discovered surprising effect using C60 and 

polythiophene as model compounds for optical 

studies, could have important implications for 

design of efficient donor-acceptor pairs. 

Future Directions 

•	 Develop low bandgap polymers with better 

matched absorption to solar spectrum. 

•	 Optimize HOMO and LUMO energy levels of 

p- and n-type materials to increase Voc. 

•	 Optimize mobility of both p- and n-type 

materials to improve efficiency. 

3.24 Optimization of Impact Ionization in 

Composite Nanocrystal Devices (Voxtel-Schut) 

Accomplishments 

•	 Modeled inorganic and organic constituent 

components and selected optimal material 

sets. 

•	 Synthesized needed nanocrystals. 

•	 Designed initial hybrid inorganic/organic 

devices. 

•	 Measured multiple excitons in nanocrystals. 

•	 Formed monolayers of nanocrystals. 

•	 Measured degree of alteration of exciton 

transitions through application of a Janus-II 

dipole. 

•	 Evaluated binding and solvation mechanisms 

of monothiol and dithiol ligands on 

nanocrystals and published studies. 

•	 Formed partnerships with Pacific Northwest 

National Laboratories (PNNL) and Sharp 

Research Laboratories (SRL) of America to 

further develop components and processes. 

Future Directions 

•	 Optimize quantum confined stark effect 

(QCSE) energy shifts through UPS 

characterization and supercritical fluid 

deposition of ligands. 

•	 Detailed characterization of carrier extraction 

efficiency through scanning tunneling 

microscopy (STM) to facilitate seamless 

integration into full device structures. 

•	 Demonstrated enhanced charge extraction 

from multi-exciton generated (MEG) carriers. 

3.25 Novel Manufacturing of Flexible III-V Thin 

Films (Wakonda-Fritzemeier) 

Accomplishments 

•	 Established reliable and scalable source for 

substrate raw materials. 

•	 Established internal capability for subscale 

manufacturing facilities. 

•	 Increased baseline cell performance by 50%. 

11 Photovoltaic

Applied Research

Exploratory Research
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Future Directions 

•	 Optimize large area processes for 

performance and manufacturability. 

•	 Increase cell performance to high commercial 

levels. 

•	 Demonstrate ability to scale to production 

volumes at competitive costs. 

4. FY 2008 Special Recognitions and Patents 

ASU 

•	 M. van Schilfgaarde received ASU Gavin 

Professorship in the School of Materials. 

•	 N. Newman elected fellow, American Physical 

Society. 

•	 M. van Schilfgaarde elected fellow, American 

Physical Society. 

•	 N. Newman began work as editor for IEEE 

Transactions on Applied Superconductivity. 

•	 Kouvetakis filed provisional patent. (ASU Case 

– 08-198-PR2) “Thin PV cell structures 

comprising Ge or GeSn on thin Si substrates”. 

•	 Kouvetakis filed provisional patent filed. (ASU 

Case – 08-198) “Hybrid Group IV/III-V 

Semiconductor structures for applications in 

PVs and silicon photonics”. 

MIT 

•	 M.G. Bawendi has been honored as the 

presenter of the Kavli Lecture in Nanoscience 

at the Materials Research Society Fall 2008 

Meeting, in recognition of his outstanding 

contributions to nanoscience and 

nanotechnology. 

Mayaterials, Inc. 

•	 Patent filed. “Low cost routes to high purity 

silicon and derivatives thereof.” 

Stanford 

•	 Yi Cui, King Abdullah University of Science 

and Technology (KAUST) Investigator Award 

(Among twelve scientists selected around the 

world, Yi Cui is the only assistant professor). 

•	 2008 Office of Naval Research (ONR) Young 

Investigator Award. 

University of Florida 

•	 J. Xue, co-organizer for fall 2007 meeting of 

the Materials Research Society (MRS) for a 

symposium on nanostructures solar cells. 

•	 J. Xue, lead co-organizer for symposium on 

organic materials and devices for sustainable 

energy systems at MRS fall 2009 meeting. 

•	 P. H. Holloway, AVS Society’s Paul. H. 

Holloway Young Investigator Award at the 55th 

AVS International Symposium. 

University of Illinois 

•	 John Rogers - fellow, Materials Research 

Society (inaugural class) (2008). 

University of Washington 

•	 Christine Luscombe, NSF Career Award. 

•	 Christine Luscombe, DARPA Young 

Investigator Award. 

•	 Alex Jen, PMSE Fellow, ACS Polymeric 

Materials Science and Engineering Division. 

•	 David Ginger, ACS Unilever Award. 

5. Major FY 2008 Publications 

ASU 

•	 Y.Y. Fang; J. Xie; J. Tolle; R. Roucka; V. R. 

D’Costa; A.V.G. Chizmeshya; J. Menendez; J. 

Kouvetakis. “A molecular-based synthetic 

approach to new group IV materials for highefficiency, low-cost solar cells and Si-based 

optoelectronics.” Journal of the American 

Chemical Society (in press). 

•	 Y.Y. Fang; J. Tolle; V.R. D’Costa; A.V.G. 

Chizmeshya; J. Menendez; J. Kouvetakis. 

“Independent band structure and strain tuning 

in group IV materials for optoelectronic and 

photovoltaic applications.” Physical Review 

Letters (minor revisions requested). 

MIT 

•	 T.P. Osedach; J.H. Alexi; C. Arango; V. 

Bulovic; S. Geyer; M. Bawendi. “Lateral 

Organic Quantum Dot Photodetector.” 

Electronic Materials Conference 2008, June 

25-27, 2008, Santa Barbara, California. 

•	 Silicon Cast Wafer Recrystallization for PV 

Applications, Eerik Hantsoo MS Thesis, MIT 

Penn State 

•	 S. Yoriya; G.K. Mor; S. Sharma; C.A. Grimes. 

“Synthesis of ordered arrays of discrete, 

partially crystalline titania nanotubes by Ti 

anodization using diethylene glycol 

electrolytes,” J. Mater. Chem., 18, 3332 

(2008). 

•	 K. Shankar; J. Bandara; M. Paulose; H. 

Weitasch; O.K. Varghese; G.K. Mor; T.J. 

LaTempa; M. Thelakkat; C.A. Grimes. “Highly 

efficient solar cells using TiO2 nanotube 

arrays sensitized with a donor-antenna dye,” 

Nano Lett., 8, 1654 (2008). 

•	 S.H. Lee; N.M. Abrams; P.G. Hoertz; G.D. 

Barber; L.I. Halaoui; T.E. Mallouk. " Coupling 

of Titania Inverse Opals to Nanocrystalline 

Titania Layers in Dye-Sensitized Solar Cells," 

J. Phys. Chem. B, 112, 14415 (2008). 

Photovoltaic

Applied Research

Exploratory Research

12
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rochester Institute of Technology 

•	 S.M. Hubbard; C.D. Cress; C.G. Bailey; R.P. 

Raffaelle. “Effect of strain compensation on 

quantum dot enhanced GaAs solar cells”, 

Appl. Phys. Lett., vo. 92, 123512 (2008). 

•	 S.M. Hubbard; C. Bailey; C.D. Cress; S. Polly; 

J. Clark; D.V. Forbes; R.P. Raffaelle; S.G. 

Bailey; D.M. Wilt. “Short circuit current 

enhancement of GaAs solar cells using strain 

compensated InAs quantum dots”, 33rd IEEE 

Photovoltaic Specialists Conference 

Proceedings, vol. 1, 250 (2008). 

Stanford 

•	 H. Peng; C. Xie; D.T. Schoen; Y. Cui. “Large 

Anisotropy of Electrical Properties in LayerStructured In2Se3 Nanowires.” Nano Lett. 8, 

1511-1516 (2008). 

•	 C.M. Hsu; S.T. Connor; M. Tang; Y. Cui. 

“Wafer-Scale Silicon Nanopillars and 

Nanocones by Langmuir-Blodgett Assembly 

and Etching,” Appl. Phy. Lett. 93, 133109 

(2008). 

•	 H.L. Peng; X.F. Zhang; R.D. Twesten; Y. Cui. 

“Vacancy Ordering and Lithium Ion Insertion in 

In2Se3 Nanowires,” Nano Letter (in 

preparation). 

University of California, Davis 

•	 A.J. Moulé.; K. Meerholz. “Intensity-dependent 

photocurrent generation at the anode in bulkheterojunction solar cells.” Applied Physics B: 

Lasers and Optics 2008, 92, (2), 209-218. 

•	 A.J. Ferguson; N. Kopidakis; S.E. Shaheen; 

G. Rumbles. “Quenching of Excitons by Holes 

in Poly(3-hexylthiophene) Films.” J. Phys. 

Chem. C 2008, 112, (26), 9865-9871. 

University of California, San Diego 

•	 D. Derkacs; W.V. Chen; P.M. Matheu; S.H. 

Lim; P.K.L. Yu; E.T. Yu. “Nanoparticle-induced 

light scattering for improved performance of 

quantum-well solar cells,” Appl. Phys. Lett. 93, 

091107 (2008). 

•	 D. Derkacs; W.V. Chen; P. Matheu; S.H. Lim; 

P.K.L. Yu; E.T. Yu. “Coupling of light scattered 

by nanoparticles into waveguide modes in 

quantum-well solar cells,” SPIE Proceedings 

7047-1 (2008). [Invited] 

•	 E.T. Yu; D. Derkacs; S.H. Lim; P. Matheu; 

D.M. Schaadt. “Plasmonic nanoparticle 

scattering for enhanced performance of 

photovoltaic and photodetector devices,” SPIE 

Proceedings 7033-66 (2008). [Invited] 

University of Colorado 

•	 J. Michl; J.C. Johnson; A. Akdag; A.E. 

Schwerin; M. Smith; Z. Havlas; A.J. Nozik. 

“Singlet Fission - Can It Be Harnessed?”, 22nd 

IUPAC Symposium on Photochemistry, July 

27 - Aug. 1, 2008, Gothenburg, Sweden. 

University of Florida 

•	 J. Xue. “Effect of Heterojunction Structure on 

Performance of Vacuum-deposited Organic 

Photovoltaic Cells,” 2008 International 

Materials Research Conference, June 9–12, 

Chongqing, China, 2008. 

•	 J. Xue; Y. Zheng; J.D. Myers; J. Ouyang. 

“Morphology Study of Vacuum-Deposited 

Pentacene:C60 Mixed Thin Films for 

Photovoltaic Applications”, AVS 55th 

International Symposium & Exhibition, Boston, 

Massachusetts, Oct. 19-24, 2008. 

University of Illinois 

•	 J. Yoon; A.J. Baca; S.I. Park; P. Elvikis; J.B. 

Geddes III; L. Li; R.H. Kim; J. Xiao S. Wang; 

T.H. Kim; M.J. Motala; B.Y. Ahn; E. Duoss; 

J.A. Lewis; R.G. Nuzzo; P.M. Ferreira; Y.Y. 

Huang; A. Rockett; J.A. Rogers. “Ultrathin 

silicon solar microcells for semitransparent, 

mechanically flexible and microconcentrator 

module designs,” Nature Materials, 7, 907 ­

915 (2008). 

University of Washington 

•	 Yip, Hau, Baek, Ma, and Jen, “Polymer Solar 

Cells That Use Self Assembled-MonolayerModified ZnO/Metals as Cathodes” Adv. 

Mater. (2008), 20, 2376. 

•	 Yip, Hau, Baek, Jen. “Self-Assembled 

Monolayer Modified ZnO/Metal Bilayer 

Cathodes for Polymer:Fullerene BulkHeterojunction Solar Cells” Appl. Phys. Lett., 

(2008), 92, 193313. 

•	 Baek, Hau, Yip, Chen, Acton and Jen. “High 

Performance Amorphous Metallated πConjugated Polymers for Field-Effect 

Transistors and Polymer Solar Cells,” Chem. 

Mater., (2008), 20, 5734. 

•	 Park, Munro, and Ginger. ”Controlling Film 

Morphology in Conjugated Polymer:Fullerene 

Blends with Surface Patterning,” J. Am. Chem. 

Soc., (2008), 130 (47), 15916. 

13 Photovoltaic

Applied Research

Exploratory Research
 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

University and Exploratory Research 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Fannie Posey Eddy (NREL), 303-384-6773, Fannie_Eddy@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-3765, marie.mapes@ee.doe.gov 

FY 2008 Budgets: $494K (NREL), $1,047K (subcontracts) 

Objectives 

•	 Explore ultimate performance limits of PV technologies, approximately doubling their sunlight-toelectricity conversion efficiencies during its course. 

•	 Improve research and development (R&D) on crystalline silicon cell efficiencies and fabrication 

methods to reduce manufacturing costs. This work is leveraged by the Center of Excellence. 

•	 Perform leading edge research in thin-film materials and solar cells. The R&D activities include 

device fabrication, device analysis, film growth, materials characterizations, and modeling. 

•	 Develop thin-film tandem cells and modules toward 25% and 20% efficiencies. 

•	 Develop multi-junction, pre-commercial concentrator modules able to convert more than one third 

of the sun’s energy to electricity. 

•	 Develop high-risk/high-payoff third-generation (3G) photovoltaic (PV) technologies beyond 2015, 

including high-efficiency and exciton-based solar cells. 

•	 Target emerging state of the art, high efficiency concepts relative to advanced super highefficiency cells to allow cost effective generation of electricity and hydrogen. 

•	 Offer scientific and technical research opportunities for minority undergraduate and graduate 

students in solar technologies via the Minority University Research Associates (MURA) project. 

Accomplishments 

•	 Completing and phasing out University and Exploratory Research (UER) Project sub contracts. 

•	 Demonstrated inverted MM 3-junction terrestrial concentrator cells with AlGaInAs transparent 

graded buffer layers by Spectrolab. 

•	 Built 1 m2 sub module and installed the high efficiency cells (from Spectrolab) by Amonix. 

•	 Completed internships; seven undergraduate students participated in NREL MURA Internship 

Program. Posters were presented by NREL-MURA interns at the 18th Workshop on Crystalline 

Silicon Solar Cells: Materials and Processes, August 3- 6, 2008, in Vail, Colorado. 

•	 Presented MURA and student research findings at the Renewable Academic Partnership 

(REAP)/ Sustainable Energy from Solar hydrogen NSF/IGERT Workshop, University of Delaware, 

July 20-22, 2008. 

Future Directions 

•	 Phase out UER Project, since sub contracts have ended with the exception of MURA project. 

•	 Continue to address key R&D issues in support of the Solar America Initiative (SAI) through 

remaining projects. 

•	 Continue to assist DOE Golden Field Office (DOE/GO) in monitoring MURA project. 

•	 Close out UER subcontracts, since project is in final phase. 

1. Introduction	 advancing the progress of high efficiency 

technologies and their demonstration in 

The University and Exploratory Research (UER) commercial prototype products. To accomplish 

project aims to explore the ultimate performance this, a wide range of complex issues are 

limits of PV technologies, approximately doubling investigated to provide initial modeling and 

their sunlight-to-electricity conversion efficiencies baseline experiments involving several advanced 

during its course. R&D is directed toward concepts. The project includes both sub contract 

Photovoltaic

Applied Research

Exploratory Research

14
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

and NREL in-house activities being executed in 

parallel to reach long-term beyond 2015 goals. To 

ensure the success of SAI, NREL is assisting in 

this effort as well as with the SAI university and 

industry activities. 

Sub contracted research include the following 

areas: (1) polycrystalline thin-film tandems; (2) 

research in III-V multijunction concentrators; (3) 

future generation research; and (4) research 

collaboration with minority universities in the 

MURA Project. 

2. Technical Approach 

The UER project consists of six separate 

programs with research sub contracted through 

industry and university partners. All of the sub 

contracts have been completed and are being 

phased out. One exception is the MURA project 

which will continue in fiscal year (FY) 2009. 

The MURA task provides scientific and technical 

research opportunities for minority undergraduate 

students to work on various solar energy 

technology projects. NREL will assist GO in the 

management of these sub contracts and the 

solicitation/award process. 

UER Agreement Tasks FY 2008 

Budget ($K) 

Polycrystalline Thin-Film Tandems * 

III-V Multijunction Concentrators * 

Future Generation Project 156 

MURA 291 

Crystalline Si Universities * 

University Center of Excellence 600 

Total** 1,541 

*Forward (FY07) Funding ending in FY08. 

**Includes NREL Exploratory Research $494. 

3. Major FY 2008 Publications 

•	 V.I. Polyakov; A.I. Rukovishnikov; B.M. Garin; 

V.P. Varnin; J.M. Dutta. “Point defects in 

undoped CVD diamond and high-purity semiinsulating SiC.” Accepted for publication in 

IEEE Transaction (May 2009 issue). 

•	 S.K. Estreicher; M. Sanati; N. Gonzalez 

Szwacki. “Fundamental Interactions of Fe in 

silicon: First-Principles Theory.” Solid State 

Phenomena, 131-133, 233-240 (2008). 

•	 S.K. Estreicher; M. Sanati; N. Gonzalez 

Szwacki. “Iron in silicon: interactions with 

radiation defects, carbon, and oxygen.” 

Physical Review, B 77, 125214/1-9 (2008). 

•	 S. Jin; Y. Yang; J.E. Medvedeva; L. Wang; S. 

Li; N. Cortes; J.R. Ireland; A.W. Metz; J. Ni; 

M.C. Hersam; A.J. Freeman; T.J. Marks. 

“Tuning the Properties of Transparent Oxide 

Conductors. Dopant Ion Size and Electronic 

Structure Effects on CdO-Based Transparent 

Conducting Oxides. Ga- and In-doped CdO 

Thin Films Grown by MOCVD,” Chem. Mater., 

20, 220 (2008). 

•	 S.P. Harvey; T.O. Mason; D.B. Buchholz; R. 

P.H. Chang; C. Koerber; A. Klein. “Carrier 

Generation and Inherent Off-Stoichiometry in 

Zn,Sn Codoped Indium Oxide (ZITO) Bulk and 

Thin-Film Specimens,” J. Am. Ceram. Soc., 

91, 467 (2008). 

•	 W.C. Sheets; E.S. Stampler; M.I. Bertoni; M. 

Sasaki; T.J. Marks; T.O. Mason; K.R. 

Poeppelmeier. “Silver Delafossite Oxides.” 

Inorg. Chem., 47, 2696 (2008). 

•	 J.H. Song; T. Akiyama; A.J. Freeman. 

“Stabilizing mechanism of the dipolar structure 

and its effects on formation of carriers in 

wurtzite films: InN and ZnO.” Phys. Rev. B, 77, 

Art. No. 035332 (2008). 

•	 J. Li; J. Liu; J.G. Evmenenko; P. Dutta; T.J. 

Marks. “Characterization of Transparent 

Conducting Oxide Surfaces Using SelfAssembled Electroactive Monolayer Probes.” 

Langmuir, 24, 5755 (2008). 

•	 D. Zubía; L. Romo; M. Rodríguez; B. Aguirre; 

R. Ordóñez; Ivan Coronado; José CruzCampa; Gregory Lush; Stella Quiñónez; John 

McClure. "Deposition and Doping of ZnTe and 

ZnCdTe Alloys. Presented at the International 

Materials Congress, Cancun, Mexico, August 

21, 2008. 

15 Photovoltaic

Applied Research

Exploratory Research
 

 

 

____________________________________________________________________________________ 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Industrial CRADAs 

Performing Organization: National Renewable Energy Laboratory 

Key Technical Contact: John Benner (NREL), 303-384-6496, john_benner@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-0565, marie.mapes@ee.doe.gov 

2008 Budget:	 $2,100K (NREL) 

Objectives 

•	 Accelerate growth of partnerships with industry to move more NREL-developed technology into 

production faster. 

•	 Lower administrative and financials barriers to partnerships for both NREL scientist and 

prospective industry at all phases of engagement from finding, forming, funding, and expanding 

collaborative development of products and processes. 

Accomplishments 

•	 Completed two solicitations for proposals. 

•	 Selected twelve projects for funding. 

•	 Stimulated nine new industry partnerships. 

Future Directions 

•	 Stimulate at least five new Cooperative Research and Development Agreements (CRADAs) that 

grow to large, multi-investigator levels. 

1. Introduction 

Transferring our technologies to industry is the 

culmination of years of research. This is also 

perhaps the most difficult stage of development. 

While NREL can point to numerous examples of 

successful tech transfer, including many patents 

that have been licensed, the majority of our 

contributions are not publicized. Vast amounts of 

knowhow, measurements, data, sample 

exchange, and joint experiments have transformed 

industry processes and products without visible 

agreements. This has contributed to blunders from 

both sides of the partnership. Our planning has 

instances of terminating support for research tied 

to a partner’s interest as well as collaborations 

with industry scientists that evaporated as 

resources were redirected. The remedy is to raise 

the visibility of the interaction through formalizing 

the agreement in a Technical Service Agreement 

(TSA) or Cooperative Research and Development 

Agreement (CRADA). The attention of 

management of the partnering companies is 

particularly enhanced when they have their own 

resources committed to the agreement. 

The commercialization CRADAs project 

accelerates growth of partnerships with industry to 

move more NREL-developed technology into 

production faster. The project lowers 

administrative and financial barriers to 

partnerships for both the NREL scientist and 

prospective industry at all phases of engagement 

from finding, forming, funding, and expanding the 

collaborative development of products and 

processes that incorporate NREL technology. 

2. Technical Approach 

The nature of the photovoltaic (PV) business has 

fundamentally changed the way that NREL must 

interact with industry. As private funding has 

rocketed past federal support and the total private 

sector investments approach $2 billion annually, 

companies have become much more concerned 

and savvy in their approach to collaborating to 

gain outside help. Moreover, there are many more 

companies seeking access to NREL’s resources. 

This change drives us toward use of a coordinated 

process to select partners and manage the 

success of each partnership. 

Photovoltaic

Applied Research

Exploratory Research

16
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Industry collaborations are grouped into four 3. Results and Accomplishments 

phases of maturity. 

•	 Phase 0 covers technologies where no 

discussions have started with potential 

industry partners. This may be due to research 

needs to be completed or patent applications 

filed. 

•	 Phase 1 collaborations describe interactions 

where NREL is working informally with a 

scientist from industry partner, perhaps 

exchanging samples and data, but no funds 

change hands and management involvement 

is minimal. 

•	 Phase 2 interactions include TSAs or CRADAs 

funded at levels of up to $100,000. This 

provides the company with an introduction to 

NREL’s business practices and ensures that 

the management of the company has engaged 

in the agreement. 

•	 Phase 3 CRADAs are major collaborations 

with NREL’s work is an integral part of the 

company’s development efforts. Our largest 

CRADA today supports $2.8 million of work at 

NREL over 3 years. 

The project supports developing relationships is 

many ways that are adjusted relative to the 

maturity of the interaction. 

•	 Funding is awarded through internal 

competition to enable and encourage NREL 

scientists to initiate and deliver research. 

Funding also lowers barriers for the 

participating companies. 

•	 Outreach to increase industry’s awareness of 

NREL’s capabilities and assistance in forming 

initial interactions. 

•	 Interface with NREL technology transfer office 

and legal office to improve execution of 

partnership agreements, intellectual property 

(IP) protection, and related business activity. 

This is a new project that will test the business 

model presented in the technical approach. 

During the first year, we created and executed two 

solicitations for proposals. The proposal briefly 

described the technical plan, industry partner, exit 

strategy, and anticipated peripheral benefit to 

NREL for engaging in the work. Reviewers assess 

the commercialization potential, the strength of the 

technical plan, and benefits to the Solar Energy 

Technologies Program. Twelve projects were 

awarded. These covered a wide range of 

technologies, such as transparent conducting 

oxides aimed for application by the glass industry, 

ink jet-printed contact technology, high 

performance multiple junction cells, evaluation of 

commercial substrates for thin-film solar cells, and 

moisture barrier coatings. In most instances, the 

name of the corporate partner is business 

sensitive or CRADA protected information. Thus, 

the specific agreements are not included in this 

report. 

4. Planned FY 2009 Activities 

Adaptability will be the hallmark of the industrial 

CRADAs project as it must fulfill the needs of a 

rapidly changing industry. During FY 2009, we will 

observe the effectiveness of the project in 

achieving its objectives. At present, most CRADAs 

are tightly focused on a single aspect of the 

development challenge, typically engaging only a 

single NREL investigator. In order to achieve the 

long-term targets of stimulating at least five new 

CRADAs that grow to large, multi-investigator 

levels, it already appears likely that the project will 

need to create a more effective process to 

generate partnerships encompassing multiple 

components of the technology under development. 

17 Photovoltaic

Applied Research

Exploratory Research
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

Seed Fund Projects 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Sarah Kurtz (NREL, Primary Contact), 303-384-6475, 

sarah_kurtz@nrel.gov 

Jeff Nelson (SNL), 505-284-1715, jsnelso@sandia.gov 

DOE HQ Technology Manager:	 Marie Mapes, 202-586-3765, marie.mapes@hq.doe.gov 

FY 2008 Budgets:	 $1,870K (NREL), $483K (SNL) 

Objectives 

•	 Provide temporary funding for exploration of new ideas, including new materials, devices, or 

processes that have not reached the proof-of-concept stage 

•	 Facilitate the Solar Energy Technologies Program (SETP) mission of transitioning 

exploratory/discovery-stage research to applied research and development (R&D), thereby 

providing a stream of next-generation photovoltaic (PV) technology options. 

Accomplishments 

•	 Synthesized n- and p-type organic semiconductor materials 

•	 Developed capability of spraying at least 3 in. x 4 in. uniform carbon nanotube films 

•	 Demonstrated increased photovoltage and blue photocurrent after addition of cadmium selenide 

(CdSe) quantum dots (QDs), demonstrating that QDs can be incorporated into an organic 

photovoltaic (OPV) device and show enhancements 

•	 Produced lead selenide (PbSe) nanocrystalline solar cell with 2.2% efficiency and > 22 mA/cm2 

•	 Demonstrated liftoff of silicon (Si) cell with ~ 1% efficiency 

•	 Investigated Si dot-dot interaction as a function of dot-dot distance and dot size 

•	 Deposited and characterized zinc-copper-oxygen (ZnCuO) alloys over a range of copper-zinc 

(CuZn) compositions. 

Future Directions 

•	 Investigate copper-zinc-tin-sulfide/selenide as a new absorber material 

•	 Explore flexible organic (OPV) made by lamination and inorganic hole transport layers for
 

excitonic solar cells.
 

1. Approach and Planned Activities 

Task #1: Doped Polymeric Molecular 

Semiconductor p-n Junction OPV 

Purpose: Investigate new approach to creating a 

stable OPV cell by using a class of materials that 

has been engineered for use as automobile paints. 

This approach is qualitatively different from other 

approaches in that it adds specific functional 

groups to create both n- and p-type material. 

Milestone: 

• By 12/08, synthesize gram quantities of n-type 

and p-type polymers and prepare first functional 

solar cells from the new materials. 

Accomplishments: 

• The synthesis/purification is proceeding well and 

the project is on track for evaluating the first solar 

cells by the end of 2008. 

Task #2: Carbon Nanotube Architectures for LowCost and High-Efficiency PV 

Purpose: Leverage the expertise already developed at NREL in synthesizing carbon nanotubes 

(CNTs) to determine their utility for use in PV 

devices. CNTs have the potential to be low cost, 

can be applied with high-speed solution phase 

processing at low temperatures, have high thermal 

stability, and may have performance (conduction 

and transmission) properties competitive with 

conventional transparent conductors. 

Photovoltaic

Applied Research

Exploratory Research

18
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Milestones: 

• By 12/08, spray deposit bulk CNT electrode with 

area >10 cm2

, T>80%, and RS<50 Ω/□. 

• By 12/08, utilize sprayed SWCNT films as 

electrodes in PV devices and evaluate system 

performance (e.g., efficiency) relative to 

conventional transparent conductive oxides 

(TCOs). Publish results in journal. 

Accomplishments: 

• Developed capability of spraying at least 3 in. x 4 

in. uniform CNT films. 

• Participated in two invited talks – J. Blackburn at 

ECS 2008 and T. Barnes at OPV 2008. 

• Achieved sprayed CNT electrodes with >10 cm2

, 

T>78%, and RS<50 Ω/□. 

• Determined that poly 3-hexylthiophene 

(P3HT)/PCBM OPV devices on single-walled 

carbon nanotubes (SWNT) electrodes with hole 

injection layer are nearly equivalent to control cells 

on indium tin oxide (ITO) (~3.8% efficiency on ITO 

vs. 3.5% on SWNTs); OPV cells on SWNT 

electrodes with no hole injection layer with 

efficiencies higher than 3%. 

Task #3: Incorporation of Third-Generation 

Mechanisms into OPV Devices 

Purpose: Explore the use of third-generation concepts such as QDs, other quantum-confined 

structures and multijunction approaches integrated 

with electroactive, conjugated polymers (P3HT) to 

develop a path to creation of solar cells with higher 

efficiencies. This work will focus specifically on 

implementation of a multijunction polymer solar 

cell, incorporating colloidal semiconductors into 

conjugated oligomers, polymers, and dendrimers. 

Milestone: 

• Demonstrate an initial single-junction 

QD/polymer device with publication. 

Accomplishments: 

• Demonstrated increased photovoltage (from 0.35 

V to 0.6 V) and an increase in blue photocurrent 

after addition of CdSe QDs (quantum efficiency 

increased from 65% to 95% at 450 nm), clearly 

showing that QDs can create enhancements in an 

OPV device. 

• CdSe QDs were capped with pyridine, NMA* Nphenyl-N’-methyldithiocarbamate and DPA* N,N’­

diphenyldithiocarbamate, and then time-resolved 

microwave conductivity (TRMC) was used to 

evaluate the lifetime of the carriers in a P3HT 

blend. Surprisingly, the NMA showed much longer 

lifetimes (desirable) than the other caps. This 

implies better charge-carrier separation, which can 

lead to improved efficiency (manuscript in 

preparation). 

Task #4: Thin III-V Solar Cells 

Purpose: Epitaxial liftoff (ELO) has been explored 

for a number of years as a means to reduce the 

cost of multijunction III-V cells. Challenges have 

been identified in both handling the lifted-off layers 

and avoiding the creation of inter-layer cracks. We 

are exploring ELO and other liftoff techniques to 

create small area cells (<1 cm2

). 

Milestone: 

• Explore techniques to lift off III-V PV cells. 

Accomplishments: 

• Chose epitaxial liftoff over other liftoff techniques. 

Task #5: Novel Nanocrystal-Based Solar Cell to 

Exploit MEG 

Purpose: Demonstrate that multiple excitons can 

be collected within a solar cell. Specifically, if QDs 

are used to enhance the probability that multiple 

excitons are generated from absorption of a single 

high-energy photon (this has already been 

demonstrated), can multiple electrons/photons be 

collected in an external circuit? 

Milestones: 

• Optimize band gaps for PbSe/lead sulfide (PbS) 

system; increase Jsc to 25 mA/cm2

; double the 

field-effect mobility; publish results in two journals. 

• Achieve 2% efficiency (AM1.5G); quantitative 

assessment of cell stability; and identification of 

degradation mechanisms, reliable and 

reproducible equivalent quantum efficiency (EQE) 

characterization, and spectroscopic demonstration 

of MEG within device quality. 

Accomplishments: 

• Produced solar cell with 2.2% efficiency and > 22 

mA/cm2 based upon forming a Schottky contact 

between PbSe NCs and the back metal electrode. 

The active layer of the solar cell consists entirely 

of PbSe NCs (2/08). 

• Developed an optical model that, used in conjunction with total reflectance measurements and 

accurate EQE measurements, can determine the 

internal quantum efficiency (IQE). The IQE can be 

used as a tool for understanding and optimizing 

solar cell performance and to accurately determine 

whether multiple excitons are successfully collected from the solar cell (6/08). 

19 Photovoltaic

Applied Research

Exploratory Research
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Task #6: Si 

Purpose: This project seeks to develop a method 

that allows the creation of crystalline silicon (c-Si) 

cells on a standard c-Si substrate and then allows 

the lifting-off of the c-Si cells, which are 10 to 20 

microns thick, from the remaining substrate. The 

substrate is then reused to create additional layers 

of cells. These cells have a small area (<1 cm2

), 

which allows for further system-level cost savings. 

Milestone: 

• Demonstrate liftoff of thin c-Si chips and cells, as
 

well as reuse of substrate.
 

Accomplishments:
 

• Demonstrated liftoff of Si cell with ~1% efficiency. 

Task #7: Multifunctional Transparent Conducting 

and Self-Healing Impermeable Barriers 

Purpose: Develop a multilayer coating grown at 

low-temperature (<80°C), resulting in a highly 

transparent coating with high electrical 

conductance, low water-vapor transmission, and 

lower cost than indium tin oxide. 

Milestone: 

• Demonstrate multilayer films with 80% transmission, <10 Ω/sq, and 0.01 g/m2

/day O2/H2O impermeability. 

Accomplishments: 

• Measured films with water vapor transport rates 

< 0.01 g/m2

/day. 

• Measured films with < 10Ω/sq and >80% 

transmission. 

Task #8: Si Quantum Dot Solar Cells 

Purpose: Explore use of Si QDs in solar cells as a 

way of tuning the optical properties while retaining 

use of an abundant, high-performance material 

(silicon). 

Milestones: 

• Create simulations package to calculate the 

electronic and optical properties of Si QDs 

embedded in foreign matrix. Select and specify the 

most promising growth method of quantum dot 

structure. 

Accomplishments: 

• Selected University of Minnesota, with its dualreactor plasma-enhanced chemical vapor 

deposition (PECVD) method, as best partner for 

growth of Si QD materials. 

• Set up the atomistic calculation model for Si dotarray and investigated the dot-dot interaction as a 

function of dot-dot distance and dot size. 

Task #9: Amorphous Oxide Semiconductors for 

Ambient Temperature Deposited PV 

Purpose: Demonstrate a metal-oxide-based, thinfilm heterojunction solar cell that can be deposited 

at ambient temperature. 

Milestones: 

• Deposit and characterize initial Zn-Cu-O material 

libraries. 

• Demonstrate amorphous metal oxide p-n diode 

with photoactive response. 

Accomplishments: 

• Deposited and characterized Zn-Cu-O alloys 

over a range of Cu-Zn compositions, identifying 

conditions for growth of amorphous material. 

• Identified the (unwanted) (+2) oxidation state of 

the Cu and reoptimized the growth conditions to 

obtain the desired (+1) oxidation state. 

2. FY 2008 Patent Application 

L. Simpson, “Thin Film Electronic Devices with 

Conductive and Transparent Gas and Moisture 

Permeation Barriers” (submitted). 

3. Major FY 2008 Publications 

Barnes, T.; Blackburn, J.; Tenent, R.; Morfa, A.; 

Heben, M.; Coutts, T. “Optimizing Carbon 

Nanotube Contacts for Use in Organic PV.” IEEE 

PVSC 33, IEEE: San Diego, CA, 2008, NREL/CP520-42550. Golden, CO: National Renewable 

Energy Laboratory. 

Tenent, R.; Barnes, T.; Heben, M.; To, B.; 

Gedvilas, L.; Blackburn, J. “Ultrasonic Spraying of 

Highly Conductive Transparent Single-Walled 

Carbon Nanotube Films for PV.” Adv. Mat., 

submitted. 

Luther, J.M.; Law, M.; Beard, M.C.; Song, Q.; 

Reese, M.O.; Ellingson, R.J.; Nozik, A.J. 

“Schottky Solar Cells Based on Colloidal 

Nanocrystal Films.” NL, 8, 3488 (2008). 

Law, M.; Beard, M.C.; Choi, S.; Luther, J.M.; 

Hanna, M.C.; Nozik, A.J. “Determining the Internal 

Quantum Efficiency of PbSe Nanocrystal Solar 

Cells with the Aid of an Optical Model.” NL, ASAP 

(2008). 

Photovoltaic

Applied Research

Exploratory Research

20
 

____________________________________________________________________________________ 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Wafer Silicon 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Qi Wang (NREL), 303-384-6681, qi_wang@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-3765, marie.mapes@hq.doe.gov 

FY 2008 Budget: $1,912K (NREL) 

Objectives 

•	 Develop low-cost and high-efficiency cell process to meet the U.S. Department of Energy’s 

(DOE’s) goal of levelized cost of energy (LCOE). 

•	 Conduct scientific research on silicon (Si) materials and energy devices. 

•	 Collaborate and leverage partnerships with U.S. solar companies on wafer-Si research efforts. 

Accomplishments 

•	 Achieved 19.3% on FZ and 18.8% on CZ a-Si/c-Si heterojunction (SHJ) solar cells on p-type 

wafer. 

•	 Achieved high open circuit voltage of more than 700 mV, which was a first at NREL, on a finished 

SHJ solar cell. 

•	 Completed the installation of Si-cluster tool in NREL’s Process Development and Integration 

Laboratory (PDIL), which can easily handle SHJ solar cells. 

•	 Completed the purchase of Czochralski (CZ) crystal grower. 

•	 Achieved narrower conductive line using ink-jet printing. 

Future Directions 

•	 Establish quicker evaluation of solar Si feedstock. 

•	 Develop high-efficiency SHJ solar cells on thin wafers (< 100 μm). 

•	 Develop novel materials for better surface passivation. 

•	 Install and operate CZ-crystal grower 

•	 Develop 5-inch heterojunction solar cells 

•	 Study the surface and bulk passivation 

•	 Develop interdigitated solar cell using heterojunction a-Si:H layer 

•	 Further develop black-Si solar cells. 

•	 Further develop direct writing contact 

•	 Develop efficient furnace and fire-through metal contact. 

1. Results and Accomplishments 

In April 2008, a CZ-crystal Si grower was ordered. 

This system can grow a Si ingot that is 3 to 4 

inches in diameter and up to 10 inch in length, or 

4.9 kilogram (kg) per load. It also has the 

capability of vacuum bake-out at 10-6 Torr. This CZ 

grower will be a vital tool to start evaluating solar 

graded Si feedstock. After completing the 

installation, we will be able to study solar grade Si 

from raw Si to solar cells and help solar industry 

partners. The system is expected to arrive at 

NREL in early February 2009 and begin operating 

in March 2009. 

The milestone for this task will be delayed 

because of the pending arrival of the CZ grower. 

The Si-heterojunction solar cell task continually 

made progress this fiscal year (FY). The task was 

focused on moving toward 2 by 2 cm2

-size cell 

from 1 by 1 cm2

. The larger area cell minimizes 

the effect of perimeter loss. We have achieved 

high open circuit voltage of more than 700 mV on 

p-type wafer using the larger size. It was a first at 

NREL – the first time reaching more than 700 mV, 

using a cell with a heterojunction structure. We 

also worked on using normal CZ p-type wafer and 

achieved the conversion efficiency of 18.8%. This 

cell shows little light induced degradation, and the 

21 Photovoltaic

Applied Research

Electronic Materials and Devices
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

results were presented at the 33rd PV Specialists 

Conference. Our goal is to aim for more than 20% 

efficiency. 

Wafer-size Si-heterojunction solar cell will be 

developed in newly installed Si-cluster tool in 

PDIL. The system was in operation in the final 

month of FY 2008, and the Si-cluster tool is in its 

tune-up phase. 

In FY 2009, we will start developing wafer-Si 

heterojunction solar cell. While waiting for the Sicluster tool to complete its tune up, the team has 

worked on wafer-Si texturing and cleaning, screen 

printing contact, and larger area e-beam metal 

deposition. Most periphery tasks of wafer-size SHJ 

process have been tested. SHJ solar cell and 

passivation of mc-Si in Si cluster tool will fully 

begin in FY 2009. 

The black Si task made the most progress and 

met the milestone of 13% efficiency. The best cell 

performance has 14.9% efficiency with Voc of 

0.609 V, 78.5% FF, and 31.3 mA/cm2 current 

density. The black Si process uses novel metal 

particles to modify the c-Si surface and creates a 

nano-structure that makes the reflection from c-Si 

near to zero, which gives it a black appearance. 

Figure 1 shows the results. 

Untreated bare c-Si has about 30% reflectance. 

The process only takes a few minutes. If it works, 

it can speed up the texturing process in c-Si cell 

manufacturing. Cell development was standard 

diffused junction process. Challenges are to 

completely remove the metal that is associated 

with the black-Si process and improve cell process 

steps to enhance Jsc. This will be a focus in FY 

2009. 

Direct writing contact uses an inkjet printer to 

make fine conductive lines on c-Si cells. In FY 

2008, we achieved 80 μm Ag line width with 10 μm 

tall printed at 180°C on an Evergreen solar c-Si 

solar cell, and 13% efficiency was reached. In FY 

2009, we will continue to narrow the line width and 

increase the thickness. 

In August 2008, 18th c-Si workshop was held in 

Vail, Colorado. Participants included professionals 

from universities, national labs, and the solar 

industry. The conference proceedings will be 

published in 2009. 

2. FY 2008 Special Recognitions and Patents 

V. Yost; H.M. Branz, “Anti-reflection etching of 

silicon surfaces catalyzed with ionic metal 

solutions,“ NREL ROI 07-17, patent filed August 

2008. 

H.M. Branz; A. Duda; D.S. Ginley; V. Yost; D.L. 

Meier; S. Ward. “Nanoparticle-based etching of 

silicon surfaces,” NREL ROI 07-10, patent filed 

March 2008. 

3. Major FY 2008 Publications 

Q. Wang; M.R. Page; E. Iwaniczko; Y.Q. Xu; L. 

Roybal; R. Bauer; B. To; H.C. Yuan; A. Duda; Y.F. 

Yan. “Crystal Silicon Heterojunction Solar Cells by 

Hot-Wire CVD: Preprint.” NREL/CP-520-42554. 

Golden, CO: National Renewable Energy 

Laboratory, 2008. 

H.M. Branz; C.W. Teplin; D.L. Young; M.R. Page; 

E. Iwaniczko; L. Roybal; R. Bauer; A.H. Mahan; Y. 

Xu; P. Stradins; T. Wang; Q. Wang. “Recent 

Advances in Hot-Wire CVD R&D at NREL: From 

18% Silicon Heterojunction Cells to Silicon Epitaxy 

at Glass-Compatible Temperatures.” Thin Solid 

Films. Vol. 516(5), 15 January 2008, pp. 743-746, 

NREL Report No. JA-520-40835 (2008). 

H.-C. Yuan; M.R. Page; E. Iwaniczko; Y. Xu; L. 

Roybal; Q. Wang; H.M. Branz; D.L. Meier. “Silicon 

Solar Cells with Front Hetero-Contact and 

Aluminum Alloy Back Junction: Preprint.” 

NREL/CP-520-42566. Golden, CO: National 

Renewable Energy Laboratory, 2008. 

M.R. Page; E. Iwaniczko; Y. Xu; L. Roybal; R. 

Bauer; H.-C.Yan; Q. Wang; D.L. Meier. 

“Photoconductive Decay Lifetime and Suns-Voc 

Diagnostics of Efficient Heterojunction Solar Cells: 

Preprint.” NREL/CP-520-42564. Golden, CO: 

National Renewable Energy Laboratory, 2008. 

Proceedings of 18th Workshop on Crystalline 

Silicon Solar Cells & Modules: Materials and 

Processes, editor Bhushan Sopori. 

S. Bhushan, et al. “Mechanisms of Front Contact 

Formation in Si Solar Cells fire-through theory.” 

Presented at the TMS 2008 Meeting, March 2008, 

New Orleans, Louisiana. 

Photovoltaic

Applied Research

Electronic Materials and Devices

22
 

 

 

 

____________________________________________________________________________________ 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Film Silicon 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Howard Branz (NREL), 303-384-6694, howard_branz@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-3765, marie.mapes@ee.doe.gov 

FY 2008 Budget: $3,307K 

Objectives 

•	 Develop photovoltaic (PV)-quality crystal silicon (Si) layers through low thermal budget epitaxial 

growth. 

•	 Develop film crystal Si PV on inexpensive substrates with seed layer coatings. 

•	 Develop baseline amorphous and nanocrystalline Si capability in PDIL cluster tool. 

Accomplishments 

•	 Demonstrated epitaxial Si growth by scalable hot-wire chemical vapor deposition (HWCVD) at 

300 nm/min at glass-compatible temperature on wafer substrates. 

•	 Grew HWCVD epitaxial Si at low temperature with dislocation density below 106 cm-2. 

•	 Doped HWCVD epitaxial Si n-type to 5 x 1015 cm-3 and produced active PV device on wafer. 

•	 Collaborated with industrial partners to demonstrate epitaxial growth on inexpensive seed layers. 

•	 Crystallized a-Si to oriented crystallites, using novel millimeter-wave annealing technique. 

•	 Published ‘cone kinetics’ model of nanocrystalline and protocrystalline Si morphology. 

•	 Demonstrated uniform 156-mm square a-Si:H deposition in PDIL cluster tool. 

Future Directions 

•	 Improve high-rate low-temperature epitaxy for crystal Si on glass and other substrates. 

•	 Deposit efficient epitaxial Si PV devices on wafers and seed layers on glass. 

•	 Collaborate with U.S. industry partners that provide seed layers for epitaxial growth. 

•	 Improve quality of high growth-rate nanocrystalline and a-Si. 

1. Introduction 

Silicon (Si) remains the material of choice for 

terrestrial PV because SI is abundant, non-toxic, 

and accepted in the marketplace. There is a welldeveloped industrial base in all forms of Si, and an 

enormous, rapidly growing, Si scientific literature. 

However Si PV costs must be reduced to reach 

the DOE 2020 goal of $0.06/kWh PV electricity. 

This requires module costs well below $1/W. 

Today, the Si feedstock cost alone is above 

$0.60/W. Though the feedstock cost will fall, it is 

unlikely that wafer Si can reach the 2020 

Roadmap goals of about $0.50/W. However, films 

of crystalline Si could reach this goal by leveraging 

the existing crystal Si infrastructure but 

circumventing the need for high-cost wafers. This 

film Si project proposal addresses key research 

problems toward the mid-term creation of a waferreplacement crystalline film Si technology and 

near-term expansion of thin-film SI industry. 

2. Technical Approach 

Our main goal was to develop the science and 

technology required for high-quality film crystal SI 

on glass or another low-cost substrate. It has been 

demonstrated by CSG Corp. that a 1.85-micron cSi film solar cell can provide nearly 30 mA/cm2 of 

current with effective light trapping. Our approach 

is to make high-quality c-Si by rapidly thickening a 

seed layer of large well-oriented crystalline grains 

by scalable hot-wire chemical vapor deposition 

(HWCVD). Our laboratory research, therefore, 

centered on improvement of low-thermal budget Si 

epitaxy, development of a doping capability, and 

first solar cell fabrications on the model system of 

epitaxial layers on wafers. The seed layer can be 

extremely thin, but must be deposited by some 

inexpensive technique. We have strong 

collaborations with three industry partners who 

believe they have technologies capable of 

depositing thin c-Si seed layers and three 

23 Photovoltaic

Applied Research

Electronic Materials and Devices
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

experimental projects to develop our own novel 

seed-layer approaches. Finally, we have also 

installed and made first depositions in a new 

cluster tool for 156-mm-square thin-film a-Si:H and 

nc-Si:H depositions, with a goal of improving the 

quality of high-rate films for thin-film Si solar cells. 

3. Results and Accomplishments 

We deposited HWCVD epitaxial layers at about 

700°C with recombination-active dislocation 

density of about 2x105 cm-2 (Fig. 1). This 

corresponds to a spacing of about 22 μm between 

disclocations --- consistent with efficient PV cells 

up to about 5-μm thick. This 40-μm n-type layer 

was deposited at about 120 nm/min. We have also 

deposited high-quality epitaxial layers on Si-oninsulator layers and on Si layers fabricated on 

borosilicate glass by several methods. 

20 μm 

Fig.1 Cathodoluminescence scan of 40-μm-thick 

HWCVD epitaxial layer on wafer Si showing about 

2x105 cm-2 recombination-active defects that 

reduce the luminescence. 

We installed flow-controllers able to meter tiny 

proportions of B2H6 and PH3 dopant gases into the 

SiH4 deposition gas and established the capability 

of doping of our epitaxial layers both n-and p-type. 

We can dope n-type layers to a Hall carrier 

concentration of 5x1015 cm-3. By comparing Hall 

and secondary ion mass spectrometry level, we 

demonstrated dopant activation near 100% across 

a wide range of both n- and p-type doping 

densities. Fig. 2 shows the measured Hall 

mobilities of n-type films; these are very near the 

mobilities calculated for ideal c-Si crystals and 

y ( 

2 /V-s) 

measured in the best n-type wafers. Of course, 

minority carriers are more critical to PV, and long 

lifetimes must be established. Near the end of FY 

2008, we grew our first 1% active PV devices 

epitaxially on highly-doped (dead) Si wafers. 

High deposition rate is critical to low capital costs 

in manufacturing. We modeled the deposition 

rates of the HWCVD epitaxial layers and can 

clearly distinguish two key deposition regimes. 

Low reactant flow rates does limit the deposition 

rate. But at high flow rates, the rate becomes 

limited instead by reactant pressure, hot-wire 

geometry, and wire current (temperature). By 

increasing the pressure and using 2 tungsten 

filaments instead of one, we increased the 

deposition rate to 300 nm/minute, which mean a 

2-μm layer is deposited in about 7 minutes. We 

have not yet discovered any barrier to even faster 

epitaxial rates, and our models of the epitaxial 

mechanism suggest that rates above 1 μm/minute 

should be possible with different wire geometries. 

1400 

1200 

1000 

800 

600 

400 

200 

0 18 10 19 20 10

 n-type mobility

 ideal wafer value 

14 15 16 17 10 10 10 10 10
 

Hall carrier concentration (cm -3)

Fig. 2 Hall mobilities of n-type HWCVD epitaxial films 

approach ideal wafer values, indicating excellent 

majority-carrier properties. 

4. Planned FY 2009 Activities 

•	 Demonstrate epitaxial growth on candidate Si 

seed layers with low defect densities. 

•	 Deposit efficient PV devices on both wafers 

and seed layers and establish T-dependence 

of HWCVD epitaxial quality. 

•	 Develop hydrogenation methods for defective 

c-Si film and devices. 

•	 Baseline efficient a-Si and nc-Si PV devices at 

large area in cluster tool. 

Photovoltaic

Applied Research

Electronic Materials and Devices

24
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5. FY 2008 Patents 

•	 Five records of invention filed for crystal Si film 

PV, ranging from heteroepitaxy on novel seed 

materials to new contacting approaches. 

•	 D.L. Young, B. Egaas, P. Stradins, “An ultrafast method for measuring the quantum 

efficiency of solar cells,” filed Sept 2008. 

6. Major FY 2008 Publications 

P. Stradins; C.W. Teplin; H.M. Branz., “Phase 

evolution in nanocrystalline silicon films: hydrogen 

dilution and the cone kinetics model,” invited 

manuscript, submitted to Phil. Mag. B. 

D.L. Young; H.M. Branz; F. Liu; R. Reedy; Q. 

Wang. “Electron transport and structure in highlyconducting P-doped polycrystalline Si thin films.” 

J. Appl. Phys., in press. 

I.T. Martin; H.M. Branz; P. Stradins; D.L. Young; 

K.M. Jones; R.C. Reedy; C.W. Teplin. “Doping of 

high-quality epitaxial silicon grown by hot-wire 

chemical vapor deposition near 700°C.” Thin Solid 

Films, in press. 

F. Liu; K.M. Jones; Y. Xu; W. Nemeth; J. Lohr; J. 

Neilson; M.J. Romero; M. Al-Jassim; D.L. Young. 

“Ultra-high crystalline-quality silicon pillars formed 

by millimeter-wave annealing of amorphous silicon 

on glass.” Submitted to Nature Materials. 

H.M. Branz; C.W. Teplin; D.L. Young; M.R. Page; 

E. Iwaniczko; L. Roybal; R. Bauer; A.H. Mahan; Y. 

Xu; P. Stradins; T. Wang; Q. Wang. “Recent 

advances in hot-wire CVD R&D at NREL: From 

18% silicon heterojunction cells to silicon epitaxy 

at glass-compatible temperatures.” Thin Solid 

Films; vol. 516; 743-746; 2007. 

J.D. Cohen; S. Datta; K. Palinginis; A.H. Mahan; 

E. Iwaniczko; Y. Xu; H.M. Branz. “Defect analysis 

of thin film Si-based alloys deposited by hot-wire 

CVD using junction capacitance methods.” Thin 

Solid Films; vol. 216; 663-669; 2007. 

C.W. Teplin; C.-S. Jiang; P. Stradins; H.M. Branz. 

“Cone kinetics model for two-phase film silicon 

deposition.” Appl. Phys. Lett.; vol. 92; 093114-6; 

2008. 

V. Gowrishankar; S.R. Scully; A.T. Chan; Q. 

Wang; H. M. Branz; M. McGehee. “Exciton 

harvesting, charge transfer and charge-carrier 

transport in amorphous-silicon nanopillar/polymer 

hybrid solar cells.” J. Applied Physics; vol. 103; 

64511-8; 2008. 

P.C. Taylor; H.M. Branz; R.W. Collins; E.A. Schiff. 

“Preface to Proceedings of the 22nd International 

Conference on Amorphous and Nanocrystalline 

Semiconductors.” J. Non-Crystalline Solids; vol. 

354; vii-viii; 2008. 

S. Datta; J.D. Cohen; Y. Xu; A.H. Mahan; H.M. 

Branz. “Junction capacitance study of an oxygen 

impurity defect exhibiting configuration relaxation 

in amorphous silicon-germanium alloys deposited 

by hot-wire CVD.” J. Non-Crystalline Solids; vol. 

354; 2126-30; 2008. 

J.R. Doyle; Y. Xu; R. Reedy; H.M. Branz; A.H. 

Mahan. “Film Stoichiometry and Gas Phase 

Chemistry in HWCVD of a-SiGe:H,” Thin Solid 

Films; vol. 516; 526-528; 2008. 

H.M. Branz; P. Stradins; C.W. Teplin. “Cone 

kinetics model: Insights into the morphologies of 

mixed-phase silicon film growth.” Materials 

Research Symposium Proceedings; vol. 1066; 

A01-03. 

S. Datta; J.D. Cohen; Y. Xu; H.M. Branz. “TwoStep Capacitance Transients from an Oxygen 

Impurity Defect.” Materials Research Symposium 

Proceedings; vol. 1066; A10-03. 

C.W. Teplin; I.T. Martin; K.M. Jones; D. Young; 

M.J. Romero; R.C. Reedy; H.M. Branz; P. 

Stradins. “Quality and Growth Rate of Hot-wire 

Chemical Vapor Deposition Epitaxial Si Layers.” 

Materials Research Symposium Proceedings; vol. 

1066, A11-06. 

I.T. Martin; C.W. Teplin; K.M. Jones; M.J. Romero; 

B. To; H.M. Branz; P. Stradins. "Mechanism of 

hot-wire chemical vapor deposition epitaxial silicon 

growth at 600 to 800°C.” Presented at 5th 

HWCVD International Conference, Cambridge, 

Massachusetts, Sept. 2008. 

H.M. Branz; K. Jones; M. Romero; C.-S. Jiang; P. 

Stradins; C.W. Teplin. “Film Silicon for 

Photovoltaics: Low-Temperature Hot-Wire CVD 

Epitaxy and Nanocrystalline Silicon Growth.” 

4th Invited talk at Workshop on the Future of 

Photovoltaics, Japan Association for Advancement 

of Science, Tokyo, Japan, March 2008. 

25 Photovoltaic

Applied Research

Electronic Materials and Devices
 

 

 

____________________________________________________________________________________ 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

Copper Indium Gallium diSelenide Research 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Miguel Contreas, 303-384-6478, miguel_contreas@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-3765, marie.mapes@ee.doe.gov 

FY 2008 Budget: $1,750K 

Objectives 

•	 Receive initial components of copper indium gallium diselenide (CIGS) platform and finalize 

design of cadmium telluride (CdTe) platform for the Process Development and Integration 

Laboratory (PDIL). 

•	 Expand intellectual property (patents) related to design of novel transparent conducting oxides or 

use in thin-film CIGS photovoltaic (PV). 

•	 Assist with development of goals and metrics associated with CIGS technology roadmaps 

including coordination of PDIL platform designs. 

Accomplishments 

•	 Installed first component, the CIGS ultra high vacuum chamber. Other components (central 

transfer chamber and three sputtering chambers) will be delivered in 2009. 

•	 Produced new world efficiency record of 20.0% for CIGS thin-film PV device. 

Future Directions 

•	 Complete environment, safety, and health (ES&H) and facilities requirements for full functionality 

of equipment in remainder of STF laboratories. 

•	 Finish installation of CIGS platform and bring into full compliance with NREL ES&H regulations. 

•	 Develop sensors for CIGS and assess strategies that establish key metric for ultimate device 

performance immediately following CIGS deposition. 

1. Introduction 

The research undertaken by the Polycrystalline 

Thin-Film Devices Group is directed at thin-film 

semiconductor materials, device properties, and 

fabrication processes to improve the efficiency, 

stability, and cost of PV solar energy conversion. 

This research can be broadly placed into three 

categories: application of capabilities to assist 

industry in addressing current problems; 

exploration of specific techniques and processes 

to develop and transfer technology improvements 

that industry will soon need; and providing 

understanding that builds a solid technical 

foundation for continuing improvement of thin-film 

PV products. Within this framework, the project 

supported thin-film technologies related to 

Molybdenum, CIGS, and transparent conductive 

oxide (TCO) thin-film technologies. Activities and 

time frames are consistent with those identified in 

the DOE Solar Program Multi-Year Technical Plan 

and related Technology Roadmaps. 

NRELs CIGS technologies lead the world in 

demonstrated cell performance while our 

innovations related to high-quality TCO 

technologies are being rapidly assimilated into the 

thin-film industry. Because thin-film PV can 

generate lower cost PV electricity than many 

historical alternatives (in $/watt), thin-film PV is the 

fastest growing segment of the PV market. 

Providing new innovations and a technical 

foundation for this rapidly expanding industry is at 

the heart of the efforts of the NREL Polycrystalline 

Thin-Film Group. 

2. Technical Approach 

The project focuses on research associated with 

CIGS device development. Activities related to 

TCO research were also funded through the CIGS 

device activity and partly through the NREL 

Fellows Research Grant to provide a full-time 

graduate student. Tasks are detailed below: 

Photovoltaic

Applied Research

Electronic Materials and Devices

26
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CIGS Research 

•	 Conduct baseline cell research, including 

advanced TCO development for substrate 

devices. 

•	 Examine device performance in progressively 

thinner absorber layers. 

•	 Improve processes for larger-scale 

manufacture of CIS with high-performance. 

•	 Examine CIGS intrinsic device stability modes. 

3. Results and Accomplishments 

The project objectives support near-term 

manufacturing, build the knowledge and 

technology base for future manufacturing 

improvements, allows for training of the next 

generation of CIGS PV device technologists, and 

sustains innovation that supports progress toward 

the future and the long-term Solar Energy 

Technologies Program goal of 15%-efficient 

commercial modules. We have steadily improved 

the quality of the layers in the CIGS device and 

achieved a world-record efficiency of 20.0%. 

Efforts continued to be impacted by significant 

efforts to re-establishing the research equipment 

of the CIGS technology area from locations in the 

Solar Energy Research Facility (SERF) to new 

locations in the Science and Technology Facility 

(S&TF) at NREL. By the beginning of FY 2008, all 

equipment had been moved to the S&TF, all 

SERF laboratories had been evacuated as per 

ES&H requirements, and approximately 50% of 

the STF-located equipment was operational as per 

ES&H requirements. It is estimated activities 

associated with re-establishment of equipment 

consumed 20%-30% of the technical staff’s time. 

All systems are being re-established as quickly as 

possible to meet rapidly expanding workload. 

In August 2007, a CIGS device was fabricated that 

that was confirmed at 19.88% efficiency. Because 

of a change in spectral conditions, this result has 

since been re-certified at 20.0%. Both results 

exceed the previous world-record efficiency of 

19.52% by a noticeable margin and have indicated 

a pathway toward even higher efficiency. A 

publication describing the process improvements 

that yielded these results was published. The 

result also confirms the equipment and procedures 

used for our CIGS research have survived the 

rigors and design modifications associated with 

the move and can again be relied upon to produce 

the high baseline performance that has placed 

NREL at the forefront of CIGS research. 

Activities related to development of novel TCOs 

for CIGS incorporation was completed. This 

involved the development of a Al-doped ZnO 

(ZnO:Al) material that was designed to achieve 

higher infrared (IR) transmission. Unlike “standard” 

ZnO:Al that contains ~2 wt.% Al2O3 and is sputter 

deposited in pure argon, our research determined 

that if a hydrogen/argon sputtering ambient is 

used, the Al2O3 content can be reduced to ~0.05 

wt.% to provide significantly improved electron 

mobility and higher carrier activation. Because 

fewer free carriers (electrons) are required to 

produce a low resistivity film, higher IR 

transparency results. Preliminary incorporation of 

this new composition of ZnO:Al into CIGS devices 

has yielded quantum efficiencies higher than 

achieved on world record CIGS devices, and so 

further testing was actively proceeding at the end 

of FY07. The second TCO project involves 

development of a ZnO + MgO alloy (ZnMgO) that 

may afford the ability to control the valance-band 

discontinuity at the Zn(Mg)O/CdS interface, 

thereby allowing higher Voc at higher gallium 

concentrations. The material may also have higher 

resistance to environmental corrosion compared to 

ZnO. Initial analysis of ZnMgO fabricated by r.f. 

sputter deposition has been encouraging, and 

results related to incorporation of the layer into 

CIGS devices have been published. 

The project related to sensor development 

proceeded exceptionally well. Through 

collaborative efforts with the measurements and 

characterization team, several important 

observations were made and published. First, it 

was re-confirmed that the minority carrier lifetime 

of the CIGS layer after CdS treatment is a strong 

indicator of ultimate device performance. Second, 

observed for the first time, the time between CIGS 

layer fabrication and CIGS deposition strongly 

affects the minority carrier lifetime, and therefore, 

the ultimate device performance. These 

observations have significant implications for 

industrial partners. First, it is important that the 

CIGS and CdS process sequences be conducted 

in a timely manner. Second, it is very difficult to 

assess carrier lifetime of the CIGS layer, unless 

appropriate equipment is at the facility where the 

CIGS is produced. Third, and most importantly, it 

is possible to develop an in-line diagnostic tool 

based on time-resolved photoluminescence that 

could be used to assess the quality of the CIGS 

layer prior to ultimate device fabrication. 

The final highlighted accomplishment relates to 

receiving the first of the three orders related to the 

27 Photovoltaic

Applied Research

Electronic Materials and Devices
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CIGS PDIL platform. This first component will 

allow for CIGS deposition within the boundaries of 

the PDIL design guidance (i.e., 6”x6” format, 

multiple runs per chamber service (up to 100), 1.1 

meter transfer height, pod transfer, cassette 

loading, and robot-compatible). After arrival, 

considerable effort was invested to fit up the 

system. Initial operation of this first phase of the 

CIGS system is expected in early FY 2009. This 

marks a significant step toward the establishment 

of the first of the PDIL platforms that are being 

designed by the Polycrystalline Thin- Films Group. 

Orders for the remaining two phases of the CIGS 

have also been placed. 

4. Planned FY 2009 Activities 

Efforts will continue to shift from the CIGS STF 

laboratories used to produce small devices and 

thin films toward efforts related to installation of 

the equipment required to establish operations in 

the CIGS PDIL. Efforts will also be expanded for 

CIGS-related cooperative research and 

development agreements (CRADAs). This and 

other planned activities are outlined below. 

•	 Complete remaining fit-up of STF laboratories 

to attain functionality of previous SERF labs. 

•	 Finalize specification and engineering for 

solution-growth CdS component. 

•	 Fit up remaining CIGS PDIL components. 

•	 Establish key metric for device performance 

immediately following CIGS deposition. 

•	 Expand research of alternative processes for 

CIGS layer deposition. 

5. FY 2008 Special Recognitions and Awards 

•	 M.A. Contreras won the 2008 HENAAC 

outstanding technical achievement award for 

his contributions to the field of solar energy. 

(www.henaac.org) 

•	 M.A. Contreras’ publication in Progress in 

Photovoltaics journal was recognized as the 

most cited paper in the field of Energy and 

Fuels. He is one of the top 10 most cited 

scientists in this field. 

(http://sciencewatch.com/ana/fea/08novdecFea/) 

6. Major FY 2008 Publications 

•	 I. Repins; M.A. Contreas; B. Egaas; C. 

DeHart; J. Scharf; C.L. Perkins; B. To; R. 

Noufi. “19.9%-Efficient ZnO/CdS/CuInGaSe2 

Solar Cell with 81.2% Fill Factor,” Prog. in 

Photovolt.: Res. and App. 16 235-239 (2008). 

•	 M.A. Contreras; I. Repins; W. Metzger; M. 

Romero; D. Abou-Ras. “Se Activity and its 

Effect on Cu(In,GaSe2 Photovoltaic Thin 

Films,” Proc. 16th Int. Conf. on Ternary and 

Multernary Compounds (ICTMC-16), 

Technical university of Berlin, Berlin, Germany 

Sep. 16-19, 2008. 

•	 D. Abou-Ras; C.T. Koch; V. Küstner; P.A. van 

Aken; U. Jahn; M.A. Contreras; R. Caballero; 

C.A. Kaufmann; R. Scheer; T. Unold; H.-W. 

Schock. “Grain-boundary types in 

chalcopyrite-type thin films and their 

correlations with film texture and electrical 

properties”, E-MRS 2008 Spring Meeting, 

Symposium L, Strasbourg, France, May 26– 

30, 2008. 

•	 W.K. Metzger; I.L. Repins; M.A. Contreras. 

“Long lifetimes in High-efficiency Cu„In,GaSe2 

Solar Cells”, Appl. Phys. Lett. 93, 022110, 

2008. 

•	 X. Li; H. Ray; C.L. Perkins; R. Noufi. “Effects 

of Mg Content on Zn1-xMgxO:Al Transparent 

Conducting Films,” Proc. of Spring MRS San 

Francisco, March 24-28, 2008. 

7. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal 

Investigator 

Location Description/Title of Research Activity FY 2008 

($K) 

Cost 

Share ($K) 

Optony Inc. Sunnyvale, CA Development of thin film CIGS solar cells 

for concentrator applications 

250 250 

JLN Solar Mill Valley, CA Development of the monolithic 

interconnection in minimodules 100 

Photovoltaic

Applied Research

Electronic Materials and Devices

28
 

 

 

____________________________________________________________________________________ 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

Cadmium Telluride 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Timothy Gessert, 303-384-6451, tim_gessert@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-3765, marie.mapes@ee.doe.gov 

FY 2008 Budget: $880K 

Objectives 

•	 Re-establish cadmium telluride (CdTe) research at Science and Technology Facility (S&TF). 

•	 Expand intellectual property (IP) for design of novel transparent conducting oxides in thin-film 

CdTe photovoltaic (PV). 

•	 Develop goals and metrics associated with CdTe Technology Roadmaps including coordination 

of Process Development and Integration Laboratory (PDIL) platform designs. 

Accomplishments 

•	 Made CdTe absorber laboratories in S&TF nearly 100% operational. 

•	 Made CdTe contact laboratories in S&TF more than 70% operational. 

•	 Made user-characterization labs and cell reliability labs 100% operational in STF. 

•	 Established role of Cu on improving minority carrier lifetime in CdTe PV devices. 

Future Directions 

•	 Complete requirements for full functionality of equipment in remainder of S&TF laboratories. 

•	 Complete initial procurement stage of CdTe PDIL equipment. 

•	 Expand minority-carrier studies to CdTe materials produced by multiple sources. 

•	 Establish ZnTe:Cu/Ti contact process using NREL CdTe absorber materials. 

•	 Accelerate research on high-bandgap absorber layers for tandem-junction polycrystalline thin-film 

PV devices. 

•	 Foster partnerships with commercial glass companies to develop PV-specific products. 

1. FY 2008 Special Recognitions and Patents 

•	 T.A. Gessert, co-organizer, “New Concepts in 

Polycrystalline PV,” 2008 European Materials 

Research Society meeting. 

•	 T.A. Gessert, chair, Vacuum Technology 

Division. Becomes program chair in October 

2008 for 2009 AVS National Symposium. 

•	 T.A. Gessert; J. Duenow; T. Barnes; T.J. 

Coutts. Patent Filed. IR 07-42, High Quality 

Transparent Conducting Oxide Thin Films. 

•	 Record of Invention filed with DOE, IR 08-28, 

X. Li and T.A. Gessert. 

•	 Patent published. T.A. Gessert; Y. Yoshida; 

T.J. Coutts. IR 04-32. Transparent Conducting 

Oxides with Controlled Dielectric Permittivity. 

2. Major FY 2008 Publications 

•	 T.A. Gessert; W.K. Metzger; P. Dippo; S.E. 

Asher; R.G. Dhere; M.R. Young. “Dependence 

of Carrier Lifetime on Cu-Contacting 

Temperature and ZnTe:Cu Thickness in 

CdS/CdTe Thin Film Solar Cells,” 2009 EMRS 

Meeting, Strassbourg, France. Accepted for 

Pub. Thin Solid Films. 

•	 R.G. Dhere; Y. Zhang; M.J. Romero; S.E. 

Asher; M. Young; B. To; R. Noufi; T.A. 

Gessert. “Investigation of Junction Properties 

of CdS/CdTe Solar Cells and Their Correlation 

to Device Properties.” 33rd IEEE PVSC 

Proceedings. 

•	 X. Li; J. Pankow; B. To; T. Gessert. 

“Comparison Between Research-Grade and 

Commercially Available SnO2 for Thin-Film 

CdTe Solar Cells.“ 33rd IEEE PVSC 

Proceedings. 

•	 L. Zhang; J.L.F. Da Silva; J. Li; Y. Yan; T.A. 

Gessert; S-H. Wei.“Effect of Co-Passivation of 

Cl and Cu on CdTe Grain Boundaries,” 

Accepted for Pub. Physical Review Letters, 

LU12095 (9/08). 

29 Photovoltaic

Applied Research

Electronic Materials and Devices
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

Concentrating Photovoltaics 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Daniel Friedman (NREL), 303-384-6472, daniel_friedman@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-3765, marie.mapes@hq.doe.gov 

FY 2008 Budget: $2,114K (NREL) 

Objectives 

•	 Demonstrate inverted lattice mismatched (iLMM) device with concentrator performance peak 

above 100 suns. 

•	 Demonstrate iLMM cell with optimized second- and third-junction band gaps. 

•	 Improve theoretical understanding of misfit and threading dislocations in III-V materials. 

•	 Study the effect of growth parameters on strain relaxation and defect properties. 

•	 Initiate development of 4-junction 2.0/1.6/1/2/0.9-eV IMM cell for efficiency approaching 50%. 

•	 Evaluate degradation mechanisms of multijunction / iLMM cells; plan for mitigation. 

•	 Develop computational tools capability to simulate the electrical, optical and thermal behavior of 

high efficiency multijunction solar cells in two and three dimensions. 

•	 Investigate barriers to creation of a mature concentrating photovoltaics (CPV) industry. 

Accomplishments 

•	 Demonstrated record-setting IMM cell with 40.8% peak efficiency at 326 suns using optimized 

1.83, 1.34, and 0.89 eV bandgaps. 

•	 Developed new dislocation core structure model for InN/GaN misfit dislocations. 

•	 Developed InGaAs growth capabilities on MBE; demonstrated metamorphic InGaAs cell. 

•	 Developed top two subcells (2.0/1.6 eV) and demonstrated tandem incorporating them. 

•	 Determined oxidation rate of AlInP window in various testing environments and vs. dopants. 

•	 Acquired suite of software tools and adapted them to calculate behavior of MJ cells. 

•	 Developed and published report on status of the CPV industry and barriers to its maturity. 

Future Directions 

•	 Improve grades for mismatched junctions; reduce resistance for higher concentration operation; 

high temperature operation and improve heat management. 

•	 Evaluate performance of different alloys in the graded layers, including AlGaInAs and AlGaAsSb; 

comparative investigation of mismatch with both tensile and compressive strain. 

•	 Assess stability and degradation mechanisms of metamorphic cells; study effect of encapsulants, 

AR coat, and metallization on AlInP window layer. 

•	 Model effects of real-world problems, develop mitigation paths, and optimize device performance, 

for effects including non-uniform irradiance and high series resistance. 

1. Introduction	 cost, targeting low LCOE for installations at the 

large-rooftop to utility scales. A study by the 

This activity develops advanced multijunction Prometheus Institute (“Concentrating Solar Power 

concentrator cells with improved performance, – Technology, Costs, and Markets”, Grama et al, 

reliability, and cost-effectiveness. We transfer the 2008, p.6) projects CPV to become competitive at 

resulting technology to the CPV industry through utility scale within the next decade. Ultimately the 

licensing and cooperative research and goal for CPV is lower LCOE than flat plate for 

development agreements (CRADAs) with commercial rooftop and utility markets. 

industrial partners. The CPV approach leverages 

the high output of the multijunction cells, while 

minimizing the cell cost as a fraction of the system 

Photovoltaic

Applied Research

Electronic Materials and Devices

30
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No. 

(in 

AOP) 

Agreement Title 

FY 2008 

Budget 

($K) 

1.1 High concentration operation of 

ILMM cell 

410 

1.2 Variable band gap ILMM 282 

1.4 Theory of dislocations 95 

1.5 LMM materials by MBE 190 

1.6 50% ILMM cell 230 

2.1 Reliability of cell components 297 

5.3 Advanced cell modeling 475 

6.2 Mature CPV Industry Study 135 efficiency (%) 

2. Results and Accomplishments 

Task 1.1 and 1.2: High-concentration, optimizedbandgap IMM cells 

Significant improvements were made to the threejunction inverted lattice mismatched (iLMM) solar 

cell. We fabricated an inverted device with two 

compositionally graded buffer layers to achieve a 

world record 40.8% efficiency under concentration. 

Defect densities were only 1x105 and 2x106 cm–2 

in the middle and bottom lattice-mismatched 

junctions respectively. 

45 

40 

35 

30 

100 1000 

40.8% 

at 

326 suns 

1	 10 

concentration (suns) 

Fig. 1.1. Efficiency of record IMM three-junction device 

as a function of concentration. 

Task 1.4: Dislocations Theory 

We studied misfit dislocations at the InN/GaN 

interface, a useful model system whose 

understanding will help with the study of the 

arsenide-phosphides used in the IMM cell. We 

found that the InN/GaN interface is composed of 

three sets of 90o partial dislocations which strongly 

interact with each other within the two-dimensional 

interface plane to exhibit long-range order. 

Based upon this initial study, odeling was then 

extended to include partial dislocations in GaAs. 

Two of these reconstructions are shown in Fig. 

1.4. Calculations show the As core prefers the 

"double period" (DP) structure and is an electron 

donor, whereas the Ga core prefers the "single 

period" (SP) structure and is an electron acceptor. 

The two dislocations will therefore behave 

differently in p-type and n-type environments. This 

may help explain some of the puzzles related to 

the interaction between dislocations and doping. 

Task 1.5: Lattice mismatched materials by MBE 

Experiments to test the effect of dopants, 

temperature, and surfactants on strain relaxation 

and device characteristics were performed. 

•	 Gross changes in morphology and strain 

relaxation indicate a dislocation pile-up at low 

growth temperatures. 

•	 Use of bismuth as a surfactant during 

mismatched growth was studied. Local 

changes in luminescence energies indicate 

the creation of point defects in the graded 

layer, which adds to the series resistance. 

•	 The addition of silicon in graded layers 

increases the defect density. Changing the 

beryllium doping in the graded layers of solar 

cells affects the position of the junction– 

possibly implying an n-type contribution to the 

carrier concentration by defects. 

•	 High quality MBE-grown metamorphic InGaAs 

solar cells were developed as a foundation for 

further LMM studies. 

•	 Acquisition and installation of a MOSS system 

on the MBE growth reactor will allow the 

stress of future metamorphic growths to be 

studied in-situ. 

Fig. 1.4. Top and side views of 60° partial dislocations in 

GaAs. A "double period" As-core dislocation structure is 

shown with a "single period" Ga-core structure (right). 

Task 1.6: 4-Junction IMM cell 

Initially, 1.6-eV, n/p GaAsP solar cells were grown 

upright on GaAs substrates, using intervening 

GaAsP step-graded layers. A baseline cell 

structure without 2-eV GaInP minority-carrier 

barrier layers was first fabricated and evaluated. 

Next, barrier layers were added to the structure 

selectively (front and back surfaces) to assess 

performance improvements. Spectral absolute 

external quantum efficiency (AEQE) 

31 Photovoltaic

Applied Research

Electronic Materials and Devices
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

measurements showed the barrier layers reduced 

substantially non-radiative recombination at both 

the front and back interfaces, when compared to 

data for the baseline cell. With both barrier layers 

included in the cell structure, the AEQE exhibited 

a “box-car” characteristic for photon energies less 

than 2 eV. Furthermore, the internal quantum 

efficiency for the double-heterostructure (DH) 

GaAsP/GaInP cells approaches unity in this range. 

Current density (voltage) (J-V) data under 

standard one-sun conditions were also taken for 

the same set of 1.6-eV GaAsP cells. The baseline 

cell gave an efficiency of 9.4%, which improved to 

12.2% for the DH cell incorporating barrier layers. 

Task 2.1: Cell Reliability 

Both experimental design of reliability testing and 

testing of individual cell components of LMM cells 

were performed. The quality and integrity of the 

AlInP window of a GaInP top cell is very important 

for high efficiency. Potentially very sensitive to 

oxidation, the damp-heat oxidation rate of AlInP 

was studied at various temperatures and 

humidities and found to be less significant than 

initial concerns. Upon the introduction of light, the 

oxidation rate increases by over 300%, a 

potentially important degradation mechanism for 

solar cells. Selenium and zinc doping of AlInP was 

also determined to increase the oxidation rate. 

Experimental design of reliability testing on latticemismatched cells was completed. Performing 

EBIC or OBIC while forward biasing or irradiating 

a device will provide information about the change 

in defect density during device operation. 

Accelerated testing conditions including forward 

biasing, temperature, and weathering with 

intermittent cell characterizations will give 

information about failure modes and frequency. 

Task 5.3: Advanced Cell Modeling 

SPICE circuit analysis: We developed a full threedimensional circuit model of a multijunction solar 

cell. The code can also calculate IV curves for 

non-uniform illumination, including cases in which 

the current mismatch between junction varies 

spatially across the cell. 

Simulation of heat flow in a concentrator module 

under non-uniform illumination: We developed a 

model to study heat flow in a concentrator solar 

cell bonded to a heat sink. It consists of a 250μmthick cell bonded to a Cu heat sink with a layer of 

thermal epoxy. The cell is non-uniformly 

illuminated with a peak concentration of ~10,000X 

and an average concentration of 1000X. 

Simulation of III-V Multijunction solar cells: We 

developed 1-D and 2-D numerical models for 

single and multijunction solar cells of GaInP, GaAs 

and Ge. Validation of the results is on going. 

Task 6.2: Mature CPV Industry Study 

A study was completed on the status of the CPV 

industry and the remaining barriers to large-scale 

growth. Shared with dozens, the study has 

consistently generated positive feedback, 

including requests for invited talks or interviews. 

5. FY 2008 Special Recognitions and Patents 

•	 R&D 100 Award: Inverted Metamorphic 

Multijunction cell; M.W. Wanlass and Emcore. 

•	 Friedman, D.J.; Geisz, J.F., U.S. Patent No. 

7,309,832 B2, "Multi-Junction Solar Cell 

Device", December 18, 2007. 

6. Major FY 2008 Publications 

•	 J.F. Geisz; D.J. Friedman; J.S. Ward; A. 

Duda; W.J. Olavarria; T.E. Moriarty; J.T. Kiehl; 

M.J. Romero; A.G. Norman; K.M. Jones. 

"40.8% efficient inverted triple-junction solar 

cell with two independently metamorphic 

junctions." Appl. Phys. Lett.; 93, 123505, (2008). 

•	 J.F. Geisz; A.X. Levander, A.G. Norman; K.M. 

Jones; M.J. Romero. "In-situ stress 

measurement for MOVPE growth of high 

efficiency lattice-mismatched solar cells." J. 

Cryst.Growth, 310, 2339 (2008). 

•	 J.F. Geisz; S. Kurtz; M.W. Wanlass; J.S. 

Ward; A. Duda; D.J. Friedman; J.M. Olson; 

W.E. McMahon; T.E. Moriarty; J.T. Kiehl; M.J. 

Romero; A.G. Norman; K.M. Jones. "Inverted 

GaInP/(In)GaAs/InGaAs triple-junction solar 

cells with low-stress metamorphic bottom 

junctions." 33rd IEEE Photovoltaic Specialists 

Conference Proceedings, San Diego, 2008. 

•	 M.A. Steiner; J.F. Geisz; R.C. Reedy; S.R. 

Kurtz. "A direct comparison of inverted and 

non-inverted growths of GaInP solar cells", 

Proceedings of the 33rd IEEE Photovoltaic 

Specialist Conference, San Diego, (2008). 

•	 S.R. Kurtz. “Opportunities and Challenges for 

Development of a Mature Concentrating 

Photovoltaic Power Industry,” 

www.nrel.gov/docs/fy08osti/43208.pdf. 

•	 S.R. Kurtz. “Current status of the CPV 

industry.” PV International 1, 121, (2008). 

Photovoltaic

Applied Research

Electronic Materials and Devices

32
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

Organic Photovoltaics and Advanced Materials 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: David Ginley (NREL), 303-384-6573, david_ginley@nrel.gov 

DOE HQ Technology Manager: Jeffrey Mazer, 202-586-2455, jeffrey.mazer@ee.doe.gov 

FY 2008 Budget: $2,241K 

Objectives 

•	 Develop organic-based thin film photovoltaics (OPV). 

•	 Apply combinatorial methods to develop improved transparent conducting oxides (TCOs). 

•	 Develop novel solution-based processes for PV including metallization and copper indium gallium 

diselenide (CIGS). 

•	 Develop laser processing facility and apply to laser nucleation of amorphous Silicon (Si). 

•	 Support cooperative research and development agreements (CRADAs) (e.g., HelioVolt, 

Evergreen Solar, BP, Konarka, TDA, Plextronics, XJET, and others). 

Accomplishments 

•	 Developed OPV device technology of organic and inorganic modifying layers for improved 

efficiency with promising initial results on scalability for spray and inkjet approaches. 

•	 Hosted first international workshop on OPV lifetime, stability, and efficiency measurements with 

Plextronics and DOE. Initiated activities in efficiency and stability round robins internationally. 

•	 Progressed in combinatorial tool set and ability to translate combinatorial results to state-of-art 

uniform films in ZnO, InZnO and CuZnO. 

•	 Received R&D 100 award and FLC Technology Transfer Award for hybrid CIGS with Heliovolt. 

Developed new ink set and ink supplier for ink-based technologies. 

•	 Made state-of-the-art quad-band laser process station operational with promising initial results on 

Si nucleation. 

Future Directions 

•	 Increase polymer synthesis effort to develop optimized materials for interfacial modification, 

active layer, and encapsulant for OPV. Hired senior polymer chemist and second post doc. 

•	 Transfer ink-based technology to partners and develop commercial supplier of NREL-based inks; 

develop use of laser processing to develop large grain template layers for thin film Si on glass. 

•	 Continue productive partnership with Solar America Initiative (SAI) and PV Incubator partners. 

•	 Show controlled nucleation for amorphous Si recrystallization. 

•	 Focus on processing to larger areas and addressing reliability and packaging issues; hold second 

International Summit on OPV lifetime, which was instrumental in revising OPV roadmap. 

•	 Develop new TCOs with focus on very high performance, stability, interfacial chemistry, and work 

function. Continue examination of amorphous systems and development of ink-based 

approaches to high performance TCOs. 

1. Results and Accomplishments technology, new characterization tools specific to 

OPV, and our initial results to address the lifetime 

1.1 Jointly with Sandia National Laboratories (intrinsic and extrinsic) of OPV devices. (SNL), develop next-generation OPV devices and 

begin to look at issues of scalability and lifetime. OPV devices with 4.2% efficiency have been Our OPV program has gained national and made and measured using polymer/fullerene international attention due to our integrated blends and ITO/PEDOT:PSS & Ca/Al electrodes. approach to new acceptor and donor development The open circuit voltage (VOC), short circuit current 

coupled to our developments in new process (JSC), and fill factor (FF) for 0.11 cm2 devices were 

33 Photovoltaic

Applied Research

Electronic Materials and Devices
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

measured to be 609 mV, 10.9 mA/cm2

, and 63%, 

respectively. Scaling up the device area resulted 

in a reduction in the fill factor of the JV data, which 

is due to an increase in the series resistance due 

to the sheet resistance of the ITO electrode 

material. Present work on the revision of the 

electrode geometry and the reduction of the series 

resistance via a metal grid has demonstrated 

promising results on improving device 

performance for large area devices. 

In an effort to initiate discussion and development 

of standard testing procedures for OPV device 

lifetimes and the degradation mechanisms in 

these devices, we helped to organize the first 

annual International Summit on OPV Stability. 

This successful event was designed to encourage 

the OPV community to come to an agreement on 

the proper testing protocols for OPV devices. 

Initial studies on OPV device lifetime and stability 

are underway. The construction of two parallel 

combinatorial degradation simulators will allow for 

careful study and control of the effects of light 

soaking, light intensity, UV absorption, 

temperature, and inert, oxygen-free, and moisturefree atmospheric conditions on device lifetime and 

degradation. These degradation setups along with 

other OPV-specific characterization techniques will 

allow for the study of the degradation mechanisms 

at work in OPV devices. Data indicates that efforts 

to improve encapsulation technologies are of great 

importance for improved OPV device lifetimes. 

The introduction of new device architectures, in 

particular inverted bulk heterojunction devices, can 

lead to the elimination of unstable low work 

function metal electrodes. This in turn has already 

led to much improved device shelf life in air 

compared to the traditional devices that employ 

air-sensitive Ca/Al electrodes. Such devices use a 

sol-gel ZnO layer to change the ITO electrode 

from a hole-collecting electrode to an electroncollecting electrode. 

In order to improve the overlap between the 

absorption of the electron donor material and the 

solar spectrum, we have synthesized conjugated 

dendrimers with band gaps down to 1.8 eV and 

conjugated polymers with band gaps down to 1.5 

eV. The dendrimer materials have been 

incorporated into bulk heterojunction devices and 

have already achieved power conversion 

efficiencies greater than 1% and have 

demonstrated VOC’s greater than 900 mV despite 

having a lower band gap than P3HT, our standard 

donor material. This indicates the flexibility that 

organic synthesis allows for in the development of 

OPV materials. 

The optimization of contacts in OPV devices is of 

great importance. This is further complicated by 

the necessity to re-optimize when change active 

layer materials due to changes in the electronic 

energy levels in these materials in order to 

efficiently extract charge. A comparison of several 

different metal electrodes for traditional bulk 

heterojunction devices proves calcium to be the 

best electrode material in terms of both 

performance and stability. 

Additionally, we have investigated the effects of 

interface modification of P3HT/ZnO bilayers with 

amorphous TiO2 deposited via atomic layer 

deposition (ALD), pulsed laser deposition (PLD) 

and solution to better understand charge 

generation and recombination processes at this 

interface. The TiO2 layer dramatically improves 

the VOC as a result of passivation of ZnO surface 

states and charge generation & lifetime as seen in 

Figure 6. In addition, a gradient in carrier 

concentration in the ZnO acceptor has also been 

shown to dramatically enhance current extraction. 

We have investigated ink-jet printing and 

ultrasonic spray deposition as methods for 

materials deposition. There is little change in 

device performance when the PEDOT hole 

transport layer is deposited via traditional spin 

coating compared to ink-jet and ultrasonic spray. 

Finally, we have been able to ultrasonic spray the 

active layer itself in air with efficiencies greater 

than 2%, and more recently efficiencies greater 

than 3% have been achieved using the same 

parameters when sprayed in a nitrogen 

atmosphere. This technique has been used to 

spray large area devices and appears to be an 

excellent method for high-throughput, large area 

deposition of organic materials in manufacturing. 

1.2 Develop combinatorial materials science 

deposition, diagnostics, and data analysis tools for 

applications to TCO materials, applying to Si, CIS, 

cadmium telluride (CdTe), and OPV. 

The combinatorial tool development has continued 

with the addition of new tools for mapping work 

function, optical properties and conductivity. We 

have now automated many of the tools and the 

associated data collection to move toward an 

integrated data management system. These have 

been applied to an increasingly broad range of 

Photovoltaic

Applied Research

Electronic Materials and Devices

34
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

problems with a focus on transparent conducting 

oxides. A key focus has been the continued 

investigation of amorphous TCO materials 

because of their excellent conductivity, 

transparency, smoothness, processability and low 

temperature deposition. 

1.3 Develop ink-jet processing of electronic 

materials for application to metallization and 

semiconductor materials for Si, CIS, and OPV. 

This work focuses on using liquid precursors to 

produce materials, such as metal contacts and 

absorber materials. These materials can either be 

deposited using inkjet printing or spray deposition. 

In the field of metal contacts a lot of progress has 

been made and our capabilities have expanded 

significantly. We have used inkjet printing for 

contacts on organic PV devices as well as CIGS 

devices. For OPV the results are not perfect yet, 

since the temperature at which the contacts can 

be printed is lower than the ideal temperature for 

the inks we have developed, leading to reduced 

conductivity of the metal and poor cell 

performance. Current effort is to develop an ink 

that will be compatible with OPV contact 

formation. In the area of contacts for CIGS, the 

effort has been very successful. When using a 

bilayer contact of nickel and silver efficiencies of 

more than 12.5% were achieved. A reference cell 

finished in a conventional fashion resulted in a cell 

with efficiency slightly above 13%. Considering the 

difference in shadow losses and the reduced cost 

of inkjet printing, makes inkjet printing very 

competitive with conventional evaporative contact. 

In the area of contact for Si PV, large steps 

forward have been taken as well. First of all the 

burn-through contact printing has improved 

significantly and we now have an ink that could 

reduce processing temperatures of Si-based cells 

by more than 100oC. Using inkjet printed contact 

cell efficiencies of over 13% were achieved on 

material that would get 13-14% efficiency with 

conventionally screen printed contacts. Also inks 

have been developed to form self-doping contacts. 

Work is shifting to develop inkjet printed contacts 

in other contact schemes. Currently we are 

working with industry to transfer the metallization 

technology. In order to do this we are working with 

industry to develop inkjet printing equipment as 

well as selecting an ink manufacturer for the inks 

developed at NREL. 

Our effort in depositing a CIGS absorber layer 

from liquid precursor materials had good results. 

Using the inks developed at NREL has resulted in 

the formation of CIGS films that have large CIGS 

grains. Cells with reasonable efficiencies have 

been made using this large grain material. It can 

be made from bilayer films as well as mixed 

material films. Films are deposited using spray 

deposition. We are improving device performance 

and developing alternative inks that will have less 

expensive ingredients in order to reduce the ink 

cost. We are actively transferring this technology 

to one of our industrial partners. 

Another absorber layer material that is under 

development for deposition by a liquid precursor is 

CdTe, developed as a nanoparticulate-based ink. 

Spray deposition is used to form a film. We have 

been successful in making optically dense thick 

films (up to 10μm with no cracks) of pure CdTe 

and are finishing these devices into cells. 

Since many PV devices contain a TCO, there is 

also an effort in developing a liquid precursorbased TCO, indium-zinc-oxide (IZO). An ink has 

been developed that can be deposited using spray 

deposition in order to form an IZO film. Films with 

good optical properties and minimal cracking have 

been deposited. The best conductivity achieved 

using the developed ink is about 60S/cm. A typical 

TCO has a conductivity of 1000-6000 S/cm, so 

improvement is needed in order for a liquid 

precursor-based TCO to be a replacement for 

conventionally deposited TCOs. 

Also, we are developing inks for an atmospheric 

processing platform (APP) for the NREL Process 

Development and Integration Laboratory (PDIL). 

This system will be located in bay 2 of the PDIL. 

The APP will have capabilities for inkjet printing, 

spray deposition, rapid thermal processing, XRD, 

XRF, sputter deposition, and evaporation. It will be 

capable of handling substrates up to 6”x6” in size. 

Everything will be located in an inert or vacuum 

atmosphere. Substrates can be moved around 

through the system without exposure to air by 

means of a linear motion system and a vacuum 

robot. The components of the system should 

arrive by December 2008, and completion of the 

system is expected in the first quarter of 2009. 

1.4 Develop advanced laser process station for 

laser scribing, laser annealing, and laser 

recrystallization of PV device structures. 

Crystallization of a-Si:H as a template layer for 

subsequent hot-wire chemical vapor deposition 

(HWCVD) epi Si growth is proceeding on three 

fronts, which are described below. 

35 Photovoltaic

Applied Research

Electronic Materials and Devices
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Seeding a-Si:H with very small crystals and have 

them grow into large crystals by thermal annealing 

before native crystallization sites nucleate 

(Collaboration with University of Minnesota/Uwe 

Korthagen) 

Using a two chamber deposition system, 

consisting of a ‘seed’ chamber attached to a 

traditional plasma enhanced CVD (PECVD) a-Si:H 

deposition system, crystalline seeds (diameter ~ 5 

nm) have been controllably introduced into an aSi:H film, resulting in a crystalline volume fraction 

(vf) varying from 0.24 to < 0.01. The resultant films 

were annealed at 600C and the vf’s were 

compared versus anneal time to an a-Si:H film 

containing no crystallite ‘seeds’. For a vf < 0.02, 

the film incubation time (time before the onset of 

crystallization) was shortened compared to that of 

an a-Si:H film, and TEM analysis showed no 

native nucleation during this time period. 

This suggests that the ‘sparsely introduced seeds’ 

can indeed grow large without any interference 

from the native nucleation sites, thus providing 

proof of concept of this idea. Work is in progress 

to examine which initial vf and which annealing 

temperature can produce the largest grains in the 

completely crystallized films. 

Laser crystallization of NREL a-Si:H films 

(Collaboration with Sharp Corporation of 

America/Steven Droes) 

Sharp has a well established crystallization 

process for a-Si:H, where they pulse the samples 

with a 4μm x 10mm laser beam spot which is then 

rastered across the entire sample, enabling full 

sample crystallization. They have examined many 

types of a-Si:H, and while the resultant sample 

crystallization is roughly similar, the sample 

electronic properties are vastly different. To date, 

they have laser annealed HWCVD samples 

containing 10-12 at % H, but which have been preannealed to evolve the majority of the bonded H 

(see Fig. 2). On the other hand, they were unable 

to crystallize a-Si:H films containing 2-3 at.% H (no 

pre-annealing), suggesting that evolution of this 

(smaller) H content is still significant enough to 

disrupt the crystallization process. Work is in 

progress to examine if films initially containing < 1 

at.% H (no pre-annealing) can be crystallized, thus 

eliminating the (energy intensive) pre-annealing 

step altogether. Work will then be initiated to 

examine the electronic properties of these films. 

Creation of ‘artificial’ nucleation center site by 

laser processing (NREL) 

Utilizing the concepts of a critical crystallite size 

and local film inhomogeneity, a model for a 

nucleation center has been advanced which 

shows that nucleation in thermally annealed a-Si:H 

occurs in the more well ordered spatial regions in 

the network, which are defined by the initial 

inhomogeneous H distributions in the as grown 

films. Based upon this model, we propose to 

create ‘artificial’ nucleation centers by laser 

processing, which will then grow into large 

crystallites byy thermal annealing. To date, thin 

(200-300 nm) a-Si:H samples have been laser 

illuminated in an area (3mm x 3mm) large enough 

to enable characterization by XRD and/or 

reflection and transmission. Initial results in this 

area yielded illuminated areas that were already 

crystalline, suggesting that the laser power needs 

to be reduced. Having shown that no crystallinity 

has been achieved upon laser processing 

(illumination), we next plan to thermally anneal 

these films to compare the structure of the film 

areas, which have been laser processed to those 

which have not been processed. 

2. Special Recognitions and Patents 

•	 R&D 100 award and FLC Technology Transfer 

Award for Hybrid CIGS with Heliovolt. 

3. Major FY 2008 Publications 

•	 M.F.A.M van Hest; C.J. Curtis; A. Miedaner; 

R.M. Pasquarelli; T. Kaydanova; P. Hersh; 

D.S. Ginley. “Direct-Write Contacts: 

33rd Metalization and Contact Formation.” 

IEEE Photovoltaic Specialist Conference 

Proceedings; 2008. 

•	 C.J. Curtis; M.F.A.M. van Hest; A. Miedaner; 

J. Nekuda; P. Hersh; J. Leisch; D.S. Ginley. 

“Spray Deposition of High Quality CuInSe2 

and CdTe Films.” 33rd IEEE Photovoltaic 

Specialist Conference Proceedings; 2008. 

•	 B. Sang; F. Adurodija; M. Taylor; A. Lim; J. 

Taylor; S. McWilliams; R. Oswald; B.J. 

Stanbery; M.F.A.M. van Hest; J. Nekuda; A. 

Miedaner; C.J. Curtis; D.S. Ginley. “Low Cost 

Copper Indium Gallium Selenide by the 

FASST Process.” 33rd IEEE Photovoltaic 

Specialist Conference Proceedings; 2008. 

•	 M.F.A.M. van Hest; David Ginley. “Future 

Directions for Solution-Based Processing of 

Inorganic Materials,” chapter in “SolutionBased Processing of Inorganic Films.” 

Photovoltaic

Applied Research

Electronic Materials and Devices

36
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

Sensitized Solar Cells 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Arthur J. Frank (NREL), 303-384-6262, Arthur_Frank@nrel.gov 

DOE HQ Technology Manager: Jeffery A. Mazer, 202-586-2455, jeffrey.mazer@ee.doe.gov 

FY 2008 Budget: $698K (NREL) 

Objectives 

•	 Develop next-generation sensitizers, architectures, and charge-conducting phases for improved 

device stability and performance. 

•	 Identify promising cell materials and configurations for highest device durability and efficiency. 

•	 Develop assembly procedures and cell-sealing techniques to increase device stability. 

•	 Obtain detailed understanding of fundamental processes that affect stability and device 

performance in collaboration with DOE’s Office of Science Basic Energy Sciences program. 

Accomplishments 

•	 Demonstrated >95% device stability over 1,000 h under continuous light soaking. 

•	 Demonstrated 19% improved device efficiency in dye-sensitized NT arrays having increased 

architectural order. 

•	 Developed first general synthetic method for growing ordered inorganic p-type semiconductor as 

a charge-conducting phase in NT arrays. 

•	 Synthesized ionic-based liquid electrolyte, delivering improved device stability. 

Future Directions 

•	 Continue to improve photoelectrode architectures, charge-conducting phases, and 

assembly/sealing techniques for enhancing device stability at increasing efficiency levels.
 

•	 Develop molecular and/or inorganic sensitizers with improved absorption across solar spectrum. 

•	 Demonstrate device(s) incorporating the above mentioned cell components. 

FY 2009 Planned Activities: 

•	 Demonstrate ordered nanostructured materials with improved electrical and/or optical properties. 

•	 Demonstrate device(s) with charge-conducting phases and/or nanostructured architecture; report 

preliminary device performance and durability results. 

•	 Demonstrate 5% efficient device with <10% efficiency loss over 1,000 h. 

•	 Synthesize and characterize low-volatile, liquid/quasi-solid and/or solid-state organic, and 

inorganic charge-conducting phases. 

1. Introduction 

The Sensitized Solar Cell Agreement applies to 

bulk heterojunction devices, featuring nanoscale, 

interpenetrating liquid/solid and solid/solid 

networks of electron- and hole-conducting 

materials. Typically, a light-harvesting molecular or 

inorganic sensitizer is located at the interface 

Agreement Title FY 2008 

Budget ($K) 

Photoelectrode architecture and 

device assembly & characterization 402 

Design/develop charge conducting 

phases 

296 

2. Results and Accomplishments between these two materials. The primary 

objectives are to evaluate laboratory cell stability Activities centered on designing and developing at different performance levels, to identify the photoelectrode architectures, charge-conducting cause of efficiency loss, and to develop next- phases, and assembly/sealing techniques for generation cell materials and configurations for improving cell stability and performance. improved device durability and efficiency. 

37 Photovoltaic

Applied Research

Electronic Materials and Devices
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Demonstrated a baseline level of device 

efficiency and stability for 1000 h. (09/08) 

We built the first apparatus at NREL that is 

capable of performing long-term stability testing 

(>10000 h) under continuous simulated solar light 

illumination. We conducted preliminary stability 

tests on TiO2 nanoparticle-based dye-sensitized 

solar cells involving (1) a reported stable new 

sensitizer and (2) an improved ionic liquid 

electrolyte in collaboration with M. Grätzel, Ecole 

Polytechnique Federale de Lausanne. The results 

demonstrated >95% device stability over 1000 h 

under continuous light soaking. The initial results 

are encouraging. They provided a baseline for 

comparing the stability and performance of 

devices incorporating other sensitizers, chargeconducting phases, and/or nanostructure 

architectures. 

•	 Demonstrated ordered electrode architecture 

with enhanced electrical and light-harvesting 

properties. (01/08) 

We identified the capillary stress created during 

evaporation of water from the mesopores of 

densely packed TiO2 nanotube arrays was of 

sufficient magnitude to induce bundling and 

microcrack formation. We developed a 

methodology involving the supercritical CO2 drying 

technique to prevent such architectural disorder. 

We also demonstrated higher photocurrent density 

and solar conversion efficiency in dye-sensitized 

cells incorporating films with the more aligned 

nanotube arrays. 

•	 Developed knowledge base to synthesize 

solid-state inorganic p-type hole conducting 

phase. (09/08) 

We identified key factors controlling the spatial 

profile of the growth of p-type inorganic hole 

conducting materials in the nanopores (< 100 nm) 

of n-type electron conducting materials. We 

simulated the synthetic conditions for 

electrodepositing hole conductors from the bottom 

of the nanoporous film upward toward the top of 

the film. The information from the simulations will 

guide the synthetic effort (FY 2009) to fill the entire 

pore network with an inorganic hole conducting 

material. 

•	 Synthesized a liquid electrolyte with improved 

stability. (09/08) 

We synthesized an ionic liquid based on an 

imidazole derivative for dye-sensitized solar cells. 

This liquid electrolyte is expected to improve the 

device stability. The initial results of performance 

and stability tests are encouraging. 

3. FY 2008 Special Recognitions and Patents 

•	 A.J. Frank, recipient of NREL’s Director Award 

for achievements in dye-sensitized solar cells. 

•	 K. Zhu, N.R. Neale, A. Miedaner, and A.J. 

Frank Nano Lett. 2007, 7, 69 was the most 

cited 2007 Nano Letters article as of 

September 2008. 

4. Major FY 2008 Publications 

A. J. Frank. “Science, Technology, and the Future 

of Sensitized Solar Cells.” Presented workshop on 

High Efficiency Photoconversion of Solar Energy 

to Electricity and Fuels: Tutorial and Critical 

Research Directions at University of Colorado at 

Boulder, Colorado, August 13-15, 2008. 

A.J. Frank. “Science, Technology and the Future 

of Sensitized Solar Cells.” Photovoltaics Beyond 

Conventional Silicon, June 17-18, 2008, Denver, 

Colorado. 

A.J. Frank. “Interfacial Photochemical Processes 

in Sensitized Nanostructured Electrodes.” 30th 

DOE Solar Photochemistry Research Conference, 

June 1-4, 2008, Charlottesville, Virginia. 

A.J. Frank. “Materials R&D Opportunities in 

Sensitized Nanostructured Solar Cells.” Presented 

at Materials Day 2008, Pennsylvania State 

University State College, April 14-15, 2008. 

A.J. Frank. “PV Conversion Technologies, 

Session: OPV, Sensitized, Seed.” Presented at 

Solar Annual Review Meeting, April 22-23, 2008, 

Austin, Texas. 

J. Van de Lagemaat; K. Zhu; K.D. Benkstein; A.J. 

Frank. “Temporal Evolution of the Electron 

Diffusion Coefficient in Electrolyte-Filled 

Mesoporous Nanocrystalline TiO2 Films.” 

Inorganica Chimica Acta. 361, 620 (2008). 

K. Zhu; T.B. Vinzant; N.R. Neale; A.J. Frank. 

“Removing Structural Disorder from Oriented TiO2 

Nanotube Arrays: Reducing the Dimensionality of 

Transport and Recombination in Dye-Sensitized 

Solar Cells.” Nano Letters 7, 3739 (2007). 

Photovoltaic

Applied Research

Electronic Materials and Devices

38
 

 

 

 

 

 

 

 

 

Measurements and Characterization 

The Measurements and Characterization (M&C) project supports the Solar Energy Technology Program 

(SETP) through the development and application of measurement and analysis techniques to solve 

scientific and technical problems that arise in the development and commercialization of photovoltaic (PV) 

technologies. Our expertise and capabilities facilitate research, development, and test and evaluation 

(T&E) in support of each of the PV technology roadmaps. 

The M&C project consists of four closely integrated core competency groups: Cell and Module 

Performance, Analytical Microscopy, Electro-Optical Characterization, and Surface Analysis. Each group 

utilizes a wide array of state-of-the-art measurements and characterization techniques and has highly 

trained staff with a combined total of more than 450 years of experience in PV materials and device 

characterization. This extensive PV experience base, coupled with the breadth of our capabilities, sets us 

apart from other organizations throughout the world (a summary of our analytical capabilities can be 

found at www.nrel.gov/pv/measurements). 

The M&C project focuses its efforts in three complementary areas: support, collaborative R&D, and 

technique development, as shown in Figure 1. M&C Support focuses on providing routine and specialized 

measurement and characterization support for the PV community through rapid and direct response to 

requests. M&C support also includes test and evaluation (T&E) and stage-gate review activities in support 

of the Solar America Initiative (SAI). Collaborative R&D focuses on contributing to and leading 

collaborative research projects to address critical issues and problems in PV technologies. Technique 

and Diagnostic Development focuses on developing and implementing new and specialized 

measurement techniques in response to specific needs in PV R&D and manufacturing. This work is done 

within the context of supporting all DOE-supported technologies and technology partners. 

Fig. 1. Schematic showing Measurements and Characterization research areas of emphasis. 

The M&C project is designed to help SETP meet its SAI 2015 targets, so the activities span a broad 

range of tasks that are focused on addressing technology-specific priorities. A summary includes: 

•	 T&E services in support of the subcontracted program and stage-gate reviews 

•	 Rapid-turnaround manufacturing process and device problem solving R&D 

•	 Process development and device optimization R&D 

•	 Cell failure analysis R&D 

•	 Module failure analysis R&D 

•	 New measurement techniques that address challenging material and device problems for mature and 

emerging PV technologies 

•	 T&E protocols to accurately measure the performance of novel cell and module structures 

•	 Measurements and characterization consulting for industry and university partners. 

In FY 2008, this project assisted customers with the test and analysis of tens of thousands of materials 

and device samples, helping them direct their research and commercial product development. The M&C 

project has a long history of working with the PV community to solve material, device, manufacturing, 

packaging, and reliability issues. We strive to develop a solid scientific foundation to help our customers 

advance their manufacturing process development, research, and reliability R&D to a higher level. 

39 Photovoltaic

Applied Research

Measurements and Characterization
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

Analytical Microscopy 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Mowafak Al-Jassim, 303-384-6602, mowafak_aljassim@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-000, marie.mapes@hq.doe.gov 

FY 2008 Budget: $2,660K 

Objectives 

•	 Provide routine and specialized measurement and characterization support for photovoltaic (PV) 

program research and industry teams. 

•	 Lead and contribute to collaborative research that addresses critical issues in PV technologies. 

•	 Develop and implement novel measurement techniques that enhance the ability to understand 

and advance fundamental PV research and development. 

Accomplishments 

•	 Provided extensive analytical microscopy support to Solar America Initiative (SAI) partners. 

Maintained cutting-edge support and acceptable turnaround time despite a nearly 50% increase 

in sample volume. 

•	 Developed two-dimensional p-n junction mapping in multicrystalline silicon (Si( solar cells and 

applied that technique to help CaliSolar optimize their junction formation process in highly 

textured Si cells. 

•	 Investigated carrier depletion behavior and grain misorientation in grain boundaries in 

polycrystalline Si thin films, in collaboration with in-house thin-film Si project.
 

•	 Designed, procured, commissioned, and tested new scanning probe microscope (AFM) and new 

scanning electron microscope (SEM) with environmental control and pod compatibility, in support 

of Process Development and Integration Laboratory (PDIL). 

•	 Investigated uniformity of ultrathin electron injection layers for organic solar cells, in collaboration 

with Konarka. 

•	 Expanded capabilities of WaferScan to better support SAI's industrial wafer Si projects. 

•	 Investigated structural and electronic properties of nanocrystalline Si:H films and devices with 

nanometer-scale resolution to help United Solar optimize their multi-junction cells. 

•	 Investigated microstructure and compositional profile of new world record copper indium gallium 

diselinide (CIGS) solar cell. 

Future Directions 

•	 Provide priority analytical microscopy support to SAI partners. 

•	 Investigate recombination and electron transport in c-Si low-angle grain boundaries to establish 

critical misorientation degrading device performance. 

•	 Complete establishment of environmentally-controlled AFM and vacuum-SEM systems, ensure 

readiness for PDIL applications; complete measurement of III-V device potential profile, and 

investigate GB potential behavior on a polycrystalline thin film. 

•	 Provide better understanding of the role of grain boundaries and intra-grain defects in affecting 

transport properties of cadium telluride (CdTe) films. 

•	 Evaluate effects of Ga flow on structure and chemistry of grain boundaries in CIGS thin films, 

including Ga concentration profile across grain boundaries. 

1. Introduction	 collaborations with external research partners in 

university and industry laboratories, PV 

The Analytical microscopy task supports all PV manufacturers, and internal research groups. 

material technologies and involves broad Each year this project assists clients with the 

Photovoltaic

Applied Research

Measurements and Characterization

40
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

analysis of thousands of materials and device 

samples, helping them to understand and direct 

work on their research and commercial product 

development. We also serve as one of the SAI test 

and evaluation facilities used to evaluate 

subcontract stage gate deliverables. 

These activities address one or more of the three 

areas crucial to meeting the goal of reducing the 

levelized cost of energy for PV to $0.06/kWh by 

2015. The three areas are (1) improving device 

and module performance, (2) reducing 

manufacturing costs, and (3) improving 

device/module reliability. 

2. Results and Accomplishments 

Supporting SAI 

The highest priority was supporting SAI projects. 

Considerable resources were devoted to 

supporting both Technology Pathway Partnerships 

and PV Incubator projects. Such projects resulted 

in a nearly 50% increase in our workload from the 

previous year. Despite this dramatic increase, we 

were able to provide state-of-the-art 

measurements at an acceptable turnaround time. 

The SAI work falls into three categories: 

measurement support, verification of deliverables, 

and research support. Three examples of the latter 

are given in this section. 

Mapping in multi-crystalline Si solar cells 

In support of CaliSolar’s Incubator project, a 

technique for two-dimensional mapping of the p-n 

junction in textured Si cells was developed and 

applied. The technique is based on scanning 

Kelvin probe force microscopy (SKPFM) and was 

further supported by device simulation. 

To get reliable potential measurements using 

SKPFM, we developed a special cross-sectional 

technique for textured, multi-crysalline Si (mc-Si) 

solar cells. A bias voltage (Vb) was applied to 

induce potential changes that were measured. 

Therefore, the V-b induced electric fielded on the 

surface, as deduced from the measured potential 

changes, can represent the electric field changes 

in the bulk, and the location at the maximum 

values of the electric field corresponds to the p-n 

junctions. This junction identification was further 

supported by device simulation using PC1D which 

corroborated our experimental findings. The most 

significant aspect of junction identification by this 

technique is its two-dimensional capability. To our 

knowledge, junction identification using SKPFM is 

the only method that can determine that. 

Carrier depletion behavior and grain misorientation 

Grain boundaries (GBs) are believed to be the 

main cause for efficiency loss in polycrystalline Si 

thin-film devices. In collaboration with NREL’s Si 

group, the structural and the microelectrical 

properties of GBs in polycrystalline Si thin films 

were investigated by electron backscattering 

diffraction (EBSD) and scanning capacitance 

microscopy (SCM). The SCM measurements 

revealed highly non-uniform carrier depletion 

among the GBs, indicating the variety of electrical 

activities are due to the complicated GB 

structures. The carrier depletion on the GBs can 

be a measure of the charged deep levels or 

impurities, and thus an indicator of the carrier 

recombination behavior. 

Comparison of SCM and EBSD measurements led 

us to the following conclusions: (1) Σ3 GBs do not 

exhibit carrier depletion and thus do not have 

charged deep levels; (2) some Σ9 GBs exhibit 

carrier depletion and some do not, indicating that 

the intrinsic Σ9 GBs do not have charged deep 

levels and the carrier depletion is due to impurity 

gettering at the GBs; (3) no close relationship 

between the carrier depletion behavior and grain 

misorientation angles and directions was found on 

random GBs; and (4) carrier depletion behavior 

does not depend only on the grain misorientation, 

but also on the facet plan where the GB is taken. 

These studies are expected to significantly impact 

GB passivation and material optimization. 

New scanning probe microscope 

We installed scanning probe microscopy (SPM) 

capabilities for large-area samples and 

environmentally-controlled measurements. 

Electrical measurement techniques based on SPM 

have the advantage of providing information such 

as surface potential, electrical conductivity, and 

doping with spatial resolution second to none. 

However, the results of these measurements are 

strongly affected by the condition of the sample 

surface. The new SPM installed in the PDIL is 

connected to a glove box, and will operated in an 

inert ambient with less than 0.1 ppm of H2O and 

O2, allowing for analysis of clean surfaces. 

The SPM has been installed, tested, and in 

operation. The sample transfer station had several 

problems, and most of them have been fixed. 

Scanning electron microscopes 

In support of the PDIL, two new scanning 

electron microscopes (SEM) were purchased. 

One microscope is an environmental tungstenfilament SEM, which is connected to a sample 

41 Photovoltaic

Applied Research

Measurements and Characterization
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

transfer/flipping station, and will be able to 

receive samples from deposition, processing, 

and analytical equipment in vacuum. The other 

system is a field-emission gun SEM that is 

suitable for high-resolution analysis. 

Uniformity of ultrathin electron injection layers 

In support of Konarka’s SAI project, we have set 

up tunneling current measurements based on 

intermittent contact AFM to support the 

development of ultrathin (5-20 nm) Electron 

Injection Layers (EIL) in Konarka's PowerPlastic. 

Ultrathin EILs are critical in achieving high 

efficiency and, therefore, nanoscale 

inhomogeneities in the EIL represents a top 

priority in Konarka's PowerPlastic development. 

Because the roughness of the underlying 

transparent electrode is similar to that of the EIL, 

the thickness of the EIL is difficult to assess. Our 

tunneling current AFM, specifically developed to 

address the uniformity of Konarka's EILs, is based 

on measuring tunneling current pulses seen during 

the oscillation of a tuning fork (TF) sensor, driven 

by an external bias applied to the metallic 

ultrasharp tip attached to the TF. 

Expand the capabilities of WaferScan 

Our NREL-developed WaferScan enables 

luminescence spectrum imaging measurements 

(spectrum-per-pixel) over a lateral scanning range 

of 3'' × 3'' (to be extended up to 6'' × 6'' in the 

PDIL) in combination with high resolution 

cathodoluminescence. We have expanded the 

capabilities of WaferScan by adding 

measurements of the local reflectivity (R) and 

diffusion length (L), both based on luminescence. 

These measurements of the diffusion length can 

be performed at any processing stage and, 

therefore, do not require fully processed Si solar 

cells. Furthermore, the estimates of the diffusion 

length are free of the artifacts resulting from 

trapping or caused by local transients in 

capacitance common to other methods. In 

addition, we have added an input channel to 

perform electron-beam-induced current (EBIC) 

measurements, which can be performed 

simultaneously with spectrum imaging. 

Properties of nanocrystalline Si:H films and 

devices with nanometer-scale resolution: 

We found that the shape and density of the 

nanocrystalline Si (nc-Si:H) nc-Si:H materials can 

be controlled by the P concentration and H dilution 

ratio during the growth. The results provided 

critical information for United Solar to synthesize 

mixed a-Si:H and nc-Si:H with desired parameters. 

Bright field (BF) TEM images revealed the 

formation of con-shape nc-Si regions. The 

electrical properties of the nc-Si:H films were 

examined by scanning probe microscopy. The 

data we provided United Solar proved critical in 

optimizing their deposition process. . 

3. Major FY 2008 Publications 

•	 A.G. Norman. “A Critical Review of 

Intermediate Band Solar Cell Experimental 

Results.” invited paper presented at the 

Materials Research Society 2008 Spring 

Meeting, San Francisco, March 2008. 

•	 F. Liu; M.J. Romero; K.M. Jones; A.G. 

Norman; M.M. Al-Jassim; D. Inns; A.G. Aberle. 

“Intragrain Defects in Polycrystalline Silicon 

Thin-Film Solar Cells on Glass by AluminumInduced Crystallization and Subsequent 

Epitaxy." Thin Solid Films; 516 (2008) 6409. 

•	 C.-S. Jiang; A. Ptak; B. Yan; H.R. Moutinho; 

J.V. Li; M.M. Al-Jassim. “Microelectrical 

Characterizations of Junction in Solar Cell 

Devices by Scanning Kelvin Probe Force 

Microscopy.” Ultramicroscopy, in press. 

•	 C.-S. Jiang; H.R.Moutinho; R. Reedy; M.M. AlJassim; A. Blosse. “Two-Dimensional Junction 

Identification in Multicrystalline Si Solar cells.” 

J. Appl. Phys., in press. 

•	 C.-S. Jiang; B. Yan; Y. Yan; C.W. Teplin; R. 

Reedy; H.R. Moutinho; M.M. Al-Jassim; J. 

Yang; S. Guha. “P-Induced Nanocrystallite 

Dispersion in Hydrogenated Mixed-Phase 

Nanacrystalline Silicon Thin Films.“ J. Appl. 

Phys.; 103, 063515 (2008). 

•	 H.R. Moutinho; R.G. Dhere; M.J. Romero; C.­

S. Jiang; B. To; M.M. Al-Jassim. “Electron 

Backscatter Diffraction of CdTe Thin Films: 

Effects of CdCl2 Treatment.” J. Vac. Sci. 

Technol.; A26, 1068 (2008). 

•	 Y. Yan; C.-S. Jiang; R. Noufi; S.-H. Wei; H.R. 

Moutinho; M.M. Al-Jassim. “Electrically Benign 

Behavior of Grain Boundaries in 

Polycrystalline CuInSe2 films.” Phys. Rev. 

Lett.; 99, 235504 (2007). 

•	 Y. Yan; K.M. Jones; C.-S. Jiang; X.Z. Wu; R. 

Noufi; M.M. Al-Jassim. “Understanding the 

Defect Physics in Polycrystalline Photovoltaic 

Materials.” Physica B; 401-402, 25 (2007). 

•	 H.R. Moutinho; R.G. Dhere; M.J. Romero; C.­

S. Jiang; B. To; M.M. Al-Jassim. 

“Recrystallization of PVD CdTe Thin Films 

Induced by CdCl2 Treatment.” 33rd IEEE 

Photovoltaics Specialists Conference 

Proceedings; May 2008, San Diego. 

Photovoltaic

Applied Research

Measurements and Characterization

42
 

 

____________________________________________________________________________________ 

 

 

 

 

 

____________________________________________________________________________________ 

Electro-Optical Characterization 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Dean Levi (NREL), 303-384-6605, Dean_Levi@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-3765, marie.mapes@ee.doe.gov 

FY 2008 Budget: $2,468K (NREL) 

Objectives 

•	 Help Solar America Initiative (SAI) subcontractors succeed by supporting collaborative research 

and development (R&D) projects, technique development, and standard measurements. 

•	 Design, procure, and build seven new Process Development and Integration Laboratory (PDIL) 

tools: Semilab tool, spectroscopic ellipsometry tool, minority carrier lifetime tool, 

photoluminescence imaging tool, reflectometer, optical processing furnace, and wafer processing 

station. 

•	 Continue advancing measurement techniques for minority carrier lifetime, minority carrier 

diffusion length, thin film optical properties, and fundamental photovoltaic (PV) device properties. 

•	 Help NREL in-house PV technology projects succeed through collaborative R&D projects, 

technique development, and standard measurements. 

Accomplishments 

•	 Supported numerous SAI Technology Pathway Partnerships (TPPs) and incubator companies 

including: BP Solar, GE Energy, Nanosolar, United Solar, Konarka, AVA Solar, Blue Square 

Energy, CaliSolar, MicroLink, PrimeStar, and Solaria. 

•	 Developed and demonstrated functional prototypes for measurement of minority carrier lifetime 

(RCPCD and uw-PCD), carrier density imaging (CDI), and photoluminescence imaging (PLI) on 

6”x6” samples for incorporation into PDIL vacuum tools in fiscal (FY) 2009. 

•	 Developed capability for one-sun SPV measurement of minority carrier diffusion length in silicon 

wafers. Also developed ability to measure the injection-level dependence of the MCDL. 

•	 Significantly advanced the understanding and potential application of time-resolved 

photoluminescence (TRPL) for on-line materials quality diagnostics for CIGS and CdTe. This 

includes a break-through in measurement of 250 nanosecond carrier lifetimes in CIGS films and 

discovery of rapid degradation of CIGS films in air. 

•	 Published computational study of the effects of grain boundaries and lifetime fluctuations on solar 

cell performance, minority carrier lifetime measurements, and their correlations for multicrystalline silicon (Si) solar cells. 

•	 Developed an integrated capacitive characterization technique to simultaneously conduct steadystate capacitive measurements (CV, AS, DLCP) to obtain rapid extraction of physical parameters. 

Future Directions 

•	 Provide top priority support for SAI subcontractors through collaborative R&D projects, technique 

development, and standard measurements. 

•	 Bring six new PDIL tools to full operational capability: spectroscopic ellipsometry tool, minority 

carrier lifetime tool, photoluminescence imaging tool, reflectometer, optical processing furnace, 

and wafer processing station. 

•	 Continue ongoing advancement of measurement techniques for minority carrier lifetime, minority 

carrier diffusion length, thin film optical properties, and fundamental PV device properties. 

•	 Determine viability of TRPL as an online diagnostic for PV manufacturing. (contingent on capital 

equipment funding) 

•	 Develop robust computational models for double and triple junction PV devices. 

•	 Support NREL in-house PV technology projects through collaborative R&D projects, technique 

development, and standard measurements. 

43 Photovoltaic

Applied Research

Measurements and Characterization
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Introduction 

The Electro-Optical Characterization team 

consists of six scientists and three technicians with 

more than 100 years of combined experience in 

the development and application of advanced 

electro-optical measurement techniques. Our goal 

is to help partners in industry, universities, and inhouse NREL teams succeed in increasing 

efficiency, reducing cost, and enhancing reliability. 

2. Technical Approach 

A priority is development and application of 

methods for measurement of minority carrier 

lifetime (MCL) and diffusion length. Experimental 

techniques for characterizing MCL include TRPL, 

resonantly coupled photoconductivity decay 

(RCPCD), microwave photoconductive decay (uwPCD), infrared free-carrier absorption (FCA), 

photoluminescence imaging (PLI), and infrared 

carrier density imaging (CDI). We are developing 

advanced capabilities in surface photovoltage 

(SPV) for measurement of minority carrier 

diffusion length. We apply a number of 

spectroscopic techniques including 

photoluminescence spectroscopy, spectroscopic 

ellipsometry, near, mid, and far-infrared 

spectroscopy, and diffuse reflectance 

spectroscopy. A number of electrical device 

characterization methods are used to determine 

defect properties and fundamental junction 

parameters including deep level transient 

spectroscopy (DLTS), capacitance-voltage (C-V), 

admittance spectroscopy (AS), drive-level 

capacitance (DLCP), and in-plane impedance 

spectroscopy. 

3. FY 2008 Special Recognitions and Patents 

Invited talks 

•	 Wyatt Metzger, “Recombination Kinetics in 

Polycrystalline Cu(In,Ga)Se2 solar cells.” 

EMRS Spring Meeting, May 25-29, 2008, 

Strasbourg, France. 

•	 Steve Johnston, “Lifetime and diffusion length 

mapping and imaging techniques for silicon 

solar cells” 18th c-Si Workshop, Aug. 3-6, 

2008, Vail, Colorado. 

•	 Bhushan Sopori, “Wafer breakage in the 

silicon photovoltaic industry”, SPIE Optics + 

Photonics, Aug. 10-14, 2008, San Diego, CA. 

•	 Bhushan Sopori. “Recent Advances in Silicon 

Solar Cells: Device Design and Processing”, 

Conference on Emerging Trends in 

Photovoltaics, March 2008, IIT Kanpur, India. 

•	 Bhushan Sopori. “Engineered Interfaces for Si 

Solar Cell Applications”, TMS Annual Meeting 

& Exhibition, Mar. 9-13, 2008, New Orleans. 

Awards 

•	 Wyatt Metzger and Dean Levi. Overall Best 

Poster Runner-Up Award. “Device Physics of 

Nanoscale Interdigitated Solar Cells”. 33rd 

IEEE Photovoltaics Specialists Conference, 

May 11-16, 2008, San Diego, CA. 

Patents 

•	 Bhushan Sopori and Artak Hambarian, Optical 

Probe for Semiconductor Characterization, US 

Patent 7,420,669, Issued Sept. 2, 2008. 

•	 Bhushan Sopori, Optical Cavity Furnace for 

Semiconductor Wafer Processing, Provisional 

filed, March 10, 2008. 

Media Coverage 

•	 AIP issued a press release based on the CIGS 

time-resolved studies published in APL [1]. 

www.aip.org/isns/reports/2008/046.html 

4. Major FY 2008 Publications 

•	 W.K. Metzger; I.L. Repins; M.A. Contreras., 

“Long Recombination Lifetimes in HighEfficiency Cu(In,Ga)se2 Solar Cells.” Applied 

Physics Letters; 93, 022110(2008). 

•	 R.K.Ahrenkiel; S.W. Johnston. “Lifetime 

Analysis of Silicon Solar Cells by Microwave 

Reflection.” Solar Energy Materials and Solar 

Cells; 92, 2008, pp. 830-835. 

•	 W.K. Metzger. “The Potential and Device 

Physics of Interdigitated Thin-Film Solar Cells, 

Journal Applied Physics; 103, 094515 (2008). 

•	 R.K. Ahrenkiel; S.W. Johnston; W.K. Metzger; 

P. Dippo. “Relationship of Band Edge 

Luminescence to Recombination Lifetime in 

Silicon Wafers.” J. of Electronic Materials; 37, 

396-402 (2008). 

•	 W.K. Metzger. “How Lifetime Fluctuations, 

Grain-Boundary Recombination, and 

Junctions, Affect Lifetime Measurements and 

Their Correlation to Silicon Solar Cell 

Performance.” Solar Energy Materials and 

Solar Cells; 92, 1123(2008). 

•	 B. Sopori; P. Rupnowski; J. Appel; V. Mehta; 

C. Li; S. Johnston. “Wafer Preparation and 

Iodine-Ethanol Passivation Procedure for 

Reproducible Minority-Carrier Lifetime 

Measurement.” 33rd IEEE PVSC, San Diego, 

May 2008. 

•	 P. Rupnowski; B. Sopori. “Strength of Si 

Wafers with Microcracks: A Theoretical 

Model,” 33rd IEEE PVSC, San Diego, 2008. 

Photovoltaic

Applied Research

Measurements and Characterization

44
 

 

 

____________________________________________________________________________________ 

 

 

 

 

____________________________________________________________________________________ 

Surface Analysis 

Performing Organization:	 National Renewable Energy Laboratory (NREL) 

Key Technical Contacts:	 Sally Asher (NREL, Primary Contact), 303-384-6450, 

sally_asher@nrel.gov 

Peter Sheldon (NREL), 303-384-6533, peter_sheldon@nrel.gov 

DOE HQ Technology Manager:	 Jeffrey Mazer, 202-586-2455, jeffrey.mazer@ee.doe.gov 

FY 2008 Budget:	 $1,767K (NREL) 

Objectives 

•	 Provide routine and specialized measurements of surfaces and interfaces to support
 

advancement of photovoltaic (PV) program research and industry partners.
 

•	 Lead and contribute to collaborative research that addresses critical issues in understanding 

surfaces and interfaces in PV technologies. 

•	 Develop and implement novel measurement techniques that enhance the ability to understand 

surface chemistry and physics of materials to advance fundamental PV research and 

development (R&D). 

Accomplishments 

•	 Provided surface analysis measurement support to more than 50 different U.S. PV companies 

and researchers in all areas of the DOE Solar Energy Technologies Program (SETP). 

•	 Worked extensively with DCA Instruments to ensure the Process Development and Integration 

Laboratory (PDIL) Auger tool will meet specifications when completed. 

•	 Monitored X-ray photoelectron spectroscopy (XPS) and flipping station construction, both tools to 

be delivered in December 2008. 

•	 Used QCM flow cell to study CdS reaction kinetics, showed how these conditions can be used to 

tune and control film morphology, thickness, and chemical reagent utilization. 

•	 Completed conceptual design and specifications for plasma/sputter/etch tool. Obtained budgetary 

numbers from vendors to refine design. 

•	 Procured a new state-of-the-art dynamic secondary ion mass spectrometer (SIMS) instrument to 

replace 30-yr-old, first generation equipment. Delivery of new system by end of March 2009. 

•	 Completed conceptual design and specifications of plasma-enhanced chemical vapor deposition 

(PECVD) tool. 

•	 In collaboration with reliability researchers, improved barrier adhesion and performance leading to 

a successful patent application. 

Future Directions 

•	 Continue to provide high level of surface analysis research and support to Solar America Initiative 

(SAI) contractors and SETP researchers. Introduce new capabilities of XPS and SIMS 

instruments to researchers. 

•	 Install, demonstrate functionality, and integrate large-platen PDIL Auger system. 

•	 Install, demonstrate functionality, and integrate new small-spot XPS in PDIL. 

•	 Conduct tests to assess cleanliness of PDIL transfer pod and affect of pod ambient on sample 

surface chemistry. 

•	 Install, demonstrate functionality, and integrate new dynamic SIMS instrument. 

•	 Complete ordering process and PDIL physical plant modifications for PECVD and
 

sputter/plasma/etch tools.
 

45 Photovoltaic

Applied Research

Measurements and Characterization
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Introduction 

Surfaces and interfaces play critical roles in 

controlling the properties of materials and in the 

operation and reliability of devices. The Surface 

Analysis project advances the understanding of 

PV materials and devices by employing surface 

science practices and techniques to investigate 

surface and interfacial properties of materials. 

Project scientists are active in three main areas: 

(1) analytical support to SAI research participants, 

conversion technology researchers, and 

researchers in reliability, (2) collaborate and lead 

research on the chemistry and physics of surfaces 

and interfaces of PV materials, and (3) advance 

the utility and understanding of our measurements 

by improving analytical methodology and by 

developing new tools for in-situ study of surface 

and interface properties. The Surface Analysis 

team contributes to and leads SETP activities 

involving surface chemistry and physics. 

2. Technical Approach 

This project uses best practices to obtain 

information about surfaces and interfaces of PV 

materials and devices. The specifications for the 

major pieces of analytical equipment currently 

utilized in our work are detailed at 

www.nrel.gov/pv/measurements/surface_analysis. 

html. The group is awaiting three new pieces of 

equipment that will add significant new capabilities 

to our analytical suite: small-spot XPS/UPS, largeplaten Auger, and low-energy depth profiling 

dynamic SIMS. 

During FY 2008, the group had priority activities in 

several areas. An important focus was on activities 

related to supporting SAI partners and 

collaborations with PV conversion technology 

researchers. We also worked with manufacturers 

of our new tools to ensure they would arrive in as 

timely a fashion as possible, while still meeting the 

performance specifications deemed important for 

the project's success. Finally, we worked to 

improve the accuracy of our results through 

internal and external collaborations. 

3. FY 2008 Special Recognitions and Patents 

Pankow, J.W.; Glick, S.W. Submitted NREL ROI 

IR 08-19 “Moisture barrier package consisting of 

flexible polymer sheet, atomic layer deposition 

interfacial layer, and PECVD moisture barrier 

overcoat layer.” 

4. Major FY 2008 Publications 

C.L. Perkins; X. Li. “A Liquid-Phase Quartz Crystal 

Microbalance for Photovoltaics Research,” 33rd 

IEEE Photovoltaics Specialists Conference 

Proceedings; May 11-16, 2008, San Diego, 

California. 

I. Repins; M.A. Contreras; B. Egaas; C. DeHart; J. 

Scharf; C.L. Perkins; B. To; R. Noufi. “19.9%-

Efficient ZnO/CdS/CuInGaSe2 Solar Cell with 

81.2% Fill Factor,” Prog. Photovolt: Res. Appl. 16 

(2008) 235–239. 

J.M. Luther; M. Law; Q. Song; C.L. Perkins; M.C. 

Beard; A.J. Nozik. “The Structural, Optical, and 

Electrical Properties of Self-Assembled Films of 

PbSe Nanocrystals Treated with 1,2-

Ethanedithiol,” ACS Nano, 2 (2008) 271-280. 

G. Teeter; S.E. Asher. “Modeling Copper Migration 

in Cadmium-Telluride Solar Cells Under DeviceProcessing and Field-Deployed Conditions,” 

Proceedings of the 33rd IEEE PVSC Proceedings; 

May 11-16, 2008, San Diego, California. 

A.J. Ptak; R. France; C.S. Jiang; R.C. Reedy. 

“Effects of Bismuth on Wide-Depletion-Width 

GaInNAs Solar Cells,” J. Vac. Sci. Techn., Part B, 

Vol. 26, 3 (2008). 

J.R. Doyle; Y. Xu; R.C. Reedy; H.M. Branz; A.H. 

Mahan. “Film Stoichiometry and Gas Dissociation 

Kinetics in Hot-Wire Chemical Vapor Deposition of 

a-SiGe:H,” Thin Solid Films, Vol. 516, 5 (2008). 

M. Sheoran; D.S. Kim; A. Rohatgi; H.F.W. 

Dekkers; G. Beaucarne; M. Young; S. Asher. 

"Hydrogen Diffusion in Silicon from PlasmaEnhanced Chemical Vapor Deposited Silicon 

Nitride Film at High Temperature,” Appl. Phys. 

Lett. Vol. 92, (172107), 2008 

X. Li; J. Pankow; B. To; T. Gessert. “Comparison 

Between Research Grade and Commercially 

Available SnO2 for Thin-Film CdTe Solar Cells,” 

33rd IEEE Photovoltaic Specialists Conference, 

May 11-16, 2008, San Diego, California. 

Photovoltaic

Applied Research

Measurements and Characterization

46
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

Cell and Module Performance 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Keith Emery (NREL), 303-880-2913, keith_emery@nrel.gov 

DOE HQ Technology Manager: Marie Mapes, 202-586-3765, marie.mapes@hq.doe.gov 

FY 2008 Budget: $2,125K (NREL) 

Objectives 

•	 Support contact technical monitors, Solar America Initiative (SAI) partners and the photovoltaic 

(PV) industry by providing accurate traceable efficiency, peak watt, quantum efficiency (QE), and 

I-V measurements with respect to standard reporting conditions. 

•	 Maintain ISO 17025 accreditation for cell and module calibrations. 

•	 Maintain primary reference cell calibrations. 

•	 Transfer I-V and QE measurement technology to SAI partners and the PV community. 

•	 Maintain and advance the state-of-the-art in I-V and QE cell and module measurements. 

•	 Continue with International Electrotechnical Commission (IEC) and American Society for Testing 

and Materials (ASTM) standards development. 

Accomplishments 

•	 Provided measurement support in the areas of cell and module performance to more than 70 PV 

research partners in industry, academia, and NREL. 

•	 Performed 6,174 I-V and QE measurements on 1,898 cells and modules for 249 groups. There 

were 5,638 cell I-V, QE and linearity measurements on 1,564 samples, and 2,361 I-V 

measurements on 618 modules. The prototype concentrator module test bed took 84,448 I-V 

curves on 9 modules including the SAI partners Boeing, Solfocus, Spectrolab, and Enfocus. 

Multijunction prototype concentrator modules were also evaluated from Greenvolts, Daido Steel, 

and Fraunhofer ISE. 

•	 Maintained ISO 17025 accreditation for primary and secondary cell and module calibrations. 

Completed periodic audits, maintenance of quality systems, calibrations, software, and 

documentation to meet A2LA requirements. 

•	 Ordered multi-source concentrator cell solar simulator with a spectrally adjustable simulator in at 

least 10 bands to accommodate all of the conceivable high efficiency concentrator cell designs 

during the next 10 years. 

•	 Installed large-area module solar simulator system and brought unit to operational status 

compliant with teams ISO 17025 quality system. The new simulator is capable of measuring 

modules as large as 137 centimeters by 200 centimeters. 

•	 Completed construction and fit-up of NREL’s Outdoor Test Facility expansion. 

•	 Reduced measurement time and uncertainty of evaluating multi-junction devices at 1-sun, 

allowing spectral sensitivity of multi-junction cells to be addressed in terms of energy production 

as a function of spectral irradiance, total irradiance and temperature and not just their 

performance with respect to fixed reference conditions. 

Future Directions 

•	 Continue to support SAI partners at the highest possible priority and level. 

•	 Continue to support the U.S. terrestrial PV community by transferring performance measurement 

technology and providing cell and module performance measurements and calibrations. 

•	 Enhance capabilities to determine the energy part of the levelized cost of energy for PV
 

technologies from flat-plate to low-X to high concentration.
 

•	 Bring newly procured simulators to an operational status and use them to determine energy 

delivered with respect to a reference year and spectral sensitivity of multi-junction technologies 

•	 Maintain ISO 17025 accreditation for primary and secondary cell and module calibrations. 

47 Photovoltaic

Applied Research

Measurements and Characterization
____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Major FY 2008 Publications 

Emery, K. “Comment on "Roles of Donor and 

Acceptor Nanodomains in 6% Efficient Thermally 

Annealed Polymer Photovoltaics," Appl. Phys. 

Lett. 90, 163511 (2007)], Appl. Phys. Lett. 91, 

266101 (2007). 

Kurtz, S.; Moriarty, T.; Kiehl, J.; Emery, K.; et. al. 

“Status and Issues in High Efficiency III-V Solar 

Cells,” Proc. 17th International Photovoltaic 

Science and Engineering Conference, Japan, 

December 3-7, 2007. 

Green, M.A.; Emery, K.; King, M.A.; Hishikawa, Y.; 

Warta, W. “Solar Cell Efficiency Tables (version 

31),” Progress in PV, vol. 16, 61 (2008). 

McMahon, W.E.; Emery, K.E.; Ottoson, L.; et. al. 

“Fill Factor as a Probe of Current-Matching for 

GaInP2/ GaAs Tandem Cells in a Concentrator 

System During Outdoor Operation,“ Progress in 

PV, 16, 213 (2008). 

Barnett, A.; Emery, K.; et. al. ”Initial Test Bed For 

Very High Efficiency Solar Cells, Proc. 33 IEEE 

PVSC, San Diego, CA, 2008. 

Rüther, R.; Rummel, S.; Anderberg, A.; et. al. 

“Performance Test of Amorphous Silicon Modules 

in Different Climate – Year Four: Progress in 

Understanding Exposure History Stabilization 

Effects,” Proc. 33 IEEE PVSC, San Diego, CA, 

2008. 

Del Cueto, J.A.; Rummel, S.; Kroposki, B.; 

Osterwald, C.; Anderberg, A. ”Stability of 

CIS/CIGS Modules at the Outdoor Test Facility 

Over the Years,” Proc. 33 IEEE PVSC, San Diego, 

CA, 2008. 

Geisz, J.F.; Moriarty, T.E.; Kiehl, J.T.; et. al. 

“Inverted GaInP/(In)GaAs/InGaAs Triple-Junction 

Solar Cells with Low Stress Metamorphic Bottom 

Junctions,” Proc. 33 IEEE PVSC, San Diego, CA, 

2008. 

Gessert, T.A.; Moriarty, T.; et. al. "Effects of Cu 

Diffusion from ZnTe:Cu/Ti Contacts on Carrier 

Lifetime of CdS/CdTe Thin Film Solar Cells," Proc. 

33 IEEE PVSC, San Diego, CA , 2008. 

Emery, K. “Photovoltaic Test Performance,” 

Photonics Spectra, p. 76, June 2008. 

Emery, K.; Moriarty, T.A. “Accurate Measurement 

of Organic Solar Cell Efficiency,” Proc. SPIE 

Optics + Photonics, session 7052-12, San Diego, 

CA, 2008. 

Emery, K. “PV Reliability Determination from I-V 

Measurement and Analysis,“ Proc. SPIE Optics + 

Photonics, session 7048-1, San Diego, CA, 2008. 

Del Cueto, T.A.; Rummel, S.; Kroposki, B.; 

Anderberg, A. ”Long-Term Performance Data and 

Analysis of CIS/CIGS Modules Deployed 

Outdoors,” Proc. SPIE Optics + Photonics, session 

7048-1, San Diego, CA, 2008. 

Green, M.A.; Emery, K.; King, D.L.; Hishikawa, Y.; 

Warta, W. “Solar Cell Efficiency Tables (version 

32),” Progress in PV, 16, 435 (2008). 

Barnett, A.; Emery, K.; et al. “Very High Efficiency 

Solar Cell Modules,” Progress in PV, 16, 852 

(2008). 

Geisz, J.F.; Moriarty, T.E.; Kiehl, J.T.; et. al. 

"40.8% Efficient Inverted Triple-Junction Solar Cell 

with Two Independently Metamorphic Junctions," 

Appl. Phys. Lett., 93, 123505 (2008). 

2. University and Industry Partners 

The group partnered with more than 250 groups, 

including measurement technology transfer and 

PV cell and module calibration services. 

Photovoltaic

Applied Research

Measurements and Characterization

48
 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

PDIL Infrastructure, Engineering, and Integration 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

DOE Golden Field Office (DOE/GO) 

Key Technical Contacts:	 Brent Nelson (NREL, Primary Contact), 303-384-6407, 

brent_nelson@nrel.gov, 

Steve Robbins (NREL), 303-384-6400, steven_robbins@nrel.gov, 

Robert White (NREL), 303-384-7802, robert_white@nrel.gov 

DOE HQ Technology Manager:	 Marie Mapes, 202-586-3765, marie.mapes@hq.doe.gov 

FY 2008 Budget:	 $1,830K (NREL) 

Objectives 

•	 Develop, improve, and implement process integration standards. 

•	 Provide project management to secure capital equipment for the Process Development and 

Integration Laboratory (PDIL). 

•	 Provide infrastructure development of facilities and equipment installation. 

•	 Develop an integrated software infrastructure within the PDIL that enables secure data access for 

the National Center for Photovoltaics (NCPV) personnel and research partners. 

•	 Work with core research teams to develop research partnerships with external collaborators, 

including advertising the PDIL to the PV industry via a Web site and other means. 

•	 Provide engineering support to design custom- or high-risk tools that would otherwise be beyond 

the reach of our research groups. 

Accomplishments 

•	 Made PDIL equipment, including the silicon thin-film workstation, the photothermal deflection 

spectroscopy (PDS), n&k spectrometer, and SemiLab, fully operational and moved the 

transparent conducting oxide (TCO) sputtering tool. 

•	 Delivered and installing the scanning electron microscope (SEM), atomic force microscopy 

(AFM), wafer wet etching station, and the copper-indium-galium-diselinide (CIGS) chamber of the 

CIGS workstation. 

•	 Placed orders, with equipment being fabricated at the vendor location, for the atmospheric 

processing workstation, X-ray photoemission spectroscopy (XPS), centralized robotic transfer 

chamber for the integrated measurement and characterization (M&C) techniques, Auger electron 

spectrometer (AES), photoluminescence (PL), minority carrier lifetime, ellipsometer chamber, and 

the remainder of the CIGS workstation. 

•	 Completed equipment designs for the cadmium-telluride (CdTe) workstation, silicon wafer 

replacement platform, plasma-enhanced chemical vapor deposition process diagnostic chamber, 

integrated plasma etch/sputter deposition chamber, reflectance spectroscopy tool, optical thermal 

annealing station, and the chemical bath deposition (CBD) of cadmium-sulfide (CdS), 

•	 Designed and implemented database architecture and ordered file and database archive 

hardware and central server for PDIL.
 

•	 Designed networking hardware for the PDIL, which is being installed. 

•	 Constructed initial harvester systems to move data from tools into file archives. 

•	 Constructed initial data extraction system to translate tool data products into database files. 

•	 Implemented a project-management database tool for tracking finances, project-management 

phases, research proposals, staffing, and industrial contacts. 

Future Directions 

•	 Finish installations of the SEM, AFM, wafer wet-etching station, CIGS workstation, atmospheric 

processing workstation, XPS, centralized robotic transfer chamber for the integrated M&C 

49 Photovoltaic

Applied Research

PDIL Infrastructure, Engineering, and Integration
 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

techniques, AES, PL, minority carrier lifetime, reflectance spectroscopy tool, optical thermal 

annealing station, and ellipsometer chamber. 

•	 Complete equipment designs and substantively complete the acquisition of CdTe workstation, 

silicon wafer replacement workstation, plasma-enhanced chemical vapor deposition process 

diagnostic chamber, integrated plasma etch/sputter deposition chamber, and CBD of CdS. 

•	 Continue integrating research equipment into the PDIL data tools, developing and improving the 

user interface and working with scientific computing to develop data analysis tools. 

1. Technical Approach 

The first step in integrating various techniques 

within, and between, platforms was developing 

standards for the common interface and 

transport elements as described in the abstract. 

To integrate a diverse tool set requires a 

“universal” maximum substrate size and shape 

to be held in a platen. The platen size and shape 

drives the requirements for the entire design. 

The various core activities within the NCPV have 

set, by consensus, the maximum substrate size 

the platen can handle to be approximately 6” by 

6”. This size supports the silicon (Si) PV 

industry that has both a “6-inch square” protocol 

in multi-crystalline Si and a “6-inch round” 

protocol in single crystalline Si. It also more than 

adequately supports the other technological 

areas studied by the NCPV with a commercially 

viable area. 

Samples can be moved between workstations 

either via intra-tool or inter-tool sample transport. 

Intra-tool transport is the movement of samples 

between techniques on the same platform. The 

actual transfer mechanism will typically be 

robotic in a central chamber but it could be a 

linear track. The intra-tool transfer height is the 

Semiconductor Equipment and Materials 

International (SEMI) standard of 1.1 m above 

the floor. 

Inter-tool transport is the movement of samples 

between techniques where those techniques do 

not share direct connection. These techniques 

could be in a stand-alone tool or a part of a 

larger platform. The sample is moved from one 

platform into the pod, which is sealed and 

disconnected from that platform before being 

wheeled to another platform, where the process 

is reversed. The transfer ambient within the pod 

can be either an atmosphere of ultra-high-purity 

inert gas or high vacuum. The use of inter-tool 

transport in a high vacuum ambient on such a 

large sample is a unique capability. 

Another integration mode is to make some of 

our techniques modular, such that they can be 

moved between platforms. Since all chambers 

connecting to platforms will use a standard 10” 

metal sealed Conflat® vacuum flange, centered 

at 1.1 m above the floor, it allows for a modular 

deposition, processing, or characterization 

technique to be docked on any given platform, 

based on project needs, strategic priorities, and 

available space. Not all techniques can be 

modular as size, sensitivity, complexity, and 

safety issues must be taken into account. 

Because there are very few techniques that are 

commercially available which are integrated onto 

a platform—and none using our standard 

sample size or inter-tool integration scheme— 

participating core activities within the NCPV 

develop their own workstations. They are in 

consultation with their industrial and university 

collaborators with regard to the specific 

techniques built into each platform. NCPV 

management oversees these plans within the 

scope of the NCPV strategic vision and available 

resources. The process-integration project 

works tactically to implement these plans 

according to the integration standards. Within 

the hardware agreement the group assists in 

equipment acquisition (prototyping, designing, 

specifying, etc.), leads in equipment installations 

(vacuum, gases, electrical, cooling, etc.), and 

provides PDIL infrastructure preparedness 

(common tools, support equipment, etc.). Within 

the software agreement, the group has 

established a PDIL network (fully cyber secure, 

databases, etc.) that integrates workstations into 

that network (IP protection), and develops user 

interfaces and data analysis tools. Within the 

project management agreement, the group 

assists projects with budgeting and scope 

management, develops communication tools, 

such as the Web site, and provides first-contact 

support for the PV community to propose 

collaborative work within the PDIL. 

Photovoltaic

Applied Research

PDIL Infrastructure, Engineering, and Integration

50
 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

Technology Pathway Partnership (TPP) 

Performing Organizations:	 Amonix; Boeing Company; BP Solar; Dow Chemical Company; GE 

Global Research; GreenRay; Konarka Technologies; Nanosolar; Soliant 

Energy; SunPower; United Solar Ovonic; National Renewable Energy 

Laboratory (NREL); Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Carolyn Elam, DOE Golden Field Office (DOE/GO), 303-275-4953, 

carolyn.elam@go.doe.gov 

Jim Payne, DOE/GO, 303-275-4756, jim.payne@go.doe.gov 

Brad Ring, DOE/GO, 303-275-4930, bradley.ring@go.doe.gov 

Holly Thomas, DOE/GO, 303-275-4818, holly.thomas@go.doe.gov 

DOE HQ Technology Manager:	 Scott Stephens, 202-586-0565, Scott.Stephens@ee.doe.gov 

FY 2008 Budgets:	 $35,500K (TPP Recipients), $665K (NREL), $225K (SNL) 

Objectives 

•	 Bring better products to market and enable new applications. Develop modular, turnkey 

photovoltaic (PV) systems that provide residential and commercial customers with a complete 

solution and attractive value proposition such as enabling building-integrated PV (BIPV) and zeroenergy homes. Develop designs and supply chains for large-field PV installations to service 

commercial and utility renewable portfolio standard (RPS)-generating requirements. Help U.S. 

companies to leapfrog global competition by providing best designed, lowest-cost solar solutions. 

•	 Foster development of domestic PV industry. Catalyze collaboration across value chain to: 

(1) squeeze out costs; (2) better optimize PV-system design; and (3) assure superior 

performance and reliability. Demonstrate novel manufacturing processes that provide U.S. 

industry with cost advantage and that facilitate manufacturing scale-up. 

•	 Increase impact of PV on U.S. energy economy and accelerate development of U.S.-produced 

PV systems, so solar electricity reaches parity with cost of electricity in grid-tied markets across 

the nation by 2015. Enable expansion of annual U.S. production capacity of PV systems from 240 

megawatts (MW) in 2005 to as much as 2,850 MW by 2010, representing 10-fold increase. Foster 

research that will lower cost of PV-generated electricity to $0.05 to $0.10 per kilowatt hour (kWh) 

by 2015 in residential, commercial, and utility markets. 

Accomplishments 

•	 Initiated 11 TPP awards. 

•	 Established roles and responsibilities, including technical monitor support by NREL and SNL. 

•	 Completed key stage-gate reviews for five projects. Completion of remaining reviews anticipated 

for early fiscal year (FY) 2009. 

Future Directions 

•	 Develop PV systems that will enable solar electricity to reach grid parity by 2015. 

•	 Expand U.S.-installed domestic capacity of PV systems to 5 to 10 gigawatts (GW). 

1. Introduction TPPs will accelerate commercialization of solar PV 

systems by 2015. The goal is to have PV 

The Technology Pathway Partnerships (TPPs) are electricity generation that is competitive with 

an integral part of the DOE Solar America Initiative conventional electricity sources in all domestic 

(SAI) and a significant enhancement of DOE’s grid-tied markets. 

business strategy of partnering with the industry to 

accelerate commercialization of PV R&D to meet 

ambitious cost and installed-capacity goals. 

51 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The specific goals of the 9-year TPP mission are: 

•	 Accelerate development of U.S.-produced PV 

systems substantively, so PV-produced electricity reaches parity with cost of electricity in 

select grid-tied target markets. 

•	 Expand U.S.-installed domestic capacity of PV 

systems to 5 to 10 gigawatts (GW). 

(e.g., natural gas, Clean Coal Technology 

plants) for wholesale. Utility systems typically 

are ground-mounted and range in size from 1 

MW to 10 MW, although much larger systems 

are in development. Designs include both 

fixed and tracking configurations. 

The following approaches are designed to address 

The cost basis of electric energy in these markets 

is the kilowatt hour (kwh), therefore the SAI TPP 

program uses targets for PV systems based on 

the levelized cost of energy (LCOE) delivered by 

these systems. This key metric is defined as the 

measure of total lifetime costs of a PV system 

divided by expected lifetime energy output, with 

appropriate adjustments for such factors as time 

value of money. The overall cost goals for the SAI 

TPP projects are shown in Table 1. 

Table 1. Cost Targets for Grid-Connected PV 

Systems in Key Market Sectors 

1 Costs are based on constant 2005 dollars. 

2 Current costs are based on electric-generation with conventional sources. 

3 Cost to customer (customer side of meter).
 4 Cost of generation (utility side of meter).
 

2. Program/Technical Approach 

The TPP efforts are focused on developing new 

and better PV solutions for the grid-tied electric 

power markets including: 

•	 Residential rooftop market. Systems are 

typically mounted on rooftops and range from 

less than 1 kW to 10 kW, most commonly 3 to 

4 kW. These systems are connected to the 

grid on the retail (customer) side of the utility 

meter and can be retrofitted for existing homes 

or integrated into new construction through 

BIPV designs. 

•	 Commercial rooftop market. Systems are 

typically mounted on the large flat roofs of 

commercial, institutional, and industrial buildings, and range in size from less than 10 kW 

to 500 kW and connected on the retail side of 

the utility meter. Retrofits and BIPV are 

possible applications in this market as well. 

•	 Utility market. These are large-scale (multimegawatt) systems displacing conventional 

utility-generated intermediate load electricity 

Market 

Sector 

Current 

U.S. 

Market 

Range 

(c/kWh)1,2 

Solar Electricity Cost—Current 

and Projected (c/kWh)1 

Benchmark Target 

2005 2010 2015 

Residential3 5.8–16.7 23–32 13–18 8–10 

Commercial3 5.4–15.0 16–22 9–12 6–8 

Utility4 4.0–7.6 13–22 10–15 5-7 

goals for these markets. 

•	 Industry-led: All technical details regarding 

approach, timelines, milestones, and system 

integration are formulated by applicants. The 

national laboratories provide critical support to 

DOE in monitoring technical progress, 

conducting tests and evaluations and directly 

supporting TPPs on specific R&D tasks. 

•	 Near- and mid-term results: Emphasis is on 

technologies with the greatest potential for 

cost competitiveness leading up to 2015. 

•	 System focus: The primary metric for SAI is 

LCOE, based upon the complete PV system 

rather than any component. SAI is working 

toward novel, integrated PV systems. 

•	 Partnerships: Industry participants are strongly 

encouraged to formulate partnerships to 

address the spectrum of possible technical 

improvements in the PV-system value chain. 

•	 Market-based. Market-oriented goals for cost, 

penetration, and job creation. All technical 

objectives established through SAI directly 

impact these market-based goals. 

Each SAI TPP project planned in three 3-year 

phases to progressively reduce the cost of 

commercially available PV systems and 

components to yield commercial products and 

production processes to achieve the LCOE goals 

and support installed capacity targets by 2015. 

•	 Phase 1. Demonstrate pilot production of 

lower-cost systems. R&D project duration of 3 

years (2007–2010) allows companies the 

flexibility to align projects with their targeted 

business model, technical capabilities, and 

product/process maturity. 

•	 Phase 2. Demonstrate replication of low-cost 

pilot production. Project duration of 3 years 

(2010–2012), with new entrants eligible. 

•	 Phase 3. Develop supply chain and distribution infrastructure. Reduce capital expenditure 

of manufacturing scale-up through targeted 

investments in areas such as equipment and 

feedstock suppliers and distribution channels. 

The awards must demonstrate the benefits of their 

project based upon LCOE and installed capacity 

Photovoltaic

Systems and Component Development

52
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

measures. Each award also falls into a class of 

either systems or subsystems defined as follows: 

•	 Systems-class projects (integrated systems): 

focus on multiple technology improvements in 

PV component and system design, integration, 

and installation. 

•	 Subsystems-class projects (componentbased): focus on component-level technology 

developments for system improvements. 

DOE funding available for systems-class awards is 

limited to $20 million, and subsystems-class 

awards are limited to $8 million per 3-year period 

and require a 50% cost share of the total project. 

The awards began in FY 2007. They are funded 

through (approximately) annual budget periods, 

which conclude with a stage-gate review 

scheduled around major technical milestone(s) or 

decision point(s). At the completion of each stagegate review, a determination is made about the 

continuation of the project into the next year. 

2.1. Stage-Gate Reviews: 

A stage-gate management approach facilitates 

rigorous project management and supports 

continuous assessment of the awards. 

Deliverables must demonstrate the ability of each 

recipient to meet the LCOE cost targets for their 

technology. LCOE values are dependent on 

system performance and manufacturing costs, 

therefore these quantities are evaluated independently (performance evaluated by NREL/SNL, and 

cost evaluated by an independent contractor to 

DOE) to assure that they are sufficient to 

demonstrate the stage-gate criteria have been 

met. DOE conducts a programmatic review and 

decision to continue to the next phase as 

proposed, continue to the next phase with 

modifications, or to discontinue the project. 

2.2. TPP Project Management Approach 

Project monitoring and technical oversight are 

conducted by a team from the DOE Golden Field 

Office, which manages and administers the 

cooperative agreements; DOE headquarters; and 

technical monitoring support from NREL and SNL. 

This management approach utilizes a technical 

monitor that is cognizant of the technology being 

developed. Technical monitors are from one of the 

DOE national laboratories (NREL or SNL). 

Figure 1. Steps of the Stage-Gate Process 

Assignments are made based on the alignment 

between the skills and experiences of lab 

personnel and the R&D activities of the project. 

The technical monitors are an integral part of the 

project management team and assist DOE in 

overseeing and assessing the TPP’s progress. 

In this capacity, they provide substantial technical 

assistance and guidance, facilitate interactions 

with additional technical experts, as needed, and 

assure timely access to DOE-funded laboratory 

resources when required for the project (e.g., test 

facilities). The technical monitors also provide 

evaluations during the stage-gate reviews and 

evaluations of technical progress against 

milestones, consult on the go/no-go decision 

points and critical success factors, and provide 

recommendations from the stage-gate reviews. 

3. Results and Accomplishments 

3.1. DOE Program Review 

DOE program review showcased the activities of 

the SAI TPP recipients in May 2008. 

3.2. Project Kickoff Meetings 

Following completion of the awards, kickoff 

meetings were held at each recipient’s facility to 

review their technology baseline and plans. 

3.3 Stage-Gate Reviews 

Results from the five stage-gate reviews follow: 

•	 Greenray Inc. (6/18/2008): 

Pass to Phase 2; continue to fund project at 

an increased funding level with required 

continuation conditions. 

•	 Amonix Inc. (6/24/2008): 

Pass to Phase 2; continue to fund project at a 

reduced funding level with continuation 

recommendations. 

53 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

•	 Boeing Co. (6/26/2008): 

Pass to Phase 2; continue to fund project at a 

reduced funding level with continuation 

recommendations. 

•	 United Solar Ovonics LLC (8/27/2008): 

Results Pending. 

•	 Konarka Technologies (9/4/2008): 

Results Pending. 

3.4 TPP Awardee Progress. 

Progress for each TPP awardee follows. 

4. Planned FY 2009 Activities 

Stage gates anticipated are shown in Table 2 

(below). 

5. Major FY 2008 Publications 

Solar Program Peer Review Agenda Overview 

(April 2008). www.energy.gov/public. 

Table 2. TPP Award Recipients, FY2008 Funding, Stage-Gate Schedule 

SAI TPP Recipient 

FY 2008 

Obligation Start Date 

First Stage-Gate 

Date 

Amonix Inc. $3,295,288 14 May 2007 6/24/2008 

The Boeing Co. $8,025,670 1 July 2007 6/26/2008 

BP Solar Inc. $4,089,000 1 Sept. 2007 1/27/2009 

Dow Chemical Co. $1,241,296 1 Aug. 2007 11/06/2008 

GE Global Research .Inc. $4,972,000 1 Sept. 2007 11/19/2008 

Greenray Inc. $735,000 1 Jan. 2007 6/18/2008 

Konarka Technology Inc. $768,000 1 July 2007 9/4/2008 

Nanosolar Inc. $3,580,000 1 Sept. 2007 11/29/2008 

Soliant Energy Inc. $2,098,991 1 Sept. 2007 2/10/2009 

SunPower Corp. $4,173,000 1 Sept. 2007 11/30/2008 

United Solar Ovonics LLC $5,808,247 30 Apr. 2007 8/27/2008 

Photovoltaic

Systems and Component Development

54
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TPP Awardee: Amonix, Inc. “Low Cost High Concentration Photovoltaic Systems for Utility Power Generation” 

Total Award Amount: $33,635K, DOE/Recipient Share $15,605K/$18,029K 

Objectives 

•	 Develop high-volume (25 MW/year), low-cost manufacturing facility in 3 years. 

•	 Redesign components of high concentration PV system for high-volume, low-cost manufacture 

and installation. 

•	 Conduct reliability testing of redesigned system components 

•	 Incorporate multijunction solar cells into redesigned system. 

Accomplishments 

•	 Redesigned and tested key system components including the MegaModule. 

•	 Opened pilot manufacturing facility in Seal Beach, California. 

•	 Manufactured five redesigned MegaModules. 

Future Directions 

•	 Complete IEC 62108 qualification and type approval of Amonix product. 

•	 Demonstrate 25 MW per year manufacturing facility. 

•	 Confirm Amonix system and project costs meet DOE LCOE targets for 2010 and 2015. 

1. Introduction 

The principal objective is to step up to high-volume 

production for Amonix’s high concentration PV 

(CPV) systems. The project implements DOE’s 

strategy of partnering with companies to 

accelerate commercialization and meet aggressive 

cost goals. The Amonix CPV system incorporates 

the world’s highest efficiency solar cells. 

2. Technical Approach 

Amonix plans to expand its manufacturing 

capacity to 25 MW/year by equipping a foundry 

dedicated to the production of redesigned multijunction cells and building a production line for 

automated manufacturing of all components of the 

MegaModule, including the cell packages, the 

receiver plate, and the module structure. 

Components of the MegaModule are being 

redesigned for low-cost and high-volume 

manufacturing, and the MegaModule depth was 

reduced to lower material costs. Fast-cure 

adhesives for lens attachment have been tested to 

reduce manufacturing time. High-volume vendors 

for the pedestal, drive, and torque tube will be 

sought. The drive, controls, and installation 

processes will be improved for high-volume 

installation and lower cost. Multi-junction cells are 

being developed and cell packages will be 

adapted to accommodate these cells. Amonix will 

fabricate and test 25 kW Si, 35 kW Si, and 50 kW 

mJ concentrators. 

3. Results and Accomplishments 

•	 Plant and equipment plan for 7-MW/year 

production facility. (4/08) 

•	 Qualification tests at Arizona State University 

of key MegaModule components. (4/08) 

•	 Redesigned 16” MegaModule maintains or 

improves performance compared with 

baseline 21” MegaModule. (4/08) 

•	 Conduct manufacturing cost study for DOE 

analysis and verification. (submitted 6/08) 

•	 Demonstrate progress toward DOE’s LCOE 

goals for 2010 using Solar Advisor Model. 

(submitted 6/08) 

The first deliverable was a detailed design plan for 

the Amonix manufacturing plant and its 

equipment. The manufacturing plant is located in 

Seal Beach, and Amonix took occupancy in 2008 

after obtaining National Environmental Protection 

Act approval through DOE. Unlike manufacturing 

of other PV technologies (crystalline silicon, thin 

films, and organic cells) there will be minimal 

wastes and emissions. 

The second deliverable was the qualification of a 

new process for MegaModule component 

assembly. The qualification, test 10.8 for humidity 

freeze, is part of the International Electrotechnical 

Commission (IEC) 62108 standard for 

“concentrator photovoltaic (CPV) modules and 

assemblies. IEC 62108, published in December 

2007, is the first international CPV standard. 

55 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The third deliverable required support from SNL to 

conduct a performance comparison between the 

16” MegaModule scheduled for production and the 

baseline 21” MegaModule constituting Amonix’s 

previous fifth generation design. The dimension 

refers to the thickness (also focal length) of the 

MegaModule shown in Figure 2; a 16” 

MegaModule requires 35% less steel (with 

corresponding less cost) than the 21” does. 

Testing was completed in 4/2008 and confirmed 

the new 16” MegaModule design performed better 

than the 21” MegaModule. 

Fig. 2 Three 16” MegaModules and two 21” 

MegaModules ready for comparison testing at 

University of Nevada Las Vegas with small 

multijunction module attached to center right 

portion of last MegaModule for reliability testing. 

Amonix submitted the fourth deliverable, a 

manufacturing cost study, and fifth deliverable, 

calculation of the levelized cost of electricity 

(LCOE) using DOE’s Solar Advisor Model (SAM), 

as part of the stage-gate review convened by DOE 

in June 2008. Manufacturing cost and LCOE 

analyses conducted by Amonix confirm that 

Amonix is on track to meet the DOE LCOE cost 

targets in 2010 and 2015. 

In addition to the above activities, Amonix has 

been central to two important collaborative CPV 

activities. Amonix has been active in the 

development of CPV standards since 1997, first 

within the IEEE working group that had a U.S. 

focus and later with the IEC Working Group 7 

(WG7--CPV) of Technical Committee 82 (PV) 

whose work encompasses international CPV 

standards. The organization of ICSC5 is the 

second important collaborative activity led by 

Amonix in 2008. Amonix co-sponsored the first 

ICSC1 in 2002, followed by three more 

conferences since then. ICSC5 is scheduled for 

November 2008 in Palm Desert, California, 

followed by a WG7 meeting. ICSC5 is cosponsored by numerous CPV companies and is 

acknowledged as the only conference organized 

by the CPV industry for the CPV industry. 

Amonix is transitioning to manufacturing a mature, 

high-concentration technology with the 16” 

MegaModule, the 6th generation CPV system, and 

increasing Amonix’ manufacturing capacity. 

Amonix installed 10 MW of Amonix MegaModule 

systems in 2007. This is the first time that 10 MW 

of any high concentration PV technology have 

been manufactured, installed, and operated. 

4. Planned FY 2009 Activities 

•	 Demonstrate progress toward DOE’s LCOE 

goals for 2010. 

•	 Commence operation of 7 MW/year 

production facility in Seal Beach. 

•	 Qualify 16”-MegaModule system to IEC 

62108. 

•	 Demonstrate successful operation and qualify 

7-MegaModules drive. 

•	 Complete installation of two 5-MegaModule 

and 7-MegaModule systems. 

•	 Procure MJ cells with 35% average efficiency, 

optimized for the concentration and spectrum 

required by the Amonix system. 

5. FY 2008 Special Recognitions and Patents 

Amonix was inducted into the Environmental Hall 

of Fame on June 8, 2008 (See Figure 5). 

6. Major FY 2008 Publications 

V. Garboushian; K. Stone; R. Gordon; A. Slade. 

"Performance of the Amonix High Concentration 

PV System in Southern Nevada." Power-Gen 

Conference 2008 Proceedings; Las Vegas, 

Nevada, (February, 2008). 

R. McConnell. “CPV Reliability—Reliability in an 

Expanding Technology,” Accelerated Aging 

Testing in PV Workshop Proceedings; April 2008, 

Lakewood, Colorado. 

V. Garboushian; R. McConnell; K. Stone; R. 

Gordon; G. Kinsey; C. Crawford. “Reliable 

Deployment of High Concentration PV Systems.” 

SPIE Optic and Photonics Conference 

Proceedings; August 2008, San Diego, California. 

Photovoltaic

Systems and Component Development

56
 

 

 

7. University and Industry Partners 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 ($K) 

University of Nevada, 

Las Vegas 

Robert Boehm 

Las Vegas, NV Installation and testing of Amonix MegaModules 245* 

Arizona State University Tempe, AZ IEC 62108 Qualification Testing 35* 

Spectrolab Inc. Sylmar, CA High Efficiency Multijunction Solar Cells 50* 

NREL Golden, CO Cooperative R&D Agreement 75* 

Cyro Industries NH Plastic Lamination R&D TBD** 

*Funded with prior year (FY 2007) funds. ** Award pending 

57 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

TPP Awardee: The Boeing Co.

“Concentrator Photovoltaic Power System” 

Total Award Amount: $45,315K, DOE/Recipient Share: $19,981K/$25,334K 

Objectives 

•	 Develop new concentrating photovoltaic (CPV) system, incorporating high-efficiency multijunction cells, for utility-scale PV power market. 

•	 Employ novel non-imaging optical design to optimally utilize the cells while addressing reliability 

and cost of the tracker and balance of systems equipment. 

•	 Increase efficiency of production multijunction solar cells for high-concentration terrestrial
 

applications from 36% to 40% by 2010.
 

•	 Reduce cost of cells by over 50% and increase cell production capacity to 1 GW/year by 2015. 

•	 Achieve a $0.15/kWh LCOE by 2010 and $0.07/$kWh by 2015. 

Accomplishments 

•	 Produced 37.8% average production efficiency cells. 

•	 Demonstrated 5-MW/yr automated cell manufacturing throughput rate. 

•	 Constructed prototypes of three CPV module designs, including one complete array. 

•	 Demonstrated over 27% module active-area efficiency. 

•	 Established path to meeting $0.15/kWh LCOE target. 

•	 Completed preliminary factory design. 

•	 Completed qualification of PV Powered 100-kW inverter with an industry-best, 10-year warranty. 

Future Directions 

•	 Investigate manufacturability of 4-junction cells. 

•	 Investigate costs and benefits of moving to very high concentration ratio optics. 

•	 Investigate protective coatings for first surface mirror and antireflective coatings for cover glass 

and secondary lens. 

1. Introduction 

Boeing has long been a leader is solar cell 

technology through its wholly-owned subsidiary, 

Spectrolab. This concentrator PV project is 

intended to leverage that technical leadership and 

to expand Spectrolab’s market in terrestrial solar 

power. Spectrolab’s leadership is in multi-junction 

(III-IV) gallium arsenide solar cells. This project 

has a dual focus: (1) increase the efficiency of 

Spectrolab’s cells while reducing cost and (2) 

develop the concentrator system that uses those 

cells to produce power. 

2. Technical Approach 

Spectrolab addressed manufacturing cost by 

demonstrated automated manufacturing 

equipment and addressed cell value by continuing 

to improve cell efficiency. Spectrolab issued a 

subcontract to Caltech for multijunction cell 

research (see Section 7). 

axis) and built various prototypes to advance the 

CPV product design. This team also pursued 

system engineering approaches to drive down 

LCOE in a verifiable manner. Team member PV 

Powered improved the reliability of its next 

generation inverter and validated its operation 

through UL certification. 

3. Results and Accomplishments 

•	 Produced 37.8% average production efficiency 

cells during engineering confidence run for the 

production C2MJ cell design and completed 

that generation’s final design review. 

•	 Implemented automated tooling at Spectrolab 

for cell manufacturing and demonstrated 

annualized production rate of 5 MW/year. 

•	 Completed construction and evaluation of 

CPV modules of three different designs and 

one complete array. 

•	 Investigated various performance and 

environmental issues and incorporated 

lessons-learned into subsequent designs. 

The Boeing Phantom Works team completed its 

selection of a preferred optical configuration (offPhotovoltaic

Systems and Component Development

58
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Demonstrated module acceptance angle of 

greater than 1.7° and active area efficiency of 

more than 27% with prototype C configuration. 

Two-axis array trackers were purchased and 

evaluated. A new tracker control algorithm was 

implemented and demonstrated. 

Team member PV Powered obtained certification 

of their new 100-kW inverter. Reliability 

improvements have allowed PV Powered to offer 

the first 10-year standard warranty in the industry. 

•	 Completed preliminary power plant system 

design. Brought on engineering, procurement, 

and construction company to assist with 

system optimization. 

•	 Created detailed LCOE model and established 

path to meet the $0.15/kWh LCOE target. 

•	 Participated in IEC WG7 standards 

committees, particularly CPV tracker and 

system energy rating committees. 

4. Planned FY 2009 Activities 

•	 Demonstrate production mean cell efficiency 

of at least 38.5%. 

•	 Perform module environmental test using 

C2MJ cells and using criteria consistent with 

IEC 62108. 

•	 Demonstrate CPV array with power output 

>250 W/m2 peak, produced with preproduction tooling. 

•	 Demonstrate pilot production of 

inverter/tracker. 

•	 Deploy system to evaluate system 

performance and LCOE model cost inputs. 

5. FY 2008 Special Recognitions and Patents 

•	 U.S. Patent No. 61/091,284, Flexible Thermal 

Cycle Test Equipment for Concentrator Solar 

Cells (provisional). 

•	 U.S. Patent No. 12/258,321, Flexible Thermal 

Cycle Test Equipment for Concentrator Solar 

Cells. 

6. Major FY 2008 Publications 

M.J. Archer; D.C. Law; S. Mesropian; A. Boca; M. 

Haddad, R.R. King; H.A. Atwater. “GaInP/GaAs 

Dual Junction Solar Cells on Ge/Si Epitaxial 

Templates”; 33rd Photovoltaic Systems 

Conference Proceedings; May 11-16, 2008, San 

Diego, California. 

D.C. Law; R.R. King; H. Yoon; M.J. Archerb; A. 

Boca; C.M. Fetzer; S. Mesropian; T. Isshiki; M. 

Haddad; K.M. Edmondson; D. Bhusari; J. Yen; 

R.A. Sherif; H.A. Atwater; N.H. Karam. “Future 

technology pathways of terrestrial III–V 

multijunction solar cells for concentrator 

photovoltaic systems”, Sol. Energy Mater. Sol. 

Cells (2008), 

R.R. King; P. Pien; R. Jones; A. Boca; K.M. 

Edmondson; D.C. Law; C.M. Fetzer; W. Hong; D. 

Bhusari; P. Hebert; M. Lau; R. Brandt; J. Ermer; 

N.H. Karam. “High-Efficiency Terrestrial 

Concentrator Multijunction Solar Cells – Research 

to Manufacturing at Spectrolab”, 5th International 

Conference on Solar Concentrators for the 

Generation of Electricity Proceedings; November 

16-19, 2008, Palm Desert, California. 

A. Plesniak; R. Jones; J. Schwartz; G. Martins; J. 

Hall, D. Whelan; P. Benítez; J.C. Miñano; A. 

Cvetkovíc. "Successful Rapid Development of a 

High Performance Concentrating Photovoltaic 

System for Utility Scale Power Generation." Poster 

presented at 5th International Conference on Solar 

Concentrators for the Generation of Electricity, 

Palm Desert, California, November 2008. 

A. Boca; K. Edmondson; R. King. “Concentrator 

Solar Cell Performance Enhancement by Way of 

Prismatic Covers.” Poster presented at 5th 

International Conference on Solar Concentrators 

for the Generation of Electricity, Palm Desert, 

California, November 2008. 

7. University and Industry Partners 

Organization/ 

Principal Investigator Location Description/Title of Research Activity 

FY 2008 

($K) 

Cost Share 

($K) 

Light Prescription 

Innovators 

Los Angeles, CA/Madrid, 

Spain Optics design support 1,756 362 

PV Powered Bend, OR Qualify 250-kW inverter 3,921 3,371 

Comau Detroit, MI Contract manufacturer 185 0 

59 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TPP Awardee: BP Solar International, Inc. “Reaching Grid Parity Using BP Solar Crystalline Silicon Technology” 

Total Award Amount: $39,693K, DOE/Recipient Share: $19,431K/$20,262K 

Objectives 

•	 Reduce module cost to 67% of 2006 costs by 2010 and to 50% of 2006 costs by 2015. 

•	 Develop process for fabrication of solar grade silicon (Si). 

•	 Optimize and implement Mono2TM casting technology to improve material quality. 

•	 Reduce wafer thickness from 220 μm in 2006 to 160 μm in 2010 and 100 μm in 2015. 

Accomplishments 

•	 Completed initial commercial demonstration of Mono2TM . 

•	 Commercial introduction of modules with U.S. produced AR-coated glass. 

•	 Development of rapid method for determining cure level in EVA modules. 

•	 Demonstrated wafering of 160 μm thick wafers using 120 μm diameter wire. 

•	 Developed accelerated test sequence to assess potential damage and power loss due to cell 

breakage. 

•	 Identified improvements necessary to reduce module manufacturing costs by 25% and verified 

technologies in the laboratory. 

Future Directions 

•	 Demonstrate 16% cell efficiency using Si cast with at least 50% solar grade material. 

•	 Implement Mono2TM in production. 

•	 Complete development of roof-integrated PV module and submit for certification. 

•	 Complete PV charge controller design, test through HALTS, and certify to UL 1741. 

•	 Verify residential and commercial systems under development will meet LCOE 2010 target goals. 

1. Introduction 

BP Solar’s TPP program is based on accelerated 

development of multicrystalline Si technology for 

use in the residential and commercial markets, 

using products specifically designed for these 

applications. The goals of this program are to 

achieve grid parity and increase production 

volume. To meet these goals, our objectives are to 

substantially reduce 1) module cost to 67% of 

today’s cost by 2010 and to 50% of today’s costs 

by 2015; and 2) system costs to 60% of today’s 

cost by 2010 and to 36% of today’s costs by 2015. 

These are projected to result in levelized cost of 

electricity of 8 to 10¢/kWh for residential systems 

and 6 to 8¢/kWh for commercial systems by 2015. 

2. Technical Approach 

The BP Solar program addresses all aspects of 

the PV product chain from raw materials including 

Si through installation of the systems at the 

customer site. To achieve parity with the grid and 

growth to gigawatt levels of production requires 

involvement of the entire product chain. Partners 

in this effort include: 

•	 Materials vendors (Dow Corning for Si, 

encapsulants and pottants, Ceradyne for 

crucibles, STR for EVA and AGC Flat Glass 

North America for glass) to lower cost, 

improve quality and performance, and assure 

material is available in the volume necessary. 

•	 Equipment vendors (Komax and ATS) to 

develop next generation of equipment for 

automated production at high volumes. 

•	 Vendors of balance of systems equipment 

(Xantrex for inverters. Comverge for energy 

dispatchablity) to improve reliability, increase 

lifetime, increase volume and lower cost. 

•	 Universities (Georgia Tech, Arizona State 

University, North Carolina State University and 

University of Central Florida) and a research 

laboratory (Palo Alto Research Center) to 

provide research support. 

•	 Utility (SMUD) will provide customer interface, 

demonstration sites, and utility prospective on 

the value of PV electricity. 

Key components of the program include: 

•	 Si purification process development of solar 

grade Si to increase availability of Si feedstock 

for PV industry. 

Photovoltaic

Systems and Component Development

60
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Casting: implementation of Mono2TM 

technology (single crystal quality at multi cost); 

•	 Wafering: thinner wafers down to 150 μm in 

2010 and to 100 μm in 2015; thinner wire; 

improved slurry and slurry recycling; and 

automated demounting and singulation of 

wafers. 

•	 Cell process: optimized design and processing 

for ultra-thin Mono2TM to achieve cell efficiency 

of 18% in 2010 and 20% in 2015. 

•	 Module: lower material costs, products 

designed for integration into specific roof 

types, and safe operation at high voltages. 

•	 Automation and process control to transition 

from hundreds of cells per hour to hundreds of 

cells per minute. 

•	 Higher efficiency, increased reliability 

inverters. 

•	 Improved low cost systems monitoring. 

•	 Reduced indirect costs through organized 

deployment channels and integrated solutions. 

3. Results and Accomplishments 

3.1 Silicon Feedstock 

Partner Dow Corning successfully produced 60 kg 

of Si with <4 ppmw B, <5 ppmw of P, and <10 

ppmw of metals. They also reported the 

production of over 1,200 kg of SGS with 4 ppmw 

of B, 5 ppmw of P, and <10 ppmw of metals. Dow 

also conducted a smelting trial at the National 

Energy Technology Labs (NETL) in Albany, 

Oregon. The trial confirmed the ability to use the 

trial produced ~95 kg Si of Si with an average 

boron and phosphorous content of 1.6 and 7.5 

ppmw, respectively, confirming that carbonaceous 

binder in the silica briquette formulation will not 

affect the reactivity of the quartz. 

3.2 Casting 

Lower-tier Ceradyne completed development of a 

SiN hard coat process for PV crucibles, and nine 

casting stations have been qualified for production 

of Mono2TM Si. A pre-production run of more than a 

megawatt of materials has begun. 

3.3 Wafering 

BP Solar completed the milestone to develop <180 

micron wafer technology and made a decision not 

to implement in BP Solar wafering at this time due 

to equipment limitations. 

A trial of 10 cuts with 120 μm diameter wire to cut 

160 μm wafers indicated that cutting performance 

on current equipment is unacceptable at either 

160- or 180-μm wafer thickness. 

3.4 Cell Process 

Dow developed an Iso-chemical texturing process 

and made a decision to implement on new cell 

lines. They also qualified low-bow Al-B paste BSF 

to be implemented for wafer thicknesses below 

200 μm. Dow completed a preliminary evaluation 

and selected an approach for back-contact cells. 

Efforts are underway to use advanced emitters, 

advanced metallization, and laser firing to increase 

thin-cell efficiencies. 

3.5 Module Development 

BP designed a residential BIPV product and is 

finalizing ordering the mold. Tests verify that the 

ethylene-vinyl acetate (EVA) can be laminated to 

the thermoplastic polyolefin (TPO)-roofing 

membrane but discolored in damp heat tests. A 

generation 2 AR-coated glass was developed that 

transmits 0.8% more power than generation 1. BP 

has deployed new, higher-energy module designs 

for test at five outdoor sites worldwide. BP also 

developed a rapid method for testing the cure 

levels in EVA and is evaluating the procedure for 

possible use in all factories. 

3.6 Manufacturing 

BP completed development of a monitoring and 

control unit for printed line width and implemented 

it in production. A second improvement is a 

monitoring and control unit for sheet resistance. 

3.7 Inverter 

Partner Xantrex designed a charge controller for 

high voltage PV systems with battery storage. The 

full prototype design was completed, and circuit 

boards, sheet metal chassis, magnetics, and other 

electronic parts were procured for 5 units. The 

complete set of circuit boards was fabricated and 

all parts installed, and one complete unit was 

assembled to support the start of the functional 

testing of the circuitry. 

3.8 Monitoring and Control 

An initial monitoring installation was completed at 

the SMUD House of the Future. The system is 

operational, and initial local dispatch and recharge 

tests have been performed. BP also completed 

connector evaluation and test and selected one for 

use. 

3.9 System Engineering 

BIPV residential roofing product installation and 

aesthetic issues discussed with channel partner. 

61 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.10 Deployment 

BP prepared a report documenting third party 

approval requirements for the installation of PV 

systems. Also, the performance model was 

updated to include diffuse light and AR-coated 

glass. 

3.11 Collaboration 

BP participated in Solar ABCs efforts in standards 

and codes development. 

4. Planned FY 2009 Activities 

•	 Produce 600 kg of SoG Si with <0.5 ppmw B, 

<1.5 ppmw P and <1 ppmw metals at a 

throughput rate of at least 60 kg/hour. 

•	 Design, construct, and demonstrate 

commercial-solar grade Si pilot line facility. 

•	 Demonstrate cast ingots with mix of solar 

grade Si to achieve 16% cell efficiency. 

•	 Complete evaluation/development of 

integrated demounting and cleaning system. 

•	 Develop process and evaluate implementation 

of 160μm wafers and cells at average 

efficiency of 17% in production, 

•	 Demonstrate and evaluate implementation of 

EVA cure-level monitoring. 

•	 Demonstrate qualification and evaluate 

implementation of faster cure encapsulant. 

•	 Complete development of roof-integrated PV 

module and submit for certification (UL and 

CEC). 

•	 Complete redesign of module for improved 

safety and reliability. 

•	 Complete development and evaluate 

implementation of membrane roofing product. 

•	 Optimize operation of new screen printer and 

evaluate implementation strategy. 

•	 Complete design of PV charge controller, test 

through HALTS, and submit for certification to 

UL 1741. 

•	 Complete arc monitor and suppression system 

evaluation/selection. 

•	 Complete design, fabrication, and test of 

prototype PV system monitor units. 

•	 Complete membrane-roofing product system 

design. 

•	 Install first prototype residential system. 

•	 Verify residential and commercial systems 

under development to meet DOE LCOE 2010 

target goals. 

5. FY 2008 Special Recognitions and Patents 

Six disclosures related to this program have been 

submitted. Three patent applications are being 

prepared, but none were submitted in FY 2008. 

6. Major FY 2008 Publications 

J.H. Wohlgemuth. “Field observations and product 

returns – What can we learn?” Accelerated Aging 

Test & Reliability in PV Workshop II Proceedings,” 

Denver, CO, 2008. 

J.H. Wohlgemuth; D.W. Cunningham; N.V. Placer; 

G.J. Kelly; A.M. Nguyen. “The effect of cell 

thickness on module reliability.” 33rd IEEE PV 

Specialist Conference Proceedings, May, 2008. 

J.H. Wohlgemuth; D.W. Cunningham; R.F. Clark; 

J.P. Posbic; J.M. Zahler; P. Garvison; D.E. 

Carlson; M. Gleaton. “Reaching grid parity using 

BP Solar crystalline silicon technology.” 33rd IEEE 

PV Specialist Conference Proceedings, May 2008. 

J.H. Wohlgemuth; D.W. Cunningham; D. Amin; J. 

Shaner; Z. Xia; J. Miller. “Using accelerated tests 

and field data to predict module reliability and 

lifetime.” 23rd European PV Solar Energy 

Conference Proceedings, Sept. 2008. 

D.W. Cunningham; A. Parr; J. Posbic; W. Poulin. 

“Performance comparison between BP Solar 

Mono2TM and traditional multicrystalline modules.” 

23rd European PV Solar Energy Conference 

Proceedings, Sept. 2008. 

J.H. Wohlgemuth. “Reliability of PV Systems.” 

SPIE Conference on Optics & Photonics 

Proceedings, Solar Energy + Applications”, San 

Diego, August, 2008. 

N.G. Stoddard; B. Wu; L. Maisano; R. Russell; J. 

Creager; R. Clark; J.M. Fernandez. "The Leading 

Edge of Silicon Casting Technology and BP 

Solar's Mono2 Wafers", 18th Workshop on 

Crystalline Silicon Solar Cells and Modules, Vail, 

CO, August, 2008. 

Photovoltaic

Systems and Component Development

62
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7. University and Industry Partners 

Organization/ 

Principal Investigator Location Description/Title of Research Activity 

FY 

2008 

($K) 

Cost 

Share 

($K) 

Dow Corning 

Gary Burns 

Haroula Reitz 

Midland, MI Solar-grade Si feedstock for the casting process. 

Develop alternative silicone encapsulation system. 745 745 

AGC Flat Glass NA 

Jean-Francois Oudard 

Kingsport, TN Develop solar glass with AR coatings. 74 94 

ATS-Ohio 

David Kelly Lewis Center, OH Develop automated thin wafers and cells handling equipment * 0 

Arizona State University 

G. Tamizhmani 

Raja Ayyanar 

Harvey Bryan 

Tempe and Mesa, 

AZ 

Evaluate PV module and array performance; monitor 

residential PV system; Model power distribution 

system and advanced power converters; design 

BIPV products. 

44 0 

Ceradyne Thermo 

Materials 

Scott Higgenbottom 

Clarkston, GA Develop large area, high purity crucibles for Si 

Casting 150 150 

Georgia institute of 

Technology 

Ajeet Rohatgi 

Atlanta, GA Design, optimize, and fabricate high-efficiency solar 

cells on BP Solar cast Si wafers 161 0 

Komax Systems York 

Brian Micciche 

York, PA Develop screen print and tabbing/stringing equipment 

for thin PV cells. * * 

PARC 

Dave Duff Palo Alto, CA Develop, qualify of a gridline printing system. * * 

Recticel 

Dirk Daems Auburn Hills, MI Design, develop residential BIPV molded module frames. * * 

Sacramento Municipal 

Utility District 

Cliff Murley 

Sacramento, CA Provide utility prospective to and demonstrations 

sites for residential and commercial PV systems. * * 

STR 

Ryan Tucker Enfield, CT Develop of low cost, high performance encapsulants. 80 80 

University of Central 

Florida 

Neelkanth Dhere 

Coco, FL Study module energy collection, PV connector 

performance and module leakage current. 80 0 

Xantrex Technology Inc. 

Mark Edmunds Burnaby, BC Develop hi-reliability, battery-backed grid-tie inverter power conversion system 0 268 

North Carolina State 

University 

George Rozgonyi 

Raliegh, NC Evaluate BP cast multi-crystalline and mono2 Si. 100 0 

*No invoices received as of 9/30/2008. 

63 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TPP Awardee: Dow Chemical Co., Inc. “Fully Integrated Building Science Solutions for 

Residential and Commercial Photovoltaic Energy Generation”
 

Total Award Amount: $19,649K, DOE/Recipient Share $9,824K/$9,825K 

Objectives 

•	 Reduce total systems cost by revolutionizing design, incorporating mass production module 

fabrication, and developing solutions that are driven by targeted applications. 

•	 Reduce LCOE for residential BIPV to $3.85/watt installed by 2010. 

Accomplishments 

•	 Validated shingle design concepts with respect to decreasing installation costs. 

•	 Determined materials needed in robust, long term packaging components. 

•	 Met minimum cell efficiency requirements for roadmap to meeting LCOE targets. 

Future Directions 

•	 Scale up pilot line for low cost manufacturing of shingle. 

•	 Transfer residential shingle developments to commercial roofing product concepts. 

1.	 Introduction 

Dow is working to develop modular, turnkey PV 

systems that provide residential and commercial 

customers with a complete solution and attractive 

value proposition. Dow’s approach to a complete 

solution is to reduce the total systems cost by 

revolutionizing the design; incorporating mass 

production module fabrication; and developing 

solutions that are driven by the targeted 

applications as opposed to reconfiguring or 

modifying modules that had been designed for 

alternative purposes (e.g., ground mounted solar 

farms and other rigid applications). Dow is 

addressing all components of a turnkey system 

through existing channels with the building, 

construction, and infrastructure markets. Dow has 

partnerships with home builders (Pulte Homes and 

Lennar Homes), access to balance of system 

components through Dow Wire and Cable, and 

channels to the roofing industry through the wholly 

owned subsidiary Dow Roofing Systems. 

2. Technical Approach 

Dow developed a shingle design ready for pilot 

scale production. A smaller version was designed 

to test interconnects, packaging materials and 

installation techniques. Several design issues 

were identified through this approach to be made 

in the full size shingle. 

Shingle design was impacted by a change in cell 

supplier. We were able to rapidly qualify another 

copper indium gallium diselenide (CIGS) 

manufacturer to aid our development. This 

manufacturer, Global Solar, Inc., operates two 

large scale CIGS PV manufacturing sites in 

Tucson, Arizona, and Berlin, Germany. 

Dow expended significant effort on materials 

characterization and development to design a 

CIGS PV cell package that was suitable for the 

shingle functional format. This was accomplished 

utilizing both external products and internal 

technology under development. 

3. Results and Accomplishments 

Milestones achieved: 

•	 Secured cell supply for prototype 

development. 

•	 Produced working prototype shingles with 

packaging material. 

•	 Produced full scale shingle. 

•	 Reviewed cost model with Navigant. 

Competitive Benchmarking, Cell Supply, and 

Shingle Development 

Dow worked to set a baseline for performance of 

competitive products in the market both from a PV 

cell perspective and a packaging materials 

perspective. 

System Engineering and Integration 

Dow is new to solar product development and 

spent a considerable amount of time developing a 

BIPV material test plan to qualify the needed 

materials to provide cell stability and long shingle 

life. In addition to an integrated test plan, a test 

Photovoltaic

Systems and Component Development

64
 

 

 

 

 

 

 

 

 

 

 

 

 

 

lab, which is now fully functional, was needed to 4. Planned FY 2009 Activities 

be acquired and equipment qualified. 

Dow is developing the BIPV product materials 

structure using a multi-generation plan to ensure 

continuous progress in terms of cost reduction 

while at the same time maintaining successful 

product performance. Many different approaches 

to achieving adequate barrier performance that will 

enable CIGS based PV shingles to perform more 

than 20 years were experimented with, tested, and 

in some cases, taken to development. Dow 

evaluates all the materials of construction with the 

total solution in mind. 

Dow is working towards a simple yet rugged and 

reliable interconnection design for the Dow Solar 

Shingle, which totally eliminates all on-the-roof 

wiring and therefore the necessity of having an 

electrician or licensed solar installer do the 

installation. As part of addressing installation 

costs, Dow validated their design with a test build 

using standard roofing contractors. 

•	 Develop equipment modifications to fit product 

design with Global Solar Energy. (Q1) 

•	 Build pilot line and start-up. (Q1) 

•	 Install and collect data on turnkey systems. 

(Q2) 

•	 Develop commercial roofing analog product. 

(Q1) 

5. FY 2008 Special Recognitions and Patents 

U.S. Provisional Patent Application No.61/098941, 

connector device for building-integrated PV 

device. 

6. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity 

FY 

2008 

($K) 

Global Solar Energy 

Jeffery Britt Tuscon, AZ Cell supplier 3 

Prost Construction 

Vaughn Prost Columbia, MO 

Install demo unit with Columbia Water and Light to 

initiate rate structure study for solar PV electricity 

production. 

35 

65 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TPP Awardee: General Electric (GE) Global Research, Inc. “A Value Chain Partnership to Accelerate U.S. PV Industry Growth” 

Total Award Amount: $46,217K, DOE/Recipient Share $20,000K/$26,217K 

Objectives 

•	 Investigate multiple technical pathways for producing modules and system components that will 

meet SAI LCOE goals and be successful in U.S. marketplace. 

•	 Address segments of U.S. PV market where GE’s technical and system integration competencies 

can have largest impact on PV system cost and performance. 

•	 Deliver into residential and commercial markets complete system of components consisting of 

module array, dc-ac inverter, and energy monitor. 

•	 Meet LCOE targets of $0.13/kWh to $0.18/kWh by 2010 and $0.08/kWh to $0.10/kWh by 2015. 

Accomplishments 

•	 Demonstrated 18% efficiency small area, single crystal Si solar cell. 

•	 Demonstrated continuous carbothermic process to convert SiO2 to high purity Si. 

•	 Demonstrated solar cells from molded wafers with efficiencies 2% (absolute) above baseline. 

•	 Developed life-time model for encapsulated CIGS cells. 

•	 Developed model comparing interconnect schemes for flexible thin film modules. 

•	 Constructed and demonstrated lab prototype residential architecture. 

•	 Designed and constructed inverter test bed capable of reproducing CEC measurement protocol. 

Future Directions 

•	 Increase reaction efficiency in solar grade Si process by 2x. 

•	 Increase for molded wafer solar cells of 1% (absolute) efficiency. 

•	 Develop prototype encapsulated, flexible thin film module. 

•	 Demonstrate high-reliability and high-efficiency residential and commercial inverter prototypes. 

1. Introduction 

GE and its partners are investigating three PV 

pathways: (1) bifacial high-efficiency Si cells and 

modules; (2) low-cost multicrystalline Si cells; and 

(3) modules and flexible thin film modules. The 

balance of system for residential and commercial 

installations is also being investigated. Innovative 

system installation strategies are being pursed as 

an additional avenue for cost reduction. 

2. Technical Approach 

GE focused on three distinct technical pathways 

for the module and a technical pathway for the 

inverter/balance of system and installation. Each 

pathway is self-contained, spans the value chain 

to include materials, solar device, and system, and 

includes critical technologies and partners. 

2.1 Bifacial High-Efficiency Silicon Module 

GE is developing a 20%+ efficient solar cell based 

on a graded a-Si on crystalline Si hybrid 

technology using a scalable fabrication process. 

The bifacial nature of this solar cell presents an 

opportunity for the fabrication of a highly effective 

2-5x concentrator module to reduce Si area while 

maintaining the form factor of a standard one-sun 

design. 

2.2 Low-Cost Multicrystalline Silicon Module 

GE is developing a solar cell based on a molded 

Si wafer in a continuous casting process that 

eliminates the waste associated with conventional 

sawing, resulting in a wafer that is 2x less 

expensive to produce. GE is working to improve 

the quality of the molded Si wafers to approach 

that of conventional polycrystalline cast wafers. 

GE has demonstrated capability for cell 

efficiencies of 12%–14% when fabricated using 

conventional cell manufacturing techniques. GE is 

also developing process using a low-cost Si 

feedstock based on a carbothermic-reduction 

process that will be less costly to scale than other 

processes currently in use. This process takes 

advantage of GE’s knowledge of high quality 

quartz manufacturing and will allow the production 

of an abundant supply of Si feedstock. 

2.3 Flexible Thin Film Module 

GE is working with vendors who are developing 

technology for CIGS on flexible substrates as a 

Photovoltaic

Systems and Component Development

66
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

source of flexible solar cells. This technology has 

great potential for low cost and the creation of 

unique building integrated products. GE has 

developed a set of packaging technologies for 

flexible organic light emitting diodes (OLEDs) that 

will be directly applied to the CIGS material. A 

novel multilayer SiN/organic film that can be 

directly deposited onto the solar cell or a 

polycarbonate sheet is the basis for a moisturetight package that provides significantly better 

protection than the Teflon-based materials being 

used. In addition to moisture protection, thin film 

packages require UV protection. GE will leverage 

its extensive experience in the area of UV 

protection of polymer films to realize a fully 

encapsulated thin film product. 

2.4 Balance of System (BOS) 

GE and partner Xantrex are working to lower 

inverter cost and improve performance by 

developing innovative new circuit designs, utilizing 

high performance components, and by taking 

advantage of higher volume component pricing 

made possible by market growth. A large element 

of the cost is embedded in the system engineering 

and integration functions and in the installation. 

GE will be working with top PV installers to identify 

internally driven cost elements related to time and 

materials, identify external factors such as local 

codes and regulations that influence costs nonuniformly, and develop a streamlined process flow. 

3. Results and Accomplishments 

3.1 Bifacial High-Efficiency Silicon Module 

GE achieved a number of key milestones, 

including 18%-cell efficiency on small area 

laboratory devices based on a graded a-Si/c-Si 

heterojunction design. This efficiency was the 

result of a significant amount of process 

development around surface passivation of the 

crystalline Si surface for high Voc and surface 

texturing for high Jsc. The GE team also 

developed a model to study the performance of 

these heterostructures. With this model, the team 

was able to study the affect of surface states at 

the a-Si/c-Si interface as well as the relationship 

between doping levels, wafer resistivity, and layer 

thickness on conversion efficiency. 

Based on business considerations, GE has 

terminated efforts for the bifacial high-efficiency Si 

module for this project and will focus future project 

efforts on low cost multi-crystalline Si modules, 

flexible thin film module, and balance of systems. 

3.2 Low-cost Multicrystalline Silicon Module 

Multicrystalline Si has been produced via 

carbothermic reduction processes with boron and 

phosphorous concentrations below 0.3 ppma. 

Furthermore, a 20% process efficiency has been 

demonstrated, as well as a pathway towards 

higher process efficiency moving forward. 

The molded wafer was initially commercialized by 

AstroPower in 2001, and GE acquired the assets 

of AstroPower. The benefit of the molded wafer 

process is that wafers are easy to handle and 

there are no costly Si-recycle loops required by 

today’s conventional casting. The critical figures of 

merit for the process are the minority carrier 

lifetime (driving efficiency) and wafer thickness. 

GE is altering the wafer thickness by changing the 

Si powder spreading apparatus and by optimizing 

the thermal profile. This thickness, combined with 

modest improvements in efficiencies will generate 

Si utilization numbers equal to casting. 

Wafers produced by the single wafer casting 

process have been processed into solar cells on a 

conventional, high volume solar cell production 

line. Cell thickness has been reduced by about 

50%, and cell efficiency increased by as much as 

50% relative to the original Astropower process. 

3.3 Flexible Thin Film Module 

GE reviewed three interconnect strategies: 

tabbed/stringed cells, shingled cells, and 

monolithically integrated cells. GE developed a 

model to predict the electrical performance, using 

input from measured contact and sheet 

resistances for the three different interconnect 

strategies under consideration. The model is being 

used to determine optimum geometric and 

materials configurations. 

CIGS cells are known to be sensitive to moisture, 

thus some type of barrier layer is needed for 

flexible modules where glass is replaced by 

permeable plastic. GE has data that indicate the 

damp heat test is a valid acceleration of real-world 

conditions, and has developed data and models to 

allow prediction of real-world lifetime for various 

packaging options. These allow GE to compute 

acceleration factors from the damp heat test. 

GE is testing packages based on laminating cells 

with encapsulant and barrier-coated plastic films. 

GE identified two fundamentally different 

stabilization schemes for transparent, but not 

inherently stable, polymer films. The first approach 

uses coatings with high-performance UV 

67 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

stabilizers, where such thin coatings are relatively • Increase of 1% (absolute) in molded wafer 

low-absorbance and degradation is governed by solar cell efficiency. 

initial absorbance and stability of UV screener 

molecule. The second UV-stabilization scheme 4.2 Flexible Thin Film Module 

uses thermoplastic cap layers on base film. Such 

thick layers are very high absorbance, and 

degradation is governed by physical erosion of the 

surface in microns/year. GE is performing 

accelerated weathering on variations of these two 

schemes, and initial data indicate there are 

several options to achieve 25-year lifetime. 

3.4 Balance of System (BOS) 

The GE team is developing a 4.8-kW residential 

inverter with dual array inputs and developed a lab 

high efficiency prototype. Preliminary reliability 

calculations show that this inverter will have 

significantly longer life than conventional designs. 

An automated test setup has been built to fully 

exercise the residential inverter. The setup 

consists of power supplies to simulate the PV 

arrays, AC loads, a computer, and oscilloscope. 

This allows GE to perform one week of testing in 

30 minutes. The full CEC test protocol can be 

easily implemented using this setup in addition to 

measuring anti-islanding capability and maximum 

power point tracking (MPPT) accuracy. 

4. Planned FY 2009 Activities 

Milestones include: 

4.1 Low-cost Multicrystalline Silicon Module 

•	 Increase by 2x solar grade silicon process 

reaction efficiency. 

•	 Fabricate an encapsulated, flexible thin film 

module prototype. 

4.3 Balance of System (BOS) 

•	 Demonstrate beta prototype of high-reliability 

and high-efficiency residential inverter. 

5. Major FY 2008 Publications 

X. Zhang; J. Fronheiser; B. Korevaar; T. Tolliver. 

"Post-treatment of a-Si/c-Si interface resulting in 

optimized passivation properties," Poster 

presentation at the 33rd IEEE PVs Specialists 

Conference, May 11–16, San Diego, CA, 2008. 

X. Zhang; J. Fronheiser; B. Korevaar; T. Tolliver. 

"Post-treatment of a-Si/c-Si interface resulting in 

optimized passivation properties," Extended 

abstract for the 33rd IEEE PVs Specialists 

Conference, May 11–16, San Diego, CA, 2008. 

B. Korevaar; X. Zhang; J. Fronheiser; T. Tolliver. 

"Influence of annealing on performance for heterojunction a-Si/c-Si devices," Poster presentation at 

the 23rd European PV Solar Energy Conference, 

Sept. 1–5, 2008, Valencia, Spain. 

B. Korevaar; X. Zhang; J. Fronheiser; and T. 

Tolliver. "Influence of annealing on performance 

for hetero-junction a-Si/c-Si devices," Extended 

abstract for the 23rd European PV Solar Energy 

Conference, Sept. 1–5, 2008, Valencia, Spain. 

6. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 ($K) 

Cost 

Share 

($K) 

Xantrex Technology, 

Inc. 

RD Merritt 

Burnaby, BC 

Canada Develop low-cost, high-reliability inverter technology. 1,300 775 

Institute of Energy 

Conversion 

Steven Hegedus 

Newark, DE 

Qualification testing of vendor-supplied devices, 

assist in specification of test devices, conditions, and 

requirements for environmental and stress testing, 

performance and environmental testing of flexiblepackaged modules. 

156 0 

Georgia Institute of 

Technology 

Ajeet Rohatgi 

Atlanta, GA Si solar cell fabrication using multicrystalline and 

single crystal wafers. 100 0 

North Carolina State 

University 

George Rozgonyi 

Raleigh, NC Detailed material characterization to understand the 

lifetime limiting defects and mechanisms in Si 

wafers. 

100 0 

Photovoltaic

Systems and Component Development

68
 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TPP Awardee: Greenray, Inc. ”Development of an AC Module System” 

Total Award Amount: $5,044K, DOE/Recipient Share: $2,522K/$2,522K 

Objectives 

•	 Develop fully-integrated plug-and-play PV system through integration of power electronics with 

high efficiency PV module. 

•	 Reduce PV system installation labor cost by half. 

•	 Increase system reliability and reduce system maintenance costs by 75%. 

•	 Increase system safety for installers and users. 

•	 Lower lifecycle cost of PV energy to meet DOE goals. 

Accomplishments 

•	 Demonstrated prototype of inverter. 

•	 Demonstrated prototype of residential mounting system. 

•	 Demonstrated prototype of data system. 

Future Directions 

•	 Complete thorough testing of inverter, including final safety certification. 

•	 Deploy AC module system prototypes with key partners for evaluation. 

1. Introduction 

The market for PV systems on the roofs of homes 

and commercial buildings is growing rapidly in the 

United States. Expectations are high that growth 

will continue for the foreseeable future. To help 

foster the widespread adoption of PV, GreenRay 

is aiming to create a true plug-and-play AC 

system, with advantages in simplicity, safety, 

performance, and cost. GreenRay is focused on 

driving cost out of PV through evolution of the 

balance-of-systems and levels of integration. 

2. Technical Approach 

GreenRay is developing three elements for the AC 

module system: high-reliability inverter, simple 

residential mounting system, and data acquisition 

system. To achieve an integrated PV system that 

simplifies installation, GreenRay is eliminating 

many of the redundant structural elements in 

today’s systems. Prototypes of the mounting 

system were developed and evaluated by an 

experienced PV installer. 

The inverter has been designed to achieve a 20­

year lifetime, improve system reliability, and 

reduce maintenance. Consultants have provided 

reviews of the inverter design to help GreenRay 

achieve its goals. The integrated data system is 

designed to take advantage of the distributed 

intelligence in the AC module system to provide 

module-level information. 

3. Results and Accomplishments 

Major results and accomplishments of the project 

are listed below: 

•	 Demonstrated operation of alpha version of 

inverter at full power with THD below 5%. 

(4/08) 

•	 Reliability analysis predicted greater than 20­

year life for inverter. (4/08) 

•	 Completed preliminary cost projections of AC 

module system show potential to achieve 

targeted lifecycle cost of energy. (5/08) 

GreenRay completed the design of its novel 

inverter in a form factor optimized for integration 

with a PV module. The alpha prototype of the 

inverter operated successfully. Consultants 

reviewed the design and suggested several 

improvements. The reliability analysis was 

completed using standard tools and methods to 

model the circuit. Results indicate the potential to 

achieve the targeted lifetime and reliability. 

Key design innovations make it possible to remove 

some mounting elements found in today’s PV 

systems. The installation labor cost savings were 

validated, and the GreenRay AC module system 

will be roughly half that of conventional systems. 

69 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

Imbedded data acquisition and communication 5. FY 2008 Special Recognitions and Patents
 

capability was tested and demonstrated. The user
 

interface features were reviewed with key Two patents were filed in FY 2008:
 

stakeholders and refined. • High reliability inverter for an AC module.
 

•	 AC module wiring method. 

4. Planned FY 2009 Activities 

•	 Complete stress and performance testing of 

AC module using in-house facilities and 

outside test labs. (06/09) 

•	 Submit AC module for final safety certification. 

(06/09) 

6. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity 

FY 2008 

($K) 

Cost Share 

($K) 

Coal Creek Design Lafayette, CO Inverter design and development $65 $0 

SANYO Energy Dallas, TX PV modules to support inverter 

and AC Module development $106 $106 

Photovoltaic

Systems and Component Development

70
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

TPP Awardee: Konarka Technologies, Inc. “Low Cost, Lightweight Solar Modules Based on Organic Photovoltaic Technology” 

Total Award Amount: $8,585K; DOE/Recipient Share: $3,656K/$4,929K 

Objectives 

•	 Improve stability by imparting oxygen and water vapor barrier properties to laminating adhesives. 

•	 Improve performance by creating new n-type carriers for PV active layer. 

•	 Improve performance and lower cost by substituting printed metal grid for high cost, vacuum 

deposited transparent semi-conductor. 

•	 Performance objective of cell efficiency ~10% with module efficiency 7%-8%. 

•	 Rooftop module lifetime objective is 10 years; cost objective <$0.2/kWh. 

Accomplishments 

•	 Increased stability: 

o	 Demonstrated effectiveness of plate-like particles on water vapor and oxygen barrier 

properties of several classes of laminating adhesives. 

o	 Demonstrated that clay fillers retain high percentage of barrier properties at 60o

C. 

o	 Identified water and oxygen degradation mechanisms, along with solutions. 

•	 Improved performance of n-Type Carriers: 

o	 Demonstrated control of lowest unoccupied molecular levels of fullerene derivatives; several 

of these derivatives exhibit electron mobility greater than PCBM. 

•	 Improved performance of printed metal grids: 

o	 Demonstrated metal grids with >80%T, <10ohms/cm2 can be printed at 100ft/min. 

o	 Demonstrated functioning cells using grid electrodes. 

•	 Reduced cost: none of these accomplishments will increase costs, and the ability to print grids at 

high speed will ultimately lower cost. However, cost was not part of the first year objectives. 

Future Directions 

•	 Continue to develop clay-filled adhesives and conduct module tests. 

•	 Develop solution-coatable barriers to replace high cost vacuum deposited barriers. (NREL) 

•	 Optimize active layers with new fullerene derivatives and new low band gap polymer donors. 

•	 Continue to investigate n-type polymers as replacements for fullerenes in active layer. 

•	 Continue to optimize silver formulations and printing processes with goal of replacing ITO. 

•	 Fabricate large area modules in our recently announced, 1-GW capacity manufacturing plant. 

1. Introduction 

Since opening in 2001, Konarka Technologies has 

been dedicated to producing solar modules at low 

cost. The latter will be achieved by using organic 

materials that can be coated or printed on flexible 

substrates from solution using low cost, high 

speed processes. The objectives of this project, 

which can be divided into stability and 

performance, are centered on making these goals 

a reality. 

2. Technical Approach 

The program started by determining the factors 

and conditions that have the greatest affect on 

stability and then proceeded to investigate 

creative, practical approaches to solving the 

problems. These approaches centered on utilizing 

commercial barriers with improved properties as 

they became available and developing adhesives 

that add to the barrier properties. 

To address performance, Konarka recognized that 

most of the available polymer donors and fullerene 

acceptors need improvement (e.g., extinction 

coefficient of the materials to incident radiation). 

This also meant that as the p-type polymer donors 

were improved, the properties of n-type 

component would also have to be modified to 

match the properties of the new polymers. In 

addition, the conductivity and transparency 

properties of the transparent electrode had to be 

improved, and since ITO on plastic substrates is 

one of the most costly components of the cell, it 

had to be replaced, if cost goals are to be 

achieved. 

71 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3. Results and Accomplishments 

For the first 14 months, Konarka focused on 

improving the stability of the modules by improving 

the barrier properties of the laminating adhesive. 

Major degradation mechanisms were identified. 

These include oxygen complexation (reversible), 

oxygen degradation (irreversible), and water 

swelling which causes interface delamination. The 

initial approach to mitigating these effects was to 

incorporate inert, plate-like clay particles into the 

adhesive and increase the mean free path of 

water and oxygen molecules. Overall reductions of 

water/oxygen transmission rates have been 

realized by this approach. However, overall cell 

stability has been achieved with another approach, 

the use of commercially available film barriers. 

Also, in order to reduce barrier film costs, a new 

approach using solution coatable barriers was 

developed. Stability can be further improved by 

using the clay-filled adhesives on the edge barrier 

of the module. 

To improve cell performance, several fullerene 

derivatives have been developed that exhibit 

improved properties. One set has shallow LUMO 

levels to match with high band gap polymer 

donors and raise the cell voltage. Another set has 

deep LUMOs to match with low band gap 

polymers. Cells have been fabricated that 

demonstrate moderate efficiency. The two types of 

fullerene derivatives are presently being produced 

to a quantity that allows optimization of cell 

performance. A second approach to improved cell 

performance involves the use of printed grids for 

increased junction illumination and decreased cell 

series resistance. Printed metallic grids have been 

demonstrated that have the desired properties of 

conductivity and transmissivity, and along with 

formulating highly conductive hole injecting layer, 

the grids can be used to replace ITO as the 

transparent electrode. 

4. Planned FY 2009 Activities 

•	 Introduce first product at recently-acquired 

250,000-ft2 manufacturing plant in New 

Bedford, Massachusetts. When fully 

operational, the coating/printing line will be 

able to produce modules capable of >1 GW 

(5% module efficiency). 

•	 Improve module stability and performance. 

•	 Improve over-laminate barriers to achieve 5­

year rooftop stability for the initial products 

(2009). 

•	 Replace currently used PET substrates with 

more stable materials. 

•	 Create and develop new p- and n-type 

materials for the active layer and by replacing 

expensive ITO transparent electrode with a 

printed silver grid to achieve 5%–7% cell and 

module efficiency. 

5. FY 2008 Special Recognitions and Patents 

United States Issued Patents (2008) 

Six patents were filed: US 7,407,831: Method for 

producing organic solar cells or photo detectors; 

US 7,413,997: Nanostructured electrode; US 

7,329,709: Photoactive materials and related 

compounds, devices, and methods; US 

7,351,907: Displays with integrated photovoltaic 

cells; US 7,414,188: Co-sensitizers for dye 

sensitized solar cells; US 7,407,831: Method for 

producing organic solar cells or photo detectors. 

6. Major FY 2008 Publications 

•	 M. Morana; M. Wegscheider; A. Bonanni; N. 

Kopidakis; S. Shaheen; M. Scharber; Z. Zhu; 

D. Waller; R. Gaudiana; C. Brabec. “Bipolar 

charge transport in PCPDTBT-PCBM bulkheterojunctions for PV applications.” 

Advanced Functional Materials (2008), 18(12), 

1757-1766. 

•	 A. Welte; C. Waldauf; C. Brabec; P.J. 

Wellmann. “Application of optical absorbance 

for the investigation of electronic and structural 

properties of sol-gel processed TiO2 films.” 

Thin Solid Films (2008), 516(20), 7256-7259. 

•	 R. Gaudiana; C. Brabec. “Fantastic plastic.” 

Nature Photonics (2008), 2(5), 287-289. 

•	 J.A. Hauch; P. Schilinsky; S.A. Choulis; S. 

Rajoelson; C.J. Brabec. “The impact of water 

vapor transmission rate on the lifetime of 

flexible polymer solar cells.” Applied Physics 

Letters (2008), 93(10), 103306/1-103306/3. 

CODEN: APPLAB ISSN:0003-6951. 

•	 C.J. Brabec; J.R. Durrant. ”Solution-processed 

organic solar cells.” MRS Bulletin (2008), 

33(7), 670-675. 

•	 C.N. Hoth; P. Schilinsky; S.A. Choulis; C.J. 

Brabec. “Printing Highly Efficient Organic 

Solar Cells.” Nano Letters (2008), 8(9), 

2806-2813. 

•	 K. Forberich; G. Dennler; M.C. Scharber; K. 

Hingerl; T. Fromherz; C.J. Brabec. 

“Performance improvement of organic solar 

cells with moth eye anti-reflection coating.” 

Thin Solid Films (2008), 516(20), 7167-7170. 

Photovoltaic

Systems and Component Development

72
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 G. Dennler; N.S. Sariciftci; C.J. Brabec. 

“Conjugated polymer-based organic solar 

cells.” Semiconducting Polymers (2nd Edition) 

(2007), 2 455-530. 

•	 A.J. Moule; A. Tsami; T.W. Buennagel; M. 

Forster; N.M. Kronenberg; M. Scharber; M. 

Koppe; M. Morana; C.J. Brabec; K. Meerholz; 

U. Scherf. “Two Novel CyclopentadithiopheneBased Alternating Copolymers as Potential 

Donor Components for High-Efficiency BulkHeterojunction-Type Solar Cells.” Chemistry of 

Materials (2008), 20(12), 4045-4050. CODEN 

•	 T. Ameri; G. Dennler; C. Waldauf; P. Denk; K. 

Forberich; M.C. Scharber; C.J. Brabec; K. 

Hingerl. „Realization, characterization, and 

optical modeling of inverted bulkheterojunction organic solar cells.” Journal of 

Applied Physics (2008), 103(8), 084506/1­

084506/6. 

•	 G. Dennler; M.C. Scharber; T. Ameri; P. Denk; 

K. Forberich; C. Waldauf; C.J. Brabec. 

“Design rules for donors in bulk-heterojunction 

tandem solar cells-towards 15% energyconversion efficiency.” Advanced Materials 

(Weinheim, Germany) (2008), 20(3), 579-583. 

•	 J.A. Hauch; P. Schilinsky; S.A. Choulis; R. 

Childers; M. Biele; C.J. Brabec. “Flexible 

organic P3HT:PCBM bulk-heterojunction 

modules with more than 1 year outdoor 

lifetime.” Solar Energy Materials & Solar Cells; 

(2008), 92(7), 727-731. 

•	 J.K. Lee; W.L. Ma; C.J. Brabec; J. Yuen; J.S. 

Moon; J.Y. Kim; K. Lee; G.C. Bazan; A.J. 

Heeger. “Processing Additives for Improved 

Efficiency from Bulk Heterojunction Solar 

Cells.” Journal of the American Chemical 

Society (2008), 130(11), 3619-3623. 

•	 J. Ramier; N. Da Costa; C.J.G. Plummer; Y. 

Leterrier; J.A.E. Manson; R. Eckert; R. 

Gaudiana. “Cohesion and adhesion of 

nanoporous TiO2 coatings on titanium wires 

for PV applications.” Thin Solid Films (2008), 

516(8), 1913-1919. 

•	 R. Mosurkal; L.A. Samuelson; J. Kumar; D. 

Waller; R. Gaudiana. “Synthesis of a Soluble 

Pentacene Derivative: 6,13-bis(mtrifluoromethyl phenyl ethenyl) Pentacene.” 

Journal of Macromolecular Science, Part A: 

Pure and Applied Chemistry (2008), 45(11), 

948-951. 

7. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity 

FY 

2008 

($K) 

Cost 

Share 

($K) 

Institute for Energy 

Conversion 

University of Delaware 

R. Birkmire 

Newark, DE Determine stability of modules under various 

conditions of temperature, humidity, and light. 

Investigate instability mechanism. 

105 76 

NREL 

David Ginley 

Golden, CO 

Improve barrier properties of perimeter seals 

by means of adding rod-like fillers to 

adhesives. Year 2, converted to solution 

coatable barriers. 

450 -

73 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TPP Recipient: Nanosolar, Inc. “Delivering Grid-Parity Solar Electricity for the Commercial Market” 

Total Award Amount: $42,616K, DOE/Recipient Share $20,000K/$22,626K 

Objectives 

•	 Achieve grid-parity economics for commercial market based on an integrated suite of innovations 

in module, inverter, and mounting technology. 

•	 Reach 2010 levelized cost of energy (LCOE) target of 6.3¢/kWh and 2015 LCOE target of 

5.5¢/kWh. 

Accomplishments 

•	 Demonstrated successful achievement of all technical milestones for Phase I including: 

o	 Achieved ~95% Indium materials utilization efficiency (MUE). 

o	 Optimized wide-web, roll-to-roll, high-MUE coating deposition methods scalable to multiple 

MW/year module manufacturing. 

o	 Demonstrated prototype modules with >80% of component cell efficiency. 

o	 Validated cell/module design through prototype testing. 

o	 Demonstrated cell and module temperature cycling stability of CIGS thin-film cells within PV 

modules per test IEC6164 10.11. 

o	 Demonstrated cell and module UV stability of CIGS thin-film cells within PV modules per tests 

IEC61646 10.8 and IEC61646 10.10. 

o	 Develop, optimize, and qualify low-cost wiring strategies for CIGS thin-film PV modules per 

tests IEC61730 and IEC61646 10.0. 

o	 Substantially exceeded power conversion efficiency (PCE) requirement for prototype 

modules at conclusion of Phase I, and with very tight PCE distribution. 

• Validated cost inputs enabling LCOE targets as calculated by DOE Solar Advisor Model (SAM). 

Future Directions 

•	 Demonstrate successful achievement of all technical milestones for Phase II of the project. 

•	 Demonstrate pilot deployment with Nanosolar modules (Phase III). 

1. Introduction 

Nanosolar’s technology is based on a printed 

semiconductor, which permits substantially 

improved cost efficiency. To implement this 

technology at grid parity, the entire system 

requires improvement and some redesigned for a 

systems-optimized perspective. Nanosolar is 

accomplishing this by developing an integrated 

suite of system components and designs based on 

innovations in module, inverter, and mounting 

technology and informed by real-world 

performance feedback. 

2. Technical Approach 

Solar Cell Technology 

Nanosolar has developed proprietary technology 

based on Copper-Indium-Gallium-diSelenide 

(CIGS) absorber technology that allows the 

printing of this semiconductor material using a 

high-speed, high-throughput roll-to-roll 

manufacturing process. A central challenge in cost 

effectively constructing an efficient, large-area 

CIGS-based solar cell or module is that the 

elements of the CIGS layer must be within a 

narrow stoichiometric ratio on nano-, meso-, and 

macroscopic length scale in all three dimensions. 

Achieving precise stoichiometric composition over 

relatively large substrate areas is difficult using 

traditional vacuum-based deposition processes. 

To address this, Nanosolar prints nanoparticulate 

CIGS precursor materials onto low-cost metal foil 

substrates and performs rapid thermal processing 

to convert the nanoparticulate coating into a CIGS 

absorber layer. This locks in the appropriate 

stochiometry into the nanoparticulate precursor 

material and ensures the required spatial 

uniformity, while permitting high speed throughput 

to minimize cost. 

Mounting System 

Optimal design of mounting structures for PV 

arrays requires the balance of several opposing 

design constraints. Specifically, such mounting 

structures need to support the inclination of the 

Photovoltaic

Systems and Component Development

74
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

module at near latitude tilt to provide maximum 

electrical output, be aerodynamic with regard to 

the wind so that the loads imposed on the 

structure by wind are minimal and minimal ballast 

or connections to the structure are necessary, and 

be relatively light weight so that the structure does 

not add significantly to the weight the roof must 

bear. Nanosolar is designing the mechanical 

structures of modules within the context of 

potential mounting systems and system reference 

designs. They are identifying the minimal 

application-specific structural

through wind-tunnel and other

developing a novel low-cost

mounting and deployment system. 

 requirements 

 tests, and 

 kWh-optimal 

Inverter technology 

In this project, we will systematically tune the kWhperformance of the system, focusing in particular 

at the module-inverter interface, to achieve the 

system performance required for our LCOE 

targets. For example, minimizing operations and 

maintenance cost at the system level requires long 

inverter life, enabled by high performance 

components, while minimal upfront inverter cost is 

enabled by low-cost. Balancing cost and 

performance in the inverter design is a key aspect 

of the inverter technology development. 

System Design 

A system reference design is being developed 

based on standardized system blocks with kWhoptimized performance, minimal site-specific 

engineering and permitting, and rapid installation. 

Our approach is based on the definition of a 

“standard” system block within which we apply our 

product design and technology innovations and 

streamline deployment with respect to the major 

application segment. 

3. Results and Accomplishments 

See accomplishments section above. 

4. Planned FY 2009 Activities 

•	 Demonstrate achievement of all technical 

milestones for Phase II. 

•	 Demonstrate pilot deployment with Nanosolar 

modules (Phase III). 

5. FY 2008 Special Recognitions and Patents 

Nanosolar developed and protected this 

technology as a combined set of trade secrets and 

three patent applications. Four additional 

applications are being prepared. 

6. University and Industry Partners 

Organization/ 

Principal Investigator Location/E-mail Description/Title of Research Activity 

FY 2008 

($K) 

FY 2008 

Cost Share 

($K) 

SunLink, LLC San Rafaal, CA 

info@sunlink.com 

Development low cost mounting 

solution thin-film module 

0 104 

75 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TPP Recipient: Soliant, Inc. “Concentrating Solar Panels: Bringing the Highest Power and Lowest Cost to the Rooftop” 

Total Award Amount: $13,660K; DOE/Recipient Share $4,887K/$8,7723K 

Objectives 

•	 Develop tracking/concentrating solar module that has the same geometric form factor as a 

conventional flat, roof mounted PV panel. 

•	 Target LCOE of $0.79/kWh in 2010. 

•	 Target efficiency of 26% in 2010 (22% for 2008 prototype, 24% for 2009 pilot). 

•	 Target performance equivalent to 600Wp in 2010 (490W for 2008 prototype, 540W for 2009 pilot). 

Accomplishments 

•	 Delivered prototype tracking/concentrating solar module that mounts to standard racking systems 

on commercial rooftops, with standard output electrical connections. 

•	 Developed prototype unit equivalent to 414W per SNL evaluation; 23% collector efficiency, 17.6% 

total area efficiency. 

•	 Buildup pilot manufacturing line to deliver pilot units October 2008. 

Future Directions 

•	 Continue to improve efficiency and power output. 

•	 Deliver pilot and volume manufactured units establishing path to goal of LCOE. 

1. Introduction 

Soliant Energy is a venture capital-backed startup 

focused on bringing advanced concentrating solar 

panels to market. They are the first company to 

integrate tracking solar concentrators into the form 

factor of conventional flat solar panels for rooftop 

applications. The Soliant design breakthrough will 

enable Soliant to put more solar power on a 

rooftop than any other solution. On any given roof, 

Soliant’s high-efficiency panels can double a 

system’s annual output relative to that of 

traditional panels. Equally important, since most 

commercial installations fill the entire roof, these 

high-efficiency panels will increase the size (in 

kW) of the average system, providing a further 

boost to the SAI’s objective to rapidly roll out US 

capacity. 

Soliant’s strategy is to sell directly into the existing 

distribution channel of installers. Soliant’s focus on 

scaling a panel manufacturing business is 

intended to minimize risk and rapidly deploy large 

capacity of new technology into the solar market. 

was completed with delivery of our prototype unit, 

validated by SNL, to meet all key objectives. 

The second phase is design validation (DV) which 

further refines the design and readies it for 

manufacturing. Soliant made substantial progress 

toward completing this phase by establishing a 

pilot manufacturing line in Monrovia, California. 

This phase is expected to be completed in 

December 2008. 

The third phase will be production validation (PV) 

and will culminate in the first large-scale deliveries 

of our product to customers by the end of 2009. 

3. Results and Accomplishments 

•	 Delivered prototype concentrating solar panel 

for SNL test and evaluation. 

•	 Made substantial progress toward completion 

of pilot manufacturing line. 

•	 Signed long-term agreement with cell supplier 

and made progress toward long-term 

agreements with other key suppliers. 

2. Technical Approach 

Soliant’s effort is intended to produce capital 

equipment with high reliability under harsh 

conditions. During the 1st phase (9/07-3/08) the 

goal was engineering validation (EV) to 

demonstrate a working product design. This phase 

The major focus of the effort in FY 2008 was to 

specify the market-entry concentrating solar panel, 

produce a working prototype for SNL’s test and 

evaluation, and make progress on completing the 

manufacturing pilot plant. Soliant specified, 

designed, produced, and validated concentrating 

solar panel that produces annual power equivalent 

Photovoltaic

Systems and Component Development

76
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

to 414Wp flat plate. The panel has a 23% collector 

efficiency and a 17.3% total area efficiency. These 

results are slightly poorer than outlined in the 

negotiated project objectives but the reasons are 

understood. In addition, detailed models produced 

during this fiscal year suggest that space/power 

tradeoffs in the current module design may result 

in a lower LCOE and higher return on investment 

than originally expected because of improvements 

in shade tolerance and spacing parameters. 

Figure 1 shows the prototype panel in a 

photograph taken at SNL during initial testing. 

Soliant began building their pilot manufacturing 

line in March 2008. The tooling was kicked off and 

contracts for long lead-time equipment let in April 

2008. They moved to the new facilities in Monrovia 

in July 2008. By the end of the FY 2008, all the 

machinery for the pilot line had been received, and 

tuning and debugging was begun. 

Figure 1. Soliant Prototype Panel at SNL 

Soliant also developed an in-house testing 

capability for a variety of environmental tests on 

panel components, paving the way for UL listing in 

2009. 

Planned activities for Soliant also included 

developing a receiver packaging capability. We 

have developed this capability and have submitted 

a report for evaluation as a stage-gate deliverable. 

Two subcontract research initiatives have been 

kicked off with MIT. Professor Jung-Hoon Chun is 

studying the manufacturing impacts of various 

alternatives in a multi-echelon supply chain. The 

other, directed by Professor Martin Culpepper, is 

investigating mechanisms for three-dimensional 

articulation of the optical element. These activities 

were delayed due to staffing complications at MIT 

and are still in the early stages of conceptual 

design. 

4. Planned FY 2009 Activities 

Early in FY 2009, Soliant expects to deliver the 

first panels produced from the pilot manufacturing 

line together with a roadmap to the projected 

LCOE. The rest of the year will be devoted to 

customer “beta” installations, obtaining UL listing 

for the product, and setting up full-scale 

manufacturing capability for delivery of UL-listed 

commercial product to paying customers in fourth 

quarter 2009. 

5. FY 2008 Special Recognitions and Patents 

Two U.S. patents were filed. 

6. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator 

Location/E-mail Description/Title of Research Activity FY 2008 

($K) 

Spectrolab, Inc. 

Jeff Peacock 

Sylmar, CA Development and supply of III-V concentrator PV cells 26 

MIT 

Prof. Jung-Hoon Chun 

Prof. Martin Culpepper 

Cambridge, MA Advanced research in manufacturing engineering 59 

SunEdison, Inc. 

Steve Voss 

Beltsville, MD Customer-perspective review of proposed panel 

specification 0 

77 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

___________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

TPP Awardee: SunPower, Inc. “Grid-Competitive Residential and Commercial Fully Automated PV Systems Technology” 

Total Award Amount: $52,647K, DOE/Recipient Share $24,700K/$27,947K 

Objectives: 

•	 Develop high-efficiency, turn-key PV systems for residential and commercial markets to deliver 

electricity at grid parity by 2010–2015. 

•	 Lower LCOE thru optimization of complete supply chain. 

•	 Create U.S.-based jobs. 

Accomplishments: 

•	 Developed solar cell with 23.8% efficiency, measured by NREL. 

•	 Developed prototype laminate for class A fire rating, delivered to NREL. 

•	 Manufactured continuous CZ-ingot growth with high lifetime materials. 

•	 Developed baseline pilot line equipment for unitary product manufacturing for commercial 

applications. 

•	 Developed state-of-the-art Engineer to Order software and implemented design software 

capabilities. 

•	 Verified modeling programs for systems performance to be within 1% of actual system 

performance. 

Future Directions: 

•	 Continue high efficiency, low cost cell development. 

•	 Begin to implement U.S.-based module manufacturing. 

•	 Develop low cost modules with fire rating and for use in bifacial applications. 

•	 Test and validate kerf free Si ‘slicing’ methods. 

1.	 Introduction 

Sunpower Corporation assembled a diverse team 

of leading companies, including several small 

businesses, to form their TPP and believe that, 

through the combined efforts, the program’s 

Levelized Cost of Energy (LCOE) goals for 2010 

and 2015 can be met. SunPower is developing 

turn-key, high-efficiency residential, commercial, 

and large ground-mounted systems that are 

designed to be cost effective in delivering 

electricity at grid parity. This systems-class TPP 

program addresses technology from Si crystal 

growth to systems installed in the field. Partners 

include SunPower, as the prime recipient, and 

Solaicx, SiGen, Dow Corning, Xantrex, Silicon 

Ribbon, and NREL, as sub-recipient partners. 

reliable inverters (Xantrex). The program involves 

development of new processes, the identification 

and evaluation of alternative, reduced cost 

materials, increased productivity in fabrication of 

products and reduced waste. System development 

includes inverters, monitoring, and overall 

streamlining of system deployment. Figure 1 

shows the value chain covered in the award. 

Figure 1. SunPower SAI TPP 

2.	 Technical Approach 

The technical approach includes tasks for the 

development of improved crystal growth 

processes (Solaicx), innovative wafer fabrication 

(SiGen), higher efficiency cells, better modules 

(Dow Corning), automated in-line cell and module 

production equipment development, product 

refinement in modules and systems, and more 

SunPower will develop turn-key, high-efficiency 

residential systems that are both attractive and 

cost effective and deliver electricity at grid parity. 

Key system attributes are LCOE competitive with 

grid power by 2015, module efficiency over 20%, 

and reduced installation time and cost. Sunpower 

intends to reduce system costs from present levels 

by over 50% by 2015. 

Photovoltaic

Systems and Component Development

78
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3. Results and Accomplishments 

SunPower increased cell conversion efficiency, 

leveraging costs across the value chain from raw 

polysilicon to installation. High efficiency cells 

reduce area-related BOS costs, module 

conversion costs, and installation labor. 

Additionally, higher efficiency systems are 

required to provide enough power for the large 

portion of residential rooftops which are space 

constrained. Higher efficiency modules allow for 

higher capacity PV arrays to be mounted within 

the roof area constraints of a home, thereby 

amortizing fixed installation and sales costs over 

more total system watts. For a given system 

power, higher efficiency often permits optimized 

positioning of the array, thereby maximizing total 

value of energy produced (including factoring in 

increased time-of-day pricing). As cost per watt of 

PV is reduced, the total system size will be 

increasingly limited by space instead of total 

system costs, making increased efficiency a 

strong lever for reducing the end user LCOE. 

SunPower manufactures 21% efficient solar cells 

in its 100 MW/year manufacturing facility. 

SunPower modules typically generate 40% more 

power than a similar sized standard crystalline 

module. In addition SunPower cells have a low 

temperature coefficient of -0.38%/C. SunPower 

modules have demonstrated up to 5% higher 

energy harvest than traditional modules with an 

the identical power rating due to their superior 

temperature coefficient and reduced sensitivity to 

spectral variation, angle of incidence, and light 

intensity. SunPower plans to continue to improve 

both conversion efficiency and cell temperature 

coefficient. Figure 2 shows the continuing 

progress toward high efficiency cells. 

Figure 2: Cell Efficiency accomplishments 

under SunPower's SAI program 

Cell efficiencies between 21% and 22% have been 

verified by NREL and are being manufactured. 

An analysis of diffusion pitch dimensions and a 

simulation model to look at efficiency losses due to 

lateral transfer of electrons indicates that 

decreasing the diffusion pitch has an efficiency 

effect greater than 0.5% absolute. Additional 

increases in efficiency have been seen with the 

new pattern design with less dark-space loss and 

smaller recombination losses. The new pitch and 

pattern design has had a net efficiency gain of 

nearly 2%. The new pattern has produced a 

narrower distribution which is more predictable for 

module builds of different wattage rating. 

This new pattern design has been implemented in 

the factory lines. All future production lines will 

include this upgrade and as SunPower increases 

production volume, this represents the major 

fraction of our production product. These new cells 

have enabled SunPower to produce a >20% 

efficient module (SNL-verified). 

Reduced Silicon, Solar Cell & Module Cost 

Solaicx has developed a high-throughput, highlifetime growth method. SiGen is working on a 

kerf-free process to produce high quality Si 

wafers. This process is expected to improve Si 

utilization by several multiples. 

SunPower has successfully incorporated 145­

micron cells in the factory, and full conversion is 

expected by the end of the year to this new 

thickness. 

Bifacial Modules: Another key focus area in the 

past year was bifacial module development. 

Prototype modules were produced with 16.8% 

front side and 10% backside efficiency. Seven test 

units were measured for bifacial performance. The 

amount of frontside Irradiance measured on the 

backside is typically about 10%-20% of the total 

irradiance. A demonstrated kWh/kWp increase of 

7.5% with T20 Tracker compared to SPR-AR 

modules was achieved. Further gains in the 

bifacial modules are possible by reducing module 

mismatch, optimizing cell, and increasing backside 

irradiance. 

Integrated Residential System Solution to Reduce 

Installation Costs: Because the grid-tied residential 

system installation cost is more than 25% of the 

total system costs, the SunPower team is also 

working to reduce these costs. 

79 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SunPower has implemented systematic design 

changes to reduce system installation time, 

training, and standardization to reduce the skill 

level required for installation (from skilled electrical 

trades to semiskilled for example), and software 

and field tool development to automate 

procedures. The streamlined installation process 

allows installers to leverage their substantial fixed 

costs over a greater volume of installations, further 

reducing the overall customer LCOE. 

SunPower deployed streamlined installation 

approaches during Phase 1. Figure 3 shows the 

Nellis AFB 14-MW project, the largest in North 

America, which used some preliminary 

approaches to streamlined deployment. Up to 1 

MW per day was installed at this site. 

Attractive System Design: SunPower’s product 

design features superior appearance with its all 

black back-contact solar cell as well as visually 

appealing module packaging. For mainstream 

adoption of solar systems, appearance will be 

important. New integrated system designs are 

necessary to facilitate the adoption of solar by a 

wider audience. SunPower developed appealing 

integrated residential systems in cooperation with 

its design partners, homebuilder advisors, and an 

architectural review board. 

Figure 3. Nellis AFB PV Installation 

Long-Term Reliability: It is critical to the success of 

the PV market. SunPower focused efforts on 

performing accelerated testing of new cell, 

module, and system technologies. Testing labs 

were established in California and the Philippines, 

closely monitoring field systems for long-term 

performance data. Si solar cells and modules have 

proven long-term performance, but innovations 

such as residential integrated roof systems must 

be carefully designed to avoid potentially higher 

operating temperatures as well as address fire and 

safety aspects unique to an integrated approach. 

In the residential market, inverter reliability in 

particular must be improved to reduce the cost 

and trouble to the homeowner of PV system 

ownership. SunPower is working with Xantrex to 

extend the field life of the inverter. Additionally, 

internet-connected system monitoring and even 

modules are proposed to enhance reliability 

testing and allowing installer partners to deliver 

proactive customer support. 

System Monitoring: SunPower is working to refine 

system modeling software under this program and 

is making significant improvements in the ability to 

predict system performance. The average actual 

kW-hr compared to the predicted kW-hr energy 

production is over 99%. Continued statistical 

analysis and program refinement are planned. 

4.	 Planned FY 2009 Activities 

•	 Develop 5 cells with target efficiency of 23%. 

•	 Develop 5 cells produced with autolinecompatible processes with efficiency greater 

than 20%. 

•	 Produce laminate for class A fire rating. 

•	 Develop next-generation prototype laminate 

for residential applications. 

•	 Manufacture prototype modules in U.S. 

•	 Implement streamlined tools and processes to 

reduce LCOE in installer network. 

5.	 Major FY 2008 Publications 

F. Henley; A. Lamm; S. Kang; Z Liu; L. Tian. 

“Direct Film Transfer (DFT) Technology for KerfFree Silicon Wafering.” 23rd European PV 

Conference Proceedings; September, 2008, 

Valencia, Spain. 

F. Henley; A. Brailove; A. Lamm; T. Heerwagen; 

E. Sauar; M. Nese; R. Steeman; B. Hammel. 

“Kerf-Free Silicon Wafering Equipment 

Configuration Using Beam-Induced Cleave.” 23rd 

European PV Conference Proceedings; 

September, 2008, Valencia, Spain. 

“Solar America Initiative Grid Competitive Systems 

Technology A Systems Driven Approach to Cost 

Reduction.” 33rd IEEE PVSC Proceedings; May 

11–16, 2008, San Diego, California. 

“Solar America Initiative Grid Competitive Systems 

Technology A Systems Driven Approach to Cost 

Photovoltaic

Systems and Component Development

80
 

 

 

 

 

 

 

 

Reduction.” PVs Summit 2008 Proceedings; June Proceedings; August 5-8, 2007, Vail Cascade 

18-20, 2008, San Diego, California. Resort, Vail, Colorado. 

“Solar America Initiative Grid Competitive Systems 

Technology A Systems Driven Approach to Cost 

Reduction.” 17th Workshop on Crystalline Silicon 

Solar Cells & Modules: Materials and Processes 

6. Industry Partners 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 ($K) 

Cost Share 

($K) 

Solaicx 

Peter Bostok 

San Jose, CA Develop continuous CZ Si ingot growing 

technique 2,092 1,046 

SiGen 

Philip Ong San Jose, CA Develop 2MeV proton implant system for fabrication of 50μm thin films 498 298 

Dow Corning 

Becky Laur Midland, MI Development of advanced polymers for solar modules 43 21 

Xantrex 

R Merritt Burnaby, BC 15-Year Inverters, identify reliability mechanisms 680 0 

NREL 

John Benner Golden, CO Solar cell measurement support 48 0 

RibbonTechnology 

Arik Donde San Jose, CA Develop float Si 429 0 

81 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

TPP Awardee: United Solar Ovonics, Inc. “Low Cost Thin Film Building-Integrated PV Systems” 

Total Award Amount: $39,849K, DOE/Recipient Share $19,339K/$20,510K 

Objectives 

•	 Address commercial BIPV market and reduce LCOE to 12.8¢/kWh in 2010 to meet DOE’s shortterm goal. 

•	 Reduce LCOE for commercial BIPV further to 7.6¢/kWh in 2015 to meet DOE’s 2015 goal. 

Accomplishments 

•	 Obtained NREL confirmed ~9.8% stable total-area (0.268 cm2

) efficiency on multi-junction device 

incorporating nc-Si, using small-area modified very high frequency (MVHF) batch reactor on 

Al/ZnO back reflector with production condition constraints. 

•	 Attained thickness uniformity ≥90% for a-Si:H, a-SiGe:H, and nc-Si:H layers deposited over large 

area (450 cm2

) using MVHF batch machine (NREL verified). 

•	 Deposited nc-Si:H films over 50” wide cathode at 0.6 nm/sec and achieved uniformity better than 

80% over 42” wide area, with photoconductivity and morphology similar to small area VHF 

research samples (NREL-verified). 

•	 Increased power rating for our product from 136 W to 140 W. 

•	 Attained ~9.3% stable total-area (0.268 cm2

) efficiency on a-Si:H/a-SiGe:H/a-SiGe:H triplejunction device, using small-area MVHF batch reactor on Al/ZnO back reflector with a-Si:H and aSiGe:H cells deposited at ≥ 0.6 nm/s. Efficiency results were measured at NREL. 

•	 Succeeded in depositing 2-3 micron thick ZnO films over 2”x2” area at ~8 nm/s and prepared on 

both Al/ZnO and Ag/ZnO back reflectors. 

•	 Completed preliminary test and analysis of several important passive components of PV 

laminates. 

•	 Developed prototypes of advanced in-line device monitoring techniques in roll to roll deposition 

machines. 

•	 Designed new cost-effective detachable solar module for easy installation. 

Future Directions 

•	 Advance state-of-the-art technology for nc-Si:H materials and solar cells for both small area and 

large area deposition and attain higher conversion efficiency with production-compatible 

parameters. 

•	 Insert new deposition technology and increase power rating of prototype laminate with increased 

power rating. 

•	 Scale up MVHF technology and explore feasibility of incorporating it in roll-to-roll production 

deposition machines. 

•	 Investigate new module designs, assembly processes, and materials in order to reduce module, 

installation, and systems level costs. 

•	 Advance cutting edge technology for in-line diagnostic tools for in-situ monitoring of device 

parameters. 

1. Introduction 

United Solar Ovonic (Uni-Solar) is working to 

develop a low cost solution for the commercial 

BIPV market. The goal of this program is to reduce 

the cost of various cost centers including modules, 

inverters and other balance of systems (BOS), and 

installation, such that the LCOE will be reduced by 

15%-20% by 2010, consistent with DOE’s 2010 

goal. In addition, they plan to develop new 

materials and new manufacturing processes for 

even higher module efficiency and lower cost 

production processes to address DOE’s 2015 

LCOE goal. The Uni-Solar team includes experts 

from universities, NREL, and industry. 

2. Technical Approach 

Based on the analysis of cost centers and cost 

reductions in each process of the product, the 

company divided the project into five tasks: solar 

module improvement, inverter and balance of 

Photovoltaic

Systems and Component Development

82
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

systems, system engineering and integration, 

deployment, project management, and TPP 

collaborative activity. 

Work on the module represents the largest portion 

of the project and underscores a multi-pronged 

thrust to reduce module cost. One subtask 

focuses on materials and process optimization of 

the current manufacturing lines to improve the 

manufacturing process to increase the efficiency 

of the product and throughput. A second subtask 

addresses the need to improve the solar cell 

device efficiency. Higher cell efficiency directly 

translates to higher product rating for the same 

footprint and thereby lower cost. One way to attain 

higher efficiency cells is to use nc-Si:H material as 

a potential replacement for a-SiGe:H alloys in the 

multijunction cell. In conjunction, the high-rate 

MVHF technology will be developed for deposition 

of a-Si:H, a-SiGe:H, and nc-Si:H materials and 

cells in order to obtain higher efficiency and 

reduce capex. The MVHF technology will be 

developed for up to production-size area 

deposition. 

Another effort is directed towards bringing down 

the cost of stainless steel substrate, wires, and 

encapsulant materials. Innovative detachable 

module solutions will be developed that will reduce 

installation cost. 

Within the Inverter and Balance of System (BOS) 

area, the work focuses on new designs and better 

integration of inverters for building integrated 

applications. In the area of system engineering 

and integration tier, the work focuses on 

inexpensive installation designs for different types 

of roofs. For deployment facilitation, the work 

focuses on demonstrating cost reductions by 

installing, monitoring, and using lessons learned 

from test arrays in different locations on different 

types of roofs. 

This project coordinates the efforts of several 

partners including equipment manufacturers, 

academia, national labs, inverter companies, and 

engineering design companies. The entities were 

selected on the basis of their competence and 

relevance to our flexible BIPV product. 

3. Results and Accomplishments 

Uni-Solar achieved target performance with both 

potential device designs and processes as listed 

under the Accomplishments section above. 

Another goal was the performance against target 

LCOE (for 2010). Uni-Solar’s average module 

selling price was ~$3.00/W for the fiscal year 

ended 6/30/08. The long-term goal is $1.10/W, 

which corresponds to a selling price of $1.83/W, 

assuming a gross margin ~40%. Using projected 

costs of inverter and balance of systems, UniSolar is on track to achieve their LCOE targets for 

2010 and 2015. 

Several other goals were achieved in 

miscellaneous areas, ranging from the small area 

high rate VHF a-Si:H, a-SiGe:H multi-junction 

solar cells, to backend process improvement and 

material reduction. A key achievement was the 

improvement of the power rating of the current 

product. Before Phase I, the current product was 

rated at 136 W and 128 W. Under Phase 1, the 

product rating increased to >140 W. 

4. Planned FY 2009 Activities 

•	 Improve small area nc-Si:H based cells at high 

deposition rates with MVHF glow discharge to 

achieve stable total-area efficiency ~11.0%. 

•	 Achieve stable aperture-area efficiency 

~10.0% for large-area a-Si:H/nc-Si:H based 

multi-junction solar cells. 

•	 Improve light-trapping in cells, possibly using 

Ag/ZnO back reflector in a roll-to-roll machine. 

Conduct appropriate reliability tests before 

qualifying Ag/ZnO back reflector for product. 

•	 Accelerate use of MVHF high rate deposition 

in the roll-to-roll deposition system, including a 

feasibility study of roll-to-roll VHF machines. 

•	 Continue to work with academia and NREL for 

better understanding of a-Si:H, a-SiGe:H, and 

nc-Si:H layers made by MVHF and explore 

new back reflectors. 

•	 Continue to work on cost reduction of stainless 

steel substrate, grid wire for current collection, 

and alternative encapsulant materials. 

•	 Conduct systems engineering and integration 

to develop detachable BIPV solution. 

•	 Continue to advance in-line diagnostic 

technology for in-situ monitoring device 

parameters. 

•	 Work with inverter companies to bring down 

cost. 

•	 Install two BIPV systems. 

83 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5. Major FY 2008 Publications 

Several other papers were submitted to journals 

and conferences, and the following are published 

papers. 

P.G. Hugger; J.D. Cohen; B. Yan; G. Yue; X. Xu; 

J. Yang; S. Guha. “Electronic properties of 

nanocrystalline Si deposited with different 

crystallite fractions and growth rates.” Mater. Res. 

Soc. Symp. Proc.; 1066 (2008), 149. 

B. Yan; G. Yue; Y. Yan; C.S. Jiang; C.W. Teplin; 

J. Yang; S. Guha. “Correlation of hydrogen dilution 

profiling to material structure and device 

performance of hydrogenated nanocrystalline 

silicon solar cells.” Mater. Res. Soc. Symp. Proc.; 

1066 (2008), 61. 

B. Yan; G. Yue; C.S. Jiang; Y. Yan; J.M. Owens; 

J. Yang; S. Guha. “Optical enhancement by 

textured back reflector in amorphous and 

nanocrystalline silicon based solar cells.” Mater. 

Res. Soc. Symp. Proc.; 1100E (2008) at 

www.mrs.org. 

T. Su; T. Ju; B. Yan; J. Yang; S. Guha; P.C. 

Taylor. “Magnetic resonance in hydrogenated 

nanocrystalline silicon thin films,” Mater. Res. Soc. 

Symp. Proc. 1066 (2008), 273. 

G. Yue; B. Yan; J. Yang; S. Guha. “Hydrogenated 

amorphous silicon and silicon germanium triple 

junction solar cells at high rate using RF and VHF 

glow discharges.” 33rd IEEE PVSC Proceedings; 

May 2008, San Diego, California, in press. 

B. Yan; G. Yue; J. Yang; S. Guha. “Correlation of 

current mismatch and fill factor in amorphous and 

nanocrystalline silicon based high efficiency multijunction solar cells.” 33rd IEEE PVSC Proceedings; 

May 2008, San Diego, California, in press. 

X. Xu; K. Lord; G. Pietka; F. Liu; K. Beernink; B. 

Yan; C. Worrel; G. DeMaggio; A. Banerjee; J. 

Yang; S. Guha. “High efficiency ultra lightweight aSi:H/a-SiGe:H/a-SiGe:H Triple-junction solar cells 

on polymer substrate using roll-to-roll technology.” 

33rd IEEE PVSC Proceedings; May 2008, San 

Diego, California, in press. 

6. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity 

FY 

2008* 

($K) 

Cost 

Share 

* ($K) 

University of Oregon 

Dr. J. David Cohen 

Eugen, OR Electronic and Optical characterization of materials for aSi:H, a-SiGe:H, and nc-Si:H materials and solar cells 142 0 

Syracuse University 

Dr. Eric Schiff Syracuse, NY 

Diagnostic development of mobility characterization tool 

for a-Si:H, a-SiGe:H and nc-Si:H solar cells and optical 

modeling studies for light trapping in a-Si:H, a-SiGe:H and 

nc-Si:H solar cells 

149 37 

Colorado School of 

Mines 

Dr. P. Craig Taylor 

Golden, CO Defect characterization of materials and devices using 

NMR, ESR, and PL 150 29 

NREL 

Dr. Pauls Stradins Golden, CO Full material characterization and modeling of high rate materials using various characterization methods 145 0 

*SAI Phase 1 awarded amounts. 

Photovoltaic

Systems and Component Development

84
 

 

 

 

____________________________________________________________________________________ 

 

 

____________________________________________________________________________________ 

 

 

 

University Partnerships 

Performing Organizations:	 Arizona State University (ASU); California Institute of Technology 

(Caltech); Georgia Tech Research Corporation (GIT); Massachusetts 

Institute of Technology (MIT); North Carolina State University (NCSU); 

Pennsylvania State University (Penn State); University of Delaware (UD); 

University of Florida (UF); University of Toledo (UT) 

Key Technical Contacts:	 Carolyn Elam (DOE/GO, Primary Contact), 303-275-4953, 

carolyn.elam@go.doe.gov 

Joe Lucas (DOE/GO), 303-275-4849, joe.lucas@go.doe.gov 

Jim Payne (DOE/GO), 303-275-4756, jim.payne@go.doe.gov 

Holly Thomas (DOE/GO), 303-275-4818, holly.thomas@go.doe.gov 

DOE HQ Technology Manager:	 Marie Mapes, 202-586-3765, marie.mapes@hq.doe.gov 

FY 2008 Budget:	 $3,500K (DOE/GO) 

Objectives 

•	 Leverage university understanding and experience to improve photovoltaic (PV) products and 

process development. 

•	 Develop projects offering direct, near-term improvements in PV products and development 

processes. 

Accomplishments 

•	 Developed multidimensional model to establish design for 20%-efficient cells with passivated 

back contact and developed structure meeting the model. (GIT) 

•	 Found suitable SS substrate base for Cu(InGa)Se2 PV devices and achieved small area device 

efficiency of 11%. (UD-Eser) 

•	 Determined reaction pathway for synthesis of CuGaSe2, CuInSe2, and CuInxGa1-xSe from basic 

precursor structures. (UF) 

•	 Produced several superlattice structures with 15% In and 68% P with fair results, and researchers 

are approaching a closely balanced superlattice.(NCSU) 

Future Directions 

•	 Evaluate engineering of receivers. (ASU) 

•	 Identify best dielectric system with reduced shunting and good optical properties. (GIT) 

•	 Develop Bragg reflector with reflectivity of > 80% and a working cell (< 1.2--1.3 eV). (NCSU) 

•	 Demonstrate 12% device on SS/SBR with evaporative and selenized Cu(InGa)Se2 films less than 

1.5 μm thick (09/09).(UD-Eser) 

•	 Fabricate and characterize InP/Si templates on 100-mm Si substrates. (CalTech) 

•	 Synthesize low-bandgap, high-mobility acene-based organic semiconductors with improved 

stability. (PennState) 

1. Introduction	 2. Technical Approach 

Universities hold a fundamental understanding of University PV Process and Product Development 

materials and device physics as well as Support awarded 11 projects in six topic areas: 

experience with lab-scale processes and prototype cadium telluride (CdTe)/1 award, copper indium 

production. This experience uniquely positions gallium diselenide (CIGS)/2 awards, concentrating 

universities in transitioning PV technology from lab PV (CPV)/3 awards, thin silicon (Si)/1 award, 

to marketplace. Market-oriented research exposes organic PV/1 award, and wafer Si/3 awards. 

students to PV-related commercialization. 

85 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Agreement Title 

FY 

2008 

Budget 

($K) 

ASU – G. Tamizhmani 

Reliability Evaluation of Concentrator 

Photovoltaic Modules per IEC Qualification 

Specifications 250 

Caltech – H.A. Atwater 

100 mm Engineered InP-on-Si Laminate 

Substrates for InP-based Multijunction 

Solar Cells 355 

GIT – A. Rohatgi 

Development of Rear Contact 

Technologies for Next Generation High 

Efficiency Commercial Si Solar Cells 356 

MIT – A. Buonassisi 

Defect Engineering, Cell Processing, and 

Modeling for High-Perfomance, Low-Cost 

Crystalline Si PV TBD 

NCSU – S.M. Bedair 

Tunable Narrow Band Gap Absorbers for 

Ultra High Efficiency Multi-junction Solar 

Cells 361 

Penn State – C.A. Grimes 

TiO2 Nanotube Array-Organic 

Semiconductor Heterojunction Solar Cells 

for Efficient, Low Cost, Large Area 

Scalable Solar Energy Conversion 499 

UD – E. Eser 

Development of a Low Cost Insulated Foil 

Substrate for Cu(InGa)Se2 PV 497 

UD – U. Das 

High Efficiency Back Contact Si 

Heterojunction Solar Cells 357 

UF – T. Anderson 

Routes for Rapid Synthesis of CuGaxIn1-

xSe2 Absorbers 194 

UT – X. Deng 

High-Rate Fabrication of a-Si-Based ThinFilm Solar Cells Using Large Area VHF 

PECVD Processes 340 

UT – R. Collins 

Improved CdTe PV Modules by 

Atmospheric Pressure Vapor Deposition 290 

3. Results and Accomplishments 

3.1 Reliability Evaluation of Concentrator 

Photovoltaic Modules per IEC Qualification 

Specifications (ASU) 

In this collaborative project, the testing cost and 

time for the concentrator photovoltaics (CPV) 

partners will be reduced by as much as 65%. 

Overall, the faster qualification/reliability testing 

and certification strategy planned will benefit the 

entire CPV community and allow the CPV 

manufacturers/technology to effectively compete 

with the flat-plate PV manufacturers/technology in 

the marketplace with independently demonstrated 

performance reliability/qualification and 

comparable testing duration. This cooperative 

project is expected to increase the production 

capacity of CPV products. 

3.2 100-mm Engineered InP-on-Si Laminate 

Substrates for InP-based Multijunction Solar Cells 

(Caltech) 

This grant expands upon recent advances in III-V 

laminate substrate development for multijunction 

solar cell technology to achieve low-cost, high 

efficiency multijunction solar cells fabricated on 

100-mm InP/Si laminate substrates. The approach 

is to scale-up Caltech’s previously developed 

InP/Si laminate substrate process for III-V 

multijunction cell fabrication to 100 mm diameter 

InP/Si substrates, developing a robust process for 

fabrication of 100-mm InP/Si substrates, and a 

cost-mode for high volume manufacturing. Wafer 

specification sfor an InP/Si substrate that is 

commercially manufacturable at high volumes will 

be established and validation from prototype 

fabrication of InGaAsP/InGaAs and 

InAlAs/InGaAsP/InGaAs multijunction solar cells. 

3.3 Development of Rear Contact Technologies 

for Next Generation High Efficiency Commercial Si 

Solar Cells (GIT) 

The objective is to develop low-cost high-quality 

rear contacts and fabricate production-ready highefficiency monocrystalline (~20%) and 

multicrystalline (17%-18%) Si solar cells. 

•	 Developed multidimensional model to 

establish design for 20%-efficient cells with 

passivated back contact. 

•	 Modeled and optimized rear contact geometry 

as function of contact spacing and surface 

recombination velocity. 

•	 Developed thermally stable dielectric for 

passivated rear contact structure that exceeds 

requirements of our model and reduces SRV 

to <100 cm/s prior to contact formation. 

3.4 Defect Engineering, Cell Processing, and 

Modeling for High-Perfomance, Low-Cost 

Crystalline Si PV (MIT) 

The objective is to close the efficiency gap 

between industrial multicrystalline Si (mc-Si) and 

monocrystalline Si solar cells, while conserving the 

economic advantage of low-cost, high-volume 

substrates inherent to mc-Si. The project objective 

will be supported by the following: (1) Identify and 

decouple the impacts of primary lifetime-limiting 

defects; and (2) Develop low-cost defect 

engineering technologies to achieve 

homogeneous and high bulk minority carrier 

Photovoltaic

Systems and Component Development

86
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

lifetimes, approaching the 100 μs range, in lowcost crystalline Si substrates; and (3) Develop 

defect-tolerant device processing technology, 

capable of supporting high-efficiency solar cells at 

low cost. 

3.5 Tunable Narrow Band Gap Absorbers for Ultra 

High Efficiency Multi-junction Solar Cells (NCSU) 

The objective is to reduce LCOE by improving the 

efficiency of III-V multi-junction solar cell and lead 

to a practical and achievable efficiency >45% 

through a four-junction cell. Using organometallic 

chemical vapor deposition at 600oC and 625oC, 

super lattice structures have successfully been 

grown with periods consisting of approximately 

15% In and 68% P with GaAs transition layers 

between each In and P layer, as confirmed by 

various measurements including SEM. 

Several superlattice structures with 15% In, 68% P 

have been produced with fair results and 

researchers are approaching a closely balanced 

superlattice. 

3.6 TiO2 Nanotube Array-Organic Semiconductor 

Heterojunction Solar Cells for Efficient, Low Cost, 

Large Area Scalable Solar Energy Conversion 

(Penn State) 

This project aims to reliably produce scalable and 

highly efficient solid state solar cells, using a 

heterojunction of TiO2 nanotube arrays and an 

organic semiconductor with a goal to manufacture 

low-cost, large-area air-stable solar cells with 

photoconversion efficiencies of 6%-8%.Four major 

technical objectives are: 

•	 Optimize performance of transparent TiO2 

nanotube array-P3HT-PCBM blend double 

heterojunction solar cells. 

•	 Synthesize functionalized pentacene 

derivatives and incorporate them into TiO2 

nanotube array hybrid solar cells in order to 

decrease band gap, increase stability, and 

improve compatibility with oxide surfaces. 

•	 Explore high-throughput fabrication techniques 

for formation of active layer organic 

semiconductor films on TiO2. 

•	 Quantify limiting parameters affecting solar 

cell performance. 

3.7 Development of a Low Cost Insulated Foil 

Substrate for Cu(InGa)Se2 PV (UD-Eser) 

The goal is to develop low cost stainless-steel 

(SS) flexible-substrate coated with hightemperature silicone-based resin (SBR) dielectric 

for use in the processing of Cu(InGa)Se2-based 

PV. 

•	 Found suitable SS substrate base for 

Cu(InGa)Se2 PV devices. 

•	 Achieved small area device efficiency of 11%. 

•	 Tested Web-transport mechanism of R2R 

system; SS-foil substrate up to 18 inch/min 

speed. 

3.8 High Efficiency Back Contact Si Heterojunction 

Solar Cells (UD-Das) 

The objective is to implement an interdigitated 

back contact (IBC) Si solar cell using low 

temperature heterojunction (HJ) depositions. The 

use of Si HJs allows a simpler design of rear 

contact solar cells and higher performance at 

lower deposition temperatures. 

•	 Demonstrated bi-layer c-Si front surface 

passivation structure of 2 nm a-Si:H / 80 nm 

SiNX with surface recombination velocity < 10 

cm/s and good antireflection properties. 

•	 Incorporated intrinsic a-Si:H (i. a-Si:H) buffer 

layer at the rear surface. A detailed device 

characterization and optimization of a-Si:H 

buffer layer provided pathways to improve fill 

factor in IBC-SHJ cells. 

3.9 Routes for Rapid Synthesis of CuGaxIn1-xSe2 

Absorbers (UF) 

The objective is to develop predictive models that 

quantitatively describe reaction pathways to 

synthesize CIGS for increased throughput from 

the shortened reaction time for absorber 

synthesis. Additional cost reductions due to 

process scale-up will be realized by providing 

quantitative rate data. The target is a synthesis 

time 2 minutes or faster. 

•	 Determined reaction pathway for synthesis of 

CuGaSe2, CuInSe2, and CuInxGa1-xSe from 

basic precursor structures. 

•	 Developed thermodynamic model describing 

contained Cu-In-Ga-Se ternary phase 

diagrams. 

•	 Built diffusion mobility database to 

quantitatively predict absorber synthesis rates. 

3.10 High-Rate Fabrication of a-Si-Based ThinFilm Solar Cells Using Large Area VHF PECVD 

(Very High Frequency Plasma-Enhanced 

Chemical Vapor Deposition) Processes (UTAnderson) 

Two objectives of this effort are (1) to develop and 

improve a large area (3 ft × 3 ft) VHF-PECVD

system for high rate fabrication of 8 Å/s a-Si and 

20 Å/s nc-Si absorber layers with high uniformity in 

film thicknesses and in material structures, and (2) 

develop and optimize large-area VHF PECVD 

87 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

processes to achieve high-performance a-Si/nc-Si 

tandem-junction solar cells with 10% stable 

efficiency. 

3.11 Improved CdTe PV Modules by Atmospheric 

Pressure Vapor Deposition (UT-Deng) 

This project will advance an atmospheric pressure 

vapor deposition (APVD) process for CdTe 

modules and to achieve module performance 

comparable to competing CdTe technologies while 

retaining the significant manufacturing cost 

advantages of APVD. Steps include: 

•	 Incorporate glass optimized for PV 

applications into the production line for 

improved module efficiency greater than 10%. 

•	 Apply spectroscopic ellipsometry in spatially 

scanning mode in on-line and other optical 

probes for real-time for process monitoring. 

•	 Develop APVD-compatible activation process. 

•	 Develop hi-performance back contact that 

does not require vacuum processing and is 

compatible with monolithic cell integration on 

glass by laser scribing. 

•	 Improve module monolithic integration process 

for greater scribe process latitude. 

•	 Verify less than 1% decay of module 

performance per year. 

4. Planned FY 2009 Activities 

ASU 

•	 Procure, install, and commission humidityfreeze chamber and damp-heat chamber; 

conduct engineering evaluation of receivers 

and systems (thermal cycling of receivers; 

outdoor exposure testing of systems) 

GIT 

•	 Develop spin-on dielectrics with low fixed 

charge density (< ±1011cm-2). (01/09, GIT) 

•	 Identify best dielectric system with reduced 

shunting and good optical properties. (01/09) 

•	 Evaluate recombination in contact window and 

assess its impact on cell performance. (04/09) 

•	 Deposit SiCx using silane-free solid source 

and evaluate surface recombination velocity 

on p-type surfaces. 

•	 Optimize design of a-Si/doped a-Si 

passivation including thickness and doping 

concentration of each a-Si layer. (07/09) 

•	 Demonstrate screen-printed passivated, local 

back contact structure can reduce or eliminate 

warping of thin wafers. (10/09) 

•	 Demonstrate a back surface recombination 

velocity below 200 cm/s and a back surface 

BSR of 90%-97% on crystalline Si solar cells. 

(10/09) 

NCSU 

•	 Develop InxGa(1-x)As x>0.3 GaAs(1-y)Py y>0.8 

and carrier concentration less than 1016/cm3

. 

(11/08) 

•	 Optimize tIn, tP, x, and y to achieve strain for 

matched structure and avoid relaxation. 

(01/09) 

•	 Design necessary masks. (07/09) 

•	 Develop Bragg reflector with reflectivity of > 

80%. (08/09). And a working cell (< 1.2--1.3 

eV). (10/09) 

UD-Eser 

•	 Demonstrate pinhole-free Si-based resin 

(SBR) coating. (03/09) 

•	 Demonstrate 12% device on SS/SBR with 

evaporative and selenized Cu(InGa)Se2 films 

less than 1.5 μm thick (09/09). 

•	 Start deposition of Na-doped Cu(InGa)Se2 

films on 5- to 10-ft. rolls with 10% device 

efficiency. 

CalTech 

•	 Fabricate and characterize InP/Si templates 

on 100-mm Si substrates. (09/09) 

Penn State-Grimes 

•	 Optimize nanotube pore size, wall thickness, 

and length in existing device configuration 

consisting of P3HTPCBM blend infiltrated into 

TiO2 nanotube arrays. 

•	 Optimize polymer blend ratio and film 

thickness. 

•	 Synthesize low-bandgap high mobility acene 

based organic semiconductors with improved 

stability. 

•	 Understand configuration of polymer chains 

inside pores and determine penetration of 

polymer into nanotubes. 

UD–Das 

•	 Investigate inorganic and organic passivation 

layers for front illuminating side of IBC-SHJ 

structure to further reduce optical losses. 

•	 Optimize plasma process for rear-side 

passivation, emitter, and contact-layer 

deposition, guided by two-dimensional 

numerical simulations. 

University of Florida 

•	 Design and prepare base-CIGS thin films, 

based on (a) elemental layers, (b) selenization 

of precursor, and (c) bilayer precursor. 

•	 Complete assessment of Cu-Ga-Se and CuGa-In ternary phase diagram. 

•	 Implement DICTRA modeling of binary metal 

couples to extract diffusion mobilities of Cu-In, 

Cu-Ga, and Ga-In and modeling of binary Se 

Photovoltaic

Systems and Component Development

88
 

 

 

 

 

 

 

 

 

 

 

 

 

 

couples to extract diffusion mobilities: Cu-Se, 

In-Se, and Ga-Se. 

UT–Deng 

•	 Complete numerical simulation of stable 

uniform plasma for large-area VHF-PECVD 

chamber. 

•	 Complete detailed engineering design and 

installation of VHF. 

•	 Modify PECVD electrode hardware, gas 

delivering system, and cathode and gas 

shower configuration to improve uniformity. 

•	 Demonstrate large area VHF PECVD 

processes for high-rate ≥8( Å/s) a -Si 

deposition with thickness non-uniformity of 

<±10%. 

UT–Collins 

•	 Determine minimum CdTe thickness and 

optimum thickness for CdS. 

•	 Determine optimum optical configuration for 

on-line scanning. 

•	 Develop scribes fabrication processes. 

5. Major FY 2008 Publications 

UD-Das 

U.K. Das; D. Xu; O. Jani; M. Lu; S. Bowden; R.W. 

Birkmire. “Designing rear surface for carrier 

transport in all back contact silicon heterojunction 

solar cells.” 

Caltech 

G.M. Kimball; N.S. Lewis; H.A. Atwater. 

Proceedings of 33rd IEEE Photovoltaic 

Specialists Conference; May 11-16, 2008, San 

Diego, California. 

6. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 

($K) 

Cost 

Share 

($K) 

ASU/G. Tamizhmani 

Solfocus/Warren 

Nishikawa 

Soliant Energy/Brad Hines 

Mountain View, 

CA 

Pasadena, CA 

Provide CPV receivers and one assembly 

for Thermal Cycling testing and Outdoor 

Exposure testing 

0 

0 

50 

50 

Caltech/H.A. Atwater 

Spectrolab/Daniel C. Law Sylmar, CA Provide assistance with cell processing, GaAS cell fabrication 375 0 

GIT/A. Rohatgi 

SiXtron Advanced 

Materials, Inc. 

Varennes, 

Quebec Canada 

Provide silane-free solid source for SiN­

/SiC-bsed AR-coatings and passivation 

layers for Si cells 

454 0 

NCSU/S.M. Bedair 

Spectrolab/Ken 

Edmondson 

Sylmar, CA Support integration of NCSU subcell into 

multi-junction cell 75 0 

Penn State/C.A. Grimes 

University of Kentucky Lexington, KY Assist in design and synthesis of organic semiconductors 499 99 

UD/E. Eser 

Dow Corning/Elizabeth 

McQuiston 

Midland, MI Develop silicone-based dielectric coated SS 

foils 497 99 

UD/U. Das 

SunPower/Richard 

Swanson 

Sunnyvale, CA Provide high-performance IBC cells 361 92 

UT/X. Deng 

Xunlight Corp./X. Deng Toledo, OH Provide materials, labor, and equipment for Xunlight’s roll-to-roll production line 

340 68 

UT/R. Collins 

Solar Fields/Norm 

Johnston 

University of Nevada, Las 

Vegas/Clemens Heske 

University of Michigan 

Perrysburg, OH 

Las Vegas, NV 

Ann Arbor, MI 

Supply large area thin film deposition 

processing 

Provide electron and photon spectroscopies 

Provide high resolution electron microscopy 

72 

25 

14 

37 

6 

89 Photovoltaic

Systems and Component Development
 

 

 

___________________________________________________________________________________ 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

Photovoltaic Technology Incubator 

Performing Organization:	 National Renewable Energy Laboratory (NREL) 

Key Technical Contact:	 Martha Symko-Davies (NREL), 303-384-6528, 

Martha_symko_davies@nrel.gov 

DOE HQ Technology Manager:	 Scott Stephens, 202-586-0565, scott.stephens@ee.doe.gov 

FY 2008 Budget:	 $10,127K (NREL) 

Objectives 

•	 Shorten the timeline for companies to transition prototype and pre-commercial photovoltaic (PV) 

technologies into pilot and full-scale manufacture. 

•	 Move companies into commercial production quickly and successfully. 

•	 Position companies to be competitive for Technology Pathway Partnership (TPP) funding 

opportunities. 

•	 Focus the efforts of subcontractors to a limited number of high-impact module technology 

improvement opportunities (TIOs) that are on the critical path to scaling-up their technology to full 

manufacture. 

Accomplishments 

•	 Completed merit criteria and analysis to select negotiations for second round of Incubator
 

subcontracts in June 2008.
 

•	 Down-selected subcontracts via Stage gate to seven subcontracts in August 2008. 

Future Directions 

•	 Issue a third letter of interest (LOI) for the Solar America Initiative (SAI) PV Incubator in fiscal 

year (FY) 2009. 

•	 Complete merit review for responses to the LOI. 

•	 Complete stage-gate review of individual progress versus deliverables by late summer 2009. 

•	 Begin negotiations with the companies selected under the second Incubator solicitation, which 

include: 1366 Technologies, Skyline Solar, Solexel, Solasta, Innovalight, and Spire Corp. 

•	 Issue a LOI for the SAI PV PRE-Incubator in FY 2009. 

1. Introduction 

The primary objective of the SAI PV Technology 

Incubator project is to shorten the timeline for 

companies to transition PV technologies into pilot 

and full-scale manufacture. The incubator concept 

generally applies to companies that are not far 

enough along in technology and product 

development pathways to be positioned to qualify 

for the first of the SAI’s Technology Pathway 

Partnership (TPP) awards. Successful participation in the SAI PV Technology Incubator project 

will quickly move companies into commercial production and position those companies to be 

competitive for the next TPP funding opportunity, 

which is expected to be issued in 2010. 

SAI provides significant opportunities for collaboration and partnership among industry and 

university researchers to develop and improve 

solar energy technologies. This SAI PV Technology Incubator project targets research and 

development on PV cell and module prototypes 

with demonstrated functionality in either large-area 

cell/module form or, preferably, prototypes 

produced in pilot-scale operations. The emphasis 

on proposed activities should be focused on the 

barriers to manufacturing scale-up and 2010 

commercialization. 

Advances are needed to achieve prototype 

modules and pilot production, which will be 

facilitated through projects funded under this LOI. 

It is expected that the subcontract duration will be 

Photovoltaic

Systems and Component Development

90
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

18 months for each award made under this 

solicitation. Entrance opportunities for the Incubator project are anticipated every 9 months as 

funding opportunities become available. The 

entrance criterion is demonstrated PV cells or 

process lab devices or modules. A successful 

demonstration for the entrance criterion is a 

quantifiable and verifiable baseline measurement. 

The successful exit criterion would be for prototype modules and pilot production demonstration 

greater than 3 megawatts per year (mW/year). 

These entry and exit criteria are provided to 

applicants as general guidelines for maturity of 

technology that the U.S. Department of Energy 

(DOE) intends to fund through this LOI, but the 

guidelines are flexible. Applicants may be more 

advanced than the stated entrance criteria at the 

time of application and may plan to be more 

advanced than ~3mW/year pilot production at the 

completion of their “incubator” project. 

2. Technical Approach 

2.1. SAI PV Incubator Management 

The Project Management and Support subtask 

addresses: (1) management of the Incubator 

project; (2) management of subcontracts awarded; 

and (3) coordination of NREL in-house activities in 

support of the small businesses. 

Table 1. PV Incubator Project Tasks and
 

Budget
 

Task Title FY 2008 

Budget ($K) 

PV Technology Incubator 

Management 11,384 

PV Technology Incubator 

Subcontracts 2,500 

2.2. SAI PV Incubator Scope 

NREL solicited LOIs from individual U.S. small 

businesses and small business-led teams that 

were working on research and development of 

demonstrated PV cell and module prototypes. 

The LOI emphasized overcoming the barriers to 

manufacturing scale-up and 2010 commercialization. 

Topic Areas include: 

•	 Novel wafer-based silicon (Si) modules 

•	 Polycrystalline thin films 

•	 Film silicon on a foreign substrate 

•	 High-efficiency cells, including 

multijunction, and concentrating PV (CPV) 

module concepts 

•	 Organic PV, dye-sensitized solar cells, or 

other polymer-based solar cells 

•	 Low-X concentration CPV systems with 

limited or 1-axis tracking module designs 

•	 Low-X Si modules, 3-10X. 

Table 2. FY 2008 PV Incubator Subcontractors 

Subcontractor Title of Subcontract 

AVA Solar Advanced CdTe PV 

Technology 

Blue Square 

Energy 

Silicon Solar Cells on Low Cost 

Substrates 

EnFocus 

Engineering 

Pilot Manufacturing of RooftopReady Solar Panels Using 

High Concentration PVs 

CaliSolar New Metallization Technique 

Suitable for 6-mW Pilot 

Production of Efficient 

Multicrystalline Solar Cells 

Using Upgraded Metallurgical 

Si 

MicroLink Epitaxial Liftoff Fabrication of 

Low-Cost, High-Efficiency, 

GaAs-Based, Dual-Junction 

Solar Cells for Concentrator 

Applications 

Plextronics Economic On-Grid Solar 

Energy via Organic Thin Film 

Technology 

PrimeStar 

Solar 

Production Scale-up of World 

Record CdTe/CdS Cell 

Solaria Development of a Wafer-Si 

Solar Cell Based LowConcentration PV Module 

SolFocus Reflective Optics CPV Panels 

Enabling Large-scale, Reliable 

Generation of Solar Energy 

Cost-competitive with Fossil 

Fuels 

SoloPower CIGS Technology based on 

Electroplating 

3. Results and Accomplishments 

AVA Solar has demonstrated consistent and 

uniform thin-film solar cell performance, a 

91 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

manufacturing friendly process capable of 

fabricating thin-film solar cell efficiency of more 

than 11% conversion efficiency (verified by NREL) 

deposited on 16.5 inch x 16.5 inch low-cost, sodalime glass substrates. Also demonstrated was a 

reliable thin-film CdTe module performance that 

passed the hot and humid test of 1000 hours at 85 

degree C and 85% relative humidity. 

Manufacturing consistency has been 

demonstrated with 5-day production runs with a 

throughput for 1 module for the absorber layer 

deposition done every 2 minutes. Thin-film CdTe 

module aperture-area conversion efficiency of 

more than 8.0% for 16.5 inch x 16.5 inch size 

substrates has been fabricated and verified by 

NREL. In addition, material utilization of the 

semiconductor layers in excess of 90% has been 

demonstrated in the pilot line. AVA Solar has 

developed a robust, industrial scale process for 

fabricating thin-film CdTe modules at a potential 

cost of less than $1/watt, which will significantly 

reduce the cost of generating solar electricity. 

The primary effort of Primestar Solar is to 

accelerate the commercialization of the highly 

efficient thin film PV technology for various 

applications such as commercial rooftop and gridtied applications. The research involves 

developing high performance prototype minimodules (6 inch x 6 inch), as well as designing 

and commissioning a pilot line for full-size 

commercial thin film power modules. The project 

involves qualifying thin-film CdTe record 

performance advanced window layers films (CTO, 

ZTO, CdS:O) for commercial low-cost 

manufacturing with films deposited uniformly 

across the mini-module glass substrates. In 

addition, film deposition rates for the window 

layers are adapted for large-scale production. 

Research was also performed to optimize the thinfilm CdTe mini-modules using the advanced 

window layers developed in this subcontract. A 

full-sized power module pilot line equipment 

design and cost estimates have also been done as 

part of the research activity. Prototype thin-film 

CdTe power modules will be fabricated in the next 

several months. 

The SolFocus effort is developing a 500x 

concentrating PV module with a folded reflective 

design in a compact frame. The design can be 

manufactured in volume and is scalable to 

gigawatt (gW) capacity. Major highlights of the 

effort include the design and construction of a 

concentration power unit with an efficiency of 

25.5% and a full-sized module constructed with 

these units that exhibited an NREL-verified 

efficiency in excess of 20%. 

SoloPower, Inc., improved their CIGS roll-to-roll 

processing and demonstrated control of their 

composition ratios to 0.94 for Cu/(In+Ga) and 0.26 

for Ga/(In+Ga). This was well within the targeted 

average ranges of a Cu/(In+Ga) ratio of 0.94 

+0.09/-0.07 and a Ga/(Ga+In) ratio of 0.26 +0.03/-

0.02. They have also demonstrated NRELverified 100-cm2 solar cell efficiencies of 12% and 

an NREL-verified 1-m2 aperture area module 

efficiency of 8.96%. 

CaliSolar, Inc., developed their cell processing 

using shadow mask electroplated front contacts 

and best known conditions resulting in the 

demonstration of twelve NREL-verified multi-Si cell 

efficiencies of 15%. They have also demonstrated 

their process capability for laser grooving of Si 

wafers at as low as 17μm, as well as 

masking/plating on Si wafer with electroplated line 

widths of as low as 32μm. This was well below 

the 30μm laser grooves and 50-μm line widths 

required under this subcontract. 

4. Planned FY 2009 Activities 

The subcontracts from the second solicitation will 

be awarded in December 2008. These 

subcontracts will then undergo a Stage-Gate 

review during the summer of 2009. At that time an 

evaluation of progress will occur and a 

determination to continue with the second 9-month 

phase of the subcontract will be made. 

A third PV Incubator Solicitation will be released in 

2009. It is anticipated that the new round of 

subcontracts will be finalized in late summer of 

2009. 

Additionally, the Pre-Incubator will be released in 

January of 2009. This project would be for the 

R&D of an early stage idea/application that would 

grow into a prototype and be a year-long effort. 

Photovoltaic

Systems and Component Development

92
 

 

 

 

 

 

 

 

5. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location/E-mail Description/Title 

of Research Activity 

FY 

2008 

($K) 

Cost 

Share 

($K) 

AVA Solar, Inc. 

Pascal Noronha 

Fort Collins, CO 

Pnoronha@avasolar.com Advanced CdTe PV Technology 571.9 290.7 

Blue Square Energy, Inc. 

Jerry Culik 

North East, MD 

jculik@bluesquareenergy.com 

Silicon Solar Cells on Low Cost Substrates 390.3 201.1 

EnFocus Engineering 

Corp. 

Jason Lu 

Sunnyvale, CA 

jason.lu@enfocuscorp.com Pilot Manufacturing of Rooftop-Ready Solar 

Panels Using High Concentration PVs 541.3 200.2 

CaliSolar, Inc. 

Alain Blosse 

Sunnyvale, CA 

alain@calisolar.com 

New Metallization Technique Suitable for 6-

MW Pilot Production of Efficient 

Multicrystalline Solar Cells Using Upgraded 

Metallurgical Si 

651.0 968.4 

MicroLink Devices 

Noren Pan 

Niles, IL 

npan@mldevices.com 

Epitaxial Liftoff Fabrication of Low-Cost, 

High-Efficiency, GaAs-Based, Dual-Junction 

Solar Cells for Concentrator Applications 

533.3 235.2 

Plextronics 

Shawn Williams 

Pittsburgh, PA 

swilliams@plextronics.com 

Economic On-Grid Solar Energy via 

Organic Thin Film Technology 1050.0 262.5 

PrimeStar Solar 

Fred Seymour 

Golden, CO 

fred.seymour@primestarsolar.c 

om 

Production Scale-up of World Record 

CdTe/CdS Cell 1008.6 492.3 

Solaria Corp. 

Kevin Gibson 

Fremont, CA 

Kevin@solaria.com 

Development of a Wafer-Si Solar Cell 

Based Low-Concentration PV Module 633.2 809.2 

Sol Focus, Inc. 

Steve Horne 

Palo Alto, CA 

steve_horne@solfocus.com 

Reflective Optics CPV Panels Enabling 

Large-scale, Reliable Generation of Solar 

Energy Cost-competitive with Fossil Fuels 

806.5 659.9 

SoloPower, Inc. 

Bulent Basol 

San Jose, CA 

bbasol@solopower.com 

Commercialization of High Efficiency Low 

Cost CIGS Technology Based on 

Electroplating 

70.7 250.8 

93 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

Thin Film PV Partnership Program 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

DOE Golden Field Office (DOE/GO) 

Key Technical Contact: Harin S. Ullal (NREL), 303-384-6486, harin_ullal@nrel.gov 

DOE HQ Technology Manager: Scott Stephens, 202-586-1201, scott.stephens@ee.doe.gov 

FY 2008 Budget: $2,266K (NREL) 

Objectives 

•	 Support the Solar America Initiative Technology Partnership Pathway project to achieve levelized 

cost of energy by 2015. 

•	 Support the near-term transition to first-time manufacturing and commercial introduction of 

reliable thin-film amorphous silicon (a-Si), copper indium diselenide (CIS), cadmium telluride 

(CdTe), and film silicon modules. 

•	 Build a technology base upon which these advanced photovoltaic (PV) technologies can continue 

to be successful in improving manufacturing and to progress in performance, reliability, and cost 

reductions, resulting in products that are able to compete in the PV marketplace. 

•	 Sustain innovation to support progress toward ambitious long-term PV cost and performance 

goals (e.g., 15% efficient modules costing less than $50/m2 and capable of lasting 30 years), 

which are appropriate for cost-competitive PV-generated electricity. 

Accomplishments 

•	 Met one important OMB/DOE/EERE/SET joule milestone. First Solar achieved a production cost 

of $1.14 per watt from $1.60 for thin film PV technology and then further reduced it to $1.08. 

•	 Provided support to assist three technology partners, U.S. manufacturing facilities, to expand: 

First Solar, 144 MWp; Uni-Solar, 160 MWp; and Global Solar, 40 MWp. 

•	 Supported industry growth, when possible, as the production of thin films in the United States 

grew from about 10 MWp in 2003 to an estimated more than 250 MWp in 2008. 

Future Direction 

•	 Phase out remaining subcontracts in the Thin Film PV Partnership Program. Of the 14 

subcontracts in FY 2008, only three subcontracts remain in FY 2009: First Solar, Global Solar, 

and University of South Florida. 008. 

1. Introduction 2. Major FY 2008 Presentations and 

Publications 

Thin-film photovoltaic (PV) technologies have 

good potential to meet ambitious cost and We have published several subcontract reports 

performance goals, such as achieving long-term and presentations. Other important publications 

goals for a levelized cost of energy by 2015. The and presentations include the following: 

Thin Film PV Partnership Program is designed 

to accelerate progress toward meeting those H.S. Ullal. “Recent Developments in Thin Film 

goals. The partnership includes subcontracted Solar Cell Technologies.” Presented at the 

research and development (R&D) in CIS, CdTe, International Conference on Solar Cells, Cochin, 

a-Si, and new thin films, such as film silicon. The Kerala, India. Jan. 21-23, 2008. 

partnership members work closely with NREL’s 

internal researchers, facilitating collaborative H.S. Ullal; B. Von Roedern. “Thin Film CIGS and 

activities with academia and U.S. thin-film CdTe PV Technologies: Commercialization, 

industry groups. Critical Issues and Applications.” Solid State 

Technology, February 2008. 

Photovoltaic

Systems and Component Development

94
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B. Von Roedern; H.S. Ullal. “The Role of 

Polycrystalline Thin Film PV Technologies in 

Competitive PV Module Markets.” 33rd 

Photovoltaic Specialist Conference Proceedings; 

May 11-16, 2008, San Diego, California. 

H.S. Ullal. “Thin Film PV Technologies.” 

Moderator at the Inter Solar North America, San 

Francisco, California. July 15-17, 2008. 

H.S. Ullal. “Overview and Challenges of Thin 

Film Solar Electric Technologies.” World 

Renewable Energy Congress X Proceedings; 

July19-25, 2008, Glasgow, Scotland, U.K. 

H.S. Ullal. “The Great Thin Film Debate.” 

Panelist at Solar Power International 2008, Oct 

13-16, 2008, San Diego, California. 

3. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location/E-mail Description/Title of Research 

Activity 

FY 2008 

($K) 

Cost 

Share 

($K) 

Colorado School of Mines 

Jim Sites 

Ft. Collins, CO 

sites@lamar.colostate.edu 

Characterization and analysis of 

CIS and CdTe devices 50 0 

Colorado State University 

W.S. Sampath 

Ft. Collins, CO 

sampath@engr.colostate.edu 

Development of a robust in-line 

manufacturing approach for CdTe, 

and stability assurance 

130 0 

First Solar, LLC 

Peter Meyers 

Perrysburg, OH 

pmeyers@firstsolar.com 

Expanding the limits of CdTe PV 

performance 70 20 

First Solar, LLC 

Roger Green 

Perrysburg, OH 

rgreen@firstsolar.com 

Development of robust high 

efficiency thin film CdTe PV 

modules 

0 0 

Global Solar Energy Tucson, AZ 

swiedman@globalsolar.com 

Cost and reliability improvements 

for CIGS based on flexible 

substrates 

1,110 1,110 

NanoSolar 

Chris Eberspacher 

Palo Alto, CA 

chris@nanosolar.com 

High-productivity annealing for thin 

film CIS PV 100 8 

University of Nevada 

Clemens Heske 

Las Vegas, NV 

heske@unlv.nevada.edu 

Characterization of the electronic 

and chemical structure at the thinfilm solar cell interfaces 157 0 

University of Oregon 

Dave Cohen 

Eugene, OR 

dcohen@oregon.uoregon.edu 

Innovative characterization of 

amorphous and thin-film silicon for 

improved module performance 

138 0 

University of South Florida 

Chris Ferekides 

Tampa, FL 

ferekide@eng.usf.edu High-efficiency CdTe cells by CSS 200 14 

University of Toledo 

Al Compaan 

Toledo, OH 

ADC@physics.utoledo.edu 

Fabrication and physics of CdTe 

devices by sputtering 245 75 

University of Toledo 

Xunming Deng 

Toledo, OH 

dengx@physics.utoledo.edu 

Fabrication and characterization of 

advanced triple-junction 

amorphous-Si-based solar cells 

270 78 

University of Utah 

Craig Taylor 

Salt Lake City, UT 

craig@physics.utah.edu 

Innovative characterization of 

amorphous and thin-film silicon for 

improved module performance 

79 0 

95 Photovoltaic

Systems and Component Development
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

PV Manufacturing R&D 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Richard Mitchell (NREL), 303-384-6479, richard_mitchell@nrel.gov 

DOE HQ Technology Manager: Jeffrey Mazer, 202-586-2455, jeffrey.mazer@ee.doe.gov 

FY 2008 Budget: $3,032K (NREL) 

Objectives 

•	 Improve photovoltaic (PV) manufacturing processes and products for terrestrial applications. 

•	 Accelerate PV manufacturing cost reductions. 

•	 Increase commercial product performance and reliability. 

•	 Lay the foundation for significantly increased production capacity. 

•	 Achieve these goals in an environmentally safe manner. 

Accomplishments 

•	 Conducted a stage-gate evaluation, as part of the annual DOE Solar Energy Technologies 

Program (SETP) Review, of U.S. industry participants in the PV Manufacturing Research and 

Development (R&D) Project to assess continuation of manufacturing R&D and select areas for 

elimination or support. 

•	 Dow Corning – Established protection-system processing on full-size module production line. 

•	 Evergreen Solar – Completed initial operation of production system for in-situ ribbon-cutting 

system. 

•	 SolarWorld – Demonstrated production of 18% efficient cells and 15% efficiency modules and 

production costs of less than $2/watt using processing developed under this subcontract. 

•	 Xantrex Technology – Completed hardware optimization for 500-kilowatt (kW) inverter: bridge 

matrix; enclosure; power supply; and control board assembler. 

Future Direction 

•	 Complete remaining documentation of research under the PVMR&D Project. 

1. Introduction 

The PV Manufacturing R&D (PVMR&D) Project 

was designed to assist the U.S. PV industry 

through a cost-shared manufacturing R&D 

partnership with the U.S. Department of Energy 

(DOE). Subcontracted research has focused on 

the U.S. PV industry’s improvement of processes 

and products, resulting in (1) a substantial 

reduction in associated manufacturing costs; (2) a 

technology foundation that supports significant 

manufacturing scale-up of 500-megawatt (MW) 

total U.S. capacity; and (3) positioning the industry 

to meet rapidly emerging large-scale deployment 

opportunities. This focus has directly supported 

the DOE Solar Energy Technologies Program 

(SETP) Advanced Materials and Devices 

activities. 

Each subcontractor has enhanced existing 

manufacturing technologies through cost-shared 

development efforts, geared toward achieving the 

overriding PVMR&D goals. Work areas have 

included (1) the improvement of module 

manufacturing processes to increase module 

reliability; (2) system and system-component 

packaging, system integration, manufacturing, and 

assembly; (3) product manufacturing flexibility; 

and (4) balance-of-systems (BOS) development, 

including storage and quality control. 

2. Technical Approach 

The PVMR&D Project is a government/industry 

partnership through cost-shared, subcontracted 

research in PV manufacturing technologies. The 

approach for the FY 2007 work effort was divided 

into two areas: (1) Project Management and 

Support subtask activities and (2) research 

Photovoltaic

Systems and Component Development

96
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

subcontracts under the FY 2003 competitive 

solicitation for large-scale module and component 

yield, durability, and reliability (YDR). 

During FY 2007, the focus of the PVMR&D Project 

was redirected to support the Technology Pathway 

Partnership (TPP) Funding Opportunity 

Agreement under the Solar America Initiative 

(SAI). As such, many of the subcontracted 

research activities under the YDR procurement 

were terminated early in order to transfer their 

research focus to newly awarded TPP research. 

2.1 PV Manufacturing R&D Management 

The Project Management and Support subtask 

addresses (1) management of the PVMR&D 

project; (2) management of subcontracts awarded 

under the YDR procurements; and (3) coordination 

of NREL’s in-house activities in support of 

PVMR&D industrial partners. The task budget is 

detailed in Table 1. 

Table 1. PVMR&D Project Tasks and Budget 

Task Title FY 2008 

Budget ($K) 

PV Manufacturing R&D Technical 

Coordination 203 

Module Yield, Durability, and 

Reliability 3,032 

2.2 Yield, Durability, and Reliability 

The FY 2008 YDR subtask comprises the costshared PVMR&D subcontracts in Table 2, 

resulting from a competitive solicitation in FY 

2003. The focus was on improving module 

manufacturing processes to increase module 

reliability, system and system-component 

packaging, system integration, manufacturing, and 

assembly; product manufacturing flexibility; and 

BOS development, including storage and quality 

control. The emphasis was on enhancing the 

reliability of the module, system components, and 

the complete system. Note that many of the 

subcontracts under this subtask were terminated 

early; therefore, the funding originally under this 

subtask was made available for use in the SAI 

TPP projects. The early termination of additional 

subcontracts has also been coordinated to 

address budget shortages due to increased 

emphasis on SAI projects. 

3. Results and Accomplishments 

3.1 Yield, Durability and Reliability 

The Large-Scale Module and Component Yield, 

Durability, and Reliability letter of interest issued in 

FY 2003 focused on addressing needs in two 

categories. Category A, PV System and 

Component Technology, largely addresses the 

nonmodule aspects of PV systems component 

manufacturing processes. Category B, PV Module 

Manufacturing Technology, primarily addresses 

aspects of module manufacturing processes. 

Under this subtask, the significant achievements 

of remaining individual subcontractors in FY 2008 

are described below. 

Dow Corning Corporation 

“High Performance Packaging Solutions for LowCost, Reliable PV Modules” 

•	 Completed scale-up activities for pilot-scale, 

protective-system production line. 

•	 Completed trials on new protective-system, 

demonstrating positive performance compared 

to results from previous processes. 

•	 Established protection-system processing on 

full-size module production line. 

Evergreen Solar, Inc. 

“Low-Cost Manufacturing of High-Efficiency, HighReliability String Ribbon Si PV Modules” 

•	 Completed implementation of production system 

for in-situ ribbon-cutting system. 

• Completed initial operation of production system 

for in-situ ribbon-cutting system. 

• Completed modification of lamination process to 

accommodate for cells in the top 2% of the 

weight distribution. 

First Solar 

“Solar Cell Design for Manufacturability” 

• Initiated design reviews of new sputter coater. 

•	 Initiated early termination of subcontracted 

research to address budget shortages due to 

increased emphasis on SAI projects. 

SolarWorld Industries America 

“Manufacturing Improvements in CZ Silicon 

Module Production” 

•	 Demonstrated prototype of 25% thinner cutting 

wire with no yield change at wafering. 

•	 Demonstrate >90% mechanical yield of thin cells 

in production line. 

•	 Demonstrated Cz-Silicon module manufacturing 

production costs of less than $2/watt. 

97 Photovoltaic

Systems and Component Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• Demonstrated production of 18% efficient cells NREL/SR-520-42420, June 2007. Golden, CO: 

and 15% efficiency modules using processing National Renewable Energy Laboratory, 

developed under this subcontract. December 2007. 

Xantrex Technology 

“Advanced, High Reliability, System Integrated 

500-kW Photovoltaic Inverter Development” 

•	 Completed design of inverter regulation and 

array tracker software. 

•	 Completed hardware optimization for 500-kW 

inverter: bridge matrix; enclosure; power supply; 

and control board assembler. 

4. Major FY 2008 Publications 

T.L. Jester. Manufacturing Improvements in Cz 

Silicon Module Production. Annual Subcontract 

Report, July 2005 -- October 2006, NREL/SR-520-

42418. Golden, CO: National Renewable Energy 

Laboratory, November 2007. 

J. Botkin. Accelerating PV Cost Effectiveness 

Through Systems Design, Engineering, and 

Quality Assurance. Final Subcontract Report, 

J. Shingleton. One-Axis Trackers – Improved 

Reliability, Durability, Performance, and Cost 

Reduction. Final Subcontract Technical Status 

Report, 2 May 2006 – 31 August 2007, NREL/SR520-42769. Golden, CO: National Renewable 

Energy Laboratory, February 2008. 

J.A. Rand. Solar Cell Design for Manufacturing. 

Final Subcontract Report, October 2005 -

September 2007, NREL/SR-520-43228. Golden, 

CO: National Renewable Energy Laboratory, May 

2008. 

R. West. Advanced, High-Reliability, SystemIntegrated 500kW PV Inverter Development. Final 

Subcontract Report, 29 September 2005 - 31 May 

2008, NREL/SR-520-43839. Golden, CO: National 

Renewable Energy Laboratory, August 2008. 

5. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location/E-mail Description/Title 

of Research Activity 

FY 

2008 

($K) 

Cost 

Share 

($K) 

Dow Corning Corporation 

Barry Ketola 

Midland, MI 

barry.ketola@dowcorning.com 

High Performance Packaging 

Solutions for Low Cost, Reliable PV 

Modules 

675 675 

Evergreen Solar, Inc. 

Jack Hanoka 

Marlboro, MA 

hanoka@evergreensolar.com 

Low-Cost Manufacturing of HighEfficiency, High-Reliability String 

Ribbon Si PV Modules 

321 321 

First Solar, LLC 

Greg Helyer 

Perrysburg, OH 

ghelyer@FIRSTSOLAR.COM 

Implementation of Reliable 

Manufacturing of Higher Efficiency 

Module 

0 0 

SolarWorld Industries America 

Theresa Jester 

Camarillo, CA 

Theresa.jester@shellsolar.com 

Manufacturing Improvements in CZ 

Silicon Module Production 1,000 1,075 

Xantrex Technology, Inc. 

Raymond Hudson 

San Luis Obispo, CA 

Ray.Hudson@xantrex.com 

Advanced, High Reliability, System 

Integrated 500-kW Photovoltaic 

Inverter Development 

0 0 

Photovoltaic

Systems and Component Development

98
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

___________________________________________________________________________________ 

Systems Modeling 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Nate Blair (NREL, Primary Contact), 303-384-7426, nate_blair@nrel.gov 

Mark Mehos (NREL), 303-384-7458, mark_mehos@nrel.gov 

Chris Cameron (SNL), 505-844-8161, cpcamer@sandia.gov 

Craig Christensen (NREL), 303-384-7510, craig_christensen@nrel.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, dan.ton@ee.doe.gov 

FY 2008 Budgets:	 $1,140K (NREL), $730K (SNL) 

Objectives 

•	 Enhance DOE Solar Energy Technologies Program (SETP) Solar Advisor Model (SAM) to 

develop capabilities to calculate energy output, energy costs, and cash flows, using up-to-date 

component and system data while enabling parametric analysis. 

•	 Validate SAM and other solar models for a variety of technologies, applications, and locations. 

•	 Guide research and development (R&D) prioritization for industry and government use and to 

provide credible energy production and cost data, using a common platform for project 

development, evaluation, and due diligence. 

•	 Provide additional tools to industry to meet their planning, R&D, siting, and other modeling needs 

to help accelerate market penetration. 

•	 Support progress evaluation at stage-gate assessments for the Solar America Initiative (SAI). 

Accomplishments 

•	 Release new SAM versions with: 

o	 Improved PV performance algorithms (e.g., SNL inverter model and CEC module model) and 

use of latest databases for each model 

o	 Detailed operating and maintenance (O&M ) inputs (e.g., annual $, $/MW, $/MWh) 

o	 Enhanced Graphical User Interface (GUI) and greater graphical output capability 

o	 Added time-of-use utility rates and automated Independent Power Producer (IPP) financing 

optimization to SAM. 

•	 Made SAM finance model with incentives operational and externally-reviewed. 

•	 Added/expanded module and inverter performance and weather databases. 

•	 Conducted first annual SAM user forum at Solar 2008 conference. 

•	 Made PVWATTS available as Web service for California Solar Initiative and others. 

•	 Evaluated SAM and other PV performance models vs. 1-year of data for cSi systems. 

•	 Conducted levelized cost of energy (LCOE) reviews for Technology Pathway Partnership stage 

gates. 

Future Directions 

•	 Acquire data on diverse PV systems and apply to model validation and evaluation, in 

collaboration with industry.
 

•	 Continue DOE and user support, including analysis for TPP stage-gate reviews, and hold a fullday user forum. 

•	 Incorporate electrical storage (and necessary control logic) within SAM for PV systems to 

examine the impact on demand-control for residential and commercial systems.
 

•	 Incorporate PVWatts as an additional option with SAM. 

•	 Examine modifying SAM backbone enable batch processing and uncertainty analysis. 

99 Photovoltaic

Test and Evaluation

Modeling and Analysis
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Introduction 

The system modeling task consists of systems 

performance and LCOE modeling and validation 

projects. The primary function of SAM is to allow 

users to investigate the impact of variations in 

physical and financial parameters to better 

understand their impact on key figures of merit for 

solar power systems. Figures of merit related to 

the cost and performance of these solar power 

systems include, but are not limited to, system 

output, peak and annual system efficiency, LCOE, 

and system capital and O&M costs. SAM is used 

widely by DOE, laboratory management, research 

staff, and throughout the solar community. Its 

combination of robust performance models for 

multiple solar technologies with detailed financial 

models in a publicly available package is unique. 

The task also supports maintenance and 

continued development of PVWATTS, which is a 

very popular model for simple performance 

estimates for PV systems. 

2. Results and Accomplishments 

There were two major milestones for SAM 

development. The first was a release of the SAM 

Version 2.0, completed in June of 2008. It included 

a variety of small enhancements but focused on: 

•	 Major update of user manual with 

documentation 

•	 Improved PV performance algorithms 

•	 Capability of using latest California Energy 

Commission (CEC) and SNL module and 

inverter databases 

•	 Detailed O&M inputs (e.g., annual $, $/MW, 

$/MWh options). 

The second milestone was the release of SAM 

Version 2.5. It includes: 

•	 Dish Stirling CSP models 

•	 Enhanced GUI and greater graphical output 

capability 

•	 Time-of-use utility rates and automated IPP 

financing optimization. 

This deliverable was due October 1 but has been 

delayed due to several bugs found in the code and 

waiting for feedback from the Dish Stirling industry 

on the pre-release version. It will be released 

during the first quarter of FY 2009. Other 

deliverables for this task focused on improved 

user support and model validation. 

User forum and user interactivity 

This was accomplished throughout the year via 

email user support, Google Group, a user survey, 

and our efforts to collect suggestions from all 

users into our list of future improvements. The first 

modeling workshop, held at Solar 2008 in San 

Diego, was well received. 

Component Performance Databases 

The PV component performance database in SAM 

has been expanded to include 421 modules for the 

SNL model, 128 modules for the CEC model, and 

369 inverters. Performance parameters for the 

inverter database are derived from test data 

published by the California Energy Commission. 

Stage Gate Support 

SAM was employed by the SAI TPPs to project 

LCOE reductions for their technologies. Navigant 

Consulting provided additional cost projections. 

SNL used the TPP and NCI data as well as 

laboratory test data, where available, to analyze 

LCOE and provide summary reports to the TPP 

stage-gate review panels. 

Performance Model Validation 

A key effort begun in FY 2008 was to validate the 

performance models that use these data by 

comparing model predictions for systems output 

versus measured output using measured weather 

data as model input. Three crystalline-silicon 

systems installed at SNL were monitored for a 

year. The results of the model comparison were 

presented in an IEEE paper. 

3. Planned FY 2009 Activities 

Activities for SAM can be broken into two general 

groupings: core activities (jointly funded by PV and 

CSP funds) and PV-specific activities. 

Core Activities 

•	 Initiate or continue to create a communication 

pathway from the users to the SAM 

development team. These activities include: 

o	 Expanded user forum, building on 2008. 

o	 Managed Internet-based user discussion 

group 

o	 Implemented enhancements, rated highly 

via our SAM user survey in F 20Y08. 

•	 Improve and augment the documentation in 

the user support area including: 

o	 Incorporate context-sensitive help system. 

Update growing list of existing 

documentation (e.g., user guide, technical 

reference manual, online help). 

Photovoltaic

Test and Evaluation

Modeling and Analysis

100
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

o	 Improve SAM Website 

o	 Add case studies of interesting SAM runs 

•	 Allow for system annual and/or hourly energy 

production to be an input. 

•	 Continue to expand the number and type of 

weather files available to SAM. 

•	 Enhance graphical capabilities through a 

variety of small activities, since it providing 

robust graphical results is a core capability. 

•	 Develop capability to run SAM in batch mode, 

which would allow examination of a specific 

output metric across a very broad range of 

inputs (enhanced level of +80k). 

Specific PV Activities 

•	 Enhance National Center of Photovoltaics 

(NCPV) presence on the team. Either a single 

person through FY 2009 or a rotating position 

will allow SAM to more adequately address 

NCPV modeling needs as well as allow for 

greater communication of SAM capabilities 

within the NCPV. 

•	 Annual 1-day workshop to focus on needs of 

TPP SAM users (enhanced level of +40k). 

•	 Add PV-Watts as a PV option in SAM. 

•	 Add module shading as an option to model. 

•	 Add ability to model electric storage (either on 

or off grid), likely in the form of batteries. 

•	 Consider impact of mounting methods. 

•	 Investigate improvements for seasonal derate. 

•	 Support the needs of the PV program by 

sponsoring university-level development of 

enhanced PV modeling capabilities relevant to 

the current systems. 

•	 Add capability to sum different system outputs 

and do financial analysis at an aggregate 

level. (e.g., enhanced level of +100k). 

•	 Develop weather and system performance 

data sets for additional climates and 

technologies. Apply the data to additional 

model validation. 

•	 Continue to add components to the module 

and inverter databases. 

•	 Perform cost and LCOE reviews at all SAI 

TPP stage gates, in collaboration with 

Navigant Consulting. 

4. Major FY 2008 Publications 

N. Blair; M. Mehos; C. Christensen. “Sensitivity of 

Concentrating Solar Power Trough Performance, 

Cost and Financing with Solar Advisor Model.” 

2008 14th Biennial CSP SolarPACES (Solar 

Power and Chemical Energy Systems) 

Symposium; March 4-7, 2008, Las Vegas, Nevada 

(CD-ROM). 

N. Blair; M. Mehos; C. Christensen; C. Cameron. 

“Modeling Photovoltaic and Concentrating Solar 

Power Trough Performance, Cost, and Financing 

with the Solar Advisor Model.” American Solar 

Energy Society Conference Solar 2008; San 

Diego, California. 

P. Gilman; N. Blair; M. Mehos; C. Christensen; S. 

Janzou; C. Cameron. “Solar Advisor Model User 

Guide for Version 2.0.” 133 pp. 

N. Blair; C. Cameron. “Solar Advisor Model.” 

NREL SEAAC Seminar Series Presentation. 

Strategic Energy Analysis Center On-line Seminar. 

. 

C. Cameron; W. Boyson; D. Riley. “Comparison of 

PV System Performance-Model Predictions with 

Measured PV System Performance.” 33rd IEEE 

PVSC, San Diego, California, 2008. 

5. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location/E-mail Description/Title of Research Activity 

FY 2008 

($K) 

Janzou Consulting 

Steve Janzou 

Evergreen, CO 

Steve_janzou@nrel.gov 

Program the front-end and basic 

engine of the Solar Advisor Model 180 

University of Wisconsin-Madison 

Prof. Sanford Klein 

Madison, WI 

Klein@engr.wisc.edu 

e.g., Develop an advanced PV 

module model 100 

Paul Gilman 

Paul Gilman 

Chicago, IL 

PaulGilman@earthlink.net 

Provides user support and 

technical writing support 60 

101 Photovoltaic

Test and Evaluation

Modeling and Analysis
 

 

 

____________________________________________________________________________________ 

 

 

 

 

Systems Analysis
 

Market, Value, and Policy Analysis
 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Lawrence Berkeley National Laboratory (LBNL) 

Key Technical Contacts:	 Robert Margolis (NREL), 202-488-2222, robert_margolis@nrel.gov 

Selya Price (NREL), 202-488-2205, selya_price@nrel.gov 

Ryan Wiser (LBNL), 510-486-5474, RHWiser@lbl.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, dan.ton@ee.doe.gov 

FY 2008 Budgets:	 $1,150K (NREL), $200K (LBNL) 

Objectives 

•	 Provide a broad range of analytical support to the U.S. Department of Energy’s (DOE) Solar 

Energy Technologies Program (SETP). 

•	 Anticipate and respond to the rapidly evolving analytical needs of SETP. 

•	 Carry out detailed analysis of existing and emerging markets, including analysis to be included in 

the annual solar market trends report. 

•	 Continue development of the Solar Deployment Systems (SolarDS) model—a PV market 

penetration model that will be compatible with broader model-development effort within the Solar 

Energy Technologies Program. 

•	 Provide inputs to, support for, and review of the annual GPRA benefits analysis process. Develop 

methods and tools for improving the quantification of the benefits and costs of distributed PV in 

the National Energy Modeling System (NEMS) and other models. 

•	 Evaluate policies and other factors that impact the value of solar energy technologies in a variety 

of markets. 

Accomplishments 

•	 Conducted a historical analysis of investment in solar energy technologies from 2000 to 2007. 

•	 Published a comprehensive report on PV financing mechanisms for the state and local 

government sector as well as carried out analysis and research for additional reports on PV 

financing in other sectors (residential, Federal, commercial and industrial). Provided PV financing 

information to large numbers of stakeholders via presentations and webinars. 

•	 Carried out analysis and compilation of data/information in preparation for publication of SETP’s 

first annual report on solar technology market, cost, and performance trends. 

•	 Continued development of the SolarDS market penetration model, including updating of financial 

incentives such as the recently passed Federal ITC and state incentive program budgets, as well 

as incorporation of additional financing options into the model. 

•	 Provided short term analysis support to SETP to respond to information requests from Congress, 

the EERE corporate office, NREL, and other stakeholders. 

Future Directions 

•	 Publish an annual solar market trends report on solar market, cost, and performance trends. 

•	 Support the annual Government Performance and Results Act (GPRA) benefits and Program 

Decision Support analysis efforts. 

•	 Carry out solar market penetration modeling/analysis utilizing the SolarDS model. 

•	 Continue research, publication, and report updating of PV financing information, including the 

State/Local, the Federal, the residential, and the Commercial and Industrial sectors. 

•	 Produce topical reports and provide general analytic support that anticipates and responds to the 

emerging critical needs of the solar industry and SETP. 

Photovoltaic

Test and Evaluation

Modeling and Analysis

102
 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• Develop resources such as publications, data sources, and models to support the ongoing 

informational, decisional, and planning needs of SETP. 

1. Introduction 

The primary objective of the market, value and 

policy analysis activity is to provide a broad range 

of analytical support to the Solar Program. The 

work carried out under this agreement anticipates 

and responds to the rapidly evolving analytical 

needs of the Solar Program. Thus while the set of 

activities to be funded under this agreement are 

outlined below, the priorities will likely change over 

the course of the year and the work plan will be 

adjusted accordingly. 

Three broad types of analysis will be carried out 

under this project including: 

•	 Market analysis: Carrying out detailed analysis 

of existing and emerging markets, conducting 

analysis and compiling data in preparation for 

publication of SETP’s first annual report on 

solar market, cost, and performance trends, 

development of the Solar Deployment 

Systems (SolarDS) market penetration model. 

•	 Value analysis: Providing inputs to, support 

for, and review of the annual GPRA benefits 

analysis process, developing methods and 

tools for improving the quantification of the 

benefits and costs of distributed PV, 

maintaining NREL’s PV Value Clearinghouse. 

•	 Policy analysis: Defining and carrying out 

analysis that meets the needs of the Solar 

Program in a timely fashion, for example 

related to issues such as the reliability, 

security and time-of-use value of PV, as well 

as the potential role of solar in the energy 

economy in the long-term. Policy analysis 

also involves analysis of potential policy 

initiatives/proposals at the federal and state 

levels. In other words, in addition to specific 

tasks (as discussed below) Policy Analysis 

includes providing general analytical support 

to the Solar Program. 

2. Technical Approach 

The market, value, and policy analysis activity 

relies on two main technical approaches. 

The first approach is to use and improve existing 

models and to develop new tools that can be 

employed to develop long-term market-penetration 

projections for solar technologies. This effort 

involves examining both the system and policy 

drivers of solar technologies in various markets in 

both the short and long term, as well as improving 

the analytical basis for projecting the SETP’s 

economic and environmental benefits. Here, the 

emphasis has been on models and modeling, for 

example, using existing models—such as the 

Energy Information Administration’s NEMS, 

MARKAL, and others—to carry out analyses. 

These analyses examine the structure of various 

models and provide feedback on how to improve 

the representation of solar technologies in existing 

models to modelers. They also help to develop 

new models, such as SolarDS, that will help meet 

the needs of the SETP and solar community more 

broadly. 

The second approach is to employ a range of 

policy analysis tools and techniques to evaluate 

policies and other factors that impact the value of 

PV technologies in a variety of markets. These 

tools and techniques include using existing 

models, spreadsheets, and other tools (such as 

surveys and gathering and synthesizing 

information from a wide range of sources). Here, 

the emphasis is on using analytical tools to 

quantify how changing policies, rate structures, 

system designs, and other factors have or will 

impact the value of solar technologies to 

consumers, utilities, governments, and other 

players. 

3. Results and Accomplishments 

Accomplishments resulting from market, policy, 

and value analysis activities in FY 2008 include: 

•	 Research and publication of PV financing 

information for the state and local government 

sector and preparation of forthcoming papers 

on PV financing in the residential, Federal, 

and commercial and industrial sectors. 

•	 A historical analysis of investment in solar 

energy technologies from 2000 to 2007, to be 

published in early FY09. 

•	 Further development of the SolarDS market 

penetration model, including updating of 

financial incentives such as the recently 

passed Federal ITC and state incentive 

program budgets and incorporation of 

103 Photovoltaic

Test and Evaluation

Modeling and Analysis
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

additional financing options. The model will be 

ready for review in early FY09. 

•	 Development of a model that allows estimation 

of the growth in manufacturing required to 

meet carbon reduction scenarios. The model 

evaluates different trajectories of carbon 

avoidance and also applies the CO2 

emissions from manufacturing PV at the time 

the panels are produced. A draft paper has 

been written evaluating scenarios where PV 

provides 10-25% of U.S. electricity by 2050. 

•	 Development of a solar financing model to 

compare the IRRs of PV systems with a 

capacity based incentive ($/kW) and a 

performance based incentive ($/kWh). The 

impact of these and other financing incentives 

and options will be evaluated further. 

•	 Providing general analytical support to the 

SETP by responding to short term requests for 

information from Congress, EERE, and other 

stakeholders plus preparation of slides and 

material for presentations given by the SETP 

Program Manager and staff. 

•	 Collection and analysis of data on installed ongrid PV system cost trends (partial cost share 

to fund LBNL). 

•	 Research and drafting of paper on utility rate 

structures. 

•	 Various analyses as captured in the reports 

and publications listed in Section 5. 

4. Planned FY 2009 Activities 

Over the next 5 years, as solar markets continue 

to grow at a record pace and solar technologies 

continue to evolve rapidly, the need for detailed, 

timely analysis will be critical for helping to guide 

policy decisions within the SETP. Thus, a number 

of ongoing analytical activities will be supported 

under this task. These ongoing activities include 

publishing an annual report on solar market, cost, 

and performance trends, developing a process for 

collection of on-grid PV installation data, producing 

and improving the annual GPRA benefits and 

Program Decision Support analysis, producing a 

series of topical policy reports, continuing to 

publish and update PV financing information, 

producing analyses based on recently developed 

models such as SolarDS, and carrying out 

analysis activities that anticipate and respond to 

the emerging critical needs of both the solar 

industry and the SETP. 

5. Major FY 2008 Publications 

M.H. Coddington; R.M. Margolis; Jørn Aabakken. 

“Utility-Interconnected Photovoltaic Systems: 

Evaluating the Rationale for the Utility-Accessible 

External Disconnect Switch.” NREL Technical 

Report (NREL/TP-581-42675). January 2008. 

K. Cory; J. Coughlin; C. Coggeshall. “Solar 

Photovoltaic Financing: Deployment on Public 

Property by State and Local Governments.” NREL 

Technical Report (NREL/TP-670-43115). May 

2008. 

P. Denholm; R.M. Margolis. “Evaluating the Limits 

of Solar Photovoltaics (PV) in Electric Power 

Systems Utilizing Energy Storage and Other 

Enabling Technologies.” Energy Policy, Vol. 35, 

pp. 4424-4433. 2007. 

P. Denholm; R.M. Margolis. “Impacts of Array 

Configuration on Land-Use Requirements for 

Large-Scale Photovoltaic Deployment in the 

United States.” Paper presented at SOLAR 2008 ­

American Solar Energy Society (ASES); May 3–8, 

2008, San Diego, California. 

P. Denholm; R.M. Margolis. “Land-use 

Requirements and the Per-capita Solar Footprint 

for Photovoltaic Generation in the United States.” 

Energy Policy, Vol. 36, pp. 3531– 3543, 2008. 

P. Denholm; R.M. Margolis; J. Milford. 

“Quantifying Avoided Fuel Use and Emissions 

from Solar Photovoltaic Generation in the Western 

United States.” Environmental Science & 

Technology. 

P. Denholm; R.M. Margolis. “Supply Curves for 

Rooftop Solar PV Generated Electricity for the 

U.S.” NREL Technical Report (NREL/TP-670­

44073). 

S. Graham; R. Katofsky; L. Frantzis; H. Sawyer; 

R.M. Margolis. “Future of Grid-Tied PV Business 

Models: What Will Happen When PV Penetration 

on the Distribution Grid is Significant?” Paper 

presented at SOLAR 2008 (American Solar 

Energy Society); May 3–8, 2008, San Diego, 

California. 

Photovoltaic

Test and Evaluation

Modeling and Analysis

104
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

Grid Integration Support 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Ben Kroposki (NREL, Primary Contact), 303-384-2979, 

benjamin_kroposki@nrel.gov 

Juan Torres (SNL, Primary Contact), 505-844-0809, jjtorre@sandia.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, dan.ton@ee.doe.gov 

FY 2008 Budgets:	 $400K (NREL), $400K (SNL) 

Objectives 

•	 Address both the technical and analytical challenges that need to be overcome in order to enable 

the penetration of high amounts of photovoltaics (PV) into the electrical power system. 

•	 Develop grid integration tests and field demonstrations that implement high-penetration PV. 

•	 Develop technical analysis, modeling, and simulation tools and economic modeling and policy 

analysis to evaluate high-penetration PV scenarios. 

•	 Develop briefing materials for stakeholders, with a focus on utility operations and planning entities 

that help them quantify the benefits and impacts of large-scale PV grid integration. 

Accomplishments 

•	 Completed and published the Renewable Systems Interconnection (RSI) Study, a series of 14 

reports on impacts, plans, and strategies to address high PV penetration on the electric grid. 

•	 Revised the draft RSI multi-year research plan. 

•	 Completed a white paper on energy storage for PV systems. 

•	 Set up Cooperative Research and Development Agreements, or CRADAs, with Sacramento 

Municipal Utility District (SMUD), Xcel Energy, and SunEdison on access to data and monitoring 

for grid integration of PV systems. Completed the initial report on data collection and monitoring. 

•	 Assisted islands of Hawaii (Kauai, Oahu, and Lanai) with planning, analysis, and engineering of 

PV systems into their electric power system. 

Future Directions 

•	 Continue collecting field data to verify early findings and steer technology research and 

development (R&D) in grid integration.
 

•	 Develop Critical Renewable Energy for Storage Technology (CREST) initiative. 

•	 Support International Energy Agency (IEA) Photovoltaic Power Systems (PVPS) Task 11 – PV 

Hybrid Systems and Microgrids. 

•	 Develop lab-based test and development sites to provide leadership and early development for 

industry efforts in implementing high-penetration PV scenarios. 

• Contreras, J.L.; Frantzis,	 L.; Blazewicz, S.; 

1. Major FY 2008 Publications Pinault, D.; Sawyer, H.; Navigant Consulting 

Inc., PV Value Analysis (February 2008). 

•	 Achilles, S.; Schramm, S.; Bebic, J. GE Global • Denholm, P.; Margolis, R.; Milford, J.; 

Research, Transmission System Performance Production Cost Modeling for High Levels of 

Analysis for High-Penetration PV (February PV Penetration (February 2008). 

2008). • Frantzis, L.; Graham, S.; Katofsky, R.; 

•	 Bebic, J. GE Global Research, Power System Sawyer, H. Navigant Consulting Inc., PV 

Planning: Emerging Practices Suitable for Business Models (February 2008). 

Evaluating the Impact of High-Penetration PV • Kroposki, B.; Margolis, R.; Kuswa, G., Torres, 

(February 2008). J.; Bower, W.; Key, T.; Ton, D. Renewable 

Systems Interconnection: Executive Summary, 

105 Photovoltaic

Test and Evaluation

PV Grid Integration
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NREL Technical Report (NREL/TP-581­

42292) (February 2008). 

•	 Liu, E.; Bebic, J. GE Global Research, 

Distribution System Voltage Performance 

Analysis for High-Penetration PV (February 

2008). 

•	 Manz, D.; Schelenz, O.; Chandra, R.; Bose, 

S.; de Rooij, M.; Bebic, J. GE Global 

Research, Enhanced Reliability of 

Photovoltaic Systems with Energy Storage 

and Controls (February 2008). 

•	 McGranaghan, M.; Ortmeyer, T.; Crudele, D.; 

Key, T.; Smith, J. (EPRI); Barker, P. (NOVA 

Energy Specialists LLC). Advanced Grid 

Planning and Operation (February 2008). 

•	 McIntyre, A. Cyber Security Analysis 

(February 2008). 

•	 Ortmeyer, T.; Dugan, R.; Crudele, D. (EPRI); 

Barker, P. (NOVA Energy Specialists LLC). 

Utility Models, Analysis, and Simulation Tools 

(February 2008). 

•	 Paidipati, J.; Frantzis, L.; Sawyer, H.; 

Kurrasch, A. (Navigant Consulting, Inc.). 

Rooftop PV Market Penetration Scenarios 

(February 2008). 

•	 Renné, D.; George, R.; Wilcox, S.; Stoffel, T.; 

Myers, D.; Heimiller, D. Solar Resource 

Assessment, NREL (February 2008). 

•	 Ton, D.; Kroposki, B.; Margolis, R.; Kuswa, G.; 

Torres, J.; Key, T. Renewable Systems 

Interconnection Distributed Photovoltaic 

Study, 17th PVSEC, Fukuoka, Japan, 

(December 2007). 

•	 Ton, D.; Kroposki, B.; Margolis, R.; Kuswa, G.; 

Torres, J.; Bower, W.; Hanley, C.; Boyes, J. 

Renewable Systems Interconnection 

Distributed PV Activities; Multi-Year Research 

Plan (MYRP) FY 2008-FY 2013 (2008). 

•	 Ton, D.; Bower, W.; Cameron, C., Solar 

Energy Grid Integration Systems (SEGIS); 

Concept Paper (2008). 

•	 Ton, D.; Kroposki, B.; Margolis, R.; Kuswa, G.; 

Torres, J; Key, T. Renewable Systems 

Interconnection Distributed Photovoltaic 

Study, 23rd European PV Solar Energy 

Conference and Exhibition, Valencia, Spain 

(September 2008). 

•	 Whitaker, C.; Newmiller, J. (BEW 

Engineering); Ropp, M. (Northern Plains 

Power Technologies); Norris, B. (Norris 

Energy Consulting). Distributed Photovoltaic 

Systems Design and Technology 

Requirements (February 2008). 

•	 Whitaker, C.; Newmiller, J. (BEW 

Engineering); Ropp, M. (Northern Plains 

Power Technologies); Norris, B. (Norris 

Energy Consulting). Test and Demonstration 

Program Definition (February 2008). 

Photovoltaic

Test and Evaluation

PV Grid Integration

106
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Inverter and Balance-of-Systems Project 

Performing Organization:	 Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Sigifredo Gonzalez (SNL, Primary Contact), 505-845-8942, 

sgonza@sandia.gov 

Ward Bower (SNL), 505-844-5206, wibower@sandia.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, dan.ton@ee.doe.gov 

FY 2008 Budget:	 $765K (SNL) 

Objectives 

•	 Develop a test platform and protocols to evaluate Solar America Initiative (SAI) state-gate
 

deliverable and Solar Energy Grid Integration Systems (SEGIS) stage-gate deliverables.
 

•	 Develop a test platform to evaluate advanced control algorithms of micro-grid applications. 

•	 Determine effects of long-term inverter operation after 2 years of outdoor operation (second set of 

inverters). These samples provide reliability information of a small grid-connected system and 

provide a platform to validate system modeling activities. 

•	 Develop new photovoltaic (PV) inverters and balance-of-system (BOS) hardware that meet 

today’s utility interconnect standards, performance requirements, and safety requirements. 

•	 Provide the standards and codes committee with consensus information and requirements flow 

between the committees and the inverter industry. Enable PV inverter manufacturers to meet 

standard and code requirements. 

Accomplishments 

•	 Conducted SAI phase 1 stage-gate deliverable evaluation on GreenRay Micro-Inverter. 

•	 Completed re-characterization evaluations on the second set of inverters undergoing long-term 

evaluations. 

•	 Conducted preliminary evaluations on Xantrex 30-kilowatt (kW) transformerless inverter. 

Continue to provide beta site evaluations on performance of inverter utilizing PV as dc source. 

•	 Determined inverter performance, power quality, and utility compatibility capabilities for one 

commercial inverter and two residential PV inverters. 

•	 Conducted preliminary validation evaluations on a PV-system performance model. 

•	 Reviewed National Electrical Code (NEC) 2011 proposed changes and participated in code 

revision process. 

Future Directions 

•	 Complete first round of long-term inverter operation evaluations and implement any significant 

inverter performance issues discovered in the long-term inverter operation evaluations and 

introduce them into the PV-system performance model. 

•	 Determine development protocols and tools needed to validate SAI stage-gate deliverables that 

target individual PV system components and the complete PV system. 

•	 Provide PV inverter manufacturers with a facility to enhance performance capabilities. 

•	 Continue to develop enhanced laboratory capabilities to evaluate SEGIS stage-gate deliverables 

that include energy management capabilities, load shedding capacities, and voltage support. 

1. Major FY 2008 Publication 

“Development of a MATLAB/Simulink Model of 

a Single-Phase Grid-Connected Photovoltaic 

System,” IEEE submitted paper. 

107 Photovoltaic

Test and Evaluation

PV Grid Integration
 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

Solar Energy Grid Integration Systems 

Performing Organization:	 Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Ward Bower (SNL, Primary Contact), 505-844-5206, 

wibower@sandia.gov 

Scott Kuszmaul (SNL), 505-844-5401, sskuszm@sandia.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, Dan.Ton@hq.doe.gov 

FY 2008 Budget:	 $3,200K (SNL) 

Objectives 

•	 Lay the groundwork for high levels of photovoltaic (PV) market and electrical grid penetration, or 

grid integration. 

•	 Enable PV systems to meet the goal of making solar power cost competitive with conventional 

sources of electricity. 

•	 Integrate systems to include energy management, energy storage, communications, and total 

system optimizations. 

•	 Commercialize and deploy advanced, clean, PV-system technology that will enhance our energy 

security and confront the serious challenge of global climate change. 

Accomplishments 

•	 Completed and published Solar Energy Grid Integration Systems (SEGIS) concept paper, used 

for SEGIS solicitation. 

•	 Completed an extremely aggressive schedule to launch the SEGIS solicitation, which was aimed 

at high PV penetration, value added, and meeting goals the Solar America Initiative (SAI) 

levelized cost of energy (LCOE): 

o	 Request for information 

o	 Request for proposals for 3-stage efforts 

o	 Evaluation criteria 

o	 Proposal receipts and evaluations (27) 

o	 Contractor selection 

o	 Placed 12 contracts 

o	 Kickoff meetings for 12 SEGIS contractors 

o	 Provided quarterly report templates 

o	 Received first quarterly reports. 

•	 Completed evaluation criteria for stage 2. 

Future Directions 

•	 Complete stage 1 Conceptual Designs and Market Analysis with down select to stage 2 and draft 

a summary report for SEGIS stage 1. 

•	 Select stage 2 contractors showing a high likelihood of success for prototype development for 

systems providing the best value to the U.S. Department of Energy (DOE) Solar Energy 

Technologies Program (SETP) and future grid integration. 

•	 Initiate SEGIS energy storage (ES) efforts to include more aggressive energy management and 

energy storage to address intermittency mitigation, utility-grid support, and system optimization 

for grid integration. 

•	 Summarize SEGIS contractor findings into future directions and prioritizations with “Status and 

Sequences” for future grid integration research and development (R&D). 

•	 Analyze SEGIS deliverables to determine impacts on LCOE as well as value added that enables 

higher penetration and higher market shares. 

Photovoltaic

Test and Evaluation

PV Grid Integration

108
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Results and Accomplishments 

All milestones except placement of the SEGIS 

contracts were level 5. All milestones were met 

within 1 day of scheduled times. The placement of 

the contracts was a level 3 milestone and was 

completed on schedule on June 26, 2008. 

Table 1: SEGIS Accomplishments 

Milestone Action Accomplishments

Announcement 

Workshop 

Completed 

April 19, ‘07 

More than 80 participants. 

General program goals 

prioritized 

Funding 

Opportunity 

Announcement (FOA) 

FOA nearly 

completed 

SNL transfer 

Sep 29, ‘07 

DOE FOA efforts abandoned 

and replaced with a new 

SNL RFP plan 

SEGIS 

Concept 

Paper 

Completed 

Oct ‘07 

Provided SEGIS objectives 

and goals WRT “High 

Penetration” 

SEGIS RFI Completed 

Oct 30, ‘07 

Request for Information 

provided technical input & a 

“Bidders List” 

SNL/DOE 

Web Pages 

Active Nov 

2007 

Provided solicitation and 

program information 

SEGIS RFP Completed 

Nov 28, ‘07 

Provided all proposal 

requirements 

Proposals 

(27) 

Completed 

Feb 4, ‘08 

27 Proposals received 

Proposals 

Evaluated 

Completed 

Mar 20, ‘08 

Clarifications/financial denial 

questions continued 

Contracts 

Placed 

Completed 

Jun 26, ‘08 

12 contracts placed to all 

contractors on same day 

Kickoff 

Meetings 

Completed 

Aug 4, ‘08 

1⁄2 -Day meetings at 

contractor facilities 

1st Quarterly 

Reports 

Received 

Sep 19, ‘08 

Reports per SNL Template 

2. Major FY 2008 Publications 

•	 Bower, W.; Ton, D.; Ropp, M.; Gonzalez, S.; 

Torres, J. “Advanced Integrated Inverters and 

Energy Management Systems”, Proceedings 

of the 17th International PV Science and 

Engineering Conference, Fukuoka, Japan, 

Dec 3-7, 2007. 

•	 Bower, W.; Ton, D. “Solar Energy Grid 

Integration Systems (SEGIS)”, Proceedings of 

the 23rd EU PV Solar Energy Conference and 

Exhibition, Valencia, Spain, Oct 2008. 

•	 Solar Energy Grid Integration Systems 

(SEGIS) Concept Paper, October 2007, 

Sandia National Laboratories, 

www.sandia.gov/SAI/files/SEGIS%20Concept 

%20Paper-071025.pdf. 

3. University and Industry Partners 

The following organizations were under contract for SEGIS research activities. Their subcontractors and 

team members are not listed. 

Figure 1. The SEGIS Concept 

Organization/ 

Principal 

Investigator 

Location/E-mail Description/Title of Research 

Activity 

FY 2008 

($K)* 

Cost 

Share 

($K)* 

Apollo Solar 

John Pfeifer 

Bethel, CT 

John.Pfeifer@ApolloSolar.com 

“An Advanced Grid-tied Inverter, 

Charge Controller, Energy Monitor and 

Internet Gateway”. Advanced modular 

components for power conversion, 

energy storage, energy management 

and a portal for communications for 

residential size solar electric systems 

are being developed. The inverters, 

charge controllers, and energy 

management systems will be able to 

communicate with utility energy portals 

for implementation of two-way power 

flows of the future. 

250 66 

109 Photovoltaic

Test and Evaluation

PV Grid Integration
 

 

 

 

 

 

 

 

 

 

 

 

 

Organization/ 

Principal 

Investigator 

Location/E-mail Description/Title of Research 

Activity 

FY 2008 

($K)* 

Cost 

Share 

($K)* 

EMTEC 

Jon 

VanDonkelaar 

Delaware, OH 

jvandonkelaar@emtec.org 

SEGIS – “An Emerson PV Inverter 

Development.” Develop large, highly 

efficient, small footprint, power 

conversion, and energy storage and 

management for commercial PV 

systems. Includes integrated grid 

controllers with smart meter interface 

to provide more predictable economics 

for power distribution and to minimize 

fluctuations in supply and demand. 

250* 66 

EnPhase 

Ragu Belur 

Petaluma, CA 

rbelur@Enphaseenergy.com 

“Nano-inverters with VAr Control and 

Energy Management System.” Develop 

a complete module-integrated solar 

electric solution controlled by an 

energy management system (EMS). 

The EMS also interfaces with utilities. 

250 66 

General 

Electric 

Rayette Fisher 

Niskayuna, NY 

fisher@crd.ge.com 

“Grid Integration of High-penetration 

Solar Energy.” Develop concepts for 

integrating solar PV generation with the 

electrical grid in both commercial and 

residential applications. The residential 

setting improvements will focus on 

integrating energy storage, responsive 

loads, and utility demand side 

management. 

250 66 

NexTech 

Power 

Systems 

Paul Savage 

Hauppauge, NY 

paul.savage@nextekpower.com 

“Advanced PV Interface Providing 

Concurrent AC & DC Power and 

Network Support (the Bi-Directional 

Nextek Power Gateway).” Evolve a 

power gateway to incorporate bidirectional current flow capability, 

higher voltage, and added functionality 

including integrated communications 

and an energy management system for 

value-added PV-utility interconnection. 

250 66 

Petra Solar 

Adje Mensah 

Somerset, NJ 

Adje.Mensah@petrasolar.com 

“Development of Economically Viable, 

Highly Integrated, Highly Modular 

SEGIS Architecture.” The development 

is for multi-layer control and 

communication with PV systems to 

achieve grid interconnectivity, cost 

reduction, system reliability, and safety 

resulting in a cost competitive, easy to 

install, modular and scalable system. 

250 66 

Premium 

Power 

Bill O’Donnell 

North Andover, MA 

bodonnell@premiumpower.com 

“Intelligent PV Inverter (Intelligent PV 

Inverter System w/energy Management 

and Optimized for use with Solar 

Energy).” Focus is on an inverter 

system that makes PV economically 

viable in terms of investment, operating 

costs, and system lifetime. The 

technical focus is an intelligent PV 

system for commercial- and utilityscale applications with an advanced 

inverter, energy management and 

optimization capabilities. 

250 66 

Princeton 

Power 

Mark Holveck 

Princeton, NJ 

dhammell@princetonpower.com 

“Demand Response Inverter.” A 

complete design for a 100-kW 

“Demand Response Inverter” based on 

250 66 

Photovoltaic

Test and Evaluation

PV Grid Integration

110
 

 

 

 

 

 

 

 

 

Organization/ 

Principal 

Investigator 

Location/E-mail Description/Title of Research 

Activity 

FY 2008 

($K)* 

Cost 

Share 

($K)* 

proprietary technology. The design will 

be optimized for low-cost, high-quality 

manufacture and will integrate control 

capabilities including dynamic energy 

storage and demand-side load 

response. 

PVPowered 

Steve Hummel 

Bend, OR 

stevehummel@pvpowered.com 

“MPPT and EMS Advancements.” 

Develop a suite of maximum power 

point tracking (MPPT) algorithms to 

optimize energy production from the 

full range of available and emerging PV 

module technologies. Two-way 

communications and integration with 

facility energy management and utility 

management networks are also being 

developed. 

250 66 

Smart Spark 

Pactrick 

Chapman 

Champaign, IL 

p.chapman@smartsparkenergy.com 

“Alternating Current PV Module with 

System Interface.” Design, construct, 

test, and commercialize an alternatingcurrent photovoltaic (ACPV) module 

with smart building system interfaces 

that provide system diagnostics, data 

logging, and an advanced utility 

interconnection. 

250 66 

University of 

Central Florida 

Robert Reedy 

(FSEC), Dr. 

Issa Batarseh 

(UCF) as co-Pi 

Orlando, FL 

reedy@fsec.ucf.edu 

“Grid-Smart Inverters.” Develop grid 

integration concepts for PV that 

incorporate optional battery storage, 

utility control, communication, 

monitoring functions, and building 

energy management systems. Also will 

validate an “anti-islanding” strategy for 

PV inverters to allow PV generation to 

remain connected during some grid 

disturbances, while meeting safety 

operation requirements. 

250 66 

VPT Energy 

Systems 

Dr Glenn Skutt 

Blacksburg, VA 

gskutt@vpt-inc.com 

“Inverter Control Card (ICC), 

Bidirectional Power Converter (BPC), 

Power Hub Controller (PHC), and 

Integrated Power Hub (IPH) with 

vehicle-grid integration.” Develop 

component circuits and an overall 

system design for an integrated energy 

system. The R&D will include inverter 

controllers that can be used with 

250 66 

existing inverters to add sophisticated 

grid interoperability, active antiislanding/intentional islanding control, 

and a bidirectional power converter for 

plug-connected vehicles 

Total 2,779 1,643 

* Exact amounts for each contractor are withheld at this time, since all contractors remain in competition for the next 

SEGIS Stage. Totals for unloaded DOE contract funds out and contractor cost share are shown in the Totals row. 

Note that total contractor cost share is 37% of the total expenditures which is considerably more than the 20% 

required per the RFP. 

111 Photovoltaic

Test and Evaluation

PV Grid Integration
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

Module Screening and Field Evaluation 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Carl Osterwald (NREL), 303-384-6764, carl_osterwald@nrel.gov 

Michael Quintana (SNL), 505-844-0474, maquint@sandia.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, dan.ton@hq.doe.gov 

FY 2008 Budgets:	 $1,945K (NREL), $320K (SNL) 

Objectives 

•	 Provide reliability/durability stage-gate testing for Solar America Initiative (SAI) Technology 

Pathway Partnerships (TPPs) and Photovoltaic (PV) Incubators. 

•	 Include objectives related to levelized cost of energy (LCOE), efficiency, dollar per peak watt, and 

other metrics associated with SAI goals (www.eere.energy.gov/solar/solar_america). 

•	 Perform field evaluations of reliability of PV systems. 

Accomplishments 

•	 Completed reliability assessment of 1-megawatt (mW) system in Napa. 

•	 Completed reliability assessments of module/inverter components for Advent Solar, Emcore, 

GreenRay, Xantrex, PV Powered, and Soliant. 

•	 Completed installation of four new environmental test chambers. 

•	 Completed thermal cycling or damp heat testing for SolFocus, DOW, GreenRay, Emcore, and 

Advent Solar. 

•	 Measured degradation rates under high-voltage stress. 

•	 Determined oxidation rate of AlInP window in various testing environments. 

Future Directions 

•	 Increase fielded system reliability assessments, linking to needs of the Service Life Prediction 

(SLP) project. 

•	 Develop field-controlled long-term system exposure activity. 

•	 Initiate a program specifically targeting acquisition of reliability data that will feed predictive model 

development with multiple partners and capture a variety of operating environments. 

•	 Provide reliability assessments/testing for SAI TPP and Incubator partners. 

•	 Continue SAI stage-gate reliability testing support. 

•	 Monitor long-term performance of small grid-tied systems at NREL and report results to industry. 

•	 Develop lab- and field-data acquisition tasks to support predictive model development efforts. 

•	 Conduct reliability assessments on fielded systems of partners, supplying data for predictive 

model development. 

•	 Facilitate and/or conduct baseline testing prior to fielding long-term exposure systems in 

collaboration with industry partners. 

•	 Increase reliability testing in fields such as corrosion, metallurgy, mechanical vibration, and other 

non-destructive techniques. 

1. Introduction	 SAI TPPs, existing manufacturers, or new U.S. 

manufacturers engaged in design and 

This initial technology screening/testing element development of PV products. 

of the overall reliability program will position the 

DOE Reliability Project to directly support PV This work complements other projects that focus 

technologies while they are in development, as on accelerated testing of components, materials, 

well as commercial products. Clients may be and modules, diagnosis of failure modes and 

Photovoltaic

Test and Evaluation

Reliability R&D

112
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

mechanisms, predictive modeling of reliability, 

and standards development. 

2. Milestones 

•	 Complete installation and fit-up of four new 

environmental chambers in the Outdoor Test 

Facility (OTF) high-bay (NREL, 10/14/2008). 

•	 Complete qualification testing scheduled for 

first-year stage-gates for the TPPs (NREL, 

9/30/2008). 

•	 Summary report of industry support activities 

provided during FY 2008 including baseline 

testing results (NREL, 9/30/2008). 

•	 Document hot-humid stress effects on 

interfacial adhesion of PV modules (NREL). 

•	 Deliver system performance reports and 

analyses to module manufacturers (NREL, 

9/30/2008). 

•	 Complete installation of Sanyo HIT Si gridtied system and begin long-term monitoring 

(NREL, 12/15/2007). 

•	 Submit a journal article for publication that 

assesses the usefulness of high voltage 

stress testing (HVST) as an accelerated test 

used in predicting module lifetime and 

identifying and accelerating failure modes 

(NREL, 8/1/2008). 

•	 Down select and initiate studies of cause 

and possible mitigation paths from among 

the degradation mechanisms listed in the 

CPV work plan or others identified as 

important (SNL, 9/4/2008). 

•	 Negotiate partnership(s) and field 

commercially available modules and 

inverters for long term exposure (SNL, 

9/30/2008). 

•	 Field minimodules/coupons (TPP 

participants given priority) expecting 

commercialized or near-commercial 

products in FY 2008 (SNL, 6/30/2008). 

3.1 New OTF Environmental Chambers (NREL) 

Using $560,000 of general equipment funds 

allocated in mid-FY 2007, four new 

environmental chambers were procured and 

installed. These replaced a number of older 

units in the high-bay laboratory of the OTF, one 

more than 20 years old. With the larger building 

electrical transformer that was installed as part 

of the OTF expansion project, new capacity 

became available for two additional large 

chambers, bringing the total to six. This new 

capacity is for SAI stage-gate deliverables and 

the new module test-to-failure effort. 

3.2 Stage-Gate Deliverable Testing (NREL/SNL) 

SAI stage-gate testing activities at NREL 

included thermal cycling of a full-sized 

concentrator module for the SolFocus program 

and damp heat exposure of glass and flexible 

thin-film laminates for Dow. Both of these 

included current-voltage by the NREL Cell & 

Module Performance group and standard wetand-dry insulation tests. The environmental 

chamber testing was performed despite utility 

and laboratory disruptions caused by the OTF 

expansion and the installation of new 

environmental chambers. SNL’s stage-gate 

support of reliability testing included damp heat 

testing of GreenRay module scale inverter 

enclosures and a field based reliability 

assessment of the Soliant module. 

3.3 Industry Support Activities (NREL/SNL) 

A number of PV manufacturers were supported 

with testing activities, including Advent Solar, 

Sunpower, Dow, SolFocus, Uni-Solar, First 

Solar, AVA Solar, Soliant, Emcore, Xantrex, 

PVPowered, GreenRay, and Schott Solar. 

Activities included 1) thermal cycling, dampheat, vibration, and UV exposure, 2) design 

assessment for reliability, and 3) side-by-side 

outdoor energy production of modules with antireflective glass. 

Fig. 1. Example of long-term small system 

performance monitoring at NREL for a Mobil 

Solar ribbon-Si array showing degradation rate 

and monthly average inverter efficiency. 

3.4 Long-term Small Array Testing (NREL) 

A number of small arrays (~1 kW) are operated 

at the OTF, using inverters to provide maximum 

power point loading with careful data logging of 

DC and AC electrical parameters to calculate 

performance over time. Monthly regressions of 

15-minute average data provide ratings to 

performance test conditions (1000 W/m2

, 20°C 

ambient, 1 m/s wind speed), from which 

degradation rates can be calculated (see Fig. 1). 

113 Photovoltaic

Test and Evaluation

Reliability R&D
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Periodic I-V curves of both the arrays and 

individual strings are also used to observe 

changes in performance. Test results are 

generated every 3 months and then reported to 

the respective manufacturers, which include 

Schott Solar, First Solar, Uni-Solar, and 

Sunpower. A new Sanyo amorphous-Silicon (aSi)/Si heterostructure system was installed, 

using 200-watt modules. 

3.5 High-Voltage Testing of CIGS Modules 

(NREL) 

Large systems often require operation of 

modules at high bias voltages. Outdoor testing 

of modules under high voltage can uncover 

degradation or failure that may be observed in 

high-voltage systems and may accelerate 

degradation that occurs at lower voltages. After 

3 years of exposure, degradation rates of 3.8­

4.7%/yr and 2.5-2.8%/yr were observed for the 

negatively and positively connected modules. 

3.6 CPV Cell Reliability (NREL) 

(Note: this work was part of the cell-level 

reliability work and is described in more detail in 

the Concentrator Crystalline Cells part of the 

Annual Report. It will be funded 100% through 

that agreement in FY 2009.) 

The quality and integrity of the AlInP window of 

a GaInP-top cell is very important for high 

efficiency in a GaAs-based multijunction solar 

cell. The AllnP is potentially very sensitive to 

oxidation. For this reason, the damp-heat 

oxidation rate of AlInP was studied at various 

temperatures and humidity levels and found to 

be less significant than initial concerns indicated. 

Upon the introduction of light, the oxidation rate 

increases by over 300%, a potentially important 

degradation mechanism for solar cells. Selenium 

and zinc doping of AlInP was also measured 

and determined to increase the oxidation rate. 

Results are shown in Fig. 2. 

3.7 Fielded Systems Monitoring and Reliability 

Assessments (SNL) 

A key input needed to build a reliability model is 

data from fielded-systems performance and 

O&M history. We developed an understanding of 

the model needs and the type of data that is 

available through our work with our initial partner 

and potential partners. This has enabled us to 

specify minimum data needs and a format. 

Another aspect of field assessment is failuremode identification. Every field assessment 

seems to yield information regarding a 

degradation or failure within components or as a 

function of interactions of components. For 

example, we observed an inverter design that 

had multiple fan failures within 18 months of 

service, causing system outages and requiring 

maintenance intervention. We also observed 

failure of position feedback devices on tracking 

systems, causing suboptimal tracking. Finally, 

we have initiated system-long term exposure 

activity to understand state-of-the-art module 

degradation rates. This teamed effort includes a 

60% contribution of product provided by 

SunPower as a fielded-system monitoring 

partner. The systems will include domestic and 

foreign-made modules with thin-film and 

crystalline technologies represented. 

Fig. 2. Time evolution of AlInP oxide layer thickness 

under various temperature and humidity 

environments. 

3. Major FY 2008 Publications 

Osterwald, C.R. Terrestrial Photovoltaic Module 

Test-to-Failure Protocol. NREL/TP-520-42893. 

Golden, CO: National Renewable Energy 

Laboratory, March 2008. 

Osterwald, C.R.; McMahon, T.J. "History of 

Accelerated and Qualification Testing of 

Terrestrial Photovoltaic Modules: a Literature 

Review." Prog. Photovolt: Res. Appl. 2008. 

Del Cueto, J.A.; Rummel, S.; Kroposki, B.; 

Osterwald, C.; Anderberg, A. “Stability of 

CIS/CIGS Modules at the Outdoor Test Facility 

over Two Decades.” Presented at the 33rd IEEE 

Photovoltaic Specialists Conference, 2008. 

Del Cueto, J.A.; Kroposki, B.; Rummel, S.; 

Anderberg, A. “Long-Term Performance Data 

and Analysis of CIS/CIGS Modules Deployed 

Outdoors.” Presented at SPIE, 2008. 

Photovoltaic

Test and Evaluation

Reliability R&D

114
 

 

 

 

 

____________________________________________________________________________________ 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

Industry Reliability and Codes 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Sarah Kurtz (NREL, Primary Contact), 303-384-6475, 

sarah_kurtz@nrel.gov 

Michael Quintana (SNL), 505-844-0474, maquint@sandia.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, dan.ton@hq.doe.gov 

FY 2008 Budgets:	 $475K (NREL), $445K (SNL) 

Objectives 

•	 Work with photovoltaic (PV) industry to set objectives for Reliability Project by holding the 

Accelerated Aging Workshop II. 

•	 Support community’s development of standards for reliability and test and evaluation. 

Accomplishments 

•	 Facilitated the Accelerated Aging Testing and Reliability in PV II Workshop. 

•	 Completed and posted a summary report of the workshop. 

•	 Supported community’s efforts, resulting in committee draft approval of IEC 61853-1 standard for 

a power-rating methodology. 

•	 Multiple standards documents were drafted, reviewed, or revised. 

Future Directions 

•	 The third Accelerated Aging Workshop is planned to be held in Albuquerque, New Mexico. 

•	 In fiscal year (FY) 2009, the PV community’s priority for standards is development of the 

framework needed for energy model validation.
 

1. Introduction 

PV products require long lifetimes and low 

degradation rates to achieve desired cost goals 

and customer acceptance. These needs are 

changing rapidly as the PV industry evolves 

rapidly. The Accelerated Aging Testing and 

Reliability in PV Workshop II was held to 

reassess the PV industry’s needs, priorities, and 

recommendations on accelerated aging and 

reliability research in light of recent growth and 

changes in both the PV industry and the DOE 

Solar Energy Technologies Program (SETP). 

Historically, a highly valued role of the national 

laboratories has been support of standards 

development. Standards provide a foundation 

for growth of a healthy industry by providing 

common test methodologies and product 

specifications. These strengthen the industry by: 

•	 Lowering testing costs by defining common 

international test methodologies, thus, 

avoiding the need to retest products for each 

market. 

•	 Defining test methodologies that reflect 

product performance in the field, thereby 

encouraging healthy product development. 

•	 Speeding customer acceptance by defining 

consistent product specifications and 

nomenclatures. 

2. Major FY 2008 Publications 

“Accelerated Aging Testing and Reliability in 

Photovoltaics Workshop II Summary Report.” 

www.eere.energy.gov/solar/solar_america/pdfs/ 

accelerated_aging_report_2008.pdf. 

Granata, J. “Role of the National Labs in Codes 

and Standards”, private report submitted to Dan 

Ton (8/08). 

115 Photovoltaic

Test and Evaluation

Reliability R&D
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

____________________________________________________________________________________ 

 

 

Service Life Prediction 

Performing Organizations: Sandia National Laboratories (SNL) 

National Renewable Energy Laboratory (NREL) 

Key Technical Contacts:	 Michael Quintana (SNL), 505-844-0474, maquint@sandia.gov, 

Sarah Kurtz (NREL), 303-384-6475, sarah_kurtz@nrel.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, dan.ton@hq.doe.gov 

FY 2008 Budgets:	 $645K (SNL), $270K (NREL) 

Objectives 

•	 Develop and apply a process with data, methodology, and a model that industry and other 

stakeholders can use to predict reliability of photovoltaic (PV) systems and components. 

Accomplishments 

•	 Established a partnership with Reliasoft, a commercial reliability software vendor, to leverage 

expertise gained in applications in other industries. 

•	 Established predictive model architecture for a typical crystalline silicon system based on one 

partner’s multi-megawatt (mW) system with 5 years service. 

•	 Secured initial data partner to populate model for development purposes. This includes mostly cSi modules; some thin film data is also available from this system. 

•	 Incorporated input from the Accelerated Aging and Reliability Workshop into the model
 

development effort.
 

•	 Factored the complexity of how failure is defined in systems versus components, revealed in 

various studies, into continuing efforts. 

•	 Demonstrated draft model NREL, U.S. Department of Energy (DOE), BP Solar, and SunEdison to 

get a variety of inputs on the model utility; reactions were positive and provided multiple levels of 

input. 

•	 Developed minimum data needs required for continued model development. This has led to a 

better understanding of model potential and criteria for subsequent efforts. 

•	 Generating interest in simulations that are beginning to produce parameters including reliability, 

availability, and design sensitivities for c-Si. 

Future Directions 

•	 Secure a minimum of three additional data partners. 

•	 Increase model fidelity by developing inputs based on accelerated life tests correlated to field 

based technology assessments. 

•	 Increase model capabilities to include basic level predictions for emerging technologies. 

•	 Increase efforts to display model development and capabilities to a variety of audiences including 

utilities, integrators, manufacturers, and financial interests at scientific and business workshops 

and conferences. 

•	 Increase modeling activity to generate greater information on inverter reliability. 

1. Major FY 2008 Publications 

Carlson, C. (Reliasoft) “Best Practice for 

Quintana, M. (SNL) “DOE Photovoltaics Achieving High Reliability PV Systems.” 

Project.” Presented at the Accelerated Aging Presented at the Accelerated Aging Testing and 

Testing and Reliability in Photovoltaics Reliability in Photovoltaics Workshop II 

Workshop II Summary Report. Summary Report. 

www.eere.energy.gov/solar/solar_america/pdfs/ www.eere.energy.gov/solar/solar_america/pdfs/ 

accelerated_aging_report_2008.pdf. accelerated_aging_report_2008.pdf. 

Photovoltaic

Test and Evaluation

Reliability R&D

116
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

Accelerated Lifetime Testing 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 David Albin (NREL, Primary Contact), 303-384-6550, david_albin@nrel.gov 

Michael Quintana (SNL), 505-844-0474, maquint@sandia.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, dan.ton@ee.doe.gov 

FY 2008 Budgets:	 $1,935K (NREL), $630K (SNL) 

Objectives 

•	 Advance the development and use of accelerated lifetime test (ALT) protocols for photovoltaic 

(PV) modules, cells, materials, and components. 

•	 Provide timely information on the fundamental stability of modules, exposed to real conditions. 

•	 Develop new, highly accelerated tests that reduce the cycle time for product development. 

•	 Develop understanding of failure and degradation mechanisms associated with PV technologies. 

Accomplishments 

•	 Identified two distinct degradation mechanisms (with activation energies of 0.6 eV and 2.9 eV) in 

NREL-made CdS/CdTe solar cells; the 2.9 eV mechanism is particularly significant as it appears 

responsible for a longer-term instability of CdTe cells stressed between 60 oC and 80 oC. 

•	 Compared damp-heat-induced degradation of ZnO, Zn1-xMgxO, ITO, and F:SnO2, quantifying the 

relative instability of ZnO for thin-film solar cells. 

•	 Improved, uncompromised by external leads, test methodology for quantifying the degradation of 

transparent conducting oxides (TCOs) in relevant, encapsulated configurations. 

•	 Defined a test-to-failure protocol as a basis for comparison of reliability of modules. 

•	 Demonstrated test methodology and measured acceleration factors for UV-induced adhesion 

loss. 

•	 Prioritized work using failure-mode analyses performed under service-life prediction (SLP) models and failure analysis. 

•	 Established strong collaborations with Solar America Initiative (SAI)-funded industrial partners. 

•	 Failure modes and effects analyses were performed for c-Si, CIS, CdTe, and residential inverters. 

•	 Conducted x-ray diagnostics to determine failure of conductive adhesive bonds post-damp heat 

tests; results of this work are being utilized in a Technology Commercialization Development 

Fund (TCDF) effort at SNL. 

•	 Designed and built an accelerated test chamber at SNL that can be coupled to a solar simulator 

for testing of CIS TCOs and barrier coatings. 

•	 Initiated efforts to develop accelerated tests at SNL that assess reliability of conductive foil tapes 

used in thin-film applications. 

Future Directions 

•	 Continue efforts to understand failure and degradation mechanisms and quantify degradation 

rates as a function of stress conditions. 

•	 Continue support of SAI and the PV industry. 

•	 Compare outdoor with accelerated stress on encapsulant adhesion. 

•	 Expand conductive foil tape accelerated life test development. 

•	 Develop ALT-based degradation model to incorporate into the SLP reliability predictive model. 

•	 Elucidate the science of thermal cycling of the die attach for concentrator cells. 

•	 Working with thin-film scientists, apply new technique to study the effects of humidity, temperature, and encapsulation on TCOs. 

117 Photovoltaic

Test and Evaluation

Reliability R&D
____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Increase applications of ALTs to inverter development and service life prediction. 

1. Introduction 

The Accelerated Lifetime Testing project supports 

the DOE Solar Energy Technologies Program Reliability Project by providing information about failure and degradation of PV technologies. Accelerated testing can provide a means for quickly identifying design or manufacturing flaws, facilitating 

their mitigation. Rapid product development benefits from highly accelerated tests. Quantitative accelerated tests can differentiate products before 

they are placed in the field. 

PV products require long lifetimes and low degradation rates to achieve desired cost goals and 

customer acceptance. Today’s PV industry is 

evolving rapidly and product development/testing 

must be completed in a time that is far shorter 

than the desired lifetime of products. Accelerated 

testing is essential for establishing some confidence in product reliability and durability. As the 

industry matures, it will become more important 

and practical to quantitatively predict degradation 

and failure rates. Careful comparison of accelerated and field-test results provides either the basis or validation of predictive models. Studies that 

quantify the effects of stress factors can be used 

to predict isolated failure/degradation rates as a 

function of stress conditions. Thus, accelerated 

testing is a key element of any reliability program. 

Packaging and component issues are particularly 

important for module durability. For mature technologies, reliability is mainly affected by packaging. Reliability is determined by the effectiveness 

of packaging in reducing moisture and other external ingress, providing durable mechanical support and protection, and maintaining adequate 

electrical and optical performance quality. The introduction of thin-film products exacerbates failure 

due to the 1-2 order reduction in cell-to-packaging 

material volume. These latter structures are more 

sensitive to moisture, physical stresses, and deleterious environments both outside and within the 

package. Unlike more mature, silicon-based technologies, the processing, cell design, and cell interconnect strategies of thin-film products are rapidly evolving. Such an environment requires the 

development of ALT protocols that can effectively 

screen product design changes as well as provide 

statistically based inputs for detailed analysis of all 

potential failure mechanisms. SLP cannot be 

achieved quickly by field-testing. Well-designed 

ALTs, the identification of degradation mechanisms, and their corresponding reaction rates (e.g., 

activation energies) provide the basis for timely 

SLPs. 

Inverter failures continue to be high on the list of 

reliability issues seen in PV systems. In part, this 

may be a result of lack of and/or less mature test 

standards for inverters. Additionally, rapidly evolving technology improvements provide a moving 

target for test standard development. Stresses 

and/or events experienced by inverters are not 

necessarily similar to modules, and especially can 

be influenced by the utility grid. This activity, along 

with the SLP task, will develop tests that adequately mirror the environments experienced by 

inverters in commercial, utility, and residential applications in varying use conditions. 

2. Technical Approach 

Numerous discussions with SNL, DOE, industrial 

partners, and internal NREL experts in different 

technology areas (CIGS, CdTe, etc.) contributed 

to the work plan. The Accelerated Aging and Reliability workshop provided critical industry feedback, identifying priorities and test needs. In the 

area of thin-film reliability, a common thread was 

the development of generalized tests and analysis 

procedures that were not specific to one technology or process. Specific needs included testing of 

materials, interconnects, window layers, and other 

cell components prior to module qualification testing. Many of the SAI partners funded in this area 

view flexible products as necessary to achieve 

DOE goals for levelized cost of electricity. 

A result of this workshop was an initial analysis of 

both rigid (glass-glass) and flexible CIGS products. This analysis was used to define priorities for 

this project that included: 

•	 Understanding degradation of flexible, thin-film 

products; specifically, understanding the role 

of TCO degradation. 

•	 Accelerated testing of adhesion of encapsulant materials. 

Another key aspect of our technical approach is 

active partnership with industry. These interactions 

are necessary for maintaining the relevancy of our 

research to SAI goals. CRADAs have been established with a CdTe manufacturer, a principal supplier of CdTe feedstock material, and a major supPhotovoltaic

Test and Evaluation

Reliability R&D

118
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

plier of packaging and coating materials. We have 

also established working relationships with flexible 

CIGS manufacturers to evaluate their packaging 

strategies using a newly developed ALT, specifically designed for that task. 

This project leveraged expertise and equipment at 

NREL associated with CdTe and CIGS cell fabrication to develop ALTs to target critical needs 

identified through industrial feedback. Strong associations with both CdTe and CIGS manufacturers were leveraged to address thin-film reliability in 

a unique, dynamic, and industrially driven fashion. 

Work has begun on mini-module and cell ALTs, 

studying different edge seals, encapsulants, and 

back-contact materials. The convolution of traditional reliability processes (encapsulation) with 

thin-film group activities (TCO, film growth, and 

metallization) will be used to develop more relevant test coupons for ALT studies. 

3. FY 2008 Special Recognitions, Awards, 

Patents, and Other Activities 

•	 J. Pern and D. Albin, committee members, 

2008 SPIE conference on “Reliability of PV 

Cells, Modules, Components, and Systems”. 

•	 D. Albin,presented an invited talk at the Univ. 

of Rochester “Process-related and Intrinsic 

Degradation in Polycrystalline, Thin-Film CdTe 

Solar Cells”. 

•	 J. Pern presented talks at both the 2008 SPIE 

conference and the Silicon workshop. 

•	 APP PV Reliability Project: J. Pern, organization committee U.S. chair, working with T. 

James, S. Kurtz, J. Nelson, J. Granata, M. 

Quintana, and Prof. Cui of SJTU to organize 

the APP International PV Reliability Workshop, 

Dec. 4-5, 2008, in SJTU, Shanghai, China. 

•	 Panosyan, Z.; Gippius, A.; Pern, F.J.; Touryan, K. “Methods and Apparatus for Making 

Diamond-Like Carbon Films,” patent application. 

4.	 Major FY 2008 Publications 

D.S. Albin. “Accelerated Stress Testing and Diagnostic Analysis of Degradation in CdTe Solar 

Cells.” 2008 SPIE Reliability of PV Cells, Modules, 

Components, and Systems, http://spie.org (2008). 

F.J. Pern, et al. “Degradation of ZnO Window 

Layer for CIGS by Damp-Heat Exposure.” 2008 

SPIE Reliability of PV Cells, Modules, Components, and Systems, available online at 

http://spie.org. (2008). 

G.J. Jorgensen; T.J. McMahon. “Accelerated and 

outdoor aging effects oh photovoltaic module interfacial adhesion properties.” Prog. in PV; 16(6), p. 

519 (2008). 

T.J. McMahon. “Solar Cell/Module Degradation 

and Failure Diagnostics.” IEEE 46th Annual Intl. 

Reliability Phys. Symp. Proceedings; p. 172 

(2008). 

M.D. Kempe; P. Thapa. “Low-Cost, Single-Layer 

Replacement for the Back-Sheet and Encapsulant 

Layers.” SPIE Proceedings; 2008, San Diego, 

California. 

M.D. Kempe, et al. “Ripping into CIGS Cells; Do 

Encapsulants Materially Impact Degradation 

Rates?” Solar Industry; 1(9), p 58-63, Oct. (2008). 

M.D. Kempe. “Accelerated UV Test Methods and 

Selection Criteria for Encapsulants of Photovoltaic 

Modules.” Atlas Testing Services Corporate Newsletter, Fall 2008. 

C. Osterwald. “Terrestrial Photovoltaic Module 

Accelerated Test-To-Failure Protocol.” NREL/TP520-42893. Golden, CO: National Renewable 

Energy Laboratory, 2008. 

J. Pern, et al. “Damp-Heat Induced Degradation of 

Transparent Conducting Oxides for Thin-Film Solar Cells.” NREL/CP-520-42525. Golden, CO: National Renewable Energy Laboratory, 2008. 

M.D. Kempe. “Accelerated UV Test Methods for 

Encapsulants of Photovoltaic Modules.” Presented 

at 33rd IEEE PVSC, 2008. 

M.D. Kempe, et al. “Stress Induced Degradation 

Modes in CIGS Mini-Modules.” Presented at 33rd 

IEEE PVSC, 2008. 

J.A. Del Cueto, et al. “Stability of CIS/CIGS Modules at the Outdoor Test Facility over Two Decades.” Presented at 33rd IEEE PVSC, 2008. 

119 Photovoltaic

Test and Evaluation

Reliability R&D
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Module, Array, and System Technology and Evaluation 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Bill Marion (NREL), 303-384-6793, bill_marion@nrel.gov 

Jennifer Granata (SNL), 505-844-8813, jegrana@sandia.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, Dan.Ton@ee.doe.gov 

FY 2008 Budgets:	 $1,575K (NREL), $890K (SNL) 

Objectives 

•	 Characterize performance and reliability of Technology Pathway Partnership (TPP) and other 

Solar America Initiative (SAI)-developed products during development and for stage-gate 

evaluations. 

•	 Develop protocols and capabilities for test and evaluation of new components and systems, 

including systems-level technologies such as concentrating photovoltaics (CPV). 

•	 Develop and maintain capabilities to define and conduct tests to provide information/data for 

validation and improvement of reliability and performance models. 

•	 Conduct baseline testing of modules, minimodules, and/or coupons for the Long Term Exposure 

activities detailed in the Reliability Project. 

Accomplishments 

•	 Performed baseline and stage-gate testing and evaluation for SAI TPP participants. (NREL/SNL) 

•	 Refurbished NREL outdoor module test facility with 45 module capacity and instrumentation 

upgraded to include global spectroradiometer. (NREL) 

•	 Completed PV module/system performance assessments at SNL for seven non-SAI industry 

partners (Entech, Advent, Evergreen, Emcore, Xantrex, PVPowered, Recurrent Energy) on >150 

samples, leading to product design optimizations. (SNL) 

•	 Developed NREL two-axis tracking test bed for testing flat-plate and concentrating PV modules, 

with tracking-error monitor and direct-normal spectroradiometer. (NREL) 

•	 Installed and analyzed data for a PV system from Open Energy to determine performance 

characteristics of a building integrated photovoltaics (BIPV) system. (NREL) 

•	 Provided assistance with measurements for the performance assessment of a 8.2-megawatt 

(mW) PV system in Alamosa, Colorado. (NREL) 

•	 Performed initial assessment of the Napa Valley College 1-mW PV system and created field 

electrical performance characterization plan. (SNL) 

•	 Initiated the upgrade of the data acquisition system at SNL Photovoltaic Systems Evaluation Lab 

(PSEL) to double testing capacity (from 4 to 8 simultaneous tests). (SNL) 

•	 Rebuilt one of SNL’s two-axis trackers to improve tracking accuracy for flat-plate and CPV 

modules to improve baseline outdoor measurements and long-term exposure. (SNL) 

•	 Achieved status as an SNL Primary Standards Laboratory satellite calibration center for spectral 

responsivity measurements. (SNL) 

Future Directions 

•	 Characterize the performance and reliability of SAI-developed products during development and 

for stage-gate evaluations with a focus on TPP and Incubator technologies that were not ready 

for evaluation in fiscal year (FY) 2008. 

•	 Develop protocols and capabilities for test and evaluation of new components and systems, 

including systems-level technologies such as new CPV technologies and new BIPV technologies. 

•	 Define and conduct tests to provide information/data for validation and improvement of systemslevel models, including reliability, inverter, and other performance models. 

•	 Transfer improved test procedures and methods to standards committees and industry. 

Photovoltaic

Test and Evaluation

Systems Engineering

120
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Results and Accomplishments 

The level 3 and 4 milestones and their date 

achieved are as follows: 

•	 Completion of all stage-gate required tests 

and reports delivered for stage-gate reviews 

(9/30/2008). 

•	 Technical report on building-integrated PV 

(BIPV) system performance (9/30/2008). 

The following sections describe the major results 

and accomplishments of the agreement. 

3.1 Stage-Gate Tests and Reporting 

SAI TPP participants were supported by SNL 

through Stage Gate testing and evaluation 

(Amonix, Greenray), baseline testing (Soliant, 

SunPower, Boeing), and on-site product 

evaluations (Boeing). Solaria CPV modules 

underwent a 3-month test at NREL that compared 

their energy production to that for nonconcentrating PV. Test reports were generated for 

Amonix, Greenray, Soliant and Sunpower in 

preparation for Stage Gate reviews. Baseline 

testing for Boeing continues, and a report will be 

generated upon testing completion. All other TPP 

participants and select incubator participants were 

contacted for baseline testing, and plans are 

underway to conduct testing for DOW, GE, AVA, 

BP Solar, and SolFocus. 

3.2 BIPV System Performance Evaluation 

To better understand the performance of 

production BIPV systems, in particular their 

operating temperatures, a BIPV system was 

installed at NREL, and its performance was 

measured. PV tiles, manufactured by Open 

Energy and that integrate with standard concrete 

roofing tiles, were used for the installation. At the 

request of the manufacturer, the PV tiles were 

installed using two different industry methods. The 

first method attaches the PV tiles directly to the 

roof sheathing with screws. The second method 

installs the PV tiles on counter battens that raise 

the PV modules an inch above the roof sheathing 

and permits additional air flow under the PV 

modules. 

Compared to the direct-mount installation, the 

improved air flow for the counter batten installation 

reduced PV modules temperatures by as much as 

10°C at midday, and overall energy production 

was increased by 3.4%. Both installations had 

temperature rise coefficients that were 5-6°C less 

than what we had expected based on minimum 

standoff height; perhaps a consequence of tileroofing systems being somewhat porous for air 

flow. 

3.3 T&E Capabilities Development 

A spectroradiometer was added to NREL’s 

Performance and Energy Rating Test Bed (PERT) 

for measuring global tilt spectral irradiance. PERT 

provides outdoor testing of 45 PV modules, with IV curves measured every 15 minutes. Between IV curve measurements, the PV modules are peakpower tracked, and average power is recorded. 

The addition of the spectral irradiance data will 

permit quantifying performance differences 

between technologies due to variations in solar 

spectrum. This is important for both energy rating 

standards and performance modeling. Software 

was also developed for reporting PV module 

performance, using IEC 61724 metrics and for 

quality assessment of PERT data. 

A test bed is under development for evaluating the 

performance of two-axis tracking PV concentrator 

and flat-plate modules. An existing two-axis 

tracker at NREL has been modified to improve its 

tracking. A spectroradiometer for the 

measurement of direct normal spectra has been 

installed for evaluating CPV sensitivity to spectral 

distribution. A PERT-type data acquisition system 

for collection of meteorological data and I-V curve 

measurements has been procured and is 

undergoing fit-up and testing. It will allow power 

measurements of up to 600 watts. Performance 

measurements of CPV modules will begin in early 

FY 2009. 

To expand outdoor module test capabilities, SNL 

is building a two-axis tracker with greater than 0.5 

degree pointing accuracy to enhance testing of 

CPV module, optics, and other balance of systems 

components. The base was completed in FY 

2008, with final construction and alignment to be 

completed in early FY 2009. This is of particular 

importance for the SAI baseline and stage gate 

testing for companies such as Boeing and 

SolFocus. In addition, SNL is doubling the data 

acquisition capacity to allow for eight modules to 

be tested simultaneously, which can be extremely 

valuable to understanding the differences between 

modules of differing technologies. 

3.4 Field Evaluations 

In December 2007, NREL provided assistance 

with measurements of solar radiation and 

meteorological parameters for Black and Veatch’s 

performance assessment of the 8.2-mW PV 

system, constructed by SunEdison in Colorado. 

121 Photovoltaic

Test and Evaluation

Systems Engineering
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In April 2008 in support of the Amonix SAI TPP 

stage-gate review, SNL performed simultaneous 

field testing of two Amonix MegaModules in Las 

Vegas, Nevada, allowing for a real-time 

comparison of two different generations of 

MegaModules. The MegaModules, nominally 5 

kW, were located at two separate sites in Las 

Vegas. Performance and weather data were 

collected over a 2-day period, and SNL generated 

a report comparing the output of the two 

MegaModules in support of Amonix’s first stage 

gate review. This comparison demonstrated the 

increase in power output in the next-generation 

MegaModule. 

Also in April 2008, SNL visited a 1-mW SunPower 

(PowerLight) installed system in Napa, California. 

The system consisted of PowerLight modules on 

single-axis trackers. Yellowed areas near junction 

boxes of all modules indicated a possible design 

flaw, leaky diodes. Performance, often linked to 

reliability issues, was assessed. Tracking errors 

observed in several trackers have provided 

impetus to understand the threshold where 

tracking error significantly affects performance. 

Cooling-fan failures on inverters within 18 months 

of installation spurred questions regarding 

performance and reliability penalties, especially if 

immediate action is not taken to replace/repair the 

fans. 

3.5 Improved Test Procedures and Methods 

NREL’s PERT data were used to develop and 

validate an accurate model for PV power that only 

requires three parameters: power at SRC, power 

temperature coefficient, and power at 200 W/m2

. 

(The ESTI lab has elected to evaluate this and 

other models for a benchmark paper on predictive 

models.) The use of the power at the 200 W/m2 

parameter allows a correction to be applied for PV 

modules that do not maintain their efficiency at low 

irradiance levels. Depending on PV module, this 

reduces the overall error in energy predictions by 

0-2%. 

In March, SNL completed 1 year of data collection 

on three, 1-kW grid-tied PV systems which were 

installed at SNL’s PV Systems Optimization 

Laboratory, shown in Figure 1. Key system 

parameters, solar radiation, and weather data 

were collected at 2-minute intervals. This data set 

was used to validate performance models against 

measured data for the models used in the Solar 

Advisor Model, and the results were published at 

the PV Specialists Conference in May 2008. 

Fig. 1. Systems installed at SNL’s PV Systems 

Optimization Laboratory 

Angle of Incidence (AOI) performance of flat-plate 

modules and off-axis tracking assessments of 

CPV modules are imperative to accurately model 

the yearly performance and calculate levelized 

cost of energy (LCOE). In 2008, SNL improved the 

precision of the outdoor module AOI test 

capability, which in turn improved the accuracy of 

the performance modeling output. 

With the rapid increase in the number and size of 

fielded PV systems in the United States, the need 

for accurate and safe field testing has escalated. 

SNL hosted a team of field-test experts from 

NREL, Southwest Research Experiment Station 

(SWRES) at New Mexico State University, and 

Southeast Regional Experiment Station (SERES) 

at the Florida Solar Energy Center in March 2008 

to discuss field-test protocols that need to be 

generated for the industry. SNL took the lead to 

generate a first draft of this protocol and work with 

the other experts to finalize a document that will 

be provided to industry at the end of FY 2009. 

2. Major FY 2008 Publications 

B. Marion. “Comparison of Predictive Models for 

Photovoltaic Module Performance.” Presented at 

2008 33rd IEEE Photovoltaic Specialists 

Conference; San Diego, California, May 11-16, 

2008. 

M. Muller; J. Rodriguez. “Performance 

Comparison of a BIPV Roofing Tile System in Two 

Mounting Configurations.” Draft report, Golden, 

CO: National Renewable Energy Laboratory, 

September, 2008. 

C. Cameron; W. Boyson; D. Riley. “Comparison of 

PV System Performance-Model Predictions with 

Measured PV System Performance.” Presented at 

2008 33rd IEEE Photovoltaic Specialists 

Conference; San Diego, California, May 11-16, 

2008. 

Photovoltaic

Test and Evaluation

Systems Engineering

122
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

PV Module Database 

Performing Organization:	 Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Dan Riley (SNL), 505-284-3152, driley@sandia.gov 

Jennifer Granata (SNL), 505-844-8813, jegrana@sandia.gov 

DOE HQ Technology Manager:	 Dan Ton, 202-586-4618, Dan.Ton@ee.doe.gov 

FY 2008 Budget:	 $180K 

Objectives 

•	 Create an algorithm to generate module performance parameters for new commercial modules 

that closely match existing modules for entry into module database, based on name plate and 

specification sheet data. 

•	 Solicit and develop an external source for empirically developed module parameters for 

database. 

•	 Provide external testing source with SNL-purchased modules for testing and inclusion into the 

module database. 

Accomplishments 

•	 Created algorithm to generate module performance parameters based on name plate and 

specification sheet data. 

•	 Added 190 modules to the database using performance parameters generated by the algorithm. 

•	 Added 10 modules to the database using test data gathered at SNL. 

•	 Generated the initial solicitation to develop the external source to take over routine module testing 

and database maintenance. 

•	 Documented key test parameters necessary for external source to take over routine module 

testing. 

•	 Hosted Atonometrics to show them SNL’s test procedures and methodologies and initiate test 

technology transfer for outdoor module performance measurements. 

•	 Visited Arizona State University Photovoltaic (PV) Test Laboratory to assess the laboratory’s 

capability to perform accurate PV module measurements and discuss future collaborative efforts. 

•	 Converted database files from an older format to a newer format, allowing better integration with 

new database software and tools. 

Future Directions 

•	 Complete solicitation for external transfer of routine module testing and database maintenance. 

•	 Develop the capabilities of the selected contractor to perform high-accuracy outdoor module 

measurements and properly analyze module measurements to attain parameters necessary for 

the SNL PV Array Performance Model. 

•	 Verify the accuracy of the contractor by testing representative modules from many U.S.-based 

module manufacturers and comparing results with the same modules tested by the contractor. 

•	 Transfer maintenance and control of the module database to the contractor. 

•	 Provide funding to contractor for the purchase and testing of new PV modules for inclusion into 

database. 

123 Photovoltaic

Test and Evaluation

Systems Engineering
 

 

 

 

____________________________________________________________________________________ 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

Energy Rating Method Validation 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Bill Marion (NREL), 303-384-6793, bill_marion@nrel.gov 

DOE HQ Technology Manager: Dan Ton, 202-586-4618, Dan.Ton@ee.doe.gov 

FY 2008 Budget: $200K (NREL) 

Objectives 

•	 Develop models, methodologies, and procedures for predicting the energy production of 

photovoltaic (PV) modules and systems. 

•	 Support the implementation of energy rating standards by evaluating and validating draft 

standards related to energy ratings. 

Accomplishments 

•	 Completed a 4-year experiment to assess the performance of amorphous silicon (a-Si) PV 

modules operating at three sites with different climates. Results published at 2008 IEEE PV 

Specialists Conference (PVSC). The purpose of the experiment was to determine light-induced 

degradation and stabilization characteristics of single- and multi-junction a-Si PV modules and the 

influence of climate and exposure history. 

•	 Evaluated and continuously measured the outdoor performance of a PV module in order to 

achieve the irradiance-temperature test requirements of the draft energy rating standard, 

International Engineering Consortium (IEC) 61853-1. 

Future Directions 

•	 Validate and evaluate studies of the draft standard IEC 61853 Photovoltaic (PV) Module 

Performance and Energy Rating–Part 1, which focused on irradiance and temperature 

performance measurements and power rating. 

•	 Develop and validate methods for correcting angle-of-incidence losses due to reflection and 

methods for accounting for variations in solar spectrum. 

1. Introduction 

PV module manufacturers have typically supplied 

a module’s power rating at standard reporting 

conditions (SRC, 1000 W/m2 irradiance, 25°C cell 

temperature, and AM1.5 spectrum). This is useful 

for comparing the performance of different 

modules at SRC, but is not necessarily a good 

predictor of performance in the field where 

irradiance, temperature, and spectrum may depart 

significantly from conditions at SRC, and the 

module’s response to these departures may be 

dependent on PV technology or manufacturer. 

An international consensus document being 

developed on energy ratings is IEC 61853, 

“Photovoltaic Module Performance Testing and 

Energy Ratings.” 

2. Major FY 2008 Publications 

R. Rüther; J. del Cueto; G. Tamizh-Mani; A.A. 

Montenegro; S. Rummel; A. Anderberg; and B. 

von Roedern. ”Performance Test Of Amorphous 

Silicon Modules In Different Climates – Year Four: 

Progress In Understanding Exposure History 

Stabilization Effects.” Presented at the 2008 33rd 

IEEE Photovoltaic Specialists Conference, May 

11-16, 2008. 

J. del Cueto. “On the Feasibility of Using PERT 

Data to Derive Module Performance as per IEC 

61853-1,” Test Report, Golden, Colorado: National 

Renewable Energy Laboratory, September 2008. 

Photovoltaic

Test and Evaluation

Systems Engineering

124
 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

Regional Experiment Stations 

Performing Organizations: Southwest Regional Energy Station (SWRES) 

Southeast Regional Experiment Station (SERES) 

Key Technical Contacts:	 Steve Palmeri (DOE Golden Field Office), 303-275-4832, 

steve.palmeri@go.doe.gov 

Holly Thomas (DOE/GO), 303-275-4818, holly.thomas@go.doe.gov 

HQ Technology Manager:	 Tom Kimbis, 202-586-7055, tom.kimbis@ee.doe.gov 

FY 2008 Budgets:	 $1,136K (SWRES), $855K (SERES) 

Objectives 

•	 Ensure that education, training, outreach, and technical support required to accelerate rate of 

nation’s photovoltaic (PV)-deployment efforts are available and effectively implemented to 

support growth of PV market. 

•	 Provide leadership and support to industry and national labs for: (1) systems, module, and 

inverter testing; (2) creating and implementing procedures, codes, and standards for quality, safe, 

and cost-effective installed systems; (3) hardware certification; and (4) addressing system 

engineering issues observed in fielded systems. 

•	 Provide technical support to DOE, national laboratories, Solar America Cites, Showcase Projects, 

and industry in execution and validation of stage gates for Technology Pathway Partnerships. 

Accomplishments 

•	 Completed second-period requirements of 3-year award and began the final period work. 

•	 Conducted product testing, system evaluations, and research and development (R&D) activities 

that related to cutting levelized cost of energy (LCOE), increasing system efficiency, and cutting 

initial costs of PV systems, particularly as required by Solar America Initiative (SAI) participants. 

•	 Provide technical outreach as member of Tiger Teams to Solar America Cities and Showcases. 

Future Directions 

•	 Continue to lead or serve as a member of Tiger Teams to Solar America Cities and Showcases. 

•	 Continued testing and evaluation of fielded PV systems for TPP stage-gate testing, general 

system benchmarking, and characterization of PV systems and components for performance, 

cost, and reliability. 

•	 Continue training and participate in development and dissemination of codes and standards. 

1. Introduction	 2. Technical Approach 

The Regional Experiment Stations (RES) consist 2.1. PV Systems Assistance Center 

of two organizations: SERES and SWRES. The Photovoltaic Systems Assistance Center 

These stations are affiliated with local (PVSAC) is a virtual laboratory comprised of universities, University of Central Florida for engineers and staff from both SWRES and SERES and New Mexico State University for SERES. PVSAC is an independent third-party SWRES. RES provide support in such areas as: evaluator to evaluate TPP interim results during •	 Module reliability R&D. their stage-gate reviews. 

•	 Inverter and BOS development. 

•	 PV systems engineering, analysis, 2.2. Infrastructure Development 

evaluation, and optimization, especially for Training, design review and approval, and codes fielded systems. and standards development are conducted. •	 Education, advance codes, and standards. 

125 Photovoltaic

Test and Evaluation

Systems Engineering
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.3. Long-Term Component Testing 

RES provide unique and severe environments 

for long-term exposure (hot/dry and hot/humid) 

for stressing PV modules and inverters in 

outdoor system-like configurations. 

3. Results and Accomplishments 

SERES: 

•	 Participated in ‘Tiger Team’ evaluation for 

Orange County Convention Center, Solar 

America Showcase. Provided extensive 

technical support through bid specification 

development and design review. 

•	 Partnered with ETL-Intertek to conduct 

performance testing of PV modules in 

accordance to UL-1703 and IEC standards. 

•	 Conducted comprehensive design reviews 

for 38 small-scale PV systems installed in 

Florida, which were evaluated for code 

compliance and basic performance criteria. 

•	 Conducted week-long course, Installing PV 

Systems, at FSEC each month. The course 

was also modified to be taught at several 

locations around the United States, including 

Solar America Cities and for workforce 

development programs such as Employ 

Florida Banner Center. More than 350 

individuals attended the courses. 

•	 Created Solar Information Office to address 

demand for information and technical 

assistance from general public. The office is 

primarily staffed by students with SERES 

staff supervisors. During an average week, 

there are more than 100 public contacts via 

email, phone, and walk-ins. 

•	 Evaluated module performance versus 

module nameplate for more than 75 PV 

modules, using data as basis for 

determining stabilized module performance 

information and long-term performance. 

•	 Installed several PV systems in Florida for 

disaster relief applications. The systems 

were primarily installed at schools that serve 

as emergency shelters, and the PV systems 

help to provide power during grid outages. 

SERES support was provided for design 

review, acceptance testing, and 

performance monitoring. 

•	 Continued data collection for side-by-side 

comparison of utility interactive inverters. 

Identical arrays were used, and performance 

was monitored continuously under real 

conditions in a hot-humid climate. 

•	 Prepared design guide for application of 

existing structural codes to attachment of PV 

arrays to residential rooftops. The work was 

done in conjunction with various partners 

with Miami-Dade Building Code Compliance 

Office, Florida International University 

Hurricane Research Center, BP Solar, 

Miami-Dade County, District 8, BEW 

Engineering, and Solar ABCS. 

•	 Provided support for Florida public policy 

regarding net-metering and resulted in an 

updated and industry-supportive role for the 

state. 

SWRES: 

•	 Served as Tiger Team lead or participant 

Solar America Cities and Showcases: Forest 

City (Oahu, HI); Tucson, AZ; Santa Rosa, 

CA; San Jose, CA; and Austin, TX. 

•	 Collaborated with SNL to review solar 

modeling activities (PVSAM, PVWatts), joint 

field test exercises, reliability tests, 

benchmark data validation, accelerated life 

testing, and instrumentation requirements. 

•	 Consulted with electrical inspectors 

nationwide on major code concerns. 

•	 Evaluated prototype systems for several 

industry clients. 

•	 Conducted Internet-based training and 

Webinar for more than 60 electricians, 

inspectors, and installers. 

•	 Trained more than 1,140 designers, 

inspectors and installers in NEC workshops 

during 3-month reporting period. 

•	 Monitored inverter performance, real-time 

performance at www.nmsu.edu/~tdi/iltf. 

4. Planned FY 2009 Activities 

•	 Continue to lead or as member of technical 

outreach Tiger Teams to Solar America 

Cities and Showcases. 

•	 Continued testing and evaluation of fielded 

PV systems for TPP stage-gate testing, as 

well as general system benchmarking PV 

systems and component performance, cost, 

and reliability characterization. 

•	 Continue training and participate in 

development and dissemination of codes 

and standards. 

•	 Support market transformation activities with 

needs that capitalize on SERES research 

and technology transfer work. 

•	 Increase capabilities in field-test and outdoor 

validation activities for hot-humid climates. 

Photovoltaic

Test and Evaluation

Systems Engineering

126
 

 

 

 

 

•	 Increase PV module testing capabilities for 

certification programs to help minimize test 

time and to reduce backlogs for industry for 

an expanding U.S. industry. 

•	 Continue expanding small residential 

inverter testing facilities. 

•	 Continue workforce development efforts 

through course offerings in PV-system 

design and installation. 

5. Patents and Publications 

SERES 

•	 R.M. Reedy; P.E. and G.H. Atmaram. 

“Recent Activities on Wider Utilization of 

Photovoltaic Technology in Florida.” 33rd 

IEEE Photovoltaic Specialists Conference 

Proceedings; May 11-16, 2008. 

•	 G. Atmaram; et al. “Need for Uniform PV 

Module Performance Testing and 

Certification.” 33rd IEEE PV Specialist 

Conference Proceedings; May 11-16, 2008, 

San Diego, California. 

SWRES 

•	 J. Wiles. "To Fuse or Not to Fuse." Home 

Power; #125, June/July 2008. 

6. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/ Title of Research Activity 

FY 2008 

($K) 

University of Central Florida 

Florida Solar Energy Center 

Bob Reedy/Stephen Barkaszi 

Cocoa, FL PV System Research and Technical 

Assistance 855 

Southwest Technology Development 

Institute 

Andrew Rosenthal 

Las Cruces, NM PV System Research 1,000 

127 Photovoltaic

Test and Evaluation

Systems Engineering
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

Solar Radiometry and Modeling 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Daryl R. Myers (NREL), 303-384-6768, daryl_myers@nrel.gov 

DOE HQ Technology Manager: Dan Ton, 202-586-4618, dan.ton@ee.doe.gov 

FY 2008 Budget: $800K (NREL) 

Objectives 

Accurate solar radiometric measurements and models reduce uncertainties associated with solar energy 

conversion systems, ultimately influencing the levelized cost of energy (LCOE). Project objectives include: 

•	 Support Measurements and Characterization ISO 17025 (General Requirements for the 

Competence of Calibration and Testing Laboratories) accreditation scope. 

•	 Provide ISO 17025-compliant broadband and spectral radiometric calibrations traceable to 

international and national reference standards. 

•	 Participate in consensus standards development (American Society for Testing and Materials, 

International Lighting Commission) related to solar system testing. 

•	 Reduce uncertainties in solar radiometric data and solar radiation models. 

•	 Transfer optical and solar measurements-related technology to the solar conversion industry. 

Accomplishments 

•	 Verified NREL reference standard stability relative to World Radiometric Reference (WRR) at 

NREL Pyrheliometer Comparison (NPC), Sandia National Laboratories, and 19 other participating 

laboratories. 

•	 Performed 30 spectral and 305 broadband solar broadband radiometer calibrations for NREL and 

solar industry partners. 

•	 Classified five industrial partner and three NREL flash solar simulators according to ASTM E927. 

•	 Transferred NREL Pulse Analysis Spectroradiometer System (PASS) technology to Spire 

Corporation through technical partnership agreement. 

•	 Published NREL PASS technology in proceedings of the Society for Photo-Optical 

Instrumentation Engineers (SPIE) technical conference. 

•	 Completed update of Commission Internationale de'Eclariage (CIE or International Lighting 

Commission) Publication 85 on Solar Simulation. 

•	 Analyzed relative performance over 11 months of 1-minute radiometric data for 15 solar 

radiometer models; produced draft NREL technical report of results. 

•	 Modified SEDES2 spectral model to convert hourly broadband solar data, referred to as TMY2, to 

hourly spectral distributions for all sky conditions; began validation process. 

•	 Modified all-sky version of Bird Clear Sky broadband solar radiation model to include ground to 

cloud to ground reflection element. 

•	 Installed new global latitude tilt and direct normal spectroradiometers at NREL’s Outdoor Test 

Facility (OTF) and Solar Radiation Research Laboratory (SRRL); spectral data Web-accessible. 

•	 Responded to 311 requests for technical information from industry, university, and DOE inquiries. 

Future Directions 

•	 Investigate short-term (submonthly) aerosol optical depth estimates to improve hourly broadband 

and spectral distribution models. 

•	 Assess commercially available solar pyrheliometers to better characterize the accuracy of direct 

beam measurements for concentrating applications. 

•	 Develop a new spectral irradiance calibration technique to reduce spectral measurement 

uncertainty by at least a factor of 2. 

•	 Apply measured and modeled solar radiation data to validation of short-term (subhourly), 

medium-term (hourly), and long-term (daily) solar radiation forecasting approaches. 

Photovoltaic

Test and Evaluation

Resource and Safety Research

128
 

 

 

____________________________________________________________________________________ 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

Solar Resource Assessment and Characterization 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact: Dave Renné (NREL), 303-384-7408, david_renne@nrel.gov 

DOE HQ Technology Manager: Dan Ton, 202-586-4618, dan.ton@ee.doe.gov 

FY 2008 Budget: $580K 

Objectives 

•	 Address system-level performance metrics by: 

o	 Improving the quality and reliability of domestic and international site-time-specific solar 

resource data sets and related meteorology to optimize solar energy system production and 

lower levelized cost of energy; 

o	 Developing solar resource data products that support efficient system design and increase 

investor confidence in system deployments; 

o	 Creating easy access to data and products for all consumers, solar developers, and planners. 

Accomplishments 

•	 Produced updated Typical Meteorological Year (TMY) database for the United States, using both 

the original 1961-1990 and 1991-2005 National Solar Radiation Database (NSRDB) data sets. 

The new data set, TMY3, is available at http://rredc.nrel.gov/solar/old_data/nsrdb/1991-2005/tmy3/. 

•	 Collaborated with NASA and others on technical results for the International Energy Agency (IEA) 

Solar Heating and Cooling (SHC) Programme Task 36 “Solar Resource Knowledge 

Management.” 

o	 Released report on benchmarking methodologies through the MESoR Programme. These 

methodologies include not only root mean square error and mean bias error statistics but also 

a second-order benchmarking scheme using Kolmogorov-Smirnoff statistics. 

o	 Demonstrated the first prototype of a Web portal, jointly through activities with Project 

MESoR. This web portal is available at http://project.mesor.net. 

o	 Tested the National Digital Forecast Database (NDFD), two versions of the European Center 

for Midrange Weather Forecasting, and a version of the Weather Research Forecasting 

model (WRF), adjusted to the Global Forecast System, at three high quality ground-based 

solar measurement sites in the United States: Colorado, Nevada, and Mississippi. 

Future Directions 

•	 Conduct test and validations of solar resource forecasting schemes. 

•	 Initiate steps to develop an in-house satellite-based solar resource assessment capability. 

•	 Pursue further updates to the NSRDB, based on 2006 data. 

•	 Investigate long-term influences on solar resources due to climate variability and trends. 

•	 Continue operating agent support to IEA/SHC Task 36 and begin the development of key
 

benchmarking studies.
 

•	 Continue to develop and publish Web-based tools and data sets to make solar resource 

information more readily accessible to users.
 

1.	 Major FY 2008 Publications S. Wilcox; W. Marion. “Development of an 

Updated Typical Meteorological Year Data Set 

for the United States.” Solar 2008 Conference D.S. Renné. “Renewable Energy Resource Data Proceedings; May 8-12, 2008, San Diego, Provide the Foundation for Effective Clean California. Energy Programs Around the World.” World 

Renewable Energy Congress – X Proceedings; 

July 2008, Glasgow, Scotland. 

129 Photovoltaic

Test and Evaluation

Resource and Safety Research
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

Environmental Health and Safety 

Performing Organization: Brookhaven National Laboratory (BNL) 

Key Technical Contact: Vasilis Fthenakis (BNL), 631-344-2830, vmf@bnl.gov 

DOE HQ Technology Manager: Alec Bulawka, 202-586-5633, alec.bulawka@ee.doe.gov 

FY 2008 Budget: $470K 

Objectives 

•	 Assist in preserving the safe and environmentally friendly nature of photovoltaics (PV) and in 

minimizing environmental health and safety (EH&S) risks and associated costs to ensure the 

public support and economic viability of PV systems. 

•	 Identify potential EH&S barriers of PV materials, processes, or applications and define strategies 

to overcome such barriers. 

•	 Maintain EH&S Research Center as the world’s best source on PV EH&S, providing accurate 

information related to EH&S issues and perceptions. 

Accomplishments 

•	 Featured in Environmental Science & Technology (ES&T) and Scientific American. 

•	 Conducted a life cycle analysis of III/V and a multi-crystalline concentrator PV; presented the 

results at the 23nd European PV Solar Energy Conference, Barcelona, Italy. 

•	 Conducted a study on lessons learnt in silane handling and presented the results at the 

IEEEPVSC, as well as a seminar, jointly with Air Products, on silane safety. 

•	 Promoted international collaborations on life cycle assessment (LCA) of PV energy technologies. 

•	 Led International Energy Agency Task 12; developed guidelines for LCA. 

•	 Recycling CdTe spent modules and manufacturing waste; improved the separations and recovery 

of Cd in high Fe industrial streams. 

•	 Assisted several companies on site-specific EH&S issues. 

•	 Answered several requests for EH&S information from the public and the industry. 

Future Directions 

•	 Conduct LCA of near-commercialization PV technologies (e.g., a-Si/microcrystalline tandem and 

CIGS). 

•	 Conduct preliminary LCA of 3rd generation PV technologies to guide the industry towards more 

environmentally friendly alternatives. 

•	 Accurately define environmental profiles of solar in comparison to other energy technologies. 

•	 Define cost of recycling spent modules and determining scenarios for cost reductions. 

•	 Assist industry in preventing accidents and releases of hazardous materials to the environment, 

and guiding them towards environmentally friendly material and process options. 

•	 Conducting LCA of integrated PV and storage systems. 

•	 Answer industry, legislators’, and public inquiries about EH&S issues in solar energy cycles. 

•	 Identify and characterize EH&S hazards associated with emerging materials, including nanomaterial forms for the U.S. Department of Energy, its contractors, and the private sector. 

1. FY 2008 Special Recognitions 

“Prospects of solar energy in the U.S.” was 

“Emissions from PV Life Cycles” was featured featured on the cover of Scientific American 

on the cover of the February issue of ES&T and (published in 19 languages) and broadcasted by 

broadcasted in the New York Times, IEEE Spiegel, EnergyBiz, Sun & Wind Energy, and 

Spectrum, Scientific American, and a Dutch several radio and TV stations. 

paper. 

Photovoltaic

Test and Evaluation

Resource and Safety Research

130
 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Solar America Board for Codes and Standards 

Performing Organizations: New Mexico State University (NMSU) 

Tucson Electric Power (TEP)
 

Research Foundation of the State University of New York (SUNY–
 

Albany)
 

Key Technical Contact: Holly Thomas (DOE/GO), 303-275-4818, holly.thomas@go.doe.gov 

DOE HQ Technology Manager: Tom Kimbis, 202-586-7055, tom.kimbis@hq.doe.gov 

FY 2008 Budget: $780K (NMSU) 

Objectives 

•	 Establish consistent support for codes and standards development to enable solar technology 

deployment on a large scale. (NMSU) 

•	 Improve the responsiveness, effectiveness, and accessibility of codes and standards in all 

markets, including federal, state, local, and utility. (NMSU) 

•	 Establish utility photovoltaic (PV)-capacity credits models to reduce market barriers and promote 

solar energy technology acceptance. (NMSU) 

•	 Develop a central repository for collection and dissemination of documents, regulations, and 

technical materials related to solar codes and standards. (NMSU) 

•	 Describe and experimentally compare methodologies quantifying the effective capacity credit of 

non-dispatchable resources, such as PV, and build consensus for proposed methodologies. 

(SUNY) 

•	 Develop, test, and verify method to accurately evaluate the capacity credit of time-variant PV 

generation and develop utility-based methods to evaluate the value of solar generation to electric 

utilities. (TEP) 

Accomplishments 

•	 Published three codes and standards study reports. (NMSU) 

•	 Convened 13 stakeholder meetings to provide input on codes and standard issues. (NMSU) 

•	 Identified major gaps in the current work on codes and standards and prioritized them for a 

strategic plan for future work. (NMSU) 

•	 Modeled two methodologies to quantify the capacity credit of dispersed PV: (1) the Effective Load 

Carrying Capability (ELCC), based upon the concept of loss of load probability, and (2) the Solar 

Load Control Capacity (SLC), based on load control with a small amount of demand response 

and/or storage to firm PV capacity. (SUNY) 

•	 Published a report, “Utility Solar Generation Valuation Methods.”(TEP) 

Future Directions 

•	 Publish four additional codes and standards study reports. Commence outreach to targeted 

audiences on report recommendations. (NMSU) 

•	 Facilitate stakeholder involvement and communication on codes and standards issues through 

stakeholder meetings, electronic newsletters, and the Solar America Board for Codes and 

Standards (ABCs) Web site. (NMSU) 

•	 Conduct fire safety research on rating of PV modules mounted on different roofing materials. 

(NMSU) 

•	 Participate in the development of international and national standards through International 

Electrotechnical Commission (IEC) Technical Committee 82 and other standard making 

organizations. (NMSU) 

131 Market Transformation

Codes and Standards
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

PV Installer Certification 

Performing Organization:	 North American Board of Certified Energy Practitioners (NABCEP) 

Key Technical Contacts:	 Margie Bates (DOE/GO, Primary Contact), 303-275-4845, 

margie.bates@go.doe.gov 

Kathleen Bolcar (DOE), 202-586-6646, kathleen.bolcar@hq.doe.gov 

DOE HQ Technology Manager:	 Tom Kimbis, 202-586-7055, tom.kimbis@hq.doe.gov 

FY 2008 Budget:	 $185K (DOE/GO) 

Objectives 

•	 Develop and implement quality credentialing and certification programs for renewable energy 

practitioners that include solar photovoltaic (PV) installer certification, solar thermal installer 

certification, recertification program, and entry-level Certificate of Knowledge of solar PV systems. 

•	 Establish competency standards to assist in the smooth growth of a renewable energy workforce. 

Accomplishments 

•	 Continued to increase the number of individuals who have achieved NABCEP certifications and 

obtained its entry-level Certificate of Knowledge of solar PV systems: 

- 164 individuals received solar PV certification in FY08, representing an increase of 22% over 

FY 2007. Total NABCEP-certified solar PV installers to date: 587. 

- 525 individuals obtained PV entry-level Certificate of Knowledge of Solar PV systems in FY 

2008, increase of more than 100% from 2007. Total NABCEP Entry-Level Certificates of 

Knowledge issued to date: 999. 

- 29 individuals obtained NABCEP solar thermal installer certification in FY 2008. Total 

NABCEP-certified solar thermal installers to date: 85 

•	 With the help of NABCEP’s volunteer pool of experts, updated the solar PV exam question bank 

and free study guide to reflect changes in the National Electric Code. 

Future Directions 

•	 Conduct an aggressive marketing and outreach campaign to ensure that there are significant 

increases in the number of test-takers pursuing NABCEP certification. 

•	 Increase awareness within the business community, state and federal agencies, and consumer 

base about the benefits of NABCEP certification. 

•	 Develop and announce a new family of certification programs that address the rapidly changing 

needs and roles in the renewable energy market. 

1. FY 2008 Special Recognitions and Awards	 3. University and Industry Partners 

•	 Received prestigious ANSI/ISO/IEC 17024 NABCEP works closely with companies and 

accreditation.	 organizations, including Interstate Renewable 

Energy Council, National Electrical Contractors 

2.	 Major FY 2008 Publications Association, Solar Rating Certification 

Corporation, National Renewable Energy Lab, 

•	 Bi-monthly NABCEP newsletters. Sandia National Lab, International Brotherhood 

•	 Three new brochures: Benefits of of Electrical Workers, BP Solar, Sharp Solar, 

Certification, Benefits to the Nation, and Powerlight, SunPower Corporation, SunEdison, 

Benefits to the States. Appalachian State University, Southwest 

Technology Development Institute, North 

Carolina Solar Center, and New York State 

Energy Research and Development Authority. 

Market Transformation

Training and Certification

132
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

Solar Decathlon 

Performing Organization: National Renewable Energy Laboratory (NREL) 

Key Technical Contact:	 Cécile Warner (NREL), 303-384-6516, cecile_warner@nrel.gov 

DOE HQ Technology Manager: Richard King, 202-586-1693, richard.king@ee.doe.gov 

FY 2008 Budget:	 $3,237K (NREL) 

Objectives 

•	 Conduct next fiscal year (FY) 2009 Solar Decathlon university competition where exclusively 

solar-powered houses will demonstrate building-integrated photovoltaics (BIPV) and solar 

technologies in marketable residential applications 

•	 Develop, release, and manage solicitations to produce FY 2009 event. 

•	 Conduct post-Decathlon instrumentation and monitoring. 

Accomplishments 

•	 Concluded implementation of 2007 Solar Decathlon university competition, which included 

releasing final regulations; firming up sponsorships; supporting teams; scoring; monitoring; and 

carrying out all aspects of event. (October 2007) 

•	 Held “Building Industry Day” for builders at 2007 Solar Decathlon. (October 2007) 

•	 Orchestrated signing of a memorandum of understanding (MOU) between U.S. Department of 

Energy (DOE) and Spain’s Housing Ministry to collaboratively develop 2010 Solar Decathlon 

Europe competition. (October 2007) 

•	 Selected 20 teams for 2009 Solar Decathlon, awarding each team a 2-year, $100,000 contract. 

Launched activities leading toward execution of 2009 event. (January 2008) 

•	 Garnered award of excellence for 2007 Solar Decathlon’s communications efforts from 2008 

International Association of Business Communicators (IABC) Southern Region Silver Quill 

Awards. (September 2008) 

Future Directions 

•	 Conduct 2009 Solar Decathlon in first quarter of FY 2010 and release solicitation for 2011 event. 

•	 Replace “Getting Around” electric car contest with new “Net Metering” contest for 2009 contest. 

•	 Assess performance of selected, occupied former Solar Decathlon houses to evaluate long-term 

implications of PV in buildings. 

•	 Continue and expand productive interactions with building industry. 

1. Introduction	 2. Technical Approach 

The Solar Decathlon fosters the widespread The Solar Decathlon’s goal is to develop and 

acceptance of PV-integrated buildings by facilitate widespread adoption of PV in the built 

overcoming technical and commercial barriers and environment, resulting in solar-powered homes 

by facilitating the integration of PV into the built and businesses that demonstrate buildingenvironment through technology development, integrated PV and solar technologies in 

applications, and key partnerships. Through this marketable applications and partnerships that 

project, PV will become a routinely accepted build on successes. 

building technology in the 21st century. 

2.1 Conduct 2007 Solar Decathlon 

The Solar Decathlon is an intercollegiate 

competition in which teams work to design, build, 

and operate the most attractive and energyefficient solar-powered homes. Twenty teams of 

133 Market Transformation

Building Integration and Finance
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

students from the United States, Canada, 

Germany, and Spain competed in the 2007 event. 

The teams, selected through a competitive 

procurement in 2005, worked on their projects 

over the intervening 2 years under NREL’s 

supervision and guidance. They transported their 

houses to the National Mall in Washington, D.C., 

where they built a “solar village” and opened their 

homes to the visiting public from October 12 to 

October 20, 2007. Teams competed against each 

other in 10 contests—some of which were scored 

by measuring performance, while others were 

scored by jurors representing expertise in 

appropriate fields. The contests tested the teams’ 

abilities to produce electricity and hot water from 

solar panels to perform all the functions of a home 

and provide power for an electric car. In addition to 

the energy-related contests, each house was 

judged on its architecture, livability, ease of 

construction, and replication of design. The teams 

provided their homes’ designs and communicated 

with the public about their homes. 

2.2 Develop and Release Solicitation for 2009 

Solar Decathlon Event 

NREL prepared and released a solicitation for the 

2009 event at the start of the 2007 event. Each 

winning university proposal was set to receive 

$100K in research funding (over two years) to 

support the innovative development of BIPV 

technology in its entry. 

2.3 Conduct Post-Decathlon Monitoring Program 

A PV building benchmarking effort to assess longterm performance of occupied Solar Decathlon 

homes after the competition was developed in FY 

2006 and the effort was continued in FY 2008. 

This comprehensive monitoring and 

instrumentation activity, together with a building 

simulation and modeling effort, works toward the 

goal of understanding and improving the design 

and performance of BIPV homes. 

Task Title FY 2008 

Budget ($K) 

Solar Decathlon (NREL) 3,237* 

*Includes activities reported in Communications and 

Outreach section of annual report. 

3. Results and Accomplishments 

3.1 Major Accomplishment: Solar Decathlon 2007 

NREL organizers and its subcontractors 

successfully carried out the 2007 Solar Decathlon 

held October 2 through October 22, 2008, on the 

National Mall in Washington, D.C. Tasks 

performed in order to achieve this goal included: 

•	 Providing scores for the 10 contests. 

•	 Performing expert judging for contests such as 

market viability, architecture engineering, Web 

sites, and house tours. 

•	 Reviewing team designs for code and 

regulation compliance. 

•	 Installing equipment. 

•	 Performing instrumentation system 

development, acquisition, and shakedown. 

•	 Distributing of communication materials (i.e., 

brochures, media kits, official program, Web 

site materials, and graphics). 

•	 Coordinating teams, sponsors, and volunteers. 

•	 Procuring stagecraft and assembly of solar 

village. 

•	 Executing procedures for safe conduct during 

entire event. 

In addition to hosting a Web site that informed 

visitors about the competition and scoring, we 

managed crowds of more than 200,000 visitors to 

the Solar Decathlon and a massive media interest 

in the future of solar energy and the next 

generation of solar practitioners and solar homes. 

3.2 Major Accomplishment: Held “Building Industry 

Day” for Builders at the 2007 Solar Decathlon 

On October 18, 2007, solar industry leaders 

conducted nine separate workshops for builders at 

the 2007 Solar Decathlon. 

3.3 Major Accomplishment: MOU for Solar 

Decathlon Europe 2010 

NREL organizers coordinated the signing of an 

MOU between DOE Assistant Secretary for 

Energy Efficiency and Renewable Energy Andy 

Karsner and Spain’s Undersecretary of Housing 

Fernando Magro Fernández to collaborate in the 

development of a Solar Decathlon Europe 

competition in 2010. 

3.4 Major Accomplishment: Received 2008 IABC 

Southern Region Silver Quill Award 

NREL organizers of the 2007 Solar Decathlon 

event garnered an award of excellence for 

communications activities that resulted in 200,000 

visitors to the National Mall, 400,000 unique 

visitors to the event Web site, more than 1,000 

related media articles and stories, and nearly 650 

million media impressions. 

Market Transformation

Building Integration and Finance

134
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.5 Major Accomplishment: Solicit and Select 

Teams for 2009 Solar Decathlon and Launch 

Activities Leading toward Execution of 2009 Event 

NREL organizers selected 20 teams (from 

proposal responses to a solicitation) to participate 

in the 2009 Solar Decathlon (see list in Section 6). 

In FY 2008, competition organizers also worked 

on designing a village micro-grid to make the 2009 

Solar Decathlon competition more consistent with 

the U.S. market for new and existing homes and 

more compatible with the Builders Challenge 

rating system. In 2009, each house will be gridtied to a village-scale micro-grid and the new “Net 

Metering” contest will enable teams to earn points 

for exporting power to the micro-grid. The 2009 

grid-connected solar village will advance the Solar 

Decathlon goals and expand the knowledge base 

for grid-connecting solar buildings. 

Milestones Supported by DOE Funding 

Milestone or 

Deliverable Due Date Status 

Announce and release 

solicitation for 2009 

event 

10/12/07 Complete 

Select and announce 

teams for 2009 event 1/20/08 Complete 

Finalize and publish 

2009 rules and building 

code 

9/30/08 Complete 

4. Planned FY 2009 Activities 

•	 Convene workshop for 2009 Solar Decathlon 

Teams in second quarter of FY 2009. 

•	 Continue activities leading toward execution of 

2009 Solar Decathlon event. 

•	 Design and prepare for installation, safe 

operation, and removal of temporary microgrid that will interconnect all 20 Solar 

Decathlon 2009 homes and supply power for 

event organizers. 

5. Major FY 2008 Publications 

C.	 Anna, Solar Decathlon: Building the Future, 

U.S. Department of Energy (Brochure) 

www.nrel.gov/docs/fy08osti/43638.pdf. 

U.S. DOE, Solar Decathlon Web site, 

www.solardecathlon.org. 

M. Wassmer, 2009 Solar Decathlon Rules and 

Regulations, 

www.solardecathlon.org/pdfs/sd2009_rules.pdf. 

M. Wassmer, 2009 Solar Decathlon Building 

Code, 

www.solardecathlon.org/pdfs/sd2009_building_code.pdf. 

6. University and Industry Partners 

Organization/ 

Principal Investigator or Contact Location/E-mail Description/Title of Research 

Activity 

FY 

2008 

($K) 

Colorado Code Consulting, LLC 

Thomas Meyers 

Berthoud, CO 

codeconsultant@gmail.com 

Complete one plan review of 20 

sets of drawings and specifications 

for the Solar Decathlon competition 

in preparation for on-site building 

inspections of the competition 

houses after they are installed on 

the National Mall in Fall 2009 

20 

Cornell University 

Matt Ulinski 

Ithaca, NY 

mu25@cornell.edu 2009 Solar Decathlon team 50 

Iowa State University 

Ulrike Passe 

Ames, IA 

upasse@iastate.edu 2009 Solar Decathlon team 50 

Penn State 

Jeffrey R. S. Brownson 

University Park, PA 

nanomech@psu.edu 2009 Solar Decathlon team 50 

Rice University 

John Casbarian 

Houston, TX 

jjc@rice.edu 2009 Solar Decathlon team 50 

Team Alberta (University of 

Calgary / SAIT Polytechnic / 

Alberta College of Art + Design / 

Mount Royal College) 

Warren Veale 

Calgary, Alberta, Canada 

veale@ucalgary.ca 2009 Solar Decathlon team 50 

135 Market Transformation

Building Integration and Finance
 

 

 

 

Organization/ 

Principal Investigator or Contact Location/E-mail Description/Title of Research Activity 

FY 

2008 

($K) 

Team Boston (Boston Architectural 

College / Tufts University) 

Jeff Stein 

Boston, MA 

jeff.stein@the-bac.edu 2009 Solar Decathlon team 50 

Team California (Santa Clara 

University / California College of 

the Arts) 

Timothy Hight 

Santa Clara, CA 

THight@scu.edu 2009 Solar Decathlon team 50 

Team Missouri (Missouri University 

of Science and Technology / 

University of Missouri) 

Katie Grantham Lough 

Rolla, MO 

kag@umr.edu 2009 Solar Decathlon team 50 

Team Ontario/BC (University of 

Waterloo / Ryerson University / 

Simon Fraser University) 

Geoffrey Thun 

Cambridge, Ontario, Canada 

studio@velikovthun.com 2009 Solar Decathlon team 50 

Technische Universität Darmstadt 

Manfred Hegger 

Darmstadt, Hesse, Germany 

hegger@ee.tu-darmstadt.de 2009 Solar Decathlon team 50 

The Ohio State University 

Mark E. Walter 

Columbus, OH 

walter.80@osu.edu 2009 Solar Decathlon team 50 

The University of Arizona 

Larry Medlin 

Tuscon, AZ 

rlmedlin@email.arizona.edu 2009 Solar Decathlon team 50 

Universidad de Puerto Rico 

Sonia M. Miranda-Palacios 

San Juan, Puerto Rico 

mirandasonia@alum.mit.edu 2009 Solar Decathlon team 50 

Universidad Politécnica de Madrid 

José Manuel Paéz Borrallo 

Madrid, Spain 

vicerector.internacional@upm.es 2009 Solar Decathlon team 50 

University of Illinois at Urbana, 

Champaign 

Patrick Chapman 

Champaign, IL 

plchapman@uiuc.edu 2009 Solar Decathlon team 50 

University of Kentucky 

Donald Colliver, Ph.D., PE 

Lexington, KY 

colliver@bae.uky.edu 2009 Solar Decathlon team 50 

University of Louisiana at Lafayette 

W. Geoff Gjertson 

Lafayette, LA 

gjertson@louisiana.edu 2009 Solar Decathlon team 50 

University of Minnesota 

Ann Johnson 

Minneapolis, MN 

Johns421@umn.edu 2009 Solar Decathlon team 50 

University of Wisconsin-Milwaukee 

Gregory Thomson and Chris 

Cornelius 

Milwaukee, WI 

thomsong@uwm.edu 2009 Solar Decathlon team 50 

Virginia Tech 

Joseph Wheeler 

Blacksburg, VA 

joewheel@vt.edu 2009 Solar Decathlon team 50 

Market Transformation

Building Integration and Finance

136
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

Solar America Showcases 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

New Mexico State University (NMSU) 

Florida Solar Energy Center (FSEC) 

Key Technical Contacts:	 Steven Palmeri (DOE/GO, Primary Contact), 303-275-4832, 

steve.palmeri@go.doe.gov 

Cecile Warner (NREL), 303-384-6516, cecile_warner@nrel.gov 

Vipin Gupta (SNL), 915-491-1158, vpgupta@sandia.gov 

Andy Rosenthal (NMSU), 505-646-1323, arosenthal@nmsu.edu 

Robert Reedy (FSEC), 321-638-1470, reedy@fsec.ucf.edu 

DOE HQ Technology Manager:	 Charlie Hemmeline, 202-586-6646, charles.hemmeline@ee.doe.gov 

FY 2008 Budget:	 $1,590K 

Objectives 

•	 Accelerate demand for solar technologies among key end-use sectors. 

•	 Assist in creating high visibility solar projects that increase public awareness of solar power. 

•	 Create replicable, large-scale projects that can become models for other U.S. entities. 

Accomplishments 

Forest City Military Communities Project 

•	 Supported a real estate project that showcases the wider adoption of solar technology. This 

project is a public-private joint venture with the Department of Navy to build or refurbish 6,500 

homes for military families on U.S. naval and marine bases in Hawaii. 

Orange County Convention Center (OCCC) Project 

•	 Provided assistance to the OCCC, in partnership with the Orlando Utilities Commission (OUC), to 

install a nominal 1-megawatt (MW) photovoltaic (PV) system on the roof of and in the area 

surrounding its North-South Building. The system will include a large rooftop system, as well as 

four experimental systems showcasing new technologies at ground-level for public viewing. 

San Jose City Project 

•	 Helped identify eight city-owned buildings that might be suitable for solar installations. These 

locations are highly visible in the San Jose downtown area and have the potential for up to 2 MW 

of total solar power. 

Future Directions 

•	 Continue to seek solar projects to support in fiscal year (FY) 2009 that accelerate demand for 

solar technologies. 

1. Introduction	 desired that the project be replicable or have 

replicable components. Although it is not expected 

The purpose of Solar America Showcases (SAS) that projects meet all of these parameters, ideally 

is to accelerate demand for solar technologies projects reflect some or most of these qualities. 

among key end-use market sectors. Under this Large-scale installations may include PV, 

activity, DOE provides technical assistance to concentrating solar power (CSP), and solar water 

large-scale, high-visibility solar installation projects heating (SWH) applications. 

that have the ability to impact the market for solar 

technologies through large project size, use of a Regarding the scale of the project, DOE looks for 

novel solar technology, and/or use of a novel projects with total capacity in excess of 100 

application for a solar technology. In addition, it is kilowatt (kW). Projects may include multiple sites 

137 Market Transformation

Technical Partnerships
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

and do not have to be co-located. In addition to 

the initial installation, the kW total may also 

include planned follow-on activities (direct 

replication efforts). Examples include installations 

in residential subdivisions, shopping centers, office 

buildings or parks, big box retail locations, 

factories, and utility solar production. 

2. Technical Approach 

SAS awarded technical assistance to four 

organizations. These organizations represented a 

broad spectrum of applications with cross-cutting 

issues that allowed the Solar America Initiative 

(SAI) to work on several barriers. These barriers 

included: 

•	 Addressing financing barriers for solar 

applications in a municipality. 

•	 Creating a request for proposal (RFP) that 

municipalities can use for soliciting bids on 

solar installations. 

•	 Developing an economically sound model for 

doing site surveys across a large housing 

complex. 

•	 Researching inverter location and 

interconnection issues. 

•	 Developing protocols for acceptance testing 

and commissioning processes on new solar 

installations. 

3. Results and Accomplishments 

3.1 Forest City Military Communities Project 

•	 Provided technical assistance necessary for 

Forest City to install a 107-kW PV system on 

the Halsey Terrace Community Center, a 

project that could create 9 MW of power that 

will benefit over 6,500 Navy and Marine Corp 

families in Honolulu, Hawaii. 

•	 Provided Forest City the know how to plan up 

to 3-kW PV systems on 759 housing units on 

Kaneohe Bay Marine Corps Base. 

3.2 Orange County Convention Center (OCCC) 

•	 Provided assistance in the development of the 

RFP document for the 1-MW PV system. 

•	 Evaluated five pre-qualification bids were 

received in the first round, although as one 

arrived 10 minutes late, it was disqualified. 

•	 After analyzing the capabilities of the 

companies, Ferreira Construction of NYC and 

Johnson Controls, Inc. (JCI) were invited to 

submit a final bid to part 2 of the RFP, and 

Orange County declared JCI the winner in late 

June. 

•	 Participated in the first design meeting in midSeptember to discuss data communication 

within the center and locations of the arrays 

around the site. 

3.3 City of San Jose Project 

The technical assistance team performed site 

evaluations, cost estimations, predicted energy 

savings, and performed cash flow analyses on the 

following buildings in the City of San Jose: 

•	 City of San Jose Central Service Yard. 

•	 4th Street Parking Garage. 

•	 Children’s Discovery Museum. 

•	 HP Pavilion. 

•	 San Jose Convention Center. 

•	 Story Road Landfill. 

•	 Las Plumas EcoPark. 

•	 San Jose/Santa Clara Water Pollution Control 

Plant. 

3.4 New Showcase Projects Selected in FY 2008 

•	 Mystic Seaport Museum in Mystic, 

Connecticut. 

•	 District Department of the Environment/District 

of Columbia Energy Office. 

•	 Zero Energy Solar PV Housing Development 

in Mesa del Sol, New Mexico. 

4. Planned FY 2009 Activities 

•	 Complete work with OCCC as well as each of 

the new projects selected in 2008. 

•	 Develop new funding opportunity 

announcements (FOAs) for specialty projects 

such as zero energy homes, microgrid 

projects, and/or MW sized systems. 

Market Transformation

Technical Partnerships

138
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

Solar America Cities 

Performing Cities Awarded in 2007: 

Ann Arbor, MI; Austin, TX, Berkeley, CA; Boston, MA; Madison, WI; New 

Orleans, LA; New York, NY; Pittsburgh, PA; Portland, OR; Salt Lake 

City, UT; San Diego, CA; San Francisco, CA; Tucson, AZ 

Performing Cities Awarded in 2008: 

Denver, CO; Houston, TX; Knoxville, TN; Milwaukee, WI; Orlando, FL; 

Philadelphia, PA; Sacramento, CA; San Antonio, TX San Jose, CA; 

Santa Rosa, CA; Seattle, WA; St. Paul-Minneapolis, MN 

Key Technical Contacts:	 Margie Bates, (DOE/GO), 303-275-4845, margie.bates@go.doe.gov 

Joe Lucas (DOE/GO), 303-275-4849, joe.lucas@go.doe.gov 

Steve Palmeri (DOE/GO), 303-275-4832, steve.palmeri@go.doe.gov 

DOE HQ Activity Manager:	 Thomas Kimbis, 202-586-8064, tom.kimbis@ee.doe.gov 

FY 2008 Budgets:	 $2,400K (DOE), $2,400K (Technical Assistance from National Labs) 

Objectives 

•	 Provide financial assistance awards, also called cooperative agreements, up to $200,000 to each of 

the 12 newly awarded cities under the Solar America Cities 2008 solicitation, in addition to 13 Solar 

America Cities awarded in 2007, with populations of 100,000 or more to propose activities that 

support the objectives of DOE and Solar America Initiative (SAI) market transformation activities. 

•	 Provide up to $200,000 in tailored technical assistance from DOE national laboratories and 

contractors to each of the 2008 recipient cities to accomplish the project goals. 

Accomplishments 

•	 Issued a second round of competitive funding opportunity announcement (FOA) and awarded $2.4 

million in financial assistance and $2.4 million in technical assistance to 12 additional U.S. cities to 

form strategic partnerships. 

•	 Held the first annual Solar America Cities meeting in Tucson, Arizona, bringing together the 2007 and 

2008 awardees to share best practices, share lessons learned, present new ideas, and engage in 

networking opportunities. 

•	 Launched a Solar America Cities Web site http://solaramericacities.energy.gov/Home.aspx. 

•	 Provided technical assistance for each of the 2007 and 2008 cities from National Renewable Energy 

Laboratory (NREL), Sandia National Laboratories (SNL), Oak Ridge National Laboratory (ORNL), 

Southwest Regional Experiment Station (SWRES) at New Mexico State University (NMSU), and 

Southeast Regional Experiment Station (SERES) at the Florida Solar Energy Center (FSEC). 

Future Directions 

•	 Integrate solar energy technologies into city energy planning and removal of market barriers to solar 

energy development that exist in urban planning charters, zoning regulations, building codes, 

permitting, and inspections procedures. 

•	 Promote solar technology among residents and local businesses through outreach, curriculum 

development, incentive programs, and other innovative approaches. 

•	 Develop a comprehensive city-government approach to solar implementation involving key 

stakeholders, utilities, and private partners. 

•	 Widespread increase in the adoption of solar energy technologies across the cities in the residential, 

commercial, and public building sectors and at utilities. 

139 Market Transformation

Technical Partnerships
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Technical Approach 

The objective of the SAC 2008 funding 

opportunity announcement (FOA) was to support 

cities ready to take a comprehensive, systemic, 

city-wide approach to solar technology that 

facilitates mainstream adoption and provides a 

model for other cities. DOE selected 13 SAC in 

June 2007 and an additional 12 cities in March 

2008 to help lay the foundation for a solar energy 

market that can serve as a model for cities 

around the nation. 

Each of the new cities submitted a proposal 

outlining its plans to build a sustainable solar 

infrastructure, streamline city-level regulations, 

and promote the adoption of mainstream solar 

technology among residents and businesses. 

Table 1. Winning Cities for 2008 

Solar America Cities 2008 FY 2008 

Budget ($K) 

Denver, CO 200 

Houston, TX 200 

Knoxville, TN 200 

Milwaukee, WI 200 

Orlando, FL 199 

Philadelphia, PA 200 

Sacramento, CA 200 

San Antonio, TX 200 

San Jose, CA 200 

Santa Rosa, CA 200 

Seattle, WA 200 

St. Paul & Minneapolis, MN 200 

On-Site Technical Assistance 

In their proposals, each city identified the 

technical assistance their projects might require 

in areas such as city planning, technology 

selection, project financing, building codes, 

architecture and community outreach. Similar 

with 2007 cities, DOE appointed a technical 

assistance lead, called a Tiger Team leader to 

each city. Members of the Tiger Team were 

drawn from the National Renewable Energy 

Laboratory (NREL) in Colorado, Sandia National 

Laboratories (SNL) in New Mexico, Oak Ridge 

National Lab (ORNL) in Tennessee, Southwest 

Regional Experiment Station (SWRES) at New 

Mexico State University, and Southeast, 

Regional Experiment Station (RES) at the Florida 

Solar Energy Center. 

2. Results and Accomplishments 

In April 2008, DOE held the first annual SAC 

meeting to share experiences, lessons learned 

and provide the 2007 and 2008 cities the 

opportunity to network. 

DOE launched a Solar America Cities Web site 

at http://solaramericacities.energy.gov/Home.aspx to 

promote the goals and accomplishments. 

Ann Arbor: completed an online database of 

solar access for Ann Arbor residences and a 

highly-visible 10-kilowatt (kW) photovoltaic (PV) 

installation. 

Austin: identified areas where solar could be the 

vehicle for teaching basic science to students 

began incorporating this knowledge into a school 

curriculum. 

Berkeley: developed an online project calculator 

and completed its marketing and outreach plan. 

Boston: developed and launched the online solar 

energy map 

(http://gis.cityofboston.gov/solarboston) and 

hosted five solar energy events with a combined 

attendance of more than 700 participants. 

Madison: developed a Web site with information 

about solar, permitting, and funding information 

and introduced an ordinance simplifying the 

permitting process for solar systems and 

removing restrictions into the legislative process. 

New Orleans: established a Web site, 

www.solarpowernola.org, as a repository for 

solar technology information and established 

North American Board of Certified Energy 

Practitioners (NABCEP) solar installer training 

program at a local college. 

New York: convened the third annual Solar 

Summit, a conference focused on implementing 

solar in New York City with leaders from utilities, 

industry, government, and academia attending 

and presenting. 

Pittsburgh: conducted several solar workshops 

with SAI city partners. 

Portland: generated Web, print, and electronic 

marketing materials, educating thousands of 

individuals throughout the region about the 

benefits of solar energy. Facilitated 

Market Transformation

Technical Partnerships

140
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

approximately 200 PV and solar thermal systems 

to residents and businesses (217 kW.) 

Salt Lake: implemented Utah’s first solar PV 

installer course at Salt Lake Community College 

and hosted two solar and National Electric Code 

(NEC) code training sessions. 

San Diego: developed the city Solar Map and 

completed an extensive survey, announced by 

the mayor, to all homes and businesses with 

solar installations, resulting in a 30% rate of 

return. 

San Francisco: developed “GoSolarSF” city 

incentive program and addressed barriers to 

installing solar on multi-tenant buildings. 

Tucson: helped develop solar installer training 

classes at Pima Community College and trained 

75 inspectors on NEC and solar installations. 

Denver: prepared presentation for the Zoning 

Code Task Force related to solar technologies 

and access laws in preparation for first major 

revision to city’s code in 50 years. 

Houston: designed and launched the Solar 

Houston Initiative Web site and developed a 

Solar Technician Curriculum (23 Credit Hours) 

for Houston Community College, geared towards 

NABCEP certification. 

Knoxville: launched a Website highlighting 

Knoxville’s SAC program at 

www.cityofknoxville.org/policy/solar. 

Milwaukee: drafted initial energy plan and 

submitted it to project stakeholder stakeholders. 

Began talks with Madison to develop a regional 

solar plan. 

Orlando: launched its new rebate program, which 

offers $200 per customer for installing a solar 

thermal system and receiving an energy audit. 

Philadelphia: conducted first round of 

stakeholder meetings to solicit feedback from 

critical stakeholders for Philadelphia’s solar 

future. 

Sacramento: identified 16 potential sites for solar 

PV, 10 existing sites, and six new construction 

sites. 

San Antonio: conducted a press conference on 

groundbreaking of a Peak Performance House, a 

solar experimental lab. 

San Jose: sponsored a Summer Solstice trade 

show with the mayor to highlight solar companies 

that offered 0% down financing for the residential 

sector and received approval from council to 

explore partnerships with utilities and solar 

generators regarding large scale solar 

installations (solar farms) on city vacant lands. 

Santa Rosa: completed a site assessment and 

preliminary design for a 65-kW solar PV support 

structure for the parking lot at the city’s 

wastewater treatment plant. 

Seattle: developed “Solar Works in Seattle!” 

workshops planned for educating City Light 

customers. 

St. Paul and Minneapolis: completed planning for 

the installation of two solar charging systems for 

plug-in hybrid cars. 

141 Market Transformation

Technical Partnerships
 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

Government Solar Installation Program (GSIP) 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts: Steven Palmeri (DOE/GO, Primary Contact), 303-275-4832, 

steve.palmeri@go.doe.gov 

Carolyn Elam (DOE/GO), 303-275-4953, carolyn.elam@go.doe.gov 

Cecile Warner (NREL), 303-384-6516, cecile_warner@nrel.gov 

Vipin Gupta (SNL), 915-491-1158, vpgupta@sandia.gov 

DOE HQ Technology Manager: Charles Hemmeline, 202-586-6646, charles.hemmeline@ee.doe.gov 

FY 2008 Budget: $280K 

Objectives 

•	 Support federal agencies to achieve commitment to purchasing 2 gigawatts (GW) of solar power 

at federal facilities and 1 GW at state and local facilities, with all transactions and installations to 

be completed by 2012 ahead of the final renewable energy purchase phase of the Energy Policy 

Act of 2005 (EPAct 2005). 

•	 Lower production costs for solar components through a market-based approach of using 

governmental energy needs to build demand for solar products and increase production.
 

•	 Maximize installation of secure, on-site renewable energy projects at all DOE sites, optimize 

affordable purchases of renewable electricity by DOE facilities, or both. 

Accomplishments 

•	 Developed a model for a federal Photovoltaic (PV) request for proposals, vetted through financial 

and solar communities and the General Services Administration (GSA). 

•	 Initiated development of a dynamic Government Solar Installation Program Web-enabled tool. 

•	 Prepared a report technically defining the solar energy opportunities for federally-owned 

Congressional office buildings in Washington, D.C.
 

•	 Prepared a report providing technical assessment of the potential for using solar energy and 

other key energy efficiency features as part of the Elephant House renovation in progress at the 

National Zoological Park in Washington, D.C. 

•	 Planned the federal PV standard offer contract/power purchase agreement with a standard lease 

model for release during fiscal year (FY) 2008. 

Future Directions 

•	 Continue assessments of governmental buildings and implementation of solar rooftop 

installations.
 

•	 Work with the DOE Federal Energy Management Program (FEMP) to identify the best federal 

buildings where solar makes the most sense. 

•	 Begin a dialog with other federal agencies to help them identify locations where solar can be 

installed in a cost-effective manner on their buildings. 

1. Introduction 

GSIP is a market-based challenge to public Initiative, a department-wide effort to reduce 

entities—federal agencies, states, cities, energy intensity across all DOE complexes by 

counties, and other local governments—to 30%. The major GSIP partners are the DOE 

increase their use of solar energy power. GISP Solar Energy Technologies Program, DOE 

is carried out in partnership with DOE’s Federal Energy Management Program, and 

Transformational Energy Action Management General Services Administration. 

Market Transformation

Technical Partnerships

142
 

 

 

 

________________________________________________________________________________ 

 

 

 

 

 

 

 

________________________________________________________________________________ 

State and Stakeholder Outreach 

Performing Organization:	 Interstate Renewable Energy Council (IREC) 

Key Technical Contacts:	 Margie Bates, (DOE/GO, Primary Contact), 303-275-4845, 

margie.bates@go.doe.gov 

Kathleen Bolcar (DOE), 202-586-2820, kathleen.bolcar@hq.doe.gov 

DOE HQ Technology Manager:	 Charles Hemmeline, 202-586-6646, charlie.hemmeline@hq.doe.gov 

FY 2008 Budget:	 $1,500K (DOE/GO) 

Objectives 

IREC’s 5-year plan is based on extensive outreach and education focused on the following activities: 

•	 Encourage and coordinate quality training workshops and accessible learning opportunities, as 

well as provide assistance to educational providers through the Workforce Training and Quality 

Assessment Project. 

•	 Connect experts with Solar America Initiative – Market Transformation (SAI-MT) stakeholders on 

key issues in a cost-effective and convenient format. 

•	 Provide models and assistance on net metering and interconnection to lower both barriers and 

cost for the installation of solar electricity through the Connecting to the Grid Project. 

•	 Monitor and participate, as appropriate, in public hearings/meetings and provide input that could 

impact solar barriers and/or commercialization through solar codes and standards public 

hearings. 

•	 Manage and maintain a Web site that offers easily accessible news, information, tools, best 

practices, and materials. 

•	 Prepare annual reports on solar market trends and impacts regarding interconnection and net 

metering, training and certification programs, state incentives, and other relevant issues. 

Accomplishments 

•	 Actively educated and supported information about net metering and interconnection in 18 states. 

•	 Published “Best Practices and Recommendations” for renewable energy training. 

•	 Published 26 issues of the IREC/SAI e-newsletter for more than 3,000 subscribers and posted on 

the IREC Web site. 

•	 Published 12 issues of the Interconnection/Net Metering e-newsletter for more than 3,200 

subscribers. 

•	 Updated job trends and occupational profile reports. 

•	 Published annual solar market trends report. 

Future Directions 

•	 Coordinate training workshops through the Workforce Training and Quality Assessment Project in 

conjunction with states, cities, and other SAI-MT stakeholders for code and building department 

officials. 

•	 Disseminate 26 issues of the SAI-MT e-newsletter during the next year and coordinate six SAI 

telephone seminars. 

•	 Disseminate 12 issues of Interconnection and Net Metering e-newsletters during the next year. 

•	 Address the infrastructure barriers with the states through the Solar Codes and Standards 

Hearing Project that supports the objectives of SAI. 

•	 Maintain the IREC Web site. 

143 Market Transformation

Technical Outreach
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Introduction 

The Interstate Renewable Energy Council 

(IREC) promotes increased stakeholder 

communications and education under the Solar 

America Initiative – Market Transformation (SAIMT) addresses infrastructure barriers to solar 

energy, and coordinates with industry, DOE, 

national laboratories, states, cities, and counties. 

2. Technical Approach 

IREC continued to promote better 

communications among stakeholders, 

addressed infrastructure barriers by promoting 

easy and fair hook-up rules to the utility grid, 

promoted quality training based on industry 

competency standards, and coordinated closely 

with multiple federal, state, and local 

stakeholders. 

With the growth of the solar market over the past 

few years and the new attention to solar energy 

solutions, workforce development and quality 

training become a critical component for this 

expanding sector. For example: 

•	 IREC works with community colleges, the 

North American Board of Certified Energy 

Practitioners, and subject matter experts. 

•	 Training is provided by an accredited body 

such as a college, university, community 

college, vocational-technical institution, or 

certified installers with instructional 

experience. 

3. Results and Accomplishments 

IREC has accomplished the following to meet 

the objective to remove institutional and market 

barriers: 

•	 Organized seven informative, interactive 

phone seminars. 

•	 Convened six workshops for code officials. 

•	 Convened two introductory workshops on 

training and one faculty development 

workshop in California. 

4. Planned FY 2009 Activities 

For solar training and certification, IREC will use 

an integrated approach that combines Webbased resources, on-site and electronic forums, 

print material, and technical assistance. IREC 

will: 

•	 Promote quality standards for training. 

•	 Conduct six phone seminars on current and 

“hot” topics. 

•	 Hold six PV workshops for code officials. 

•	 Hold four solar thermal workshops for code 

officials. 

•	 Conduct two introductory training 

workshops. 

•	 Hold at least one faculty development 

workshop. 

•	 Publish 12 interconnection/net metering 

models. 

5. Major FY 2008 Publications 

•	 Best Practices and Recommended 

Guidelines for Training, September 2008. 

•	 Annual Trends and Update Report, 

September 2008. Distributed at IREC’s 

Annual Meeting in October 2008. 

•	 Published 26 issues of the IREC/SAI ENewsletter. 

•	 Occupational Profiles of Solar Industry, 

August 2008. 

5th •	 edition of the Connecting to the Grid 

Guide. 

6. University and Industry Partners 

IREC works closely with many groups, industry, and community colleges, which include the following: 

•	 North Carolina Solar Center at North Carolina State University 

• The Southwest Technology Development Institute at New Mexico State University 

•	 New York State Energy Research and Development Authority 

•	 North American Board of Certified Energy Practitioners 

•	 Hudson Valley Community College 

•	 Lane Community College 

•	 Industry and Stakeholder Groups. 

Market Transformation

Technical Outreach

144
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

State and Utility Outreach 

Performing Organizations: National Conference of State Legislatures (NCSL) 

Clean Energy Group, Inc. (CEG)
 

National Association of Regulatory Utility Commissioners (NARUC)
 

Solar Electric Power Association (SEPA)
 

Key Technical Contact:	 Steven Palmeri, 303-275-4832, steve.palmeri@go.doe.gov 

DOE HQ Technology Manager:	 Charlie Hemmeline, 202-586-6646, charlie.hemmeline@hq.doe.gov 

FY 2008 Budgets:	 $83K NCSL*, $83K CEG*, $71K NARUC* 

$175K SEPA 

* (FY 2007 Funds) 

Objectives 

•	 Build relationships with state decision makers (such as state legislatures, energy office personnel, 

public utility commissions, and air quality office personnel) responsible for enacting policies, 

programs, and plans that are key drivers for solar technology market transformation. 

•	 Provide key state actors with solar best practices and up-to-date, accurate information about 

solar technology characteristics. 

•	 Enlist the assistance of a utility membership organization to deliver key technical and educational 

assistance to utilities to promote their acceptance and use of solar. 

Accomplishments 

•	 Created Solar State Legislation (www.ncsl.org/programs/energy/energypolicy.cfm) to provide a 

readily accessible database of current and previous years' bills on energy issues. The database 

is searchable by energy topic and by state. (NCSL) 

•	 Launched the program Web site (www.statesadvancingsolar.org) that serves as a resource for 

state policy makers and decision makers interested in developing a solar program. (CEG) 

•	 Released the "Solar Energy Technology and Policy Reference Guide" 

(www.naruc.org/programs.cfm?c=Domestic), which includes information on solar regulatory 

policies, technologies, and state and industry perspectives. (NARUC) 

•	 Released “The Peer Matching Online Tool” (www.solarelectricpower.org/peer/), a service to share 

information and best practices to help utilities improve their solar programs. The database is 

searchable by location, utility type, experience, or by solar program type. (SEPA) 

Future Directions 

•	 Continue working on LegisBriefs and Solar Energy Institute sessions, as well as the solar energy 

database for solar legislators. (NCSL) 

•	 Develop a state solar program survey. (CEG) 

•	 Hold a regional dialogue for the Northeast and Mid-Atlantic to examine the regional solar
 

initiative. (NARUC)
 

•	 Develop a solar program options tool (SPOT) and an online resource library. (SEPA) 

1. Technical Approach	 • SEPA has extensive experience working with 

utility partners and was chosen to lead the 

To reach the targeted stakeholders in state outreach efforts in this area. 

government and utility companies, the DOE Solar • CEG, NARUC, and NCSL were chosen to 

Energy Technologies Program awarded perform outreach to the states. 

cooperative agreements to four organizations that These organizations have a broad membership 

have expertise in working with these entities. network that has effectively done outreach to the 

targeted stakeholders in the United States. 

145 Market Transformation

Technical Outreach
 

 

 

 

____________________________________________________________________________________ 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

Support Activities 

Performing Organization: CH2M Hill, Inc.
 

Key Technical Contact: Joe Lucas (DOE Golden Field Office), 303-275-4849, 

joe.lucas@go.doe.gov 

DOE HQ Technology Manager: Tom Kimbis (DOE), 202-586-7055, tom.kimbis@hq.doe.gov 

FY 2008 Budget: $277K 

Objectives 

•	 Provide supplemental technical assistance to the market transformation projects. 

•	 Serve in a coordination and communication role to ensure collaboration of Tiger Team members, 

across geographic areas, to maximize limited resources, avoid duplication of efforts, and achieve 

the highest quality product and delivery of services to the recipients. 

Future Direction 

•	 Continue providing support to market transformation projects, as needed. 

1. Introduction and Approach 

CH2M Hill was competitively awarded a 5-year 

contract to be a technical assistance provider and 

Tiger Team integrator. In this role, CH2M Hill 

provides technical assistance to the DOE Solar 

Energy Technologies Program Market 

Transformation projects, including, but not limited 

to, Solar America Cities, Solar America 

Showcases, and Government Solar Installation 

Program projects. 

Technical assistance is provided to the recipients 

by Tiger Teams, teams purposefully assembled to 

provide subject matter and technical expertise in 

specific areas, in order to address the needs and 

further the goals of each project. The Tiger Teams 

are primarily comprised of technical experts from 

the National Renewable Energy Laboratory, 

Sandia National Laboratories, Oak Ridge National 

Laboratory, and the Southwest and Southeast 

Regional Experiment Stations, which are housed 

at New Mexico State University and Florida Solar 

Energy Center, respectively. CH2M Hill 

participates as a member of the Tiger Teams to 

provide technical expertise to the recipients in 

addition to and complementary to that of the 

national laboratories and regional experiment 

stations. 

The scope of the CH2M Hill products and services 

includes on-site technical assistance to recipients 

across the United States and its territories for 

activities that include: solar technology assistance, 

city/municipal planning, market/financial analysis 

support, architectural/structural analysis support, 

technical project implementation, communication, 

outreach and education, and project management. 

Market Transformation

Technical Outreach

146
 

 

 

 

 

 

 

 

 

 

Solar Thermal Overview 

Frank (Tex) Wilkins, CSP Team Leader 

In November 2007, the U.S. Department of Energy (DOE) announced that the department would 

support a dozen concentrating solar power projects (CSP) projects with more than $27 million in 

funding over 3 years. Work also began with the Bureau of Land Management (BLM) to identify 

the best sites on federal land in the West for building utility-scale solar power plants. 

In September 2008, DOE announced that it would support 15 CSP projects with more than $35 

million over 4 years. A week later, the 30% investment tax credit (ITC) for developers of solar 

power was extended for 8 years. Thus, FY 2008 began and ended with the arrival of exciting new 

concepts that could impact CSP for years to come. Many of these will move CSP technology 

toward its goal of becoming competitive in the intermediate power market by 2015. 

The projects resulting from the two solicitations mentioned above provide a good indicator of 

DOE’s priorities for CSP. The first solicitation funded trough, Fresnel, dish, and power tower 

technologies. It also funded work on mirrors and thermal storage. This was the first CSP 

solicitation in several years, and its objective was to look at a wide variety of new ideas. The 

second solicitation funded 14 thermal storage concepts and one for advanced heat transfer fluids. 

This focus on thermal storage is indicative of the increased importance DOE is placing on energy 

storage. All of the work done through these 27 contracts will be given an in-depth review at the 

end of their first-phase work (concept feasibility, which takes typically 9-12 months) to determine 

which will be allowed to move on to phase 2 (design and prototype development, which typically 

takes 15-24 months). 

In addition to strengthening the program with the addition of industrial and university contracts, 

steps were taken to rebuild CSP capabilities at SNL and NREL. Funding was made available to 

increase the staffs at both labs, whose efforts resulted in some significant achievements during 

FY 2008. These included improvement in the design and reliability of the Stirling dish-engine 

system, improvement in the heat transfer properties of molten salt, the completion of a report to 

Congress identifying methods of minimizing the use of water by CSP power plants, development 

of a high-temperature/low emissivity receiver, development of optical tools that assist industry in 

evaluating their products, and the expansion of capabilities of the Solar Advisor Model, which has 

become important to the CSP industry. Funding was also made available to upgrade the National 

Solar Thermal Testing Facility at SNL after a long period of relative neglect. 

During FY 2008, our attention turned to a potential roadblock to CSP deployment: land 

availability. Utility-scale solar power plants require a lot of land. A 300-MW plant, for example, 

requires 3 to 4 square miles of relatively flat land. To address this issue, we began working with 

BLM, which manages 219 million acres of federal land in the southwestern United States. 

Although most of this land has excellent solar resources, much of it is too hilly or has 

environmental restrictions that keep it from being available for solar development. DOE and BLM 

became co-leads in a solar programmatic environmental impact statement (PEIS); its objective is 

to find suitable land for solar technology. Argonne National Laboratory was selected to assist in 

identifying land with a slope of 5 degrees or less, a solar resource greater than 6.5 kWh/m2

/day, 

no environmental or cultural restrictions, and access to transmission. This effort will conclude with 

the issuance of the final PEIS in March 2010. We are also working with the Western Governors’ 

Association and the California Renewable Energy Transmission Initiative, both of which are in the 

process of identifying land suitable for renewable energy projects. 

Although the CSP program activity was suffused with optimism, no new CSP projects began to be 

constructed during the year. For much of the year, construction was held back by the end-of-year 

termination of the 30% ITC. When the ITC was finally extended, industry found that the national 

recession had dried up sources of investment. As one industry leader lamented: “We got the ITC 

only to find there was no ’I’ available.” Hopefully, economic policies will unleash the investment 

147 Solar Thermal
 

 

needed for industry to begin building CSP plants in FY 2009. This is important because the cost 

reductions necessary for achieving the CSP intermediate power goal are brought about through a 

combination of R&D and the building of projects. 

A summary of the solar heating and cooling activities are also included in this section, but the 

management of these activities was moved into the DOE Building Technologies Program. 

Solar Thermal 148
 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

Parabolic Trough Research and Development 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Chuck Kutscher (NREL, Primary Contact), 303-384-7521, 

chuck_kutscher@nrel.gov 

Greg Kolb (SNL), 505-844-1887, gjkolb@sandia.gov 

DOE HQ Technology Manager:	 Thomas Rueckert, 202-586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budgets:	 $2,149K (NREL), $600K (SNL) 

Objectives 

•	 Support near-term parabolic trough technology for central station power generation. 

•	 Support development of advanced technologies for next-generation parabolic trough solar fields, 

thermal energy storage, and power plant technologies to meet DOE long-term goals. 

•	 Support expansion of U.S. industry to supply parabolic trough technology. 

•	 Support continued SunLab, joint effort between SNL and NREL in support of DOE’s research and 

development (R&D) activities on concentrating solar power (CSP) technologies, collaboration on 

parabolic trough technology development and testing. 

Accomplishments 

Trough Solar Field 

Reflector Optical Measurement 

•	 Used Video Scanning Hartmann Optical Test (VSHOT) instrument to evaluate mirrors from 

Guardian Glass and Naugatuck Glass and parabolic trough collectors from Abengoa and SkyFuel 

with capability transferred to Solar Systems. 

•	 Developed two new VSHOT systems: one portable system for full aperture trough 

characterization in the field and at industry partner facilities and a system for laboratory testing of 

flat and single-axis curvature mirrors. (NREL) 

TOP Alignment 

•	 Used TOP alignment tool, aligned six trough modules at the Saguaro Solar Plant. Acquired TOP 

alignment data for one loop at every LS2 solar plant in California. Using this data, aligned two 

loops at the SEGS plants with an estimated 5%–10% performance improvement. (SNL) 

Receiver Heat Loss 

•	 Tested latest Schott and Solel receiver tubes and performed preliminary experiments on impact 

of xenon/hydrogen and argon/hydrogen mixtures in receiver vacuum space. (NREL)
 

Hydrogen Mitigation
 

• Developed model of hydrogen generation and transport in parabolic solar collector field. (NREL) 

Optical Efficiency Test Loop 

•	 Completed construction of the outdoor optical efficiency test loop and tested Acciona/Gossamer 

8-meter parabolic trough. (NREL)
 

Advanced Trough Materials
 

• Selected U.S. industry partner to rapidly commercialize improved solar selective coating. (NREL) 

Salt Freeze/Thaw Experiments 

• Configured test loop and began series of freeze/thaw tests. (SNL)
 

Distant Observer Technique
 

•	 Completed feasibility study on use of Distant Observer technique and found it could provide a 

rapid and inexpensive means to detect optical alignment problems in the solar field. (NREL) 

Power Cycle and Balance of Plant 

Plant Optimization and Costing 

•	 Validated steam cycle component correlations used in the Solar Advisor Model (SAM) and 

determine costs of Rankine cycle components to be incorporated into SAM. 

149 Solar Thermal

Concentrating Solar Power

Parabolic Trough Development
 

 

 

 

 

 

 

 

 

 

 

________________________________________________________________________________ 

 

 

Heat Rejection 

•	 Produced joint report for Congress on reducing water consumption in CSP. (NREL) 

Trough Systems Integration 

Trough R&D Management 

• Organized and hosted nine parabolic trough sessions at SolarPACES conference. (NREL) 

Industry Support 

•	 Provided technical support to a wide range of CSP companies, including SkyFuel, Abengoa, 

Schott, Solel, and Solar Systems and prepared report summarizing this assistance. (NREL) 

Future Directions 

Trough Solar Field 

Reflector Optical Measurement 

•	 Continue to improve VSHOT capability, specifically by extending it to measure larger reflector 

apertures and longer sections of reflector. (NREL) 

• Extend capability of VSHOT to examine impacts of structural loads on reflector shape.
 

Top Alignment
 

•	 Improve algorithm calculating amount of mirror adjustments. 

•	 Align one or more loops at an LS2 parabolic trough plant and document the improvement. (SNL) 

•	 Design truck-mounted version of TOP Alignment system and will work on licensing TOP
 

Alignment technology to an outside company. (SNL)
 

• Develop TOP Alignment system for LS3 type trough designs
 

Receiver Heat Loss
 

•	 Expand capability of receiver heat loss measurement rig for faster tests and testing of longer 

receiver tubes. This apparatus will see continued use for the testing of newest industry receiver 

tubes and for tubes incorporating NREL’s latest high-performance absorber coating. (NREL) 

Hydrogen Mitigation 

•	 Establish working agreement with SEGS plant to perform on-site testing of procedures and/or 

methods that will remove hydrogen from the heat transfer fluid within the HCEs, and expansion 

tank of the power plant. (NREL) 

Optical Efficiency Test Loop 

•	 Conduct optical efficiency measurements of new SkyTrough parabolic collector, including both 

normal incidence and incident angle modifier tests. Also test additional state-of-the-art collector. 

(NREL) 

• Upgrade software and rotating platform control box. (SNL)
 

Advanced Trough Materials
 

• Work with our licensing partner to develop advanced selective surface. (NREL)
 

Salt Freeze/Thaw Experiments
 

•	 Conduct about 20 freeze/thaw cycles, or until failure, to determine effect of salt in trough 

receivers when it freezes and when it is thawed out and document test in a report.
 

Distant Observer Technique
 

•	 Develop and test airborne experimental technique to measure optical performance of parabolic 

trough collector field and test it at an operating plant. 

Power Cycle and Balance-of-Plant 

Plant Optimization and Costing 

• Develop parabolic trough collector field model with storage, using molten salt heat transfer fluid. 

Heat Rejection 

•	 Conduct analysis to optimize parallel hybrid cooling systems for trough plants in several climates. 

Industry Support 

•	 Continue to support industry contracts and other industry support on an as-needed basis. 

1. Technical Approach The parabolic trough R&D effort is broken into 

three areas: (1) trough solar field, (2) power cycle 

and balance-of-plant, and (3) industry support. 

Solar Thermal

Concentrating Solar Power

Parabolic Trough Development

150
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.1 Trough Solar Field 

The solar field technology agreement focuses on 

SunLab development of new parabolic trough 

solar technology and tools for evaluation of trough 

technology. The focus is on these areas: reflector 

optical measurement, TOP Alignment system, 

receiver heat loss, hydrogen mitigation, optical 

efficiency test loop, advanced trough materials, 

salt freeze/thaw experiments, and distant observer 

technique. 

1.2 Power Cycle and Balance of Plant 

The Power Cycle and Balance of Plant agreement 

focuses on improving overall parabolic plant 

performance. The work is focused on plant 

optimization and costing and heat rejection. 

1.3 Systems Integration 

This activity focuses on general support for trough 

technologies and technical support to industry. 

2. Results and Accomplishments 

2.1 Solar Field Technology 

Reflector Optical Measurement 

The VSHOT instrument evaluated the accuracy of 

parabolic trough collectors from Abengoa and 

SkyFuel. This capability was specifically used to 

greatly improve the optical accuracy of SkyFuel’s 

new SkyTrough collector that utilizes a polymer 

film reflector. We also performed VSHOT 

characterization of new mirror technology for 

Guardian Glass and Naugatuck Glass and 

developed two new VSHOT systems, one portable 

system for full aperture trough characterization in 

the field and at industry partner facilities and a 

system for laboratory testing of flat and single-axis 

curvature mirrors. 

TOP Alignment 

The time to acquire data was reduced from 70 

seconds/module to 35 seconds/module. There are 

several ideas to reduce this time even further. 

Considering there are close to 5,000 modules for 

each 30 megawatt (mW) trough plant, reducing 

this time is very important. The quality of pictures 

taken by the cameras has been improved by using 

higher resolution cameras, but mostly by 

controlling the contrast of the pictures. This has 

greatly improved and reduced the time in 

analyzing the pictures. Tests were completed at 

the Saguaro parabolic trough power plant and at 

SEGS. Using this process has led to an estimated 

10% improvement in the aligned loop at SEGSVI. 

Receiver Heat Loss 

NREL tested the latest Schott and Solel receiver 

tubes and performed preliminary experiments on 

the impact of xenon/hydrogen mixtures in the 

vacuum space. 

Hydrogen Mitigation 

NREL developed a computer model of hydrogen 

generation and transport within a parabolic trough 

plant and identified several means for removing 

hydrogen. 

Optical Efficiency Test Loop 

NREL completed the construction, data 

acquisition, and shakedown testing of the new 

outdoor optical efficiency test loop. We mounted 

an Acciona/Gossamer 8-meter parabolic trough 

and Schott receiver tubes and measured optical 

efficiency values obtaining approximately 75%. 

Advanced Trough Materials 

Patent filed in FY 2008 on ROI 05-02 “High 

Temperature Solar Selective Coatings”. Worked 

with the NREL Technology Transfer Office to 

identify a U.S. industry partner to rapidly 

commercialize and license the improved solar 

selective coating. NREL reached an agreement 

with Schott to license our low-emissivity absorber 

coating. 

Figure 1. Pictured is NREL#6A solar selective coating 

deposited by directly and reactively evaporating the 

layers by elemental co-deposition. 

Salt Freeze/Thaw Experiments 

SNL set up a new system with data acquisition, 

controller, impedance heating system and set up 

three trough modules for the freeze/thaw test. 

Initial testing showed the impedance heat system 

did have the power to properly heat two receivers 

but not three. One was removed, and the 

remaining two were filled with salt. Due to 

equipment problems, testing is still ongoing. 

151 Solar Thermal

Concentrating Solar Power

Parabolic Trough Development
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Distant Observer Technique 

A feasibility study was performed on the use of a 

Distant Observer technique to determine the 

accuracy of a parabolic trough collector field and 

concluded that this method could provide a rapid 

and inexpensive means to detect performance 

problems in the field, from both mirror and receiver 

misalignment. 

FY 2008 Milestones: 

•	 Demo TOP systems in Arizona. (2/29/08) 

•	 Complete laboratory testing and technical 

report on the heat loss performance of one or 

more next-generation heat collection 

elements. (12/31/07) 

•	 Complete laboratory testing and technical 

report on heat loss performance of one or 

more next-generation heat collection 

elements. (12/31/07) 

•	 Complete instrumentation and qualification 

tests optical efficiency test loop. (3/31/08) 

•	 Complete optical testing of one or more 

industry-supplied collector designs integrated 

with next-generation heat collection element. 

(9/30/08) 

•	 Assess efficacy of a distant observer tool 

capable of rapid analysis of large sections of 

collector fields in feasibility study. (9/30/08) 

2.2 Power Cycle and Balance of Plant 

Plant Optimization and Costing 

Nexant performed an analysis comparing the 

Rankine steam cycle performance predicted by 

EES (the tool used for SAM) to GateCycle 

analyses. This showed the energy production 

predicted by the EES model was within 3% of the 

energy predicted by GateCycle, thus validating 

SAM. A spreadsheet model was developed to 

determine the costs of Rankine cycle components 

to be incorporated into SAM. 

Heat Rejection 

In response to a Congressional request, a joint 

report, “Concentrating Solar Power Commercial 

Application Study: Reducing Water Consumption 

of Concentrating Solar Power Electricity 

Generation,” was produced. This report reviewed 

a number of studies of power plant cooling system 

options and concluded that water used for heat 

rejection can be reduced 80% via a hybrid parallel 

water/air cooling system with only couple percent 

drop in power output. Whereas air cooling would 

increase levelized electricity cost by about 8% 

compared to a water-cooled plant, it is estimated 

that a parallel system would have a penalty of only 

about half that much, although further work is 

needed to fully optimize the parallel system. 

FY 2008 Milestones: 

•	 Complete report on CSP power plant water 

needs and how to address them. (3/1/08) 

2.3 Systems Integration 

FY 2008 Milestones: 

•	 Organize parabolic trough and thermal storage 

R&D sessions for SolarPACES Symposium in 

the U.S. (3/31/08) 

•	 End-of-year report summarizing activities in 

support of FOA contractors. (10/31/08) 

•	 Report summarizing industry support 

activities. (10/31/08) 

3. Major FY 2008 Publications 

E. Lupfert; K.J. Riffelmann; H. Price; F. 

Burkholder; Tim Moss. “Experimental Analysis of 

Overall Thermal Properties of Parabolic Trough 

Receivers”, ASME Journal, 2007. 

M. Lausten; C. Kutscher. “Concentrating Solar 

Power Commercial Application Study: Reducing 

Water Consumption of Concentrating Solar Power 

Electricity Generation.” 

F. Burkholder; M. Brandemuehl; C. Kutscher; E. 

Wolfrum. “Heat Conduction of Inert Gas-Hydrogen 

Mixtures in Parabolic Trough Receivers,” 

presented at the ASME International Conference 

on Energy Sustainability in Jacksonville, Florida, 

August 2008. 

G. Jorgensen; F. Burkholder; A. Gray; T. 

Wendelin. “FY 2008 CSP Milestone Report: 

Assess the Efficacy of an Aerial Distant Observer 

Tool Capable of Rapid Analysis of Large Sections 

of Collector Fields.” 

C. Kennedy. “Progress to Develop an Advanced 

Solar-Selective Coating” presented at 2008 

SolarPaces Symposium in Las Vegas, Nevada, on 

March 2008. Selected for publication in ASMEJournal of Solar Energy Engineering (JSEE). 

Solar Thermal

Concentrating Solar Power

Parabolic Trough Development

152
 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

Industry Projects 

Performing Organizations:	 Alcoa, Inc. 

Abengoa Solar, Inc. 

Key Technical Contacts:	 Carolyn Elam, DOE Golden Field Office (DOE/GO), 303-275-4953, 

carolyn.elam@go.doe.gov 

Jim Payne, DOE/GO, 303-275-4756, jim.payne@go.doe.gov 

Brad Ring, DOE/GO, 303-275-4930, brad.ring@go.doe.gov 

DOE HQ Technology Managers:Frank (Tex) Wilkins, (202) 586-1684, frank.wilkins@ee.doe.gov 

Tommy Rueckert, (202) 586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budgets:	 $2,022K Recipients 

Objectives 

•	 Develop energy supply technologies that are reliable, affordable, and environmentally sound. 

Expand national electricity generation portfolio to increase energy security by diversifying 

domestic energy supply options. Concentrating solar power (CSP) is one of the most attractive 

renewable energy options in the Southwest U.S., with a nominal levelized cost of energy (LCOE) 

target of 7-10¢/kWh by 2015 and 5-7¢/kWh by 2020. 

•	 Advance U.S.-based trough technology by encouraging development and eventual U.S. 

manufacturing of key parabolic trough components or subsystems. 

•	 Emphasize design for manufacturability and/or near-term (commercial applications within the next 

5 years) U.S. supply of key parabolic trough components or subsystems. 

Accomplishments 

•	 Held merit review of applications in September and announced selections in October 2007. 

•	 Negotiated and awarded all three CSP parabolic trough development awards by mid-2008. 

•	 Defined roles and responsibilities of program management team, including technical advisors at 

the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories. 

Future Directions 

•	 Evaluate progress toward critical milestones and decisions will be made at the end of the each 

project’s first phase, starting in FY 2009 and extending into FY 2010. 

1. Introduction 

The selected projects are: 

These CSP trough development activities within 

are expected to produce commercial parabolic 

trough components or subsystems within the 

next 5 years enabling CSP to meet a nominal 

levelized cost of energy (LCOE) target of 7­

10¢/kWh by 2015 and 5-7¢/kWh by 2020. 

One objective of this area of interest is to 

advance U.S. based trough technology by 

encouraging the development and eventual U.S. 

manufacturing of key parabolic trough 

components or subsystems that can only be 

obtained from a limited number of foreign 

companies. 

Organization, PI, and Agreement Title 

FY 2008 

Budget 

($K) 

Alcoa, Inc. - Adam Schaut 

“Reflector Technology Development and 

System Design for CSP Technologies” 

1,098 

Abengoa Solar, Inc. - Keith Boyle 

“Development of Advanced Polymeric 

Reflector for Concentrating Solar Power” 

439 

Abengoa Solar, Inc. - Hank Price 

“Development of Next-Generation Parabolic 

Trough Collectors and Components for CSP 

Applications" 

485 

153 Solar Thermal

Concentrating Solar Power

Parabolic Trough Development
 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

Reflector Technology Development and System Design for CSP Technologies (Alcoa) 

Total Award: $3,658K, DOE/Recipient Share: $2,128K/$1,530K 

Objectives 

•	 Develop aluminum-intensive collector that provides superior total life cycle cost. 

•	 Achieve 25%-50% cost savings for the solar field, lowering LCOE at least 20%. 

•	 Achieve high performance optical performance and superior outdoor durability (10 Years). 

•	 Positively impact U.S. manufacturing base. 

Accomplishments 

•	 Pursued two independent approaches to reflective surface. 

•	 Evaluated various structural design architectural approaches before selecting “wingbox” design. 

•	 Maximized material utilization efficiency while maintaining structural rigidity and strength. 

•	 Developed cost models using concurrent FEA analysis with Solar Advisor Model LCOE
 

calculations.
 

Future Directions 

•	 Complete Phase 1 reflective surface and structural design activities. 

•	 Perform a detailed design of the down-selected concept from Phase 1, develop a prototype, and 

validate performance. 

•	 Developed detailed design (3D CAD), structural analysis (finite element analysis or FEA), and 

detailed cost modeling of the prototype. 

•	 Complete internal critical design review of the prototype. 

•	 Fabricate, evaluate and verify the full scale prototype. 

•	 Revise framework for Phase 2, based on Phase 1 results. 

1. Introduction 

Current baseline solar trough collectors differ in 

supporting structure (aluminum space frame vs. 

steel torque-box), but both predominantly use 

parabolic, silver-metallized glass mirrors, which 

have disadvantages such as fragility, weight, and 

cost. Alcoa is using an optimized system design 

approach to develop an aluminum-intensive 

collector. 

2.	 Results and Accomplishments 

Two aluminum-based reflective surface 

development approaches were finalized; thin film 

and silver film. For thin film, deposition testing on 

coated and leveled aluminum sheets was 

performed and tested via accelerated procedures. 

More than 25 different actual coil-coated aluminum 

samples were tested, and two good candidates 

were identified. A laminate of a batch silvermetalized clear film adhesively bonded onto an 

aluminum sheet is under testing. 

Alcoa evaluated options for incorporating the 

reflective surface as a structurally significant 

component of the solar trough assembly and 

identified three basic architectures: space frame, 

torque box, and monocoque, or “wingbox.” 

Preliminary structural evaluations indicated the 

wingbox approach has the most potential for 

efficient material utilization based on the goal of 

incorporating a stressed-skin approach. Analysis 

of this design continues with encouraging results. 

3. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 (k) 

CSP Services (DLR)/ 

Eckhard Luepfert Cologne, Germany Subcontractor to Alcoa, Inc., CSP technology and performance expertise $27* 

*Included in the total Phase I 

Solar Thermal

Concentrating Solar Power

Parabolic Trough Development

154
 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

Development of Advanced Polymeric Reflector for Concentrating Solar Power 

(Abengoa Solar, Inc.) 

Total Award: $2,076K, DOE/Recipient Share: $1,512K/$565K 

Objectives 

•	 Reduce cost of parabolic trough collector systems by reducing cost of reflector. 

•	 Develop reflector technology that will be used in Abengoa Solar’s U.S. projects that are planned 

for initial operation in 2010-2013 timeframe. 

•	 Source as much collector technology (e.g., reflector components) from U.S. sources as possible. 

Future Directions 

•	 Transfer and validate initial process, since phase 1 started at end of FY 20008. 

•	 Complete Phase 1 objectives. 

•	 Use phase 1 results to show a reasonable path to reduced LCOE. 

1. Introduction 

The Abengoa team is evaluating the possibility of 

commercial production of a lab-scale advanced 

solar reflector material (ASRM) for CSP. The 

technology has the potential for lower cost 

reflectors, and possible design flexibility which 

may lead to entirely new approaches to low-cost 

concentrator design. 

2. Technical Approach 

The ASRM (produced in 2003 under sponsorship 

by NREL) will be scaled up from laboratory-scale 

to limited production runs on a commercial-scale 

48-inch wide roll coater. During Phase 1, the 

scale-up to commercial roll-to-roll coating will be 

tested and validated, and production costs will be 

modeled. During Phase 2, the process will be 

scaled up to a 1⁄2-width pilot production system. 

The operating information will be used to create a 

full-scale reflector to demonstrate the technical 

and cost specifications of the system and to refine 

the cost model. This phase will demonstrate 

limited scale-up and cost effects of that scaling 

effort. During Phase 3, the team will scale the 

ASRM up to full width to demonstrate pilot 

production runs. The products from this test run 

will be used in a full scale reflector to test the 

product in the field. Outdoor reflector performance 

of the production-scale product will also be 

demonstrated. 

3. University and Industry Partners 

Task work will start in FY 2009, so the following chart refers to the FY 2009 first-phase costs. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 ($K) 

Cost Share 

($K) 

SAIC 

Dr. Russell Smilgys McLean, VA 

Transition and adoption of previous 

ASRM work into commercial 

environment 

102 2.5 

CSI/Marian 

Mike Martin San Diego, CA 

Integration of new ASRM into 

commercial equipment and scale-up of 

production 

246 16.25 

Swisher & Assoc. 

Dr. Richard Swisher Northfield, MN Transition, adaption, and model revision 

for new ASRM 63 0 

155 Solar Thermal

Concentrating Solar Power

Parabolic Trough Development
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Development of Next-Generation Parabolic Trough Collectors and Components 

for CSP Applications (Abengoa Solar, Inc.) 

Total Award: $606K, DOE/Recipient Share: $485K/$121K 

Objectives 

•	 Reduce cost of collector technologies that could be deployed in first U.S. CSP plants in 2010– 

2013 time frames. 

•	 Develop alternative collector structures, components, and field deployment techniques. 

•	 Employ innovative approaches to developing next generation of lower-cost parabolic trough 

technologies that can compete on equal footing with conventional power generation. 

•	 Build on results of initial phases, complete initial deployment of new generation of trough
 

technology aimed at achieving major cost reductions for medium-term deployments.
 

Accomplishments 

•	 Generated generally applicable collector cost metrics. 

•	 Detailed finite element analysis models of three collector design possibilities. 

•	 Characterized conflict in existing collector wind tunnel studies’ design implications. 

Future Directions 

•	 Finalize assessment of existing designs and foundations, specify and advanced collector, and 

perform construction labor review. 

•	 Complete small-scale prototype testing (Phase 2). 

•	 Expand to full-loop scale testing and validation (Phase 2). 

•	 Complete advanced collector design and fabrication (Phase 2). 

1. Introduction 

The goal is to develop the technology that is 

needed to build a competitive parabolic trough 

industry for the U.S. utility market. To achieve this 

objective, the project plans to reduce the cost of 

collector technologies and use innovative 

approaches to develop the next generation of 

lower cost parabolic trough technology. 

2. Technical Approach 

Phase 1 focuses on analysis and assessment of 

collector designs, foundations, and fabrication 

techniques. The team will conduct a detailed 

evaluation of existing collector designs, first 

specifying the metrics by which they will be 

evaluated, then evaluate them using comparable 

testing environments and methods. Next, the team 

will analyze foundation designs for material and 

fabrication cost reductions. The team will 

determine possible new collector design criteria 

and will specify an advanced collector based on 

cost impacts using metrics developed earlier. 

Subsequently, the team will conduct a construction 

labor review. Outside experts (i.e. academia) will 

be consulted to analyze and review project 

construction and fabrication techniques for 

possible cost savings. 

3.	 Results and Accomplishments 

A uniform set of metrics for collector comparison 

(operations, survival, cost) has been developed 

and the documentation is in progress. These 

metrics are being used in the evaluation tasks. 

Work continues on the side-by-side comparison of 

module designs. These comparisons encompass 

optical, structural, and cost analysis. The cost 

comparisons are fully developed and can be 

quickly adapted for ‘what-if’ scenarios. The optical 

analysis provides a reasonable basis for 

comparison, with additional detail from ray tracing 

about 75% complete. The benefits and drawbacks 

of each design are nearly complete, with work 

remaining in structural comparisons. 

The fabrication of prototype modules is 20% 

complete. The ASTR0 jigs are in progress, and 

module materials have been delivered. Structural 

testing data has been located that may save time 

and cost in the evaluation of the module’s 

performance. 

Experience at Abengoa’s Solana plant is being 

used in the assessment of foundation structures. 

Basic analysis of trade offs and cost is underway 

for a detailed analysis and design. 

Solar Thermal

Concentrating Solar Power

Parabolic Trough Development

156
____________________________________________________________________________________ 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

Dish Engine Research and Development 

Performing Organization: Sandia National Laboratories (SNL) 

Key Technical Contact: Charles Andraka (SNL), 505-844-8573, ceandra@sandia.gov 

DOE HQ Technology Manager: Thomas Rueckert, 202-586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budget:	 $1,471K 

Objectives 

•	 Improve reliability and reduce cost of dish/engine components and systems. 

•	 Support industry in commercialization of the technology. 

•	 Perform research and development on dish/engine system components and systems. 

•	 Test, evaluate, and improve performance of dish/engine components and systems. 

•	 Develop tools for industry to characterize their systems and components 

Accomplishments 

•	 Continued to operate, maintain, and improve the Stirling Energy Systems (SES) six-dish model 

power plant, cataloging more than 100 development areas. 

•	 Participated as a key member of the commercial product design team. 

•	 Developed real-time mirror characterization prototype system for 100% inspection of mirrors on 

assembly line. 

•	 Developed engine simulator for development of modern engine control hardware and software. 

•	 Mentored new solar engineers through SNL programs and at industry partners. 

•	 Developed tradeoff study of facet performance and cost to guide commercialization efforts. 

•	 Assisted Infinia in optical design and systems design of 3-kilowatt (kW) free piston Stirling engine 

(FPSE) dish system. 

•	 Enhanced CIRCE2 model to support finite element analysis-modeled deflections. 

•	 Participated in funding opportunity announcement (FOA) team for dish Brayton system. 

Future Directions 

Primary activities in fiscal year (FY) 2009 will support industry’s efforts toward commercialization: 

•	 Continue to evaluate the reliability of the six-dish mini-power plant. 

•	 Identify and resolve operational and reliability issues. 

•	 Install and commission four pre-production dish systems at SNL. 

•	 Retrofit and commission six model power plant (MPP) dishes with production units. 

•	 Develop highly automated rapid alignment system for production dishes. 

•	 Continue to participate on commercial product design team. 

•	 Install two next-generation Infinia dish systems at SNL. 

•	 Continue to support Infinia’s commercialization effort. 

•	 Evaluate possible additional dish/engine products, as needed. 

1. Introduction	 SES is pursuing the aggressive deployment of 

25-kW dish-Stirling systems for bulk power 

Staff members work closely with the industry to generation. The success of the MPP has led to 

improve dish-Stirling system performance and SES agreements with Southern California Edison 

reliability and to support industry deployment in for up to 850 megawatts (MW) of power and with 

the near term. While SNL continued to gain San Diego Gas and Electric for up to 900 MW. 

operational experience with the SES 6-dish MPP, Infinia, previously Stirling Technology Corporation 

the primary focus was on next-generation system (STC), has developed a system around a 3-kW 

design, with an emphasis on manufacturability. free-piston Stirling engine. This system is 

157 Solar Thermal

Concentrating Solar Power

Dish/Stirling R&D
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

hermetically sealed and requires no maintenance. 

Infinia plans both large and small deployments 

and has targeted photovoltaics as a competitor. 

SNL was involved in the conceptual design, 

detailed design, and deployment of the first 

prototype systems. SNL has entered into a 

memorandum of understanding with Infinia to 

support several Infinia staff on SNL premises. A 

prototype dish was set up at SNL, and optically 

characterized, providing feedback to the facet 

manufacturer. 

2. Results and Accomplishments 

By the end of FY 2008, the MPP dish systems had 

accumulated over a total of 24,000 hours on sun. 

The performance of the system continues to 

exceed the performance of the MDC systems, 

primarily as a result of improved system optics, 

alignment, and cooling. 

On January 31, 2008, SES and SNL set a world 

record for sunlight to grid electricity with one of the 

MPP units. This new record was 31.25% net 

conversion efficiency, averaged over a full hour of 

operation. This significant accomplishment was 

awards a “Breakthrough Award” by Popular 

Mechanics, recognition of life-changing and 

society-changing technical accomplishments. 

SES has used the reliability data captured in the 

Failure Reporting, Analysis, and Corrective Action 

System (FRACAS) to guide the design work 

during the commercialization effort. Many of the 

issues are software related, and the solutions 

have been folded into the software specification. 

Likewise, their engine manufacturer has 

addressed outstanding issues in the design of the 

commercial engine. This formalized path from 

testing to final design is key to producing a highly 

reliable system. SES and Linamar will install a 

number of production engines in test cells to 

provide accelerated testing of the commercial 

package. 

Continued refinement of the dish system leading 

to the commercial system has led to a weight 

reduction of nearly 6,000 pounds and resulted in a 

stiffer optical system. This was facilitated over the 

last 3 years by SNL’s optical code (CIRCE2) 

combined with SES’s structural model. SES’s steel 

fabrication partner has designed a highly 

automated fabrication plant in conjunction with the 

redesign effort. The refinement of this design is 

continuing, taking into account the key 

environmental implications of the California sites. 

The combination of CIRCE2 with the structural 

modeling has been a key insight by SNL and 

implementation by the SES team. We have 

continued to refine this connection. While most of 

the work performed to date imposed structural 

deflections as rigid-body rotations of the facets, 

new improvements to CIRCE2 will allow the actual 

facets to be shape-distorted in the optical model, 

based on finite element model results. 

SNL continued the development of an alignment 

system suitable for high rate production. Such a 

system requires computer interpretation of the 

alignment status, and digital feedback to 

technicians or to actuators. We have developed an 

approach based on fringe reflection 

measurements, and we have tested key 

components of the software. The approach 

appears to be very robust within a significant 

range of mirror quality. 

A spinoff of the alignment tool has been a facet 

characterization system, also based on fringe 

reflection techniques. This tool accurately 

measures slope errors and shape errors of facets 

in less than 10 seconds, allowing application to the 

production line for quality control. 

SES announced the delivery of their application for 

certification for the Solar 2 plant in California, and 

the acceptance of this documentation as “data 

adequate”. This is a key document leading to the 

deployment of systems in California. 

SNL also continued to support Infinia in the 

development of its 3-kW dish engine system with 

two prototype systems to be installed at SNL. 

Infinia completed a prototype system at its 

headquarters in Kennewick, Washington, to refine 

system controls and performance. 

SNL published an ASME paper that explores the 

relationship between facet optical performance 

and system economic performance. The thesis of 

the paper, confirmed through the analysis 

presented, discusses the affordability of quality 

optics, or conversely, in high temperature 

systems, the cost savings of “cheap” optics is 

typically more than offset by revenue losses and 

loss of system value. This has been a key and 

consistent finding in the SNL dish development 

activities, starting in the Cummins and Advanced 

Dish Development System efforts. 

Solar Thermal

Concentrating Solar Power

Dish/Stirling R&D

158
 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

Industry Projects 

Performing Organizations:	 Brayton Energy 

Infinia Corporation 

Key Technical Contacts:	 Carolyn Elam, DOE Golden Field Office (DOE/GO), 303-275-4953, 

carolyn.elam@go.doe.gov 

Jim Payne, DOE/GO, 303-275-4756, jim.payne@go.doe.gov 

Brad Ring, DOE/GO, 303-275-4930, brad.ring@go.doe.gov 

DOE HQ Technology Managers:Frank (Tex) Wilkins, (202) 586-1684, frank.wilkins@ee.doe.gov 

Tommy Rueckert, (202) 586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budgets:	 $595K (Recipients) 

Objectives 

•	 Develop energy supply technologies that are reliable, affordable, and environmentally sound. 

Expand national electricity generation portfolio to increase energy security by diversifying 

domestic energy supply options. Concentrating solar power (CSP) is one of the most attractive 

renewable energy options in southwest U.S., with a nominal levelized cost of energy (LCOE) 

target of 7-10¢/kWh by 2015 and 5-7¢/kWh by 2020. 

•	 Provide preliminary exploration/feasibility of new CSP approaches for electrical power production. 

In-depth systems analysis is desired that specifies characteristics of system (e.g., size, 

components, operating temperature, component and system efficiencies, storage and heat 

transfer fluids), major technical barriers and proposed approaches to overcoming them, estimated 

system and component costs, and operation and maintenance costs. 

Accomplishments 

•	 Held merit review of applications in September and announced selections in October 2007. 

•	 Negotiated CSP Dish/Stirling research and development awards, awarded by mid-2008. 

•	 Defined roles and responsibilities of program management team, including technical advisors at 

the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories (SNL). 

Future Directions 

•	 Evaluate progress toward critical milestones and decisions will be made at the end of the each 

project’s first phase, starting in FY 2009 and extending into FY 2010. 

1. Technical Approach 

The funding opportunity announcement (FOA) 

investigated three areas to address market 

barriers for utility-scale generation of CSP 

technologies: thermal storage; trough 

component manufacturing; and advanced CSP 

systems and/or components (Dish/Stirling R&D). 

Organization, PI, and Agreement Title 

FY 2008 

Budget 

($K) 

Brayton Energy - James Kesseli 

“Brayton Solar Power Conversion System” 

274 

Infinia Corporation - Qiu Songgang 

“30-kW Maintenance Free Stirling Engine 

for High Performance Dish Concentrating 

Solar Power” 

321 

The selected projects are listed in the table 

below. 

159 Solar Thermal

Concentrating Solar Power

Dish/Stirling R&D
 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

Brayton Solar Power Conversion System (Brayton Energy) 

Total Award: $4,269K, DOE/Recipient Share: $2,300K/$1,969K 

Objectives 

•	 Design and demonstrate novel Dish-Brayton hybrid concentration solar power module. 

•	 Achieve LCOE of $0.075 to 0.10/kWH with an engine lifetime of 40,000 hours. 

•	 Achieve low emissions in alternate modes using natural gas, ethanols, or bio-oils. 

Accomplishments 

•	 Completed Phase 1, delivering 232-page technical report. 

•	 Applied proven components and design principals to Dish-Brayton design. 

•	 Prepared novel solar receiver design, subjected to review by U.S. government labs. 

•	 Operated air-bearing turboalternator at full speed on bench-test rig, without heat. 

Future Directions 

•	 Fabricate and test purpose-built gas turbine engine with hydrocarbon fuels. 

•	 Integrate receiver and engine with purpose-built solar concentrator. 

•	 Test and characterize two subassemblies: 

o	 Turboalternatort: complete power conversion system in a laboratory setting with hybrid fuel 

systems but no solar receiver, measuring efficiencies and emission levels. 

o	 Solar receiver: in lab environment and 320-square meter dish, characterizing cavity and 

overall heat losses. 

1. Introduction 

Brayton Energy has performed extensive design 

and analysis of a novel CSP conversion system. 

The system employs a specialized recuperated 

gas turbine generator with a solar receiver. 

Prototype units will be fabricated, and an 

assembly plant for volume manufacturing begun 

near Phoenix. The focus is on the engine/receiver 

module design and component tests. 

2. Results and Accomplishments 

The design of the turbo-alternator and recuperator 

are complete and analysis is ongoing for durability 

of critical elements in the design. The LCOE 

analysis is complete and has met objectives, 

based upon performance analyses, capital cost, 

and life/maintenance expectations. Findings 

support the achievability of near-term DOE cost 

targets of $0.075 to $0.10/kWh. The final design 

employs intercooling, high levels of recuperation 

and re-heat, enabling engine thermal-electric 

efficiency to exceed 37% at moderate turbine inlet 

temperatures. A detailed a bill or materials has 

been prepared for the engine and receiver, to 

assist fabrication in Phase 2. 

3. FY 2008 Special Recognitions and Patents 

Brayton Energy has received two patents on this 

system on power conversion systems and variable 

position turbine nozzle. Six other filings related to 

recuperators, turbomachinery, and solar receivers 

have been submitted to the U.S. patent office. 

4. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 ($K) 

Cost Share 

($K) 

Oak Ridge National 

Labs/Dr. Bruce Pint Oak Ridge, TN High-temperature materials evaluation 26 0 

SolarCAT Inc., 

Herb Hayden Glendale, AZ 

Dish design, fabrication, testing. Assembly 

factory deployment. 100-MWe site 

development 

0 73 

Solar Thermal

Concentrating Solar Power

Dish/Stirling R&D

160
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

30-kW Maintenance-Free Stirling Engine for High-Performance Dish Concentrating Solar Power 

(Infinia Corporation) 

Total Award: $3,196K, DOE/Recipient Share: $2,062K/$1,134K 

Objectives 

•	 Develop 30-kW CSP system that utilizes a multi-cylinder free-piston Stirling engine (MCFPSE). 

•	 Provide prototype engine design for Phase 1, demonstration 30-kW engine prototype for phase 2, 

and field test a production-like prototype for phase 3. 

Accomplishments 

•	 Preliminary design of six-cylinder fully balanced, dual-engine configuration almost complete, with 

projected engine performance of 58%, Carnot and engine/alternator efficiency approaching 33%. 

Future Directions 

•	 Finalize prototype engine design, fabricate and assemble engine, and test and evaluate engine. 

•	 Complete preliminary LCOE cost analysis. 

•	 Complete Integration design of engine with Science Applications International Corporation Gen 1 

dish for demonstration. 

•	 Finalized preliminary design of the 30-kW multi-cylinder engine. 

•	 Complete manufacturing cost analysis for the engine and dish. 

•	 Verify impact of reduced engine operating and maintenance (O&M) costs on LCOE of CSP 

system. 

•	 Determine any residual technical or cost barriers. 

1. Introduction 

For dish Stirling CSP, two issues of concern are 

engine life/reliability and O&M costs. The objective 

is to address these concerns with a maintenancefree 30-kW MCFPSE for Dish Stirling CSP 

applications, improving reliability and lowering 

costs. 

2. Technical Approach 

Infinia focused on the preliminary design and 

analysis of a 30-kW multi-cylinder configuration. 

The approach is to adapt prior MCFPSE 

conceptual design approaches to develop a 30-kW 

design, heavily leveraging the existing 3-kW 

commercial engine. To facilitate this process, 

SAGE analysis is used to evaluate 3- and 6-

cylinder designs and other factors. 

3. Results and Accomplishments 

Infinia completed the SAGE analysis and selected 

a fully balanced 6-cylinder configuration composed 

of two 3-cylinder engine modules. The engine 

performance is excellent at 58% of Carnot with 

engine/alternator efficiency exceeding 33%. The 

conceptual design of a hybrid heater head was 

selected. Linear alternator optimization was 

conducted to estimate the efficiency, weight, and 

size of the linear alternator. The engine controller 

conceptual design is largely finished. Cost 

analysis for the engine and dish is ongoing. 

4. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 ($K) 

Butler Sun Solutions 

Barry Butler 

Solana Beach, CA Sourcing of dish and dish costing analysis 3 

Consultant 

Barry Penswick 

Stevenson, WA Stirling engine design 27 

161 Solar Thermal

Concentrating Solar Power

Dish/Stirling R&D
 

 

____________________________________________________________________________________ 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Storage Components 

Performing Organization:	 Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Nathan Siegel (SNL), 505-284-2033, npsiege@sandia.gov 

Bob Bradshaw (SNL), 925-294-3229, rwbrads@sandia.gov 

Greg Kolb (SNL), 505-844-1887, gjkolb@sandia.gov 

Tom Mancini (SNL), 505-844-8643, trmanci@sandia.gov 

DOE HQ Technology Manager:	 Thomas Rueckert, 202-586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budget:	 $93K (SNL) 

Objectives 

•	 Develop components and systems necessary for incorporating thermal storage into concentrating 

solar power (CSP) facilities. 

•	 Support industrial partners who are developing thermal storage technologies. 

Accomplishments 

•	 Completed preliminary design of a test facility upgrade to evaluate components (e.g., heat 

exchangers, pumps, valves, instrumentation) required by power plants, using molten salt heat 

transfer and storage fluids. 

Future Directions 

•	 Support funding opportunity announcement (FOA) awardees. 

1. Results and Accomplishments 

Freeze Recovery 

•	 Constructed impedance heating test platform. 

• Performed preliminary freeze/thaw studies. 

Several industry partners have proposed using 

molten salt in the field for parabolic trough plants. 

A strategy must be developed that will enable the 

facility to recover from a freeze. One option is to 

treat the HCEs as electrical resistors that can be 

used to thaw the frozen salt within them when an 

electrical current is applied. Questions remain as 

to whether the HCEs can be adequately heated in 

this manner without damage. We are exposing the 

HCEs, which have been filled with salt, to 

successive freeze thaw cycles. Preliminary results 

show some tube motion during cycling due to 

induced stresses. In addition, Solar Millennium, a 

FOA awardee, has requested test support using 

this platform. 

Molten Salt Test Facility Design 

•	 Completed preliminary facility design. 

•	 Began industry workshop planning to further 

define the required upgrades and test and 

evaluation needs. 

There is an industry-wide need for qualification 

and de-risking of the components used to handle 

heat transfer and thermal storage media, 

particularly molten salts. A suitable test and 

evaluation platform does not exist. To meet 

industry needs, our design of the upgraded facility 

would be built off of existing infrastructure and be 

able to accommodate an expanded suite of 

component testing and development. We are 

soliciting input from industry partners in fully 

defining the capabilities of the facility. 

2. Planned FY 2009 Activities 

Freeze Recovery 

•	 Continue evaluating the impedance heating 

strategy and identifying technical hurdles. 

•	 Develop inroads with international partners 

working on similar technologies. 

Molten Salt Test Facility Design 

•	 Host industry workshop for design input. 

•	 Complete conceptual design. 

•	 Place a contract with an A&E firm to begin the 

detailed design. 

•	 Place construction contracts and begin 

construction. 

Solar Thermal

Concentrating Solar Power

Thermal Storage R&D

162
 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

Storage Systems 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Mark Mehos (NREL), 303-384-7458, mark_mehos@nrel.gov 

Tom Mancini (SNL), 505-844-8643, trmanci@sandia.gov 

Nathan Siegel (SNL), 505)284-2033, npsiege@sandia.gov 

Greg Glatzmaier (NREL), 303-384-7470, greg_glatzmaier@nrel.gov 

DOE HQ Technology Manager:	 Thomas Rueckert, 202-586-0942, Thomas.Rueckert@ee.doe.gov 

FY 2008 Budgets:	 $319K (NREL), $130K (SNL) 

Objectives 

•	 Develop conceptual designs for thermal storage of a molten salt system that uses stratified 

storage of hot and cold fluids. 

•	 Assess the potential for reducing the cost and complexity of the storage systems for power 

generation from CSP. 

Accomplishments 

•	 Developed sizes and nominal conceptual designs for single and multiple storage tanks for CSP 

power system of nominal 280-MWe capacity. (NREL) 

•	 Developed CFD analyses results for transient heat transfer between filler media and molten salt. 

•	 Developed two-dimensional analyses results for flow and heat transfer in tanks with and without 

filler material. (NREL) 

•	 Established long-term behavior of stratified tanks charged and discharged with salts of constant 

temperature. (NREL) 

•	 Evaluated the use of multiple tanks (such that they may be binned as the collection temperature 

varies with solar radiation intensity). (NREL) 

Future Directions 

•	 Analyze material requirements and performance of thermocline systems as a function of the 

number of storage vessels (1 – 6). (NREL) 

•	 Analyze operational strategies for multiple storage vessel systems (1 – 6). (NREL) 

•	 Analyze operation under nonideal conditions including input fluid with varying temperature. 

(NREL) 

•	 Further characterize the dynamic response of the filler material to a change in fluid temperature 

and estimate the effect on thermocline degradation. (NREL) 

•	 Integrate performance results and material estimates into new cost models. (NREL) 

•	 Estimate the cost benefits of using thermocline storage as opposed to constant temperature, twotank storage. (NREL) 

1. Introduction	 NREL 

For this study, we assumed a power plant nominal 

The objective of the thermal storage modeling name plate capacity of 280 MWe, to be located in 

activity is to develop advanced technologies and the arid deserts of Arizona. Detailed flow and 

effective integrated thermal storage systems thermal modeling was developed and analyzed 

directed at meeting the DOE Concentrated Solar using modern computational fluid dynamics (CFD) 

Power (CSP) subprogram goals. software from Fluent. We limited our study to a 

storage capacity of 6 hours. The storage tanks 

2. Technical Approach were assumed to be filled with sand and rocks to 

make up 75% of the volume. We defined the 

163 Solar Thermal

Concentrating Solar Power

Thermal Storage R&D
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

geometric and thermal loss characteristics of the 

chosen tank(s). Throughout the simulations, cold 

and hot salts were assumed to be available at 

constant temperatures of 300o

C and 385oC, 

respectively. 

For the power plant of 280 MWe capacity, a sixhour thermal storage requirement amounts to 

about 20 GJ and a stored mass of 153,000 metric 

tons of salt. The molten salt volume is about 

85,000 cubic meters (23 million gallons). With the 

effective withdrawal volume being less than the 

tank overall volume, we used a nominal 100,000­

m3 tank for the simulations for this preliminary 

study. A mixture of quartzite rocks along with silica 

sand was chosen as the filler material. The 

quartzite rocks were nominal 3⁄4 inch (sieve 0.75, 

with nominal 20-mm particle size) in size. Sand 

sieved was in the 8 to 12 sieve range, with a 

nominal particle size of 2 mm. The mixture 

occupied seventy-five percent of the storage tank 

volume. 

SNL 

We developed a model of an advanced parabolic 

trough system that incorporates several 

improvements relative to current technology 

including increased concentration ratio and higher 

operating temperature. 

3. Results and Accomplishments 

NREL 

To assess whether these solid particles would 

respond fast enough to the surrounding flow of 

molten, we conducted a transient conduction/ 

convention study of the heat transfer between the 

solid and the liquid. The time response for heating 

and cooling of the solids is important in 

maintaining sharp thermocline as the fluid is 

withdrawn. 

Using CFD analysis, we modeled the heat transfer 

from a single solid sphere to the molten salt. At the 

end of roughly 10 minutes, we note that the solid 

has cooled off considerably, attaining a maximum 

temperature of only 306o

C in the core. At this time, 

the heat content of the sphere is less than 5% of 

its initial content. Simulation of a single particle 

was followed by analysis of a complete tank 

geometry with baffles to diffuse the vertical 

momentum of the incoming salt streams. A 

nominal 100-m diameter tank with a height of 15 m 

was chosen. Cold molten salt was introduced at 

an inlet velocity of 1 m/s; this would correspond to 

a discharge rate of about 8 hours for the entire 

tank volume. Side wall heat losses were set at 100 

W/m2 for all the external walls including top and 

bottom. Modeling results indicate that the 

thermocline is well maintained throughout the 

withdrawal process. This analysis shows that 

thermoclines in stratified tanks can be well 

maintained. 

SNL 

•	 Performed an initial system analysis of an 

advanced parabolic trough system (2X 

Trough) having double the concentration ratio 

of current systems 

Lowering the LCOE for parabolic trough power 

plants requires several technical advances 

including increased concentration ratio, better 

selective surfaces, higher temperature operation, 

and thermal storage. We modeled a facility having 

these attributes to determine the level of the 

specific performance and cost gains. The results 

indicate that high temperature operation (500°C) 

can only be efficiently achieved if the 

concentration ratio is doubled and better selective 

coatings are used on the HCE. 

4. Planned FY 2009 Activities 

NREL 

•	 Develop operational strategies to increase the 

overall effectiveness of the storage system 

•	 Analyze material requirements and 

performance of thermocline systems as a 

function of the number of storage vessels (1 – 

6), 

•	 Analyze operational strategies for multiple 

storage vessel systems (1 – 6), 

•	 Analyze operation under nonideal conditions 

including expected temperature swings in the 

hot and cold salts, 

•	 Further characterize the dynamic response of 

the filler material to a change in fluid 

temperature and estimate the effect on 

thermocline degradation, 

•	 Estimate the cost benefits of using thermocline 

storage as opposed to constant temperature, 

two-tank storage. 

SNL 

•	 Construct a finite-element structural/optics 

model of the advanced 2X trough initially 

analyzed in FY 2008. 

Solar Thermal

Concentrating Solar Power

Thermal Storage R&D

164
 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

Advanced Heat Transfer Fluid Development 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Mark Mehos (NREL), 303-384-7458, mark_mehos@nrel.gov 

Tom Mancini (SNL), 505-844-8643, trmanci@sandia.gov 

Robert Bradshaw (SNL), 925-294-3229, rwbrads@sandia.gov 

Greg Glatzmaier (NREL), 303-384-7470, greg_glatzmaier@nrel.gov 

Nathan Siegel (SNL), 505-284-2033, npsiege@sandia.gov 

DOE HQ Technology Manager:	 Thomas Rueckert, 202-586-0942, Thomas.Rueckert@ee.doe.gov 

FY 2008 Budgets:	 $169K (NREL), $56K (SNL) 

Objectives 

•	 Develop advanced heat transfer fluids (HTF) for power towers and parabolic troughs in an effort 

to improve dispatchability and achieve levelized cost of energy (LCOE) goals. (SNL) 

•	 Formulate HTF for advanced parabolic troughs enabling higher operating temperatures (500°C) 

than current fluids and thus higher efficiency (LCOE objective ~7¢/kWh). (SNL) 

•	 Increase thermal storage densities by a factor of five over current storage materials for solar 

thermal systems. (NREL) 

•	 Explore a new class of nanotechnology-based heat transfer and thermal storage materials with 

enhanced thermophysical properties. (NREL) 

Accomplishments 

•	 Developed multi-component molten nitrate salt mixtures that solidify below 100°C. (SNL) 

•	 Demonstrated thermal stability of these salts to 500 oC and completed long-term corrosion testing 

of carbon and stainless steels. (SNL) 

•	 Performed molecular dynamics (MD) simulations to elucidate the microscopic mechanism of 

solid/liquid phase transitions for bare aluminum nanoparticles without surrounding fluid. (NREL) 

•	 Predicted theoretical heat capacities for several nanoparticles in different categories that agreed 

with the corresponding experimental results for these particles. (NREL) 

Future Directions 

•	 Perform extensive MD for more diverse sizes of particles, ranging from 70 to 100 atoms, and for 

encapsulated aluminum nanoparticles in core-shell structures. (NREL) 

•	 Investigate the nanoscale melting of these encapsulated structures and clarify the role of the 

ligands and the partial oxidation on the performance of the thermal storage materials. (NREL) 

•	 Compare experimental results with theoretical results and develop more accurate models for 

these new experimental systems. (NREL) 

•	 Extend physical property determinations of molten nitrate salt HTF to include density, heat 

capacity and thermal conductivity. (SNL) 

•	 Complete evaluation of 3,000-hour corrosion test specimens to confirm suitable materials of 

construction corresponding to the new molten salt HTF. (SNL) 

•	 Complete exploratory study of nitrate-nitrite molten salt system for low-melting compositions and 

preliminary evaluation of viscosity and chemical stability. (SNL) 

•	 Determine effects of impurities in bulk commodity grades of constituent nitrate salts. (SNL) 

•	 Explore MD computational methods to discover better low-melting salt compositions. (SNL) 

1. Technical Approach	 published phase diagrams for freezing point data, 

then expand the basis of formulations to include 

SNL’s strategy for developing improved molten constituents that promised lower liquidus 

nitrate salt heat transfer fluid (HTF) was to survey temperatures. A limited combinatorial 

165 Solar Thermal

Concentrating Solar Power

Thermal Storage R&D
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

experimental matrix was used to observe lowmelting mixtures and to estimate the direction of 

optimal composition for the next sequence of 

experiments. The candidate low-melting salt 

mixtures were then subject to determinations of 

chemical stability, viscosity, and corrosion activity. 

NREL’s goal is to increase, by the use of new 

nanoscale materials, thermal storage densities by 

a factor of five over the current state of the art for 

solar thermal systems. To achieve this goal, we 

are exploring a new class of nanotechnologybased heat transfer and thermal storage materials: 

(1) nanoscale “capsule” structures containing 

solid/solid, solid/liquid, or solid/gas phase change 

materials (nanoPCMs) as thermal storage 

materials and (2) nanoparticles suspended in 

fluids (nanoFLUIDs) as heat transfer fluids that 

may also act as thermal storage fluids.. 

2. Results and Accomplishments 

SNL 

•	 Developed multi-component molten nitrate salt 

mixtures that solidify below 100°C by limited 

combinatorial experiments and demonstrated 

their chemical stability to 500°C. 

•	 Determined viscosity of molten salt HTF as 

suitable for applications in trough systems. 

•	 Completed long-term exposure phase of 

corrosion testing of container alloys ranging 

from stainless steels to carbon steel. 

This project achieved an innovation in an HTF 

capable of both low and high temperature 

operation and well suited for parabolic trough 

facilities as a direct replacement for the relatively 

costly organic HTF currently in use. Mixtures of 

the four salts (sodium, potassium, lithium and 

calcium nitrates) were identified that display 

liquidus temperatures less than 100°C. 

Exploratory lab work investigated the properties of 

mixtures of nitrate (NO3-) and nitrite (NO2-1) salts. 

The cations added to the mixtures were sodium, 

potassium, and lithium. Preliminary results indicate 

that low-melting salts are achievable with mixed 

anion compositions and melting points near 80 °C 

were observed for a 1:1 mol ratio of nitrate-nitrite. 

NREL 

The melting point of aluminum can be controlled 

by selecting a size of aluminum particles, ranging o

C o from a bulk value of 660 to 150 for C

nanoparticles with 50-60 atoms. These phase 

change temperatures match with the operating 

temperature range (220-600 o

C) of molten salt 

HTF. This tunability of size-dependent melting 

points enables the thermal storage systems to 

operate efficiently with multiple phase change 

temperatures. A fundamental understanding of 

phase-change behavior of the nanoparticles is 

crucial for the design of efficient thermal storage 

materials. 

We performed molecular dynamics (MD) 

simulations to elucidate the microscopic 

mechanism of the solid/liquid phase transition for 

bare aluminum nanoparticles without HTF. The 

melting points and the latent heat of nanoparticles 

depend sensitively on the inter-atomic potentials 

and the geometry of nanoparticles. We found that 

the theoretical heat capacities agree well with the 

experimental results, proving the predictive power 

of our theoretical methods. 

The melting transition from solid-like to liquid-like 

particles is not abrupt, as in the bulk, but occurs 

over a finite temperature range, within which the 

liquid-like and solid-like phases coexist. Thus, the 

heat capacity curve for this nanoparticle shows a 

broad peak, rather than the sharp peak seen in the 

bulk case. The peak of the heat capacity appears 

at a significantly lowered temperature of 340 o

C as 

compared to the bulk melting point (660 o

C). The 

overestimated heat capacities at low temperature 

are attributed to the quantum effect of vibrations, 

which is ignored in our simulations. 

3. FY 2008 Special Recognitions and Patents 

R.W. Bradshaw; D.A. Brosseau. Patent 

application S-112,575, Low-Melting Point 

Inorganic Nitrate Salt Heat Transfer Fluid, filed 

May 12, 2008, in USPO review. (SNL) 

4. Major FY 2008 Publications 

SNL 

•	 R.W. Bradshaw; D.A. Brosseau. “Improved 

Molten Salt Formulations for HTF in Parabolic 

Trough Solar Power Systems.” SolarPACES 

2008; March 4-7, Las Vegas, Nevada. 

•	 R.W. Bradshaw; N.P. Siegel. “Molten Nitrate 

Salt Development for Thermal Energy Storage 

in Parabolic Trough Solar Power Systems.” 

Paper ES2008-54174, ASME 2nd International 

Conference on Energy Sustainability; Aug. 10­

14, 2008, Jacksonville, Florida. 

•	 G.J. Kolb; R.B. Diver. “Conceptual Design of 

an Advanced Trough Utilizing a Molten Salt 

Working Fluid.” SolarPACES 2008. 

Solar Thermal

Concentrating Solar Power

Thermal Storage R&D

166
 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

Industry Projects 

Performing Organizations: Abengoa Solar, Inc. 

Hamilton Sundstrand Corporation 

Key Technical Contacts:	 Carolyn Elam, DOE Golden Field Office (DOE/GO), 303-275-4953, 

carolyn.elam@go.doe.gov 

Jim Payne, DOE/GO, 303-275-4756, jim.payne@go.doe.gov 

Brad Ring, DOE/GO, 303-275-4930, brad.ring@go.doe.gov 

DOE HQ Technology Managers:Frank (Tex) Wilkins, (202) 586-1684, frank.wilkins@ee.doe.gov 

Tommy Rueckert, (202) 586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budgets:	 $862K Recipients 

Objectives 

•	 Develop energy supply technologies that are reliable, affordable, and environmentally sound. 

Expand national electricity generation portfolio to increase energy security by diversifying 

domestic energy supply options. Concentrating solar power (CSP) is one of the most attractive 

renewable energy options in southwest U.S., with a nominal levelized cost of energy (LCOE) 

target of 7-10¢/kWh by 2015 and 5-7¢/kWh by 2020. 

•	 Develop low cost, high temperature storage that enables CSP trough systems to reach nominal 

levelized cost of energy (LCOE) target of 5-7¢/kWh with storage (12 – 17 hours) by 2020. To 

achieve these targets, storage cost of less than $15/kWh thermal is desired with round trip 

efficiencies at or greater than 93%. 

Accomplishments 

•	 Held merit review of applications in September and announced selections in October 2007. 

•	 Negotiated and awarded CSP thermal storage awards. 

•	 Defined roles and responsibilities of program management team, including technical advisors at 

the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories (SNL). 

Future Directions 

•	 Evaluate progress toward critical milestones and decisions will be made at the end of the each 

project’s first phase, starting in FY 2009 and extending into FY 2010. 

1. Introduction 

The CSP thermal storage R&D activities are 

expected to develop low cost, high temperature 

storage that enables trough technologies to 

reach a nominal levelized cost of energy (LCOE) 

target of 5-7¢/kWh with storage (12 – 17 hours) 

by 2020. To achieve this goal, storage cost of 

less than $15/kWh thermal is desired with round 

trip efficiencies at or greater than 93%. . 

The selected projects are: 

Organization, PI and Agreement Title 

FY 2008 

Budget 

($K) 

Abengoa Solar Inc., Bruce Kelly 

“Development of Molten Salt Heat 

Transfer Fluid Technology for Parabolic 

Trough Solar Power Plants” 

500 

Hamilton Sundstrand Corporation, 

Michael McDowell 

“Concentrating Solar Power-Molten Salt 

Pump” 

362 

167 Solar Thermal

Concentrating Solar Power

Thermal Storage R&D
 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

Development of Molten-Salt Heat Transfer Fluid Technology for
 

Parabolic Trough Solar Power Plants (Abengoa Solar, Inc.)
 

Total Award: $625K, DOE/Recipient Share: $500K/$125K 

Objectives 

•	 Determine economic potential of low freeze point molten salts. 

•	 Develop technologies required for use of molten salts. 

•	 Conduct field tests necessary for introduction of molten salts in commercial project. 

Accomplishments 

•	 Completed draft design basis for a molten salt parabolic trough plant. 

•	 Used GateCycle program calibration calculations, using previous heat balances. 

•	 Developed heat balances, collector field piping layouts, and steam generator designs for
 

reference Therminol and baseline molten salt plants.
 

•	 Assembled initial capital cost data for reference to Therminol plant with baseline molten salt plant. 

Future Directions 

•	 Test prototype components for molten salt use (ball joints, high temperature receivers). 

•	 Develop detailed models of thermocline thermal energy storage system. 

•	 Use Phase 1 results to illustrate reduced LCOE and risk mitigation. 

1. Introduction 

Commercial parabolic trough projects use an 

organic fluid as the heat transport fluid (HTF) in 

the collector field and the steam generator. The 

high vapor pressure of this fluid requires an 

indirect thermal storage system. The project will 

determine whether inorganic fluids offer a 

sufficient reduction in LCOE to pursue further 

development and to develop the components 

required for molten salt use. 

2. Results and Accomplishments 

Abengoa developed solar field piping layouts for 

both the baseline Therminol (organic HTF) and the 

reference molten salt plant, with an option to use 

molten salts with very low (~100 °C) melting 

points. Preliminary analysis of the low melting 

point salts are focused on economic concerns, 

performing a design tradeoff between the higher 

cost of these salts and the lower equipment cost 

entailed by their use. Heat balances were also 

developed for the reference Therminol, and the 

baseline molten salt plants. An engineering 

assessment, using capital cost data, is being 

developed for the reference Therminol and the 

baseline molten salt plants, based on the 250­

MWe Solana project for Arizona Public Service. 

Hamilton Sundstrand Corporation Concentrating Solar Power - Molten Salt Pump 

Total Award: $4,374K, DOE/Recipient Share: $3,219K/$1,155K 

1. Introduction 

This is a new project that started work on Oct. 1, 2008. 

2. Technical Approach 

The intent of this project is to design, build and test a long-shafted, molten salt pump necessary for a 

thermal storage system in a commercial-scale solar trough plant. The level of technical innovation 

necessary for this project reflects the need to expand the performance envelope range of long-shafted 

molten salt pumps. The high operating temperature of the design will demonstrate a bearing design able 

to work in most solar thermal plants that utilize molten salt as a thermal storage medium. The pump 

design shall be extensible to a solar power tower application by adding pumping stages to reach head 

levels necessary for solar power tower types of solar thermal power plants. 

Solar Thermal

Concentrating Solar Power

Thermal Storage R&D

168
 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

Advanced Concepts R&D 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

DOE Golden Field Office (DOE/GO) 

Key Technical Contacts:	 Cheryl Kennedy (NREL, Primary Contact), 303-384-6272, 

cheryl_kennedy@nrel.gov 

Greg Kolb (SNL), 505-844-1887, gjkolb@sandia.gov 

DOE HQ Technology Manager:	 Thomas Rueckert, 202-586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budgets:	 $283K (NREL)*, $233K (SNL)** 

*$210K and **$163K will carryover to FY 2009 

Objectives 

•	 Develop technology that dramatically reduces cost of concentrating solar power (CSP) to less 

than 10¢/kWh by 2015. 

•	 Advance mirror technologies, reducing cost of mirrors by half by moving from heavy glass mirrors 

to lightweight front-surface reflectors that include surface coatings to reduce soiling. (NREL) 

•	 Develop advanced reflector materials that are low in cost (less than $2.50/ft2 or $26.90/m2

) and 

maintain high specular reflectance (90%–95% into a 4-mrad cone angle) for long lifetimes (20 to 

30 years) under severe outdoor environments. (NREL) 

•	 Test durability of optical materials to determine lifetime of solar reflector materials. (NREL) 

•	 Support development of advanced power tower systems. (SNL) 

Accomplishments 

•	 Performed durability testing and published results of optical materials that potentially reduce cost 

of levelized cost of energy (LCOE) of CSP to less than 10¢/kWh by 2015. (NREL) 

•	 Provided significant industry support to CSP and concentrating photovoltaic (CPV) industries on 

solar reflectors. (NREL) 

•	 Trained power tower developer to use SNL’s design and analysis software. (SNL) 

•	 Performed first test of heliostat at distance of 1 mile. (SNL) 

Future Directions 

•	 Continue durability testing of optical materials to determine lifetime of solar reflector materials. 

(NREL) 

•	 Continue optical characterization of advanced reflector materials, accelerated and outdoor testing 

of commercial, experimental, CSP FOA, CSP industry, and CRADA supplied reflector materials to 

determine lifetime of solar reflector materials, and support of industry/program needs. (NREL) 

•	 Analyze and publish testing results of reflector materials applied to CSP technologies. (NREL) 

•	 Develop with industry advanced power tower and trough components. (SNL) 

1. Results and Accomplishments • Compared durability of silvered thin-glass, 

copper-free, and lead-free mirrors after 

1.1 Advanced Concepts R&D Agreement	 accelerated exposure testing (AET) and outdoor 

• Completed installation of new accelerated exposure testing (OET) at Golden, Colorado 

exposure chambers (i.e., 1st Ci5000, Ci4000, (NREL); Miami, Florida (FLA); Phoenix, Arizona 

and BlueM) to test durability of commercial and (APS); and Northern Territory, Australia. (6/08) 

experimental solar mirrors. (7/08) • Provided status of test results of candidate solar 

•	 Determined optical performance, lifetimes, and mirror samples and identified promising 

cost goals for advanced reflectors consistent candidates and how advanced solar mirrors will 

with CSP program objectives. (4/08) help meet cost goal for electricity. (11/08) 

169 Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DOE and the CSP industry agreed that 

modification of the historical specular reflectance 

requirements, cost goals, qualification tests, and 

standards for solar mirrors need to be determined 

by the international industry, based on utility costs 

and technology needs. These changes will require 

significant industry acceptance and will continue 

into FY 2009. Until then, the outdated 1992 

reflector cost goal of a $1/ft2 was dropped and 

replaced with “reduce mirror cost by half”. 

The Advanced Concepts task participated as a 

committee member and plenary presenter for DOE 

Specialty Glass Needs for the U.S. Solar Industry 

Workshop; participated in CSP road mapping; and 

task member of International Energy Agency Task 

III: Solar Technology and Advanced Applications. 

Advanced solar reflector research and durability 

testing of reflectors, supplied by industry, is 

ongoing. Flabeg converted their mirror line to 4- or 

5-mm glass and a new low-lead paint system in 

2003. Side-by-side exposure testing began in 

2005. The original mirrors with the high-lead paint 

system appear to exhibit better optical durability 

than the new reduced-lead mirrors. The high-lead 

mirrors have degraded 1.7% and the reduced-lead 

mirrors have degraded 2.8% after 45 months. 

Significant corrosion has been observed in 

deployed thin-glass mirrors in CSP and CPV 

plants in Arizona and Australia. Some thin-glass 

silvered copper-free lead-free mirrors sold for 

outdoor applications have not passed the 

minimum requirements for mirrors to qualify for 

indoor applications. More than 40 experiments of 

thin glass mirrors are in AET and OET from nearly 

all of the world thin-glass mirror suppliers. 

Completion of a technical paper is pending the 

results of new samples and humidity experiments. 

Alanod (Germany) developed an aluminum solar 

reflector with a nanocomposite oxide protective 

layer that has improved durability in urban and 

industrialized (polluted) locations. Preliminary 

exposure testing results of Alanod’s Miro-Sun 

samples (received in 2005) are encouraging, and 

the durability testing is ongoing. 

A polymeric solar reflector has been developed 

through collaborative research between 

ReflecTech and NREL. The initial pilot-run 

material shows minimal loss in solar-weighted 

reflectance after 5 years of real-time outdoor 

exposure. However, accelerated WeatherOmeter 

(WOM) results showed significant reflectance loss 

earlier than anticipated from the proof-of-concept 

materials. Modifications to the baseline 

construction were identified and incorporated into 

the third pilot-plant run that should improve the 

WOM durability. Testing is ongoing, and the 

material is being field-tested. Based on AET, 

Glass, ReflecTech, and Alanod mirrors should 

meet 10-year lifetime goals. Since the chemistry 

and construction of all solar reflectors has 

significantly changed, all commercially available 

reflectors have been in OET for less than 4 years. 

1.2 Advanced Concepts FOA Support 

NREL supported four CSP solar reflector FOA 

awardees: 3M, Abengoa, Alcoa, and PPG. 

1.3 CEC/CSP Collaboration 

The market study for CSP/CPV collaboration was 

not placed. The milestone was reassigned to 

Selya Price, NREL senior energy analyst, and 

added to FY 2009 System Analysis milestones. 

1.4 Advanced Power Tower Components 

Solar Reserve and Rocketdyne are 

commercializing power tower technology. The 

computational resources of the in-house codes are 

extensive, becoming an impediment to the quick 

turn-around requirements of their commercial 

venture. So, SNL trained them on the use of SNL’s 

DELSOL and SOLERGY computer codes, less 

computationally extensive but accurately predicts 

power tower optical design and performance. 

The Solar Reserve tower plant is capable of 

producing 100 MWe or more. The heliostat field 

within their commercial plant is more than 10 times 

larger than was demonstrated at Solar Two, where 

the distance from the tower to the furthest heliostat 

was 0.25 mile versus 1 mile in a commercial plant. 

SNL performed a 1-mile test by aiming a 95-m2 

heliostat at towers located 1 mile away. Test data 

indicated the spot size was 20 meters in diameter, 

similar to DELSOL prediction. 

2. Planned FY 2009 Activities 

•	 Upgrade database of candidate solar mirrors to 

Web based. (3/09) 

•	 Survey CSP and reflector supplier industry and 

use SAM to determine specular requirements 

and cost goal. (3/09) 

•	 Report durability of silvered thin-glass copperfree and lead-free mirrors after exposure to 

Ci5000 WOM and damp-heat at different 

humidity conditions and OET. (6/09) 

Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts

170
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Document assessment of existing relevant 

accelerated reliability test procedures, applicable 

to materials, components, and systems. (6/09) 

•	 Develop instrument to measure specular 

reflectance at 2-mrad cone at different 

wavelengths on curved substrate. (9/09) 

•	 Provide status of test results of candidate solar 

mirror samples and identify promising 

candidates and how advanced solar mirrors will 

help meet cost goal for electricity. (9/09) 

•	 Help eSolar assess performance and reliability 

of their steam-type power towers (7/09). 

•	 Modernize SNL’s power tower design and 

analysis software (9/09). 

•	 Begin to explore development of 2X trough, i.e. 

double concentration of today’s trough (9/09). 

3. Major FY 2008 Publications 

C. Kennedy. “Advances in CSP Collectors: Mirrors 

and Solar-Selective Coatings.” Proceedings of 

Association of Industrial Metallizers, Coaters and 

Laminators (AIMCAL) Fall Technical Conference 

2007 and 21st International Vacuum Web Coating 

Conference; October 2007, Scottsdale, Arizona. 

C. Kennedy. “Advances in CSP Collectors: Mirrors 

and Solar-Selective Coatings.” Vac. Tech. Coat, 

June (2008). 

C. Kennedy, “Advancements in CSP (CSP) 

Reflectors and Solar-Selective Coatings.” 

Proceedings of E3 2007 - The Midwest's Premiere 

Energy, Economic, and Environmental Conference 

Proceedings; November 2007, University of 

Minnesota, Minneapolis, Minnesota. 

C. Kennedy. “Optics Reliability for Concentrators.” 

SPIE 2008 Conference Proceedings; August 

2008, San Diego, California. 

G.J. Kolb; R. Diver. “Conceptual Design of an 

Advanced Trough Utilizing a Molten Salt Working 

Fluid (2X Trough).” SolarPACES Conference 

Proceedings; March 2008, Las Vegas, Nevada. 

4. University and Industry Partners 

Significant industry interaction occurred with CSP 

reflector manufacturers and CPV manufacturers 

on the durability of solar mirrors. A partial list 

includes: 3M, A Better Focus, Abengoa, ACA, 

Acciona, Aerospace Group, AGC (Glaverbel), 

Alanod, Alcan, Alcoa, Alvek, Ammonix, Applied 

Image, Arch Aluminum & Glass, Arontis, Atlas, 

Ausra,BEI Space, Blach & Vetch, Boeing, 

Cardinal Glass, CENIM/CSIC, Chevron, Chisso, 

CNRC, Concentrator Optics, Convergent Solar, 

Cooper Lighting, Corning, Cosmo Films, Cyanto, 

Dow Chemical, Dow Corning, Emcore, Energy 

Innovations, Enfocu, ESG, eSolar, Evonik, FEP, 

Flabeg, Gardner Glass, Google, GreenVolts, 

Guardian, HelioFocus, Honeywell, Hydro 

Aluminum, Infinia, International Solar 

technologies, ITRI, JDSU, JX Crystals, Kearney & 

Assoc., K&B Assoc, KERI, Light Prescription 

Innovators, Luz II, MegaWatt Solar, Nanotron, 

Naugatuck, Nitinol, Northside, ORNL, PARC, 

Pilkington, PPG, Pratt & Whitney, Praxair, QPanel, 

RAflector, Raytheon, ReflecTech, Replex, Rio 

Glass, Rocky Development, Rohm & Haas, 

Rooney Eng., SAIC, Saint Gobain, Sandia, 

Sandvik, Schott, SEIA, SkyFuel, Skyline Solar, 

Spraylat, SolarGenix, SolarTech USA, Solaria, 

Solel, SolFocus, Soliant, Solucar, Solyndra, 

Southwall, SPAWAR, Spinnaker Energy, Spraylat, 

SRI International, Stanford, Stirling Energy 

Systems, SunPower, Sunray, SunTechnics, 

Surface Optics, Symmorphix, United Solar, 

University of Baleric Islands, University of 

California Merced, University of Colorado, 

University of Hartford, University of Minnesota, 

Valspar, Veridian, Von Ardenne, Wooly Parsons, 

Xcel Energy, Xerocoat. 

The following organizations partnered in the 

research activities. 

Organization/ 

Principal Investigator Location/E-mail Description/Title of Research 

Activity 

FY 2008 

($K) 

Cost 

Share 

($K) 

Solar Systems 

Ken Cheah 

Melbourne, Australia 

Kcheah@solarsystems.com.au 

CRADA/Optical durability of thinglass mirror panels 35.2* 39.3** 

SolFocus 

Mark Spencer 

Mountain View, CA 

mark_spencer@solfocus.com 

CRADA/Durability of small mirror 

dishes and front surface 

reflectors and bond joints 

100.4† 234.0‡ 

*NREL Funded Amount: $29.3.2k 10/1/07 - 1/25/08 + $5.8k directly paid travel expenses 6/30/08 

**Sponsor Contract Value $39.3k 6/6/07 - 1/25/08 

†NREL Funded Amount: $100.4k 10/1/07 - 9/30/08 

‡Sponsor Contract Value $234.0k 6/15/07 through 8/14/11 

171 Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts
 

 

 

 

____________________________________________________________________________________ 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

Thermochemical Project 

Performing Organization: Sandia National Laboratories (SNL) 

Key Technical Contact: Cheryl Ghanbari, 505-845-3426, cghanba@sandia.gov 

DOE HQ Technology Manager: Thomas Rueckert, 202-586-0942, Thomas.Rueckert@doe.ee.gov 

FY 2008 Budget: $1,000K 

Objective 

•	 Upgrade heliostat control system for Central Receiver Test Facility (CRTF) at the National Solar 

Thermal Test Facility (NSTTF). 

Accomplishments 

•	 Completed the design of the new control system. 

•	 Built and tested a prototype of the control system upgrade hardware and communications. 

•	 Purchased new motors and encoders for the drives. 

Future Directions 

•	 Complete installation of controls hardware and test the system. 

•	 Complete α-level design of the master control system and test it. 

1. Introduction 

Over the last 32 years, SNL has successfully 

tested 13 central receivers and performed 

numerous other large-scale tests using the 5-

megawatt thermal (MWth) CRTF, located at the 

NSTTF in Albuquerque, New Mexico. In addition 

to testing the central receiver (a.k.a. power tower 

receivers), the facility has been used to perform 

work-for-others test in support of several National 

Aeronautics and Space Administration (NASA) 

centers, U.S. Air Force, and other DOE customers 

as part of its designated-user facility role. 

Due to its age, the CRTF has operated with 

obsolete hardware in the heliostat field and 

software in the control room. Much of this 

equipment is no longer supported by the original 

vendors, and spare parts are either non-existent or 

very expensive to procure. Additionally, the 

performance requirements for the control system 

have changed significantly during the past 32 

years, and the existing system can no longer meet 

test requirements. 

Therefore, we are developing a new control 

system for the 5-MWth CRTF at the NSTTF. The 

new control system will include upgrades in 

hardware, motors encoders and field control, and 

software for the master control system for the field. 

Fig. 1 Central Receiver Test Facility at SNL’s 

National Solar Thermal Test Facility 

2. Technical Approach 

Already been approved by the CRTF staff, the 

design lists the lessons learned throughout the 32 

years of operation at the CRTF and describes a 

new control system built to address the limitations 

of the current design and to upgrade hardware to 

modern control technology. 

Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts

172
 

 

 

 

 

 

 

 

 

 

 

3. Results and Accomplishments 

•	 Developed lessons-learned document for field 

operation and control, identifying needs and 

issues. 

•	 Reviewed hardware and software alternatives 

and down selected a design to meet cost and 

performance objectives. 

•	 Purchased motors and encoder hardware. 

•	 Tested a prototype design. 

4. Planned FY 2009 Activities 

We will complete validation of the design and 

upgrade the hardware and software at the CRTF 

facility, based on the validated design. This 

process will be completed in phases. 

The first phase consists of completing the 

development of a new heliostat controller (HCE). 

The HCE is the unit that directly controls the 

movement of a single heliostat. 

The second phase of the upgrade consists of 

assembling, installing and testing HCE units to 

control a small but significant part of the heliostat 

field. This will allow us to develop and test the 

communications system for managing multiple 

heliostats. 

The third phase consists of developing and testing 

the master control system (MCS). The MCS is the 

field control system that the facility’s operators use 

to design and operate a test. 

Finally, the fourth phase of the upgrade will consist 

of duplicating several of our customers’ tests, with 

dummy samples, to validate the operation of the 

field. 

173 Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts
 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

Industry Projects 

Performing Organizations:	 PPG Industries; SkyFuel, Inc.; 3M Company; Hamilton Sundstrand 

Corporation; Solar Millennium, LLC 

Key Technical Contacts:	 Carolyn Elam, DOE Golden Field Office (DOE/GO), 303-275-4953, 

carolyn.elam@go.doe.gov 

Jim Payne, DOE/GO, 303-275-4756, jim.payne@go.doe.gov 

Brad Ring, DOE/GO, 303-275-4930, brad.ring@go.doe.gov 

DOE HQ Technology Managers:Frank (Tex) Wilkins, 202-586-1684, frank.wilkins@ee.doe.gov 

Tommy Rueckert, 202-586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budgets:	 $3,086K Recipients 

Objectives 

•	 Develop energy supply technologies that are reliable, affordable, and environmentally sound. 

Expand national electricity generation portfolio which will increase energy security by diversifying 

domestic energy supply options for use both in normal and emergency situations. CSP is of the 

most attractive renewable energy options in southwest U.S., with a nominal levelized cost of 

energy (LCOE) target of 7-10¢/kWh by 2015 and 5-7¢/kWh by 2020. 

•	 Identify concepts that can generate low-cost power (under 7¢/kWh) with storage (12-17 hours) by 

2020. 

Accomplishments 

•	 Held merit review of the applications in September and announced selections in October 2007. 

•	 Negotiated and awarded advanced CSP concepts awards. 

•	 Defined roles and responsibilities of program management team, including technical advisors at 

the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories (SNL). 

Future Directions 

•	 Evaluate progress toward critical milestones and decisions will be made at the end of the each 

project’s first phase, starting in FY 2009 and extending into FY 2010. 

1. Introduction 

Advanced CSP concepts activities are expected 

to identify concepts that can generate low cost 

power with a nominal levelized cost of energy 

(LCOE) target of under 7¢/kWh with storage (12­

17 hours) by 2020. The funding opportunity 

announcement (FOA) investigated three areas 

to address market barriers for utility-scale 

generation of CSP technologies: thermal 

storage; trough component manufacturing; and 

advanced CSP systems and/or components. 

The selected projects are: 

Organization, PI and Agreement Title 

FY 2008 

Budget 

($K) 

PPG Industries, Inc.-James McCamy, 

“High Performance Reflector Panels for 

774 

Concentrating Solar Power Assemblies” 

SkyFuel Inc. – Randy Gee, 

“Commercial Development off an 

Advanced, High-Temperature, LinearFresnel Based Concentrating Solar Power 

Concept” 

385 

3M Company – Susannah Clear, 

“Cleanable and Hardcoat Coatings for 

Increased Durability of Silvered Polymeric 

Mirrors” 

350 

Hamilton Sundstrand Corporation – 

Michael McDowell, 

“Solar Power Tower Receiver 

Development” 

313 

Solar Millennium, LLC – Michael 

McDowell, “Advanced High Temperature 

Trough Development” 

1,264 

Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts

174
 

 

____________________________________________________________________________________ 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

High Performance Reflector Panels for Concentrating Solar Power Assemblies (PPG) 

Total Award: $3,639K, DOE/Recipient Share: $2,185K (DOE), $1,453K (Recipient) 

Objectives 

•	 Develop and commercialize large-area high value mirrors (HVM) with lower cost and higher 

performance, resulting in reduced LCOE. 

•	 Develop one or more protective coatings and associated application process. 

•	 Develop mirrors with different (flat/bent) geometries and mechanical strengths. 

Accomplishments 

•	 Identified two primary candidates for organic protective coating. 

•	 Demonstrated feasibility of producing mirrors with different geometries and strengths. 

•	 Indicated expected 7.5% improvement in LCOE with evaluation of produced mirrors. 

Future Directions 

•	 Focus on process development for low-cost manufacturing of large-area mirrors having differing 

geometries and mechanical strengths. 

1. Introduction 

PPG plans to develop and commercialize largearea mirrors that are superior in value, in terms of 

cost and performance, to existing mirrors available 

on the market today. The expected outcomes are 

a design and fabrication process for a mirror 

having a high solar weighted specular reflectance, 

minimal optical performance degradation over the 

service lifetime, and a cost to the CSP systems 

builder that reduces the overall capital expenditure 

of the CSP system. 

2. Technical Approach 

PPG is conducting R&D into alternate materials, 

structures, and fabrication processes for reflector 

components. The base material for this work is 

their high-transmission SOLARPHIRE® low-iron 

glass. PPG will evaluate various reflecting layers 

with protective back coatings applied to the 

second surface for optical performance, durability, 

and environmental resistance. PPG will also 

evaluate whether it may be possible to bend the 

resulting mirror into a parabolic or other 

advantageous shape using standard equipment. 

3. Results and Accomplishments 

PPG used damp heat (85o

C / 85%RH) testing as 

the initial screening test to determine potential 

materials candidates for the organic protective 

coating. Five different encapsulant compositions 

were identified. Further testing on these five 

coatings has indentified primary and secondary 

coating materials. Mirrors with different shapes 

and treatments were tested for compatibility with 

the encapsulants. Acceptable results were 

obtained in all cases. The Solar Advisory Model 

(SAM) was used to evaluate the impact on LCOE 

and total capital expenditure due to changes in 

performance and anticipated cost for the mirror 

under development in this project. For all the 

systems modeled, the candidate’s HVM showed 

5% or better improvement in both LCOE and total 

capital expenditure (for the entire CSP system) 

when compared with the baseline mirror. 

4. Planned FY 2009 Activities 

•	 Develop/demonstrate mirror processes 

necessary for low-cost fabrication of these 

mirrors by end of Phase 2. 

•	 Develop protective coating with optical layers; 

identify process parameters required for 

manufacturing. 

•	 Develop a high rate fabrication process. 

•	 Identify manufacturing process parameters, 

equipment, and technical challenges 

associated with larger scale, high-rate, mirror 

fabrication. 

•	 Field test large-area prototype mirrors. 

175 Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts
 

____________________________________________________________________________________ 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

Commercial Development off an Advanced, High-Temperature, Linear-Fresnel Based
 

Concentrating Solar Power Concept (SkyFuel)
 

Total Award: $4,139K, DOE/Recipient Share: $2,423K (DOE), $1,716K (Recipient) 

Objectives 

•	 Develop advanced CSP system using linear Fresnel reflective technology. 

•	 Enable use of molten salt as a heat transfer fluid (HTF) in linear concentrator systems and as 

direct thermal energy storage. 

Accomplishments 

•	 Initiated detailed conceptual design work and completed baseline wind-tunnel testing. 

•	 Compared SkyFuel’s trough technology to linear power tower technology. 

•	 Developed advanced in-house optical and thermal analytical capability. 

Future Directions 

•	 Complete collector design, analysis and optimization. 

•	 Design, prototype and demonstrate advanced, high-precision, low-cost reflector panel designs 

and advanced receiver designs for linear Fresnel systems. 

•	 Refine wind tunnel testing and structural characterization activities for collector design. 

•	 Assess overall performance and economic efficacy of the Linear Power Tower design relative to 

SkyFuel’s SkyTroughTM parabolic trough concentrator. 

1. Introduction	 (winter) 

The objective of SkyFuel’s proposed multi-phased 

project is to develop an advanced CSP system, 

using linear Fresnel reflective technology, to 

achieve significantly lower delivered electricity 

costs from utility-scale solar thermal power plants. 

The design uses molten-salt HTF to enable higher 

operating temperatures and direct thermal 

storage, eliminating the need for heat exchangers. (summer) 

2. Results and Accomplishments 

The advantages of linear Fresnel can be 

combined with cutting edge reflective film and 

receiver technology to allow the design of a 

system with a high degree of economic merit. 

SkyFuel completed wind tunnel testing and is 

using the results to help guide and optimize its 

reflector panel design. An analysis defined the Fig. 1. A comparison between the daily performance of significant level differences in optical character a trough and Fresnel system in the winter and summer. that influences cost targets for Linear Fresnel, and 

overall system design for the energy market, and 

are illustrated in Figure 1. 

3. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 ($K) 

Cost Share 

($K) 

CPP Wind Engineering Fort Collins, CO Collector wind tunnel testing, structural load 

characterization 100 28 

Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts

176
 

 

____________________________________________________________________________________ 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

Cleanable and Hardcoat Coatings for Increased Durability of Silvered Polymeric Mirrors (3M) 

Total Award: $3,614K, DOE/Recipient Share: $2,312K (DOE), $1,302K (Recipient) 

Objectives 

•	 Develop durable and/or cleanable coatings specifically for silvered polymeric mirrors having 

polymethylmethacrylate (PMMA) front surfaces. 

•	 Demonstrate manufacturing processes for these durable and/or cleanable coatings. 

•	 Evaluate and validate the performance of these mirrors and their LCOE costs. 

Accomplishments 

•	 Screened chemistries and approaches for durable hardcoats and cleanable coatings. 

•	 Identified three top hardcoat formulations that approach the performance of glass. 

•	 Developed coating processes for these formulations and began environmental testing. 

•	 Began development of additives and modifications to formulations to improve cleanability. 

Future Directions 

•	 Perform accelerated weathering and performance testing on samples. 

•	 Select process conditions that are suitable for scale-up to manufacturing. 

•	 Recommend top five candidates for hardcoat coatings and for cleanable coatings. 

•	 Optimize coating conditions on a roll-to-roll coater for the top candidates. 

•	 Collect soiling and cleanability data. 

•	 Develop LCOE model to evaluate performance of coated versus uncoated PMMA mirrors. 

1. Introduction 

Silvered polymeric mirrors with protective acrylic 

front surfaces show promise as alternative lowcost replacements for thick glass mirrors in 

parabolic trough CSP installations, and have the 

potential to reduce the installed system cost and 

LCOE for a trough installation substantially. 3M 

plans to address two aspects of silvered polymeric 

mirror films related to long-term durability– 

abrasion resistance and anti-soiling surfaces of 

the acrylic protective layer. 

2. Technical Approach 

3M’s approach is to screen candidate hardcoat 

and cleanable coatings, use accelerated aging to 

test for durability and performance, and develop 

process optimization on samples with greatest 

promise. Top candidates will be evaluated to 

determine their feasibility for manufacturing and 

roll-to-roll coating processes. During phase 2, 

PPG will develop laboratory and pilot-scale 

equipment for selected coatings. Results from 

bench and pilot work will be incorporated into the 

economic model, and final candidates will be 

selected for scale-up to large width, manufacturing 

scale, mirror coating in the final phase of the 

project. Coated mirror film from this phase will 

undergo field trial weathering and results analyzed 

and incorporated into LCOE calculations. 

3. Results and Accomplishments 

PPG screened and selected approximately 20 

candidate hardcoat materials with representative 

chemistries and coating methods. Screening 

criteria included UV, thermal and hydrolytic 

stability, expected abrasion resistance, 

compatibility with mirror surfaces, and cleanability. 

A preliminary economic study based on the SAM 

model was begun. From this analysis, three 

candidates approached glass in abrasion 

resistance and two others are promising. After 

2,000 hours of accelerated weathering, the first 

three candidates have shown little degradation. 

Optimizing the top formulations and their 

respective coating, curing, and/or drying 

conditions is underway and manufacturing 

approaches appropriate for these selected 

compositions have been identified. 

4. Major FY 2008 Publications 

R. Messner. “Cleanable and Hardcoat Coatings for 

Increased Durability of Silvered Polymeric 

Mirrors,” DOE Annual Solar Peer Review, April 22­

24, Austin, TX, 2008. 

177 Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts
____________________________________________________________________________________ 

 

 

 

 

Hamilton Sundstrand Corporation Solar Power Tower Receiver Development 

Total Award: $2,881K, DOE/Recipient Share: $1,856K (DOE), $1,025K (Recipient) 

1. Introduction 

The objective of this project is to validate the manufacturability of a large-scale molten salt receiver panel 

and then confirm its operation in prototypic solar flux. This work is an important step in reducing the 

levelized cost of energy (LCOE) from a central receiver solar power plant. 

2. Technical Approach 

The key technical risk to building larger power towers is building the larger receiver systems, specifically 

the issues involved with key receiver panel features such as the large headers and longer tubes. 

Therefore, this proposed technology project includes the design, fabrication and testing of an advanced 

molten salt prototypic sub-scale receiver panel that can be utilized in a large receiver system. The overall 

project is divided into three phases; concept feasibility, technology design and prototype development, 

and field validation. 

3. Results & Accomplishments 

The project started work on 10/01/2008. 

Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts

178
 

____________________________________________________________________________________ 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

Advanced High Temperature Trough Development (Solar Millennium) 

Total Award: $5,919K, DOE/Recipient Share: $3,311K (DOE), $2,608K (Recipient) 

Objectives 

•	 Lower LCOE of Trough Power through advanced molten salt heat transfer fluids and improved 

collector. 

•	 Evaluate benefits and costs of molten salt as an HTF in a full sized solar field. 

•	 Complete design and installation of next generation collector at Kramer Junction as test platform. 

•	 Modify test loop to be a molten salt parabolic trough test system. 

Accomplishments 

•	 Completed molten salt evaluation study, showing 12% decrease in LCOE. 

•	 Improved understanding of freeze protection systems as design basis for test loop. 

•	 Developed commissioning/decommissioning operations strategy using water dilution. 

•	 Improved understanding of detailed design requirements for molten salt-based plant. 

Future Directions 

•	 Construct test loop and evaluate construction methods, verify optical shape, and validate 

assembly procedures. 

•	 Validate baseline loop performance. 

•	 Complete detailed systems designs for molten salt test loop. 

1. Introduction 

Solar Millennium had several key technical 

achievements that resulted in proposing this 

project, using molten salts as a heat transfer fluid 

(HTF). New, low melting point salts open up a 

variety of strategies, and a wider collector aperture 

can be designed for different HTFs. 

2. Results and Accomplishments 

Phase 1 was completed. The company completed 

a study demonstrating that a molten salt plant has 

the potential to reduce LCOE by 12%. The study 

was based upon a 100MW plant with 8 hours of 

thermal storage. Efficiencies are gained because 

molten salt operates at a higher temperature, and 

in a pressurized system this results in higher 

temperature steam which increases the power 

turbine’s efficiency. Storage efficiency also 

improves, as the higher delta T in molten salt 

storage fluid is more efficient when compared to 

oil as a HTF, and is therefore lower cost. The 

study found an 8 hour Thermal Energy Storage 

system for a 100 MW plant costs 45% less with 

salt compared to an oil HTF. The studies also 

identified several methods to commission and 

decommission a salt-solar field, alleviating salt 

freezing issues. The company also continued 

working to improve the collector assembly, and 

redesigned the jig for the Kramer Junction Phase 

2 test loop. 

3. Major FY 2008 Publications 

Dracker and Riffelmann. “Advanced High 

Temperature Trough Collector Development,” 

2008 Solar Annual Review Meeting April 22-24, 

Austin, Texas. 

4. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 ($K) 

Nexant, Inc. 

Babul Patel San Francisco CA Nexant performed several subsystem analysis and process designs for the molten salt plant. 80 

SEGS V Plant 

Harvey Stephens Kramer Junction, CA Provided use of Kramer Junction site for Test Loop activities 0 

Flagsol GmbH 

Dr. Frieder Borgmeier Cologne, Germany Salt Property testing and long term stability test 0 

179 Solar Thermal

Concentrating Solar Power

Advanced CSP Concepts
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

Southwest Stakeholder Outreach 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Mark Mehos (NREL), 303-384-7458, mark_mehos@nrel.gov 

Tom Mancini (SNL), 505-844-8643, trmanci@sandia.gov 

DOE HQ Technology Manager:	 Tommy Rueckert, 202-586-0942, Thomas.Rueckert@ee.doe.gov 

FY 2008 Budgets:	 $160K (NREL), $56K (SNL) 

Objective 

•	 Act as an information resource to concentrating solar power (CSP) stakeholders in accordance 

with the DOE southwest stakeholder outreach activity. Stakeholders include federal/state/local 

governments, utilities, regulatory commissions, the Western Governors’ Association (WGA), the 

Bureau of Land Management (BLM), and various transmission groups. 

Accomplishments 

•	 Presented “CSP Markets and Policy Impacts” to former Vice President and Nobel Laureate Al 

Gore, January 9, 2008, New York, New York. 

•	 Presented “Utility Scale Solar: Opportunities and Obstacles” to U.S. House Subcommittee on 

Energy and Environment, Committee on Science and Technology, Field Hearing, March 17, 

2008, Tucson, Arizona. 

•	 Presented CSP overview to the Western Interstate Energy Board (WIEB) Committee on Regional 

Electric Power, April 8, 2008, San Diego, California. 

•	 Presented CSP overview to National Association of Regulatory Utility Commissioners (NARUC) 

Summer Annual Meeting special session on Implications of Climate Change Policy for State 

Regulators, July 23-24, 2008, Portland, Oregon. 

Future Direction 

•	 This agreement has been discontinued in fiscal year (FY) 2009; however, stakeholder outreach 

activities will be continued within the FY 2009 market transformation agreements. 

1. Introduction 

The long-term goal of the CSP subprogram is to 

develop CSP systems that produce electricity that 

is competitive with electricity from conventional 

fossil-fuel power technologies in identified 

markets, e.g., intermediate and baseload power. 

Detailed systems analyses have shown that major 

factors contributing to cost reduction include 1) 

technology research and development to improve 

performance and reduce component costs, 2) 

solar plant scale-up to minimize project 

development and operations and maintenance 

costs, and 3) deployment to take advantage of 

volume production and learning. The work 

performed within the southwest stakeholder 

outreach agreement supports outreach efforts 

intended to encourage these last two avenues for 

cost reduction. The outreach efforts rely heavily on 

work funded under the market analysis/grid 

integration, resource assessment, and solar 

advisor support agreements within the CSP 

market transformation activities. 

2. Major FY 2008 Publications 

M. Mehos. “Another Pathway to Large-Scale 

Power Generation: Concentrating Solar Power.” 

MRS Bulletin, Vol. 33 (April 2008). 

Solar Thermal

Concentrating Solar Power

CSP Market Transformation

180
____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

CSP Resource Assessment 

Performing Organization:	 National Renewable Energy Laboratory (NREL) 

Key Technical Contacts:	 Craig Turchi (NREL), 303-384-7565, craig_turchi@nrel.gov 

Dave Renné (NREL), 303-384-7408, david_renne@nrel.gov 

Tom Stoffel (NREL), 303-384-6395, thomas_stoffel@nrel.gov 

DOE HQ Technology Manager:	 Thomas Rueckert, 202-586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budget:	 $650K (NREL) 

Objectives 

•	 Provide high-quality, reliable solar resource information, including information on the long-term 

variability and trend characteristics, that allows policymakers and developers to evaluate the 

potential of concentrating solar power (CSP). 

•	 Identify and qualify solar resource measurement equipment suitable for CSP applications. 

•	 Maintain and expand the ease-of-use of solar resource databases and models. 

Accomplishments 

•	 Released an updated National Solar Radiation Database (NSRDB) that contains a substantial 

increase in the number of stations with hourly direct normal irradiance (DNI) data estimates in 

comparison to those in the previous version. 

•	 Developed Typical Meteorological Year (TMY) data sets relevant for CSP plant operations from 

the updated NSRDB 

•	 Created a Solar Prospector Web tool to allow easy access to satellite-derived solar resource data 

in the United States. 

•	 Performed a preliminary assimilation of several solar resource forecasting methods pertinent to 

CSP operations. 

•	 Developed specifications for solar monitoring stations with a range of performance and costs. 

Compiled requests for measurements sites and selected a subset of 12 sites for FY 2009 

deployment of instrumentation. Cooperative Research and Development Agreements (CRADAs) 

are in process. 

Future Directions 

•	 Deploy ground measurement stations with data collection and processing available from the 

NREL Measurement & Instrumentation Data Center (http://ww.nrel.gov/midc), consistent with the 

applicable CRADA. 

•	 Utilize incoming ground data to validate and refine satellite-based resource models. 

•	 Investigate hourly and day-ahead forecasting methods for DNI. 

•	 Document and disseminate resource information using tools such as Geographic Information 

Systems (GIS) to provide the data to CSP stakeholders in an understandable and easy-to-use 

fashion. 

1. Major FY 2008 Publications 

S. Wilcox; W. Marion. “Users Manual for TMY3 Data 

Sets.” NREL/TP-581-43156. Golden, CO: National 

Renewable Energy Laboratory, 2008. 

www.nrel.gov/docs/fy08osti/43156.pdf. 

D. Renné; R. George; S. Wilcox; T. Stoffel; D. 

Myers; D. Heimiller. “Solar Resource Assessment.” 

NREL/TP-581-42301.Golden, CO: National 

Renewable Energy Laboratory, 2008. 

J. Michalsky; C. Gueymard; P. Kiedron; B. McArthur; 

R. Philipona; T. Stoffel. “Proposed Working 

Standard for the Measurement of Diffuse Horizontal 

Shortwave Irradiance,” J. of Geophysical Research; 

2007; p. 112. 

181 Solar Thermal

Concentrating Solar Power

CSP Market Transformation
____________________________________________________________________________________ 

 

 

 

 

 

 

Market Analysis and Grid Integration 

Performing Organization:	 National Renewable Energy Laboratory (NREL) 

Key Technical Contacts:	 Craig Turchi (NREL), 303-384-7565, craig_turchi@nrel.gov 

Mark Mehos (NREL), 303-384-7458, mark_mehos@nrel.gov 

Nate Blair (NREL), 303-384-7426, nate_blair@nrel.gov 

DOE HQ Technology Manager:	 Tommy Rueckert, 202-586-0942, Thomas.Rueckert@ee.doe.gov 

FY 2008 Budget:	 $535K (NREL) 

Objectives 

•	 Provide support for concentrating solar power (CSP) subprogram analysis efforts relating to 

large-scale implementation of CSP in the southwestern United States. 

•	 Support CSP-specific analysis related to implementation of the systems-driven approach within 

the DOE Solar Energy Technologies Program (SETP). 

•	 Support DOE and Energy Information Administration analysis requests on an as-needed basis. 

Accomplishments 

•	 Adapted the Wind Deployment System Model (WinDS) to include CSP parabolic trough with 

storage. Subsequent addition of other renewable energy models resulted in establishment of a 

more general Regional Energy Deployment System model (ReEDS). 

•	 Used ReEDS for policy impact analysis, such as the 30% Investment Tax Credit, and research 

and development (R&D) impact analysis. Shared results with Al Gore’s Climate Change Solutions 

Summit. 

•	 Participated in and supported regional transmission analysis efforts, including analysis supporting 

the ongoing western wind and solar integration study and the involvement within Western 

Renewable Energy Zone (WREZ) study group. 

•	 Established CSP Market Transformation Project to encompass the growing and diverse factors 

(land access, environmental impact, transmission, grid integration, etc.) affecting CSP market 

penetration. 

Future Directions 

Specific market transformation activities will include: 

•	 Modify ReEDS to include CSP systems without storage to assess advantages of CSP 

configurations with storage (e.g., troughs or towers) versus solar configurations without storage 

(e.g., Dish/Stirling or photovoltaic) 

•	 Continue CSP stakeholder outreach (e.g., staff in state energy, economic, and environment 

offices and utilities) 

•	 Continue to improve and promote tools for Geographic Information Systems (GIS), market 

analysis, and economic impact analysis for use in supporting the activities described above 

•	 Continue providing support of CSP model development in the Solar Advisor Model framework 

•	 Continue and expand work related to market penetration, with a new emphasis on grid integration 

and expansion studies 

•	 Initiate efforts on a Programmatic Environmental Impact Statement (PEIS) for solar energy 

development on southwestern lands administered by the Bureau of Land Management (BLM). 

Solar Thermal

Concentrating Solar Power

CSP Market Transformation

182
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

Solar Advisor Support 

Performing Organization:	 National Renewable Energy Laboratory (NREL) 

Key Technical Contacts:	 Craig Turchi (NREL, Primary Contact), 303-384-7565, 

craig_turchi@nrel.gov 

Nate Blair (NREL), 303-384-7426, nate_blair@nrel.gov 

Mark Mehos (NREL), 303-384-7458, mark_mehos@nrel.gov 

DOE HQ Technology Manager:	 Tommy Rueckert, 202-586-0942, Thomas.Rueckert@ee.doe.gov 

FY 2008 Budget:	 $250K (NREL) 

Objectives 

•	 Maintain and expand the Solar Advisor Model (SAM), which allows calculated energy output, 

energy costs, and cash flows using up-to-date component and system data while enabling 

parametric analysis. 

•	 Utilize SAM for analysis of concentrating solar power (CSP) configurations for a variety of 

applications and locations to identify configurations that predict the lowest levelized cost of 

energy (LCOE). 

•	 Promote SAM use by industry and government to guide research and development (R&D) 

priorities and to provide credible energy production and cost data using a common platform for 

project development, evaluation, and due diligence. 

Accomplishments 

•	 Released SAM 2.0 and Users Guide. Improvements included a generic technology option for 

consistent comparison with conventional fuel-based technologies, a third-party ownership option 

to commercial projects, new workbook and graphing features, and a compressed file format 

(SCIF) that stores only inputs in small files for easier file sharing. 

•	 Implemented dry-cooling capability for CSP systems. 

•	 Added new Solel UVAC3 heat-collection element (HCE) to CSP model library. 

•	 Developed Dish/Stirling performance model (supported by University of Wisconsin subcontract), 

which is currently in beta-testing. 

•	 SAM experienced a significant increase in use by CSP stakeholders (laboratories, industry, 

developers, and investors) in fiscal year (FY) 2008. 

Future Directions 

•	 Continue to expand SAM with added features and improve the speed and ease of use of the 

code. FY 2009 activities will include: 

o	 A major update (Version 3.0) of the code and user manual 

o	 Debugged Dish/Stirling model 

o	 Inclusion of Power Tower model 

o	 Improved Rankine cycle model (applicable to trough and tower system simulations) 

o	 Improved financial optimization algorithm 

•	 Host a SAM users’ workshop to promote use of the software and solicit additional feedback from 

stakeholders. 

183 Solar Thermal

Concentrating Solar Power

CSP Market Transformation
 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

Programmatic Environmental Impact Study 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

DOE Golden Field Office (DOE/GO) 

Key Technical Contacts:	 Doug Dahle (NREL, Primary Contact), 303-384-7513 

Lisa Jorgenson (DOE/GO), 303-275-4906 

DOE HQ Technology Manager:	 Tommy Rueckert, 202-586-0942, Thomas.Rueckert@ee.doe.gov 

FY 2008 Budget:	 $125K (NREL) 

Objectives 

•	 Provide NREL solar technology expertise to support development of Bureau of Land 

Management (BLM)/DOE Solar Programmatic Environmental Impact Statement (PEIS).
 

•	 Support and present at public scoping meetings in six states. 

•	 Provide solar, concentrating solar power and photovoltaic, geographic information system (GIS) 

mapping data for six southwest states (Arizona, California, Colorado, New Mexico, Nevada, and 

Utah). 

Accomplishments 

•	 Launched Solar PEIS Information Center Web site http://solareis.anl.gov – May 2, 2008. 

•	 Developed NREL presentation component for solar PEIS scoping meetings. 

•	 Participated in 11 public scoping meetings on July 10, 2008: 

o	 Riverside, California 

o	 Barstow, California 

o	 Las Vegas, Nevada 

o	 Sacramento, California 

o	 Denver, Colorado 

o	 Phoenix, Arizona 

o	 Salt Lake City, Utah 

o	 Albuquerque, New Mexico 

o	 Tucson, Arizona 

o	 San Luis Obispo, California 

o	 El Centro, California. 

•	 Provided GIS solar data and recommended exclusions for Argonne National Laboratory (ANL) 

development of maps for PEIS alternatives. 

•	 Performed technical review of PEIS Solar Technology Overview appendix. 

•	 Provided consultation and advice for two ANL/BLM/DOE solar project planning meetings. 

•	 Completed preliminary solar CSP and PV resource maps with exclusions for BLM lands in six 

southwestern states – May 23, 2008. 

Future Directions 

In fiscal year (FY) 2009, these are the goals: 

•	 Lead solar power plant site tours for ANL team. 

•	 Provide technical input and review of draft PEIS. 

•	 Conduct GIS analysis and run Regional Energy Deployment System (ReEDS) model for PEIS 

alternatives. 

• Offer technical response to public comments from scoping meetings and draft PEIS (2nd quarter). 

In FY 2010, these are the goals: 

•	 Provide technical input, review, and comments for final PEIS (3rd quarter). 

Solar Thermal

Concentrating Solar Power

CSP Market Transformation

184
 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

SHC Systems Development and Market Development 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL)
 

Solar Rating and Certification Corporation (SRCC)
 

Key Technical Contacts:	 Tim Merrigan (NREL, Primary Contact), 303-384-7349, 

tim_merrigan@nrel.gov 

Greg Kolb (SNL), 505-844-1887, gjkolb@sandia.gov 

DOE HQ Technology Manager:	 Bob Hassett, 202-586-8163, robert.hassett@hq.doe.gov 

FY 2008 Budgets:	 $1,110K (NREL), $100K (SNL), $500K (SRCC) 

Objectives 

•	 Identify the solar thermal systems that can significantly contribute to attaining cost-neutral zeroenergy homes. 

•	 Support field trials and refinement of low-cost solar water heaters in mild climates that reduce the 

levelized cost of energy by at least 50%. (NREL) 

•	 Provide technical support for the emerging U.S. solar water heater market. (SRCC) 

•	 Improve reliability of fielded systems. (SNL) 

Accomplishments 

•	 Supported development of a low-cost, solar water heating system, the second to enter the 

marketplace in FY 2008. The SunCache is a glazed, passive-type, polymer solar water heating 

system that can be purchased at less than half the cost of copper, aluminum, and glass solar 

water heating systems. (NREL) 

•	 Established durability of proposed polymer components, including glazings and connectors. 

(NREL) 

•	 Helped to produce combined photovoltaic (PV)/thermal component models for system simulation. 

(NREL) 

•	 Identified liquid desiccant-based cooling systems as preferred for solar-activated cooling, and 

explored synergies with strong liquid-desiccant as a latent heat storage mechanism. (NREL) 

•	 Created reliability data base of fielded systems. (SNL) 

Future Directions 

•	 Continue development of exemplary low-cost solar water heating systems for zero-energy homes 

in cold climates. (NREL) 

•	 Continue development of combined PV/thermal systems for zero-energy homes that will be costcompetitive with conventional technologies and that can be used for water heating and space 

conditioning as well as electricity production. (NREL) 

•	 Develop tools for assessing and optimizing solar thermal systems addressing major end uses of 

water heating, space heating, and/or space cooling in zero-energy homes. (NREL) 

•	 Develop system design guidelines to improve reliability and availability. (SNL) 

1. Introduction	 supply technologies with energy efficiency 

technologies. 

Solar Heating and Cooling (SHC) is now an 

integral part of the R&D effort to reach the zero- SHC consists of research and technology 

energy buildings goal. In 2008, SHC was development activities for solar water heating 

transferred from the Solar Energy Technologies (SWH) and solar space conditioning systems for 

Program to the Building Technologies (BT) heating, cooling and dehumidification. The 

Program to more effectively integrate SHC energy program works with industry, the national 

185 Solar Thermal

Solar Heating and Lighting Overview
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

laboratories, and others to develop and 

demonstrate systems and components that will 

improve the reliability and reduce the cost of these 

solar systems. To ensure that safe and reliable 

systems are installed, the program also supports 

the testing and certification activities of the Solar 

Rating and Certification Corporation (SRCC). 

One of the primary goals of BT is to have costneutral zero-energy homes (ZEH) in all U.S. 

climate zones by 2020. Although ZEH are readily 

attainable with today’s technologies, the cost is 

prohibitively high and not cost-neutral. The 

transfer of SHC into BT recognizes that solar 

thermal is a critical element of a cost-neutral ZEH. 

To support the ZEH effort, SHC research includes 

the development of active solar systems that costeffectively meet the sensible and latent thermal 

energy loads of ZEH, including water heating and 

space conditioning loads associated with heating, 

cooling and dehumidification. 

Development of low-cost SWH remains as part of 

the SHC R&D effort, because the water-heating 

load is a relatively large percentage of total load 

(especially in ZEH) and is hard to reduce by other 

means. Gas tankless water heaters are becoming 

popular, but they can achieve only ~30% savings. 

Further reductions require SWH, and are 

necessary in going to the 50% savings level and 

beyond. SHC will also continue to support the 

existing SWH industry, which is essential to 

providing the products for ZEH. 

In FY 2008, the expanded SHC effort focused on 

the following activities: 

•	 Low-cost solar water heaters for ZEH 

•	 Combined solar heating, cooling, and water 

heating systems for ZEH 

•	 Solar electric/solar thermal pathways to ZEH 

•	 IEA Solar Heating & Cooling (SH&C) 

Program 

•	 System certification and reliability. 

2. Technical Approach 

Low-cost solar water heaters for ZEH: Simple, 

durable and low-cost solar hot water systems are 

one of the technologies needed to reach the BT 

Program goal of net zero-energy homes by 2020. 

The overall objective of this activity is to develop 

low-cost solar water heaters for ZEH in cold 

climates that will be cost-competitive with 

conventional technologies. Significant advances 

in materials, design, and manufacturability are 

required to lower the cost of solar water heaters, 

improve their performance, and make installation 

easier. For example, for active systems in which 

storage is separate from the collector, storage is a 

major cost component. 

Combined solar heating, cooling and water 

heating systems for ZEH: A combined system 

allows for better overall utilization, multi-use, and 

potentially larger jobs. The objective is to develop 

low-cost combined three-function (“triple play”) 

systems that have high solar fractions. Innovative 

approaches are clearly needed. 

Solar electric/solar thermal pathways to ZEH: 

An average single-family home requires a 4-6 kW 

PV system to provide sufficient on-site renewable 

energy generation. A PV array of this size does 

not typically allow sufficient south-facing roof 

space for any solar thermal collectors that could 

be used to meet a meaningful portion of the 

home’s thermal loads, i.e., space conditioning and 

water heating. Therefore, a ZEH requires a 

combined solar electric/solar thermal system that 

will be cost-competitive with conventional 

technologies and that can be used for water 

heating and space cooling as well as for electricity 

production. 

IEA Solar Heating & Cooling (SH&C) Program: 

Collaboration with the International Energy Agency 

(IEA) SH&C Implementing Agreement provides 

added value, benefit and merit to DOE SHC by 

leveraging its limited resources through taskshared RD&D activities in countries participating in 

IEA. Current and planned activities include solar 

rating and certification, polymeric materials for 

solar thermal applications, solar air-conditioning 

and refrigeration, PV/thermal systems, testing and 

validation of building energy simulation tools, and 

advanced storage concepts for solar thermal 

systems in low energy buildings. 

System certification and reliability: In support of 

the Solar Investment Tax Credit provisions of the 

Energy Policy Act of 2005 requiring SRCC 

certification, in FY 2008 SRCC certified 83 solar 

collectors and 81 solar water heating systems. By 

the end of the fiscal year, there were a total of 252 

SRCC-certified solar collectors from 61 companies 

and 707 SRCC-certified solar water heating 

systems from 29 companies. Annual performance 

summaries for all SRCC-certified systems are now 

available for 100 cities. SRCC also worked with 

the Florida Solar Energy Center to improve solar 

Solar Thermal

Solar Heating and Lighting Overview

186
 

 

 

 

 

 

 

 

collector performance testing operations as well as 

to develop revised accreditation policies for new 

testing laboratories. 

Although SHW systems have been in use for 

many years, very little is documented about their 

long-term reliability. Certifying agencies, like 

SRCC, use laboratory tests from new systems in 

controlled settings, but few tests are conducted for 

long-term performance and reliability. The best 

reliability data come from fielded systems. 

However, installations tend to be geographically 

dispersed and information about performance and 

reliability are collected sporadically. Current and 

planned activities include data collection and 

analysis that ultimately lead to design 

improvements that increase system reliability and 

availability. 

3. Results and Accomplishments 

DOE supported the development of a low-cost, 

solar water heating system, the second one to 

enter the marketplace. The SunCache is a glazed, 

passive-type, polymer solar water heating system 

that costs less than half as much as current 

copper, aluminum, and glass solar water heating 

systems. The SunCache was certified by the 

SRCC in June 2008. 

Researchers also established the durability of 

proposed polymer components, including glazings 

and connectors. 

Program members also helped to produce 

combined PV/thermal component models for 

system simulation. 

SNL launched a study of SHW reliability with more 

than 10 organizations providing input. The study 

will be completed in FY 2009 and 

recommendations to improve long-term system 

reliability and availability will be made to SRCC. 

Finally, program participants identified liquid 

desiccant-based cooling systems as preferred for 

solar-activated cooling. They also explored 

synergies with strong liquid-desiccant as a latent 

heat storage mechanism. 

187 Solar Thermal

Solar Heating and Lighting Overview
Solar Thermal 188

Solar Heating and Lighting Overview
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

Program Management 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Key Technical Contacts: 

Sandia National Laboratories (SNL) 

Sentech Incorporated 

McNeil Technologies 

Roland Hulstrom (NREL), 303-384-6420, roland_hulstrom@nrel.gov 

Charles Hanley (SNL), 505-844-4435, cjhanle@sandia.gov 

Mike Reed (Sentech), 240-223-5509, mreed@sentech.org 

Lumas Kendrick (McNeil), 703-921-1632, lumas@kendrick.com 

DOE HQ Technology Manager: Thomas Rueckert, DOE, 202-586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budgets: $1,813K (NREL), $1,326K (SNL), $1,326K (Sentech), $225K (McNeil) 

Objectives 

•	 Effectively plan, administer, manage, and review the NREL/SNL Solar Program, which includes 

photovoltaics (PV), concentrating solar power (CSP), and solar hot water (SHW) research and 

development. (NREL/SNL) 

•	 Provide technical analysis and support services to the DOE Solar Energy Technologies Program 

(SETP). (Sentech) 

•	 Provide technical support for grid integration activities. (McNeil) 

Accomplishments 

•	 Successfully implemented PV, CSP and SHW science, R&D, and market transformation 

activities, as directed by DOE through the FY 2008 Annual Operating Plan. (NREL/SNL)
 

•	 Organized 2 1⁄2-day CSP roadmap meeting in Albuquerque, New Mexico. (SNL) 

•	 Completed PV installation on the roof of the DOE’s Forrestal Building. (Sentech) 

•	 Completed 2008 Solar Program Technical Risk Analysis Pilot Project. (Sentech) 

•	 Completed Solar America Cities Web site and tracking database. (Sentech) 

•	 Helped develop advanced inverter solicitation development, documentation, and analysis. 

(McNeil) 

Future Directions 

•	 Support SETP management of the overall in both its PV and CSP efforts. (NREL/SNL) 

•	 Plan, administer, manage, and review the Solar Program at the national labs. (NREL/SNL) 

•	 Continue market transformation activities, risk analysis, and CSP/Bureau of Land Management 

support, expanded support for PV and Grid Integration. (Sentech) 

1. Technical Approach 

NREL 

In supporting the management of the overall Solar 

Energy Technologies Program, the activities 

include, but are not limited to,: developing and 

implementing the FY 2008 Annual Operating Plan 

(AOP) for NREL R&D and market transformation 

activities; tracking AOP and Joule milestones and 

performance; analyzing technical activities and 

adjusting course based on results; developing 

multi-year and strategic plans with DOE guidance; 

preparing for and implementing program reviews; 

manage and administer the PV, CSP, and SHW 

programs at NREL; track and manage budgets; 

and prepare information/reports as requested. 

NREL solar activities are managed by Roland 

Hulstrom. 

SNL 

SNL will continue to manage its contributions to all 

of the above-mentioned activities, reports, plans, 

and strategy development. This is all coordinated 

closely with NREL and SETP. The CSP activities 

are managed by Jeffrey Nelson with day-to-day 

management being the responsibility of Thomas 

189 Systems Integration and Coordination
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mancini. The PV activities are managed by 

Charles Hanley. 

Sentech 

Sentech provides technical and analytical support 

to SETP, including systems analysis, GPRA, 

PART, Joule metrics, risk analysis, carbon and 

other environmental benefits, and technical and 

economic review of proposals submitted to the 

Program. Sentech also provides support in 

planning, coordinating, facilitating, documenting 

and reporting on SETP meetings, including peer 

reviews, technical workshops, and annual 

meetings. 

McNeil 

McNeil provides technical support for the 

advanced inverter activities and related balance of 

systems activities; assists in development of 

program planning documents and supporting 

analyses; assists with technical meetings; and 

prepares reports. 

Agreement Title FY 2008 

Budget ($K) 

NREL Program Management 1,813 

SNL Program Management 1,326 

Sentech Technical Support 1,326 

McNeil Grid Integration Support 225 

2. Results and Accomplishments 

NREL 

•	 Supported the DOE-EERE CPS transition to 

the Basic and Applied Research & 

Development Integration (BARDI) business 

management system, utilizing CPS as the 

NREL FY 2008 AOP. 

SNL 

•	 Completed development of FY 2008 Annual 

Operating Plan and assured completion of all 

FY 2008 CPS milestones. 

•	 Provided SETP support to evaluation, 

validation, and analysis activities, as well as 

other general program support, through onsite assignment of Joe Tillerson. 

•	 Contributed to development and execution of 

all appropriate program meetings, such as the 

annual review, the FY 2009 AOP development 

meetings, and other related events. 

Sentech 

•	 Completed and published the SETP MultiYear Program Plan 2008-2012 (April, 2008). 

•	 Supported the planning and installation of a 

PV installation on the roof of DOE’s Forrestal 

Building in September. 

•	 Completed in July the 2008 Solar Program 

Technical Risk Analysis Pilot Project, soliciting 

input from industry, national lab, and 

academia experts for projected improvements 

of PV and CSP technologies resulting from 

DOE program activities. 

•	 Supported the development and design of the 

Solar America Cities Web site and tracking 

database. 

McNeil 

•	 Assisted in the documentation and analysis to 

support implementation of solicitations for 

advanced inverter activities. 

3. Planned FY 2009 Activities 

NREL 

•	 Support SETP management with PV and CSP 

efforts. The activities include: developing and 

implementing the FY 2009 AOP for NREL 

R&D and market transformation activities; 

track AOP and Joule milestones and 

performance; analyzing technical activities and 

adjusting course based on results; developing 

multi-year and strategic plans per DOE 

guidance; preparing for and implementing 

program reviews as required; manage and 

administer the PV and CSP activates; track 

and manage budgets; and prepare 

information/reports as requested. 

SNL 

•	 Participate in all of the above-mentioned 

program management activities, in close 

coordination with NREL and SETP. 

•	 Work with DOE CSP leadership to develop 

strategic and near-term plans consistent to 

support accelerated commercial development 

and deployment of CSP systems. 

•	 Hire new staff in support of expanded R&D 

funding and testing at the NSTTF, as well as 

to meet current and future PV program 

commitments. 

Sentech 

•	 Lead the revision and update of the risk 

analysis process for SETP by addressing 

issues identified in the pilot risk project and 

identifying a new and expanded pool of 

experts to provide input. 

•	 Continue to support CSP activities, including 

CSP funding award evaluations and reviews, 

the coordinated Program Environmental 

Impact Statement (PEIS) development and 

planning for a possible new DOE/BLM 

renewable energy project land lease 

management program. 

•	 Continue to support the Market 

Transformation activities, including Solar 

Systems Integration and Coordination 190
 

 

 

 

 

 

 

America Cities, Solar America Showcase 

review and award selection, workforce 

development, codes and standards, and state 

and utility technical outreach activities. 

•	 Expand its support services to the PV and 

Grid Integration subprograms by supporting 

and participating in technical workshops, 

program planning and analyses, and stagegate reviews. 

•	 Assist SETP in planning and conducting the 

peer review in March 2009. 

4. FY 2008 Special Recognitions and Patents 

Sentech 

•	 K. Lynn, recognized by DOE in appreciation 

for his contribution to rebuilding New Orleans 

with clean energy and efficient technologies 

for its schools, homes, and citizens. 

•	 K. Lynn, received 2008 Transformational 

Energy Action Management Special 

Achievement Award for Technology 

Demonstration, presented by Department of 

Energy Federal Energy Management 

Program. 

5. Major FY 2008 Publications 

NREL/SNL 

• FY 2008 Annual Operating Plan 

Sentech 

•	 Solar Energy Technologies Program MultiYear Program Plan 2008-2012. 

•	 SETP Report to Congress on CSP Water 

Consumption. 

191 Systems Integration and Coordination
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

Equipment and Facilities 

Performing Organizations: Sandia National Laboratories (SNL) 

National Renewable Energy Laboratory (NREL) 

Key Technical Contacts:	 Thomas R. Mancini (SNL), 505-844-8643, trmanci@sandia.gov 

Charles Hanley (SNL), 505-844-4435, cjhanle@sandia.gov 

Cheryl Kennedy (NREL), 303-384-6272, cheryl_kennedy@nrel.gov 

DOE HQ Technology Manager:	 Thomas Rueckert, 202-586-0942, thomas.rueckert@ee.doe.gov 

FY 2008 Budgets:	 $1,424K (SNL), $420.8K* (NREL) *Includes $137.8K in carryover from FY 2007 

Objectives 

•	 Maintain core capabilities within photovoltaic R&D and prepare for characterization challenges 

with new components and systems configurations. (SNL) 

•	 Maintain up-to-date training requirements for staff at the National Solar Thermal Test Facility 

(NSTTF) and implement new training requirements when needed. (SNL) 

•	 Maintain safe operational conditions for the test facilities at the NSTTF. (SNL) 

•	 Bring all electrical equipment operated at the NSTTF into nationally recognized testing laboratory 

(NRTL) compliance per SNL, DOE, and Occupational Safety and Health Administration (OSHA). 

(SNL) 

•	 Rebuild and upgrade optical measurement and accelerated exposure testing (AET) capabilities 

and maintain preeminence as the world leader in mirror durability testing. (NREL) 

Accomplishments 

•	 Achieved NRTL compliance for about 75% of the NSTTF site. (SNL) 

•	 Procured, as planned, new PV equipment. (SNL) 

•	 Developed draft 5-year PV equipment recapitalization plan, which was submitted to DOE. (SNL) 

•	 Procured and installed new concentrating solar power (CSP) optical and AET equipment. (NREL) 

Future Directions 

•	 Begin major upgrades in facilities at the NSTTF in FY 2009. (SNL) 

•	 Complete NRTL compliance for Central Receiver Test Facility (CRTF) heliostat field and a few 

other outstanding pieces of equipment. (SNL) 

•	 Expand recapitalization plan from equipment to cover facilities, assuring preparedness for
 

upcoming R&D opportunities and challenges. (SNL)
 

•	 Continue to replace aging and largely unserviceable equipment. (SNL and NREL) 

1. Results and Accomplishments	 challenges. The Solar Energy Grid Integration 

Equipment and Facilities FY 2008 

Budget ($K) 

PV Capital Equipment (SNL) 360 

CSP Facilities Operation (SNL) 1,064 

CSP Capital Equipment (NREL) 420.8 

Total 1,844.8 

Systems (SEGIS) activities will need a set of 

hardware deliverables that will require new 

infrastructure to conduct developmental and 

evaluative testing. In the laboratory, we have 

dramatically increased our capability to conduct 

parallel module, array, and systems 

characterizations through the acquisition of new 

outdoor monitoring systems. 1.1 PV Capital Equipment (SNL) 

Capital equipment funds were well utilized in the In one area, rather than purchase a new tracker to procurement and installation of equipment conduct high-accuracy characterizations of 

necessary, as we prepare for upcoming R&D concentrating PV systems (another growing 

Systems Integration and Coordination 192
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

need/challenge), we acquired an unused tracker 

from a local PV manufacturer and spent 

considerably less on its install and refurbishment 

than a new tracker would have cost. This tracker is 

installed and being fitted for full operation. 

Additional purchases are described below: 

UV-Visible-IR Optical Spectrophotometer 

The Cary 5000 spectrophotometer and diffuse 

reflectance accessory was purchased as a 

replacement unit for an outdated Cary 5 that no 

longer operated up to the specifications of the 

instrument and was no longer supported by the 

manufacturer. The new instrument was upgraded 

to produce more accuracy in measurements as a 

result of electrically cooled photodetectors. 

Outdoor Performance Characterization System 

These systems are needed to collect performance 

data from modules tested on the trackers. This 

addition will upgrade and expand outdoor 

performance characterization capabilities. The 

data acquisition equipment supports modeling, 

reliability, and test and evaluation activities. 

Inverter R&D Validation DC Power Source 

The addition of a 20-kW PV power supply has 

enabled SNL’s Distributed Energy Technologies 

Laboratory (DETL) to analyze the effectiveness of 

the MPPT algorithms of commercial and 

developmental PV inverters and report the findings 

to researchers and engineers working on 

improving the reliability and performance of their 

SAI and other products. 

AC/DC Calibration Standards 

The voltage and current standards enable the 

DETL to conduct end-to-end AC and DC 

calibrations on all of data acquisition systems. The 

calibration procedure is needed when conducting 

assessment on the performance of developmental 

hardware associated with industry support. 

1.2 CSP Capital Equipment & Facilities (SNL) 

NSTTF – TRAINING 

The NSTTF is devoted to the development and 

test of next-generation CSP systems. The NSTTF 

was built in the late 1970s on 117 acres and 

comprises an 8-acre heliostat field and power 

tower, molten-salt test loop, rotating platform for 

solar thermal testing of trough concentrators, 16­

kW solar furnace, facilities for dish engine testing, 

engine test facility, and numerous buildings and 

specialized test equipment. 

This activity involves all of the training 

requirements at the NSTTF. Recurring training 

includes: hazardous waste and environmental 

management, lockout/tagout, first aid, respiratory 

protection, R&D electrical safety training, safe 

operations of hand trucks and pallet jacks, forklift 

training, fall prevention, rigging, hoisting 

evacuation team, metal working liquids and 

lubricants, chemical carcinogens, compressed 

gases, adhesives, corrosives, asbestos, laser 

safety, and laboratory standards. 

NSTTF – Basic Operations 

Ongoing activities at the NSTTF include safety 

and readiness testing and inspection associated 

with the following: chemical safety, confined 

spaces, cranes and rigging, electrical safety, 

environmental regulations, environmental 

management, evacuation, fire protection, 

hazardous waste, hoisting and rigging, lasers, 

local exhaust ventilation, lockout/tagout, machine 

shops, respiratory and hearing protection, 

compliance reviews, corporate stand-downs, and 

property inventory. General activities include: 

maintain OUO, site security, safety, monitor site 

access, coordinate maintenance and deliveries 

SNL security, computer security, Foreign Corrupt 

Practices Act, counterintelligence, EEO/AA, ethics, 

drug free workplace, OUO, export control, 

property, diversity, annual review of site security 

plan, SNL satellite badge office, process foreign 

national requests, coordinate tours, and process 

out-of-hours access. 

NSTTF – NRTL Certification 

All facilities must be certified NRTL compliant. 

Much of the equipment installed at the NSTTF is 

one-of-a-kind or built specifically to meet a 

particular test requirement. Consequently, a large 

part of test and operations equipment has never 

been tested or certified by a Nationally 

Recognized Testing Laboratory. In order to bring 

equipment into compliance, SNL has staff who are 

trained to inspect equipment and determine the 

appropriate actions to be taken to bring it into 

compliance. For equipment that is modified for 

operation, we have it reinspected and certified as 

NRTL compliant. 

Throughout the initial evaluation phase, which 

started in FY 2007, over 500 items were inspected 

and identified as non-NRTL compliant. The only 

remaining items that need to be inspected and 

certified are associated with on-going controls 

upgrades in the CRTF heliostat field. 

193 Systems Integration and Coordination
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.3 CSP Capital Equipment & Facilities (NREL) 

Historically, the accelerated exposure chambers 

used to test the long-term durability of solar 

mirrors and glazing materials have been primarily 

an Atlas Ci65 (Ci65) WeatherOmeter (WOM) and 

an Atlas Ci5000 WOM (Ci5000). The Ci65 and 

Ci5000 WOMs were purchased in 1995 and 1998; 

the Ci65 is no longer manufactured nor supported 

by Atlas. If new capital equipment was not 

purchased, NREL could lose its preeminence and 

the U.S. mirror and solar industry could lose a 

valuable resource costing them market share. 

In the FY 2008 budget, $283k was allocated, 

specifically $61K for a reflectometer, $87K for a 

spectrophotometer, and $135k for a WOM (#2). A 

major expected accomplishment of this project 

included upgrading the optical measurement and 

AET capabilities. 

A new Perkin-Elmer Lambda 1050 UV-VIS-NIR 

dual beam spectrophotometer with 150-mm 

integrating-sphere and universal reflectance 

accessory (URA) attachments was purchased to 

measure the hemispherical reflectance, 

transmittance, and absorptance of samples. The 

150-mm integrating sphere attachment is able to 

measure relative reflectivity with higher resolution, 

better accuracy, and faster speed than the 

Lambda 9 and 900. 

Surface Optics Corporation (SOC) hand-held 

directional hemispherical reflectance (DHR) 

reflectometer was purchased to replace/upgrade 

the +20-yr-old D&S 15R to measure specular 

reflectance of solar mirrors and with the purchase 

of a second head, the emittance of solar selective 

coatings. A second head was purchased to 

measure absorption and emittance of solar 

selective coatings. In addition, two remote control 

accessories were purchased to measure the 

samples on a lab bench. The SOC instruments 

were delivered and installed Aug 08. 

The conversion of FY 2007 Other Direct Cost 

(ODC) funds to capital equipment funds was 

requested for the purchase of a new CSP Ci5000 

WOM, which was purchased in FY 2007 and 

delivered and installed in FY 2008 to replace the 

SH Ci5000 exposure space. When installed, this 

Ci5000 WOM#1 was at its 350-sample capacity. 

A large factory refurbished BlueM FRS humidity 

test chambers was purchased in FY 2007 (factory 

refurbished $8.5k; new >$45k) and installed in FY 

2008 to operate at 85oC /85% RH/dark. The BlueM 

FRS test chamber is much larger than the bench 

ovens and runs in the dark with no solar 

irradiation. 

Glass mirrors sold for outdoor applications have 

not passed the minimum ASTM standard tests 

required for glass mirrors to qualify for indoor 

applications. NREL did not have the capability to 

perform these ASTM tests. NREL purchased a 

corrosion test chamber to allow glass mirrors to be 

qualified in short periods of time (i.e., 120 or 480 

h) before performing the long-term durability 

testing of the materials in the WOM. The list price 

of the upgraded BCX2000 would normally cost 

$27,674, after the Atlas promotion, the cost was 

$12,582. The BCX was ordered in FY 2007, 

delivered in FY 2008, and installed in FY 2009. 

A second CSP Ci5000 was ordered in June and 

delivered in October. It replaces the unserviceable 

Ci65 WOM, This installation is awaiting 

subcontract quotes. In July, an additional, $152.2k 

of FY08 ODC money was requested to be 

converted from operating to capital to purchase a 

third Ci5000 WOM with extended temperature 

capability. With the extended temperature option, 

a refrigeration unit extends the temperature range 

for the standard Ci5000 WOM from 40°C —120°C 

to -10°C —120°C (with light). It is scheduled for 

delivery on Feb. 3, 2009. 

A Tenney T10RS1 ($28k) was ordered in August 

and delivered in November 2008 to operate at 

85oC cycling to -40oC /85%RH/dark. The chamber 

will systematically cycle the temperature and/or 

relative humidity exposure conditions for thin glass 

and front surface reflector samples. The 

installation is awaiting subcontract quotes. 

2. Planned FY 2009 Activities 

2.1 PV Capital Equipment (SNL) 

SNL has received no FY 2009 budget for capital 

equipment; thus, we have no planned activities. 

We will be updating our 5-year strategic capital 

and facility recapitalization plan and will be 

submitting this to DOE. 

2.2 CSP Facilities Operation (SNL) 

NSTTF Basic Operations 

•	 Molten-salt facilities for testing valves, 

instrumentation, flex hoses, freeze/thaw, etc. It 

is yet to be determined what types of pumps 

are to be tested. An industry meeting is 

planned to pursue this. 

Systems Integration and Coordination 194
 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Upgrade instrumentation and controls at 

engine test facility. 

•	 Laboratory test equipment – oscilloscopes, 

power meters, etc. 

•	 Complete refurbishment of the heliostat 

control system. 

•	 Bring in temporary office space (portable 

building) for expanding visitors needs. 

•	 Pull fiber optic communications to 9981. 

•	 Install digital phone capability at NSTTF. 

•	 Clean up/remodel office space. 

NRTL Certification 

•	 Complete the heliostat field upgrades and 

inspect and certify modifications. 

•	 Address non-NRTL issues associated with the 

solar furnace heliostat and the large area ATS 

heliostat. 

2.3 CSP Capital Equipment (NREL) 

The installation of the equipment ordered in FY 

2008 should be complete, specifically the CSP 

Ci5000#2, Ci5000#3, and Tenney. We plan to 

purchase a 4th CSP Ci5000 WOM to test the CSP 

subcontract materials samples and with different 

weathering protocols. We also expect to purchase 

a new solar simulator to replace the solar 

simulator that reached the end of its serviceable 

lifetime in FY 2006. The solar simulator will be 

used to test the FOA subcontract materials using 

the service lifetime methodology and with different 

weathering protocols. A new Mocon oxygen 

permeation instrument will be purchased to rapidly 

screen oxygen permeation barrier properties of 

hardcoats, front surface mirrors, and back 

coatings. In addition, two subcontracts are 

planned to upgrade the current database of optical 

materials containing more than 1,000 experiments, 

20,000 samples, and 300,000 measurements and 

to develop a laboratory instrument capable of 

measuring specular reflectance at a 2-mrad cone 

angle or less accurately and repeatedly at different 

wavelengths on a curved substrate. 

195 Systems Integration and Coordination
 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

Communications 

Performing Organization:	 National Renewable Energy Laboratory 

Key Technical Contacts:	 Ruby Nahan (NREL, Primary Contact), 303-384-7401, 

ruby_nahan@nrel.gov 

Linh Truong (NREL), 303-384-6624, linh_truong@nrel.gov 

DOE HQ Technology Manager:	 Thomas Rueckert, 202-586-0942, thomas.rueckert.ee.doe.gov 

FY 2008 Budget:	 $790.8K (NREL) 

Objectives 

•	 Provide communications strategy, execution, production, and evaluation to meet the core 

communications needs of the Solar Energy Technologies Program (SETP) and its Market
 

Transformation activities.
 

Accomplishments 

•	 Maintained and updated SETP Web site (approximately 300 pages and 650 files), making 

changes to better reflect the current activities of the program. 

•	 Produced 12 new documents, including the FY 2007 SETP Annual Report, and contributed to 

programmatic documents, such as the quarterly newsletter. 

•	 Represented the program at the National League of Cities, International Builders’ Show (IBS), 

American Solar Energy Society’s Solar 2008 conference, National Association of Homebuilder’s 

Greenbuilding conference, Pacific Coast Builders conference, and completed all preparations for 

Solar Electric Power Association’s Solar Power International conference. 

•	 Conducted strategic communications planning with Market Transformation team. 

•	 Consulted with program partners and subcontractors on strategy and specific communications 

products. 

Future Directions 

•	 Conduct further strategic planning to ensure the communications tactics meet the most current 

and essential needs of the program. 

•	 Make significant changes to the Web site to better meet the needs of program partners and 

industry. 

•	 Evaluate efficacy of and make changes to exhibiting activities to ensure they are meeting current 

needs of the program. 

•	 Support Market Transformation to ensure that critical information about these activities is 

captured and available for its stakeholders, so that they can better emulate these activities within 

their own sphere of influence. 

•	 Enhance support to Concentrating Solar Power subprogram: target CSP-specific conferences, 

develop new exhibit, and outreach materials. 

1. Introduction	 • Exhibit planning, design, and staffing 

•	 Web site development and maintenance 

We provide comprehensive communications • Communications consulting for partners who 

services to SETP. These services include: do not have expertise available. 

•	 Strategic planning to ensure specific activities 

are necessary and are conducted in the most 

cost-effective and efficient way possible 

•	 Writing, designing, and producing print 

products for programmatic, technical, and 

outreach audiences 

Agreement Title FY 2008 

Budget ($K) 

Core Program Communications 578.8 

Market Transformation 

Communications 

212 

Systems Integration and Coordination 196
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2. Results and Accomplishments	 and outreach tactics for each report, and we 

•	 Conducted a 2-day strategic communications 

planning meeting for Market Transformation 

projects to identify communications goals, 

target audiences, key messages, and specific 

tactics. We provided a list of tactics to DOE to 

prioritize and assign for completion. 

•	 Produced FY 2007 SETP Annual Report, 

coordinating individual reports on all SETP 

activities. We edited, produced, printed, and 

distributed the report. 

•	 Promoted the benefits of incorporating solar in 

new home construction at IBS. SETP 

exhibited along with other federal agencies in 

a larger pavilion, entitled "Ask the Experts." 

With nearly 100,000 IBS attendees, the 

pavilion garnered 600 leads from attendees 

interested in energy efficiency and solar. 

Three new publications were produced for the 

builder audience. For the Greenbuilding 

conference, we incorporated lessons learned 

from IBS and developed a new, single 

publication for builders, which is one of the 

most popular PDFs on the Web. 

•	 Developed a completely new presence for the 

program at Solar Power International, 

including tagline, exhibit, and four fact sheets. 

•	 Responded to ~150 Webmaster inquiries from 

a wide range of users and developed a 

comprehensive maintenance plan to ensure 

every page of the EERE solar Web site is 

updated regularly. Ongoing posting requests 

such as funding announcements and activity 

prospectus were met throughout the year. 

•	 Expanded CSP content to better represent the 

program activities. 

•	 Developed an on-line repository for solar 

images for use by the program, labs, 

subcontractors, and partners. Using a free 

software tool (Google Picasa), we created a 

folder structure and populated them with PV, 

BIPV, and CSP photos with captions. 

•	 Supported Solar America Cities and Solar 

America Showcases in a variety of ways. We 

updated and produced multiple publications 

for the funding announcement for 12 new 

cities. We also updated Web content, timed to 

go live with the Secretary’s announcement of 

the cities. We developed publications to assist 

cities in understanding the technical 

assistance process. 

•	 Provided communications consulting to the 

Solar America Board for Codes and 

Standards. We work to identify key audiences 

helped to develop one-page overviews for 

outreach activities. 

3. Major FY 2008 Products 

Web site: www.solar.energy.gov 

DOE Solar Photo Gallery: 

www.picasaweb.google.com/solargallery 

Publications: 

•	 “A Homebuilders Guide to Going Solar” 

www.solar.energy.gov/pdfs/43076.pdf 

•	 “Furthering Energy Security,” NREL Report 

No. FS-840-42780; DOE/GO-102008-2560, 

(2008). www.nrel.gov/docs/fy08osti/42780.pdf 

•	 “Making Cents Out of Solar: Put More Power 

into Your Building Plans,” NREL Report No. 

BR-840-42731; DOE/GO-102008-2553, 

(2008). 

www.solar.energy.gov/pdfs/making_cents.pdf 

•	 “Planning for PV: The Value and Cost of Solar 

Electricity,” NREL Report No. FS-840-42733; 

DOE/GO-102008-2555,(2008) . 

www.solar.energy.gov/pdfs/planning_for_pv.pdf 

•	 “Solar America Showcases,” NREL Report No. 

FS-520-42654; DOE/GO-102008-2547, 

(2008). www.nrel.gov/docs/gen/fy08/42654.pdf 

•	 “Solar America City - San Diego, California,” 

NREL Report No. FS-840-43097; DOE/GO102008-2603, (2008). 

www.nrel.gov/docs/fy08osti/43097.pdf 

•	 “Solar Energy Technologies Program 

Concentrating Solar Power,” NREL Report No. 

FS-840-43685; DOE/GO-102008-2649, 

(2008). www.solar.energy.gov/pdfs/43685.pdf 

•	 “Solar Energy Technologies Program Grid 

Integration,” NREL Report No. FS-840-43682; 

DOE/GO-102008-2646, (2008). 

www.solar.energy.gov/pdfs/43682.pdf 

•	 “Solar Energy Technologies Program Market 

Transformation,” NREL Report No. FS-840-

43683; DOE/GO-102008-2647, (2008). 

www.solar.energy.gov/pdfs/43683.pdf 

•	 “Solar Energy Technologies Program 

Photovoltaics,” NREL Report No. FS-840-

43684; DOE/GO-102008-2648, (2008). 

www.solar.energy.gov/pdfs/43684.pdf 

•	 “Solar Successes: The Best of Today's Energy 

Efficient Homes,” NREL Report No. FS-840-

42732; DOE/GO-102008-2554, (2008). 

www.solar.energy.gov/pdfs/solar_success.pdf 

197 Systems Integration and Coordination
 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

International Activities 

Performing Organizations: National Renewable Energy Laboratory (NREL) 

Sandia National Laboratories (SNL) 

Key Technical Contacts:	 Ruby Nahan (NREL), 303-384-7401, ruby_nahan@nrel.gov 

Tom Mancini (SNL), 505-844-8643, trmanci@sandia.gov 

DOE HQ Technology Manager:	 Kathleen Bolcar, 202-586-2820, kathleen.bolcar@hq.doe.gov 

FY 2008 Budgets:	 $125K (NREL), $25K (SNL) 

Objectives 

International Energy Agency (IEA) Photovoltaic Power Systems (PVPS) Programme 

•	 Act as operating agent for Task 10, Urban Scale PV Applications. 

•	 Represent U.S. in Task 1, Exchange and Dissemination of Information on PVPS. 

•	 Organize or participate in meetings and workshops and submit deliverables as required by the 

membership agreement. 

IEA Concentrating Solar Power (CSP) Solar Power and Chemical Energy Systems (SolarPACES) 

•	 Provide operating agent for implementing agreement (IA). 

•	 Coordinate activities of Task 1 CSP Electric Power Systems. 

•	 Organize and chair two meetings. 

Accomplishments 

PVPS Programme 

•	 Produced the U.S. content for the 2007 IEA PVPS Annual Report and the 2007 National Survey 

Report of PV Power Applications in the United States. (Task 1) 

•	 Represented the United States at the Task 1 Annual Meeting in Nice, France. (Task 1) 

•	 Represented the United States at the technical experts meeting in Kedah, Malaysia and the 

Executive Committee meeting (ExCo) and operating agents meeting in Oslo, Norway. (Task 10) 

CSP SolarPACES 

•	 Completed and submitted annual report. 

•	 Organized and held the 2008 SolarPACES CSP Symposium in Las Vegas, Nevada, with 450 

attendees and more than 130 technical papers presented. 

Future Directions 

•	 Complete 2008 IEA PVPS Annual Report and 2008 National Survey Report (Task 1). 

•	 Improve IEA PVPS Web site (Task 1). 

•	 Disseminate information, such as Annual Report, National Survey Report, and PV Power
 

Newsletter to U.S. audiences. (Task 1)
 

•	 Coordinate U.S. participation by organizing, leading, and attending technical experts meetings; 

developing status reports and presentations for ExCo meetings; and attending the ExCo 

meetings and IEA PVPS Operating Agents meetings. (Task 10) 

•	 Review Implementing Agreement Charter and determine how to incorporate industry formally into 

task activities. (SolarPACES) 

1. Major FY 2008 Publications	 L. Poole; P. Maycock; W. Bower. National 

Survey Report of PV Power Applications in the 

Annual Report 2007, International Energy United States 2007, International Energy 

Agency PV Power Systems, April 2008. Agency Cooperative Programme on 

Photovoltaic Power Systems, June 2008. 

IEA Solar Power and Chemical Energy Systems, 

Annual Report, 2007. 

Systems Integration and Coordination 198
 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

 

 

EERE Crosscutting Activities 

Performing Organizations:	 U.S. Department of Energy (DOE) Office of Energy Efficiency and 

Renewable Energy (EERE) Programs 

Key Technical Contact:	 Thomas Rueckert, 202-586-0942, thomas.rueckert@ee.doe.gov 

DOE HQ Technology Manager:	 Daniel Birns, DOE, 202-586-8767, daniel.birns@ee.doe.gov 

FY 2008 Budgets:	 $5,967K (EERE), $1,548K (Congressional Rescission) 

Objectives 

•	 Provide funds for Office of Energy Efficiency and Renewable Energy (EERE)-wide projects that 

cut across multiple technologies and are best funded and managed at the EERE level. 

•	 Adhere to Congressional rescission, which are appropriated funds that are returned to Congress. 

Accomplishments 

•	 Completed photovoltaic (PV) panel installation on the DOE Forrestal building. 

•	 Supported Greensburg (www.greensburggreentown.org/) and New Orleans Rebuild Projects. 

•	 Supported Hawaii Clean Energy Project (www.eere-pmc.energy.gov/Hawaii.aspx). 

Future Directions 

•	 Continue to support Hawaii Clean Energy Initiative. 

•	 Develop bi-lateral agreement with Israel. 

•	 Provide EERE with analytic support to selected projects, as needed 

1. Project Summary 

These funds are managed by EERE, primarily by 

the technology managers in the Office of Planning, 

Budget, and Analysis. These projects range from 

technology specific (e.g. Forrestal PV System) to 

crosscutting efforts (e.g. Hawaii Clean Energy 

Project). Funding allocations are based on the 

relevance of a project to a given technology area. 

These funding allocations do not require a special 

request to Congress, as they relate to the goals of 

each program area within EERE. 

The following organizations performed the tasks 

listed below: National Renewable Energy 

Laboratory (NREL), Oak Ridge National 

Laboratory (ORNL), TMS, Sentech, Sandia 

National Laboratories (SNL), Energetics, and 

others that will be determined at a later time. 

Agreement Title Performer 

Budget 

($K) 

Forrestal PV System DOE HQ 2,059 

Tech Communications NREL/ORNL 744 

Climate Change Analysis NREL 302 

China EE Buildings Various 270 

ORBS – Science on Sphere NREL 243 

Hawaii Clean Energy Various 222 

Deloitte EE-20 Support TMS 198 

Innovation Study NREL 175 

Sentech Technical Services Sentech 167 

Greensburg Rebuild NREL 159 

New Orleans Rebuild NREL 150 

Sentech Support Services Sentech 149 

Entrepreneur in Residence Various 105 

Advanced Buildings in India Various 100 

DCA Audit DCAA 96 

TAO & Commercialization TMS 95 

Department of Defense 

(DOD)/DOE Partnership NREL 87 

Tech Communications Sandia 82 

American Assoc. for the 

Adv. of Science Fellows ORISE 78 

Greening the Parks NPS 77 

Info and Know - DSIRE NC 57 

Support Services Various 46 

Remain Corp Priority TBD 40 

EERE-Asia Solar Decathlon NREL 40 

SBIR Review Energetics 40 

DOD National Defense Infra TBD 40 

199 Systems Integration and Coordination
NREL Tech Trans NREL 35 

CA Clean Tech CA 28 

NREM Conference CFRS 25 

Greenpower TBD 25 

Morocco Collaboration TBD 24 

New Energy Finance DOE HQ 11 

Systems Integration and Coordination 200
 

____________________________________________________________________________________ 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

Small Business Innovation Research 

Performing Organization: DOE HQ Solar Energy Technologies Program 

DOE HQ Technology Manager: Alec Bulawka, 202-586-5633, alec.bulawka@ee.doe.gov 

FY 2008 Budget: $3,450K 

Objectives 

•	 Support small business energy research and development (R&D). 

•	 Implement Executive Order 13329, which involves assisting the private sector in manufacturing 

innovation. 

•	 Continue to pursue wise cost/benefit investments. 

•	 Augment the core research of the U.S. Department of Energy (DOE) Solar Program. 

•	 Effectively support the Solar America Initiative (SAI). 

Accomplishments 

•	 Produced films of aluminum ink on a silicon substrate. 

•	 Successfully developed holographic optical elements solar application. 

•	 Developed a new photovoltaic (PV) concentrator configuration based on novel reflective lens 

concept and ring-array concentrator design for flat plate. 

•	 Developed a PV manufacturing diagnostics system capable of analyzing structured surfaces. 

•	 Developed a new method for the synthesis of fullerene derivatives. 

•	 Optimized the reflective performance of gold materials applied to glass in solar mirrors. 

•	 Successfully developed and optimized the flexible sol-gel hybrid matrix (nanocomposite adhesive 

system with excellent optical properties, durability and flexibility). 

•	 Achieved targeted level of printed CIGS AM1.5g power conversion efficiency constructed on a 

flexible foil substrate (vs. glass-based), supporting the enablement of grid-parity solar energy. 

Future Directions 

•	 Improve ink formulations and processing methods to lower the resistivity and improve adhesion. 

•	 Evaluate crucibles and coatings for production of the highest quality feedstocks. 

•	 Build and evaluate a true-scale prototype of the Ring-Array Concentrator PV module for the 

subsequent product development and commercialization. 

•	 Develop a thin-film analysis algorithm and validate and test the developed PV manufacturing 

diagnostics system. 

•	 Develop software to support production grade Resonance Ultrasonic Vibration (RUV) system 

prototype and test at industrial environment. 

•	 Correlate experimental and quantum chemical results to establish predictive pathways for
 

fullerene derivatives optimization and novel device fabrication.
 

•	 Continue optimizing surface functionalization methods for glass to create homogeneous coating 

layers for dielectric mirror fabrication (to improve solar thermal conversion efficiency in collectors). 

1. Introduction	 Program has contributed $18 million and received 

$41 million in research funding. 

Each year, ten federal departments and agencies, 

including DOE, are required by the Small Business As in the past, the Solar Program has also 

Innovation Research (SBIR) Program to reserve a benefited to a large extent this past year from the 

portion of their R&D funds for award to small, Office of Basic Energy Sciences contribution, 

U.S.-owned businesses. Over the life of the SBIR again mostly in nanotechnology topics for PV in 

Program, the DOE Solar Energy Technologies 2007. The 2008 Solar Program is nested mainly 

in the Solar Energy (Topic 23) SBIR category. 

201 Systems Integration and Coordination
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Once again the SBIR activities complements the 

DOE Solar Program Multi-Year Technical Plan 

because they continue to augment and support 

the core program, in all respects, with integrated 

solutions from the vast U.S. small business 

community. The community continues to 

participate actively in the Solar America Initiative 

(SAI) through carefully selected and tailored 

supportive solicitations. 

2. Technical Approach 

Renewable energy technologies have achieved 

significant advances in recent years, but further 

improvements are needed if they are to reach their 

full potential. The solar technologies included in 

the scope of this SBIR work address both solar 

electric, PV, and concentrating solar power (CSP) 

systems. Grant applications for FY 2008 were 

required to clearly demonstrate the applicants’ 

ability to proceed to hardware development 

fabrication, testing, and manufacture of 

technologies. 

3. Results and Accomplishments 

Several SBIR awards advanced their goals and 

produced very encouraging results of their R&D to 

date. (See table below) 

4. Planned FY 2009 Activities 

Further development of PV and CSP systems, as 

well as systems integration, will be addressed 

through creative and innovative approaches in 

engineering and design, new materials, and new 

processes. A concerted effort has been made to 

have the SBIR activity, once again, dovetail in 

support of the SAI. 

4.1 PV Devices with Reduced Silicon Intensity – 

The growth of the semiconductor and solar 

industries has put increasing pressure on limited 

supplies of high-quality silicon, thus driving up the 

price of the material by up to 200% to 800%. 

Development is underway for a number of 

processes aimed at reducing the use of silicon (Si) 

material. Kerfless wafering, epitaxial growth, direct 

solidification, and recrystallization are all thin 

crystalline silicon processes that promise Si 

intensity well below 3g/W with cells above 15% 

efficiency. 

4.2 High Efficiency Organic (OPV) or Sensitized 

Photovoltaic Cells – Lightweight and flexible 

conjugated polymer-based solar cells currently 

suffer from low efficiency. Nonetheless such cells 

represent a highly promising area of low cost PV 

technology, offering greatly increased functionality 

and potential to meet future challenges of 

scalability, flexibility, integration and cost. A more 

effective utilization of the incident solar spectrum 

(beyond the current wavelength limitation) and into 

the near infra-red could provide significant 

improvement in OPV performance. 

4.3 Advanced Concentrating Systems – Recent 

progress in high efficiency multijunction cells has 

fostered considerable interest in concentrating PV. 

The majority of efforts in this area involve 

traditional, non-imaging high-concentration (100-

1000X) optics and square cells approximately 

1cm2 in area. Although many companies are 

beginning to mass produce such concentrating 

systems, their designs suffer from inherent 

limitations: (1) the requirement for conventional 2-

axis tracking, which increases cost and reduces 

field packing density; and (2) the significant 

material requirements (i.e., for framing, support, 

etc.), which adds cost, complicates manufacture, 

and creates reliability concerns. Innovative 

concentrating solutions that overcome either of 

these limitations are of pertinent interest. 

For utility-scale solar thermal power generation, 

system capital cost reductions and improved 

dispatchability are necessary to increase the 

market penetration of CSP. In particular, 

advancements are needed for solar-collection-field 

cost reduction, low cost, high-performance thermal 

energy storage (TES) and high-temperature, highheat-capacity heat transfer fluids (HTF). 

4.4 Device Manufacturing, Packaging and 

Assembly – There is room for improvement in the 

area of module packaging and assembly. Areas of 

interest include (1) module technologies – such as 

low-cost, flexible encapsulants, light trapping 

layers, advanced contacts, and advanced 

transparent conductors, which offer increased 

performance/reliability or reduced costs broadly 

across the PV industry; (2) building-integrated 

module designs, optimized system configurations, 

and innovative deployment options, which offer 

dramatically lower installation and maintenance 

costs than conventional approaches; and (3) 

approaches to improve the lifetime of photovoltaic 

systems (such as thermal management, material 

compatibility, and other systems impacted by the 

physical environment) and components (such as 

inverters, sensors, connectors, capacitors, surge 

protection, integrated circuits, and input/output 

Systems Integration and Coordination 202
 

 

 

 

 

 

 

 

 

 

 

ports) subject to electrical noise, mechanical 5. Major FY 2008 Publications 

abuse, and the like. Also, sensor and control 

technologies are needed to ensure that newly The SBIR Program holds the awardee responsible 

emerging PV systems (with improved for a final report at the end of both Phase 1 and 

performance/reliability) can be manufactured to Phase 2. The SBIR Office in Germantown, 

quality standards. Maryland, has on file the final reports of all the 

projects awarded in the past. 

6. University and Industry Partners 

The following organizations partnered in the project’s research activities during FY 2008. 

Organization/ 

Principal Investigator Location/E-mail Description/Title of Research Activity FY 2008 ($K) 

Applied Nanotech. Inc. 

Dr. Max Roundhill 

Austin, TX 

mroundhill@appliednanotech. 

net 

Solar energy materials solutions for 

cells and modules 100* 

Luminit, LLC 

Dr. Kevin Yu 

Torrance, CA 

kyu@luminitco.com 

Multifunctional UV curable Sol-Ge 100* 

Spire Corporation 

Dr. William R. Neal 

Bedford, MA 

wrneal@spirecorp.com 

Microcrack Detection in Crystalline 

Silicon Solar Cells 99.7* 

Crystal Systems, Inc. 

Dr. David Bruce Joyce 

Salem, MA 

djoyce@crystalsystems.com 

Material Utilization and Waste 

Reduction through Kerf Recycling 98.3* 

Sky Train Corporation 

Mr. Karl William Palm Harbor, FL 

kguenther@skytraincorp.com 

Energy Exchanger For a Solar-Powered 

Monorail/Light Rail 100* 

Luminit, LLC 

Mr. Kevin Yu Torrance, CA 

kyu@luminitco.com 

Flexible Spectrum Splitting Holographic 

Concentrator 750** 

SVV Technology 

Innovations, Inc. 

Dr. Sergiy Vasylyev 

McClellan, CA 

vasilyev@svvti.com High Performance PV Concentrator 750** 

Luna Innovations 

Incorporated 

Dr. Vladimir Kochergin 

Roanoke, VA 

submissions@lunainnovations. 

com 

High-Throughput In-Line PV 

Manufacturing Diagnostic System 750** 

Ultrasonic 

Technologies, Inc. 

Dr. Sergei Ostapenko 

Wesley Chapel, FL 

sergei.ostapenko@ultrasonicte 

ch.com 

In-line Crack Detection in Silicon Solar 

Cell Production Using Resonance 

Ultrasonic Vibrations 737** 

Nanosolar, Inc. 

Dr. Chris Eberspacher Palo Alto, CA 

chris@nanosolar.com 

Printed Solar Cell Using Nanostructured 

Ink 750** 

TDA Research, Inc. 

Dr. Michael D. Diener 

Wheat Ridge, CO 

mikee@tda.com 

Improved Fullerenes for OPV 750** 

NanoSonic, Inc. 

Mrs. Michelle Berg 

Blacksburg, VA 

mberg@nanosonic.com 

High Performance, Low-Cost 

Nanostructured Mirror Surfaces 750** 

Midwest 

Optoelectronics, LLC 

Dr. Aarohi S. Vijh 

Toledo, OH 

vijh@mwoe.com 

Novel Interconnection Process for 

Lightweight Flexible Photovoltaic 

Modules 746** 

* Phase I funding.
 

** Phase II funding paid over 2 years.
 

203 Systems Integration and Coordination
 

 

 

 

____________________________________________________________________________________ 

 

____________________________________________________________________________________ 

 

 

 

 

 

 

 

 

 

Congressional Earmarks 

Performing Organizations:	 CEC Stuyvesant Cove, Inc. (CEC); CENTRIA, Inc.; Crowder College; 

Eikos, Inc.; Greenfield Community College; Hackensack University 

Medical Center; Nevada Institute for Renewable Energy 

Commercialization (NIREC); North Dakota State University (NDSU); Nye 

County, NV; Regents of New Mexico State University (NMSU); 

Rensselaer Polytechnic Institute (RPI); Rural Development, Inc.; San 

Francisco Public Utilities Commission; Solar Energy Consortium: 

University of Arizona; University of Arkansas at Little Rock (UALR); 

University of Hartford; University of Louisville Research Foundation, Inc.; 

University of Nebraska at Kearney; University of Nevada, Las Vegas 

Research Foundation 

Key Technical Contacts:	 Carolyn Elam (DOE/GO, Primary Contact), 303-275-4953, 

carolyn.elam@go.doe.gov 

Margie Bates (DOE/GO), 303-275-4845, margie.bates@go.doe.gov 

Joe Lucas (DOE/GO), 303-275-4849, joe.lucas@go.doe.gov 

Steve Palmeri (DOE/GO), 303-275-4832, steve.palmeri@go.doe.gov 

Jim Payne (DOE/GO), 303-275-4756, jim.payne@go.doe.gov 

Brad Ring (DOE/GO), 303-275-4930, brad.ring@go.doe.gov 

Holly Thomas (DOE/GO), 303-275-4818, holly.thomas@go.doe.gov 

DOE HQ Technology Manager:	 Thomas Rueckert, 202-586-0942, thomas.rueckert.ee.doe.gov 

FY 2008 Budget:	 $18,665K (DOE/GO) 

Objectives 

•	 Fund 18 congressional earmarks, 15 new awards and three continuation awards, through the 

Consolidated Appropriations Act, 2008. 

•	 Conduct research related to DOE Solar Energy Technologies Program and Solar America 

Initiative (SAI) program objectives. 

Accomplishments 

•	 Awarded 15 new congressional earmarks and three continuation awards. 

1. Introduction 

Eighteen congressionally directed projects were 

negotiated and funded in fiscal year (FY) 2008. 

These funds were directed by the Consolidated 

Appropriations Act, 2008. The projects were fullyfunded this year, although several are multi-year. 

2. Technical Approach 

Two of the 18 awards were continuations of 

existing, previously funded projects. In addition to 

the 18 projects funded in 2008, four projects from 

prior years were active during FY 2008, although 

they received no additional funding. The awards 

are summarized in the following table: 

Agreement Title 

FY 2008 

Budget 

($K) 

CEC Stuyvesant Cove, Inc.; Christopher 

Collins 

(Solar 2 Green Energy, Arts & Education 

Center) 492 

CENTRIA, Inc.; Richard A. Mowrey 

(Building-Integrated Photovoltaic Solar 

Energy System ) 295 

Crowder College; Dan Eberle 

(Crowder College Missouri Alternative & 

Renewable Energy Technology (MARET) 

Center) 0* 

Eikos, Inc.; Paul J. Glatkowski 

(Transparent Coatings for Solar Cell 

Research Project ) 1,818 

Greenfield Community College; Glen 

Haywood 394 

Systems Integration and Coordination 204
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Agreement Title 

FY 2008 

Budget 

($K) 

(Sustainable Energy Model Greenhouse) 

Hackensack University Medical Center; 

Helen Cunning 

(Hackensack University Medical Center 

Green Building Project) 0* 

Nevada Institute for Renewable Energy 

Commercialization; Christine Gulbranson 

(Renewable Energy Research and 

Development) 1,476 

North Dakota State University; Dr. Philip 

Boudjouk 

(Center for Nanoscale Energy) 5,904 

Nye County; Pam Webster 

(Nye County Renewable Energy 

Feasibility Study) 492 

Regents of New Mexico State University; 

Shuguang Deng 

(High Efficiency Cascade Solar Cells ) 984 

Rensselaer Polytechnic Institute; Anna 

Dyson 

(Rensselaer Polytechnic Institute Green 

Build) 0* 

Rural Development, Inc.; Anne Perkins 

(Wisdom Way Solar Village ) 394 

San Francisco Public Utilities 

Commission; John F. Doyle 

(MUNI Ways and Structures Building 

Integrated Solar Membrane Project) 610 

The Solar Energy Consortium; Vincent 

Cozzolino 

(Solar Consortium of New York 

Photovoltaic Research and Development 

Center ) 1,476 

University of Arizona; Roger Angel 

(Development of Concentrator PV 

Systems for Solar Electricity) 984 

University of Arkansas at Little Rock; Dr. 

Alexandru Biris 

(Novel Photovoltaic Devices Based on 

Polymeric and Carbon Nanostructured 

Materials) 1,181** 

University of Hartford; Dr. Barry T. Lubin 

(Evaluation of Economic Benefits of 

Distributed Photovoltaic Systems) 492 

University of Louisville Research 

Foundation, Inc.; M. Keith Sharp 

(Sustainable Buildings: Using Active Solar 

Power) 394** 

University of Nebraska at Kearney; 

Christopher L. Exstrom 

(CIBS Solar Cell Development ) 935 

University of Nevada - Las Vegas 

Research Foundation; Wilber Pittinger 

(Photonics Research and Development) 0* 

University of Nevada, Las Vegas ; Dr. 

Biswajit Das 

(Solar Cell Nanotechnology) 738 

Agreement Title 

FY 2008 

Budget 

($K) 

University of Nevada, Las Vegas 

Research Foundation ; Wilbur Pittinger 

(Solar Technology Center) 

0* 

* Funded with prior year funds 

** Continuation of existing (prior year) Congressional 

Earmark 

3. Accomplishments and Future Directions 

3.1 Solar 2 Green Energy, Arts & Education 

Center (CEC - Collins) 

Objective 

•	 Complete preliminary design work on a netzero energy consumption, Leadership in 

Energy and Environmental Design (LEED) 

platinum-rated center, located in New York. 

3.2 Building-Integrated Photovoltaic (PV) Solar 

Energy System (CENTRIA – Mowrey) 

Objectives 

•	 Increase adoption of solar energy by 

developing standard designs for buildingintegrated PV (BIPV). 

•	 Develop standard PV-system designs, 

specifications, and support for standing-seam 

roof manufacturers, including electrical 

component design, roof wire management, 

testing, commercialization, and complete 

standards development. 

3.3 Crowder College Missouri Alternative & 

Renewable Energy Technology (MARET) Center 

(Crowder College – Eberle) 

Objective 

•	 Develop 27,500-ft2 facility as a living 

laboratory to support solar and other 

renewable energy development through 

professional degrees, new product 

commercialization, renewables business 

incubation, and consumer education. 

Accomplishments 

•	 Completed work on prototype roof section, 

modular bays, and site and structural plans for 

first phase of construction. 

Future Directions 

•	 Finish environmental assessment to comply 

with National Environmental Policy Act 

(NEPA) standards. 

•	 Complete design work on the integrated 

mechanical and electrical energy collection, 

recovery and exchange systems. 

205 Systems Integration and Coordination
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.4 Transparent Coatings for Solar Cell Research 

Project (Eikos – Glatkowski) 

Objectives 

•	 Synthesize and characterize novel 

nanomaterials for transparent conductive 

coatings (TCCs) for use in thin-film PV and 

other energy applications. 

•	 Formulate inks for printing high conductivity 

nanomaterial-based coatings. 

•	 Demonstrate coating environmental stability. 

•	 Evaluate cost-performance-processing 

tradeoffs. 

Accomplishments 

•	 Surveying TCC performance, processing, and 

cost metrics for comparison with 

nanomaterials TCCs. 

• Synthesized nanomaterials for TCCs. 

Future Directions 

•	 Create novel high-performance, 

environmentally-stable nanomaterial TCCs. 

•	 Integrate these coatings into thin film organic 

and polycrystalline PV. 

3.5 Sustainable Energy Model Greenhouse 

(Greenfield Community College – Haywood) 

Objectives 

•	 Build a zero-net energy impact solar 

greenhouse that incorporates passive solar 

design, thermal storage, energy conservation 

features, PV, and an active geothermal 

heating system. 

3.6 Hackensack University Medical Center Green 

Building Project (Cunning) 

Objectives 

•	 Develop a LEED-certified medical facility with 

PV system and associated complementary 

energy efficiency equipment and materials. 

3.7 Renewable Energy Research and 

Development (NIREC - Gulbranson) 

Objectives 

•	 Move research from Nevada academic 

institutions into viable businesses. 

Accomplishments 

•	 Sponsored week-long Green Technology 

Entrepreneurship Academy for graduate 

students, post-docs, and faculty (7/08). 

•	 Assembled coalition of institutional research 

partners. 

•	 Set up Entrepreneurs-in-Residence (EIR) 

Program and appointed 2 EIRs. 

•	 Issued competitive request for proposal (RFP) 

and awarded approximately $320,000 to four 

projects. 

Future Directions 

•	 NIREC will continue to search for, assess, and 

award funds to deserving projects. 

•	 Annual RFP planned, integrating researchers, 

experienced entrepreneurs, business 

executives. 

•	 Partnering with Nevada Small Business 

Development Center to sponsoring a 2009 

Small Business Innovation Research (SBIR) 

conference on energy. 

3.8 Center for Nanoscale Energy (NDSU – 

Boudjouk) 

Objectives 

•	 Investigate applicability of liquid silanes as 

precursors to flexible PV that utilize 

semiconducting silicon as basis of the 

sunlight-absorbing layer. 

•	 Investigate low-temperature routes to siliconbased solar cells on glass substrates and 

evaluate hybrid organic/inorganic strategies 

that might allow flexible PV on plastic 

substrates. 

•	 Investigate integration of printed active and 

passive components into local control 

electronics for solar panels. 

Accomplishments 

•	 Plasma enhanced chemical vapor deposition 

(PECVD) of both a-Si and alloys (i.e., SiN and 

SiOx) using Si6H12. 

•	 Established system coupling a printing 

methodology with laser annealing under inert 

atmosphere. 

•	 Developed schematics and electrical models 

for max power-point tracking system. 

Future Directions 

•	 Refine PECVD of a-Si from Si6H12 and 

compare to other precursors (e.g., silane, 

disilane, trisilane). 

•	 Establish route to printed silicon from Si6H12 ­

based inks where low-temperature treatments 

yield materials that maintain carrier properties 

appropriate device for the application. 

•	 Demonstrate panel-based maximum 

powerpoint tracking system. 

3.9 Nye County Renewable Energy Feasibility 

Study (Nye County – Webster) 

Objectives 

•	 Develop comprehensive land use and 

infrastructure plans for the Amargosa Valley 

and Beatty areas. 

•	 Develop land use and community 

preparedness plans. 

Systems Integration and Coordination 206
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

•	 Develop a feasible design for Barrick Mine 

Energy Park for energy production projects 

and university-directed educational and 

energy research programs at the site. 

•	 Measure and characterize wind behavior in 

support of a feasibility study of Beatty-area 

wind energy generation projects. 

•	 Evaluate potential effectiveness of PVpowered county buildings. 

•	 Evaluate potential performance, benefits, 

costs, and long-term sustainability of a new 

landfill with one or more concepts: biomass 

energy production, feedstock availability, 

recyclables diversion, and similar practices. 

3.10 High Efficiency Cascade Solar Cells (NMSU– 

Deng) 

Objectives 

•	 Develop new organic semiconducting PV. 

•	 Develop band-enhancing layers. 

•	 Study mechanisms of percolation for charge 

transfer in new organic semiconductors. 

•	 Use cascade solar cell architecture to develop 

semiconductors. 

Accomplishments 

•	 Initiated composite fabrication using 

nanotubes and polymers. 

•	 Built two chemical vapor deposition reactors 

for synthesizing carbon nanotubes (CNTs). 

•	 Performed preliminary studies on synthesis 

conditions affecting CNT quality. 

•	 Launched computer cluster for modeling and 

simulations. 

•	 Initiated theoretical studies of the structures 

and physical characteristics of electro-active 

nanoscale systems. 

Future Directions 

•	 Synthesize single-walled, double-walled, multiwalled, and nitrogen and boron-doped CNTs. 

•	 Develop suitable nanocomposites for all 

aspects of new architecture. 

•	 Obtain spectroscopic and morphological 

control of nanocomposites through materials 

characterization. 

•	 Optimize nanocomposites for use in a flat 

panel cell, develop new cells. 

•	 Continue theoretical studies of functionalized 

and doped CNTs and self-assembled 

complexes between organic molecules and 

nanotubes and initiate theoretical studies of 

optically active nanoparticles embedded in 

emissive polymers. 

Objectives 

•	 Complete testing of a building-scale curtain 

wall prototype for a daylighting system that 

incorporates concentrating modules for heat 

and power production with dramatically 

reduced cost payback periods. 

•	 Achieve system goal levelized cost of energy 

(LCOE) of $0.19/kWh; efficiency (72.2-80.9% 

combined); $2.68 per peak watt. 

Accomplishments 

•	 Completed testing of prototype version 4.1 

(See Figure 1). 

•	 Value engineering and reduction by 50% of all 

components for version 5. 

Figure 1. IC Solar Façade – Version 4.1 

Future Directions 

•	 Independent testing of IC Solar Module at 

NREL (3/09). 

•	 Independent testing of curtain-wall panel(s) 

with 100 modules at BEESL Labs and the 

Syracuse Center for Excellence in Energy and 

Environmental Systems. 

3.12 Wisdom Way Solar Village (Rural 

Development, Inc. – Perkins) 

Objectives 

•	 Enhance Wisdom Way Solar Village, 20 prototypical “near zero*net energy” affordable 

homes by adding solar hot water systems and 

high efficiency windows. Researchers with the 

DOE “Building America Program” will monitor 

the homes for performance. 

•	 Enable residents to reduce their energy 

budgets for electricity, heat, and hot water to 

as low as $300 per year (in 2007 dollars). 

3.13 MUNI Ways and Structures Building 

Integrated Solar Membrane Project (San 

Francisco Public Utilities Commission – Doyle) 

3.11 Rensselaer Polytechnic Institute Green Build 

(Rensselaer Polytechnic Institute – Dyson) 

207 Systems Integration and Coordination
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Objectives 

•	 Install BIPV system using best available 

highest efficiency technology to provide about 

25% of the total facility load of an average of 

52,560 kWh per month. 

Accomplishments 

•	 Completed preliminary roof structural and 

electrical evaluation as well as California 

Environmental Quality Act (CEQA) 

requirements. 

•	 Completed preliminary designs for installation 

of BIPV on the facility roof, specified 

monitoring of BIPV system. 

Future Directions 

•	 Advertise RFP 1/09. 

•	 Start construction in late summer 2009 with 

completion estimated for December 2009. 

3.14 Solar Consortium of NY PV R&D Center 

(TSEC – Cozzolino) 

Objectives 

•	 TSEC is an industry-led not-for-profit realizing 

the promise of solar energy by mobilizing 

resources of New York State. 

Accomplishments 

•	 Collaborated with NYS economic development 

agencies and NY Power Authority for Globe 

Specialty Metal’s solar grade silicon 

manufacturing facility in Niagara Falls, New 

York, resulting in 500 new jobs. 

•	 Coordinated Clarkson University project to 

develop unique manufacturing process to 

enhance feasibility of Globe’s solar-grade 

manufacturing. 

•	 Created a projected additional 600 jobs to 

New York State by applying region’s 

technology skills to enhancing products and 

processing. 

•	 Coordinated SUNY New Paltz Solar usage 

projects (apple farm, solar for 3 Ulster County, 

NY hospitals, off-grid PV Air National Guard 

installation Newburgh NY, new LED approach 

from Brite Components). 

Future Directions 

•	 Expand use of off-grid applications of solar 

energy products and to drive increases in the 

region’s work force through business attraction 

and expansion. 

3.15 Development of Concentrator PV Systems for 

Solar Electricity (U of Arizona – Angel) 

Objectives 

•	 Develop and test a focal plane generator 

capable of delivering > 1 kW at the dish focus. 

•	 Develop and test a 3m-test reflector dish. 

•	 Develop outreach program by integrating solar 

activity into educational program Biosphere II. 

3.16 Novel PV Devices Based on Polymeric and 

Carbon Nanostructured Materials (U of Arkansas 

at Little Rock – Biris) 

Objectives 

•	 Incorporate unique optical and electronic 

properties of carbon nanotubes for improved 

performance of PV devices. Single-wall 

carbon nanotubes (SWNTs) will be directly 

configured as energy conversion materials to 

fabricate thin-film solar cells, with nanotubes 

serving as both photogeneration sites and 

charge carriers collecting/transport layers. 

Accomplishments 

•	 Synthesized carbon nanotubes using a variety 

of catalysts and methods. 

•	 Synthesized P3HT product at larger scale. 

•	 Fabricated very first hybrid-PV devices based 

on single wall carbon nanotube/n-silicon 

heterojunctions. 

•	 Synthesized polyaniline (PANI) by the selfstabilized dispersion polymerization (SSDP) 

technique and processed into thin films for 

hole transport materials (HTMs). 

•	 Synthesized Graphite-Polyaniline (G-PANI) 

and processed 60/40 composite into pristine 

films for contact layer (electrode) as possible 

replacement for Al and Ca. 

•	 Characterized bulk properties of G-PANI 

composites. 

•	 Developed methods for producing magnetic 

and soluble MWNTs using lignins and tannins. 

•	 p-GaN / InxGa1-xN / n-GaN (PiN) nanorods 

were grown by plasma assisted molecularbeam-epitaxy (MBE) method. 

•	 Control of nanorod diameter for n-GaN from 

70 nm to 150 nm achieved by varying growth 

temperature. 

•	 Demonstrated 30% In incorporation into 

InxGa1-xN layer, producing a 2.3 eV bandgap. 

Future Directions 

•	 Characterize SSDP-PANI thin films for HTMs. 

•	 Characterize pristine G-PANI films for 

electrodes to replace Ca and Al. 

•	 Demonstrate carbon nanotube length control. 

•	 Fabricate and characterize carbon nanotube 

composite cell structures. 

•	 Develop and characterize transparent carbon 

nanotube based electrodynamic screens for 

dust mitigation for solar panels 

•	 Study quantum confinement effect of light and 

charge carriers in the nanostructures. 

Systems Integration and Coordination 208
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.17 Evaluation of Economic Benefits of 

Distributed PV Systems (U of Hartford – Lubin) 

Objectives 

•	 Use existing research to develop economic 

and engineering models. 

•	 Use existing PV installations to obtain data on 

both generation and load. 

•	 Use engineering models to calculate effective 

load carrying capacity and as input to the 

economic model to predict multiple value 

streams that accrue from distributed 

generation using PV. 

Accomplishments 

•	 Organized advisory board, includes utilities 

and utility-related companies. 

•	 Established basis of models to relate 

Equivalent Load Carrying Capacity to value 

streams. 

Future Directions 

•	 Continue to collect local insolation data. 

•	 Investigate potential storage strategies. 

•	 Use PV installation at the University of 

Hartford to develop and validate models. 

•	 Work with owner operated and third party 

owners for access to their generation and host 

companies load data. 

3.18 Sustainable Buildings: Using Active Solar 

Power (U of Louisville – Sharp) 

Objectives 

•	 Install solar technologies; demonstrate to 

public officials, developers, commercial 

establishments, industries, and citizens the 

benefits of using solar technologies. 

•	 2005 project established an Energy Center. 

FY 2008 funding to continue FY 2005 and 

2006 activities for two research projects (Solar 

Hydrogen Electric Power System and Solar 

Heat Pipe), PV demonstration, and 2 

educational subprojects (training for installers 

of solar electric systems, and education). 

Future Directions 

•	 Collaborate with Kentucky Solar Partnership to 

conduct educational outreach through a 

renewable energy roadshow. 

3.19 CIBS Solar Cell Development (University of 

Nebraska at Kearney – Exstrom) 

Objectives 

•	 Fabricate and study new VP material, copper 

indium boron diselenide, CuInxB1-xSe2 (CIBS). 

•	 Through chemical composition changes, 

exceed CuIn1-xGaxSe2 (CIGS) PV efficiencies 

with CIBS goals of 25% (single-film) and 15% 

(module). 

Accomplishments 

•	 Optimized solvothermal reaction conditions to 

produce a first-generation nanocrystalline 

CIBS material. 

•	 Initial investigations into ex-situ sequential and 

simultaneous selenization/sulfurization of 

Cu(In0.5B0.5) precursors were performed. 

Initial X-ray diffraction data indicate that sulfur 

has been incorporated into the CuInSe2 lattice 

to some degree. 

Future Directions 

•	 Investigate and optimize annealing effects on 

model nanocrystalline chalcopyrites and CIBS. 

•	 Determine primary reaction and annealing 

factors that determine boron composition 

control in CIBS. 

•	 Develop CIBS nanocrystalline-to-thin-film 

processing via rapid thermal annealing, inkjet 

spray techniques, or related technology. 

•	 Deposit CIS and CIBS films using the in-situ 

deposition chamber. 

•	 Deposit CuIn and CuInB precursor films and 

subject them to various ex-situ 

selenization/sulfurization procedures. 

3.20 Photonics Research and Development 

(UNLV – Pittinger) 

Objectives 

•	 Develop advanced lighting technologies. 

•	 Establish photonics academics along with 

research and development at UNLV to 

improve lighting technologies. 

•	 Provide credentialed lighting professionals for 

the national industry. 

Accomplishments 

•	 Improved understanding of the characteristics 

of quantum dot LEDs. 

•	 Improved efficiency of green LEDs. 

•	 Established and enhanced UNLV Display 

Lighting Laboratory. 

Future Directions 

•	 Continue to develop process parameters for 

synthesizing high quality CdSe QD’s with an 

increased percentage of monocrystalline 

particles. 

•	 Continue to collaborate with Boston University; 

additional RTA-treated samples will be 

investigated by WDS x-ray mapping to provide 

more information on the contact formation 

mechanism. 

•	 Commercialize hybrid solar lighting 

technology. 

209 Systems Integration and Coordination
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.21 Solar Cell Nanotechnology (UNLV – Das) 

Objectives 

•	 Develop low cost non-lithographic nanofabrication technology to fabricatie thin-film 

porous templates as well as uniform arrays of 

semiconductor nanostructures to make high 

efficiency solar cells. These are expected to 

have very high energy conversion efficiencies 

due to the increased absorption coefficients of 

semiconductor nanostructures. Thin film 

porous templates can be used to optimize 

surface texturing of solar cells for additional 

enhanced energy conversion efficiency. 

3.22 Solar Technology Center (UNLV – Pittinger) 

Objectives 

•	 Develop solar and renewable energy 

information center within Eldorado Valley 

Energy Zone. 

•	 Provide public information services on both 

current and emerging solar and other 

renewable energy technologies. 

•	 Provide schools and interested public a 

practical means of observing solar and other 

renewable energy systems. 

•	 Provide a facility for demonstration and 

research on existing and emerging renewable 

energy technologies. 

Accomplishments 

•	 Performed civil engineering activities for site 

development, began NEPA process, including 

preparation of environmental assessment. 

•	 Began procurement process for securing 

modular building for a center.
 

Future Directions
 

•	 Pending DOE approval on Environmental 

Assessment (NEPA), proceed with Phase II – 

installation of building and related 

infrastructure. 

•	 Identify and enter into research partnerships. 

4. FY 2008 Special Recognitions and Patents 

Eikos, Inc 

•	 Innovator of the Year, Small Times 

2007Finalist, Paul Glatkowski. 

•	 NASA Certificate of Recognition, Electrically 

Conductive Coatings with High thermal 

Oxidative Stability and Low Thermal 

Conduction, 2008, Paul Glatkowski. 

RPI 

•	 IN 219411, titled "Concentrating Type Solar 

Collection and Daylighting System Within 

Glazed Building Envelopes" issued on 

05/06/2008 

UALR 

•	 “Multi-Junction Solar Cell”, U.S. patent 

pending (07) File #: 60/897,542. 

5. Major FY 2008 Publications 

Eikos, Inc. 

•	 D.A. Britz, et al. “Highly Transparent Carbon 

Nanotube Films for ESD Protection,” 

Proceedings of SPRAT XX, Sept. 25-27, 

Cleveland, OH, 2007. 

•	 M.A. Contreras, et al. “Replacement of 

transparent conductive oxides by single-wall 

carbon nanotubes in Cu(In,Ga)Se-2-based 

solar cells,” J. of Physical Chemistry C, 111, 

14045-14048 (2007). 

TSEC 

•	 State University of New York at New Paltz 

Case Study 

University of Nebraska at Kearney 

•	 J. Olejníček,et al. “A Non-vacuum Process for 

Preparing Nanocrystalline CuIn1-xGaxSe 

Materials Involving an Open-air Solvothermal 

Reaction,” International Materials Research 

Congress, Aug. 17-21, Cancun, Mexico, 2008. 

•	 J. Olejníček, et al. “A Non-vacuum Process for 

Preparing Nanocrystalline CuIn1-xGaxSe 

Materials Involving an Open-air Solvothermal 

Reaction,” Solar Mater. Solar Cells, submitted 

for publication. 

UALR (29 published or submitted, including the 

following): 

•	 Z. Li, et al. “SOCl2 enhanced photovoltaic 

conversion of single wall carbon nanotube/nsilicon heterojunctions”, Applied Physics 

Letters – accepted-in press, 2008. 

•	 Y. Xu, et. al.“Surface Area and Thermal 

Stability Effect of the MgO Supported 

Catalysts for the Synthesis of Carbon 

Nanotubes”, J. of Materials Chemistry – 

accepted-in press, 2008. 

•	 Z. Li, et al. “Influence of CO2 on Carbon 

Nanotube Growth by Using Hydrocarbon as 

Carbon Source”, Chemical Communications, 

28, 3260-3262, 2008. 

•	 A.R. Biris, et al. “High Quality Double Wall 

Carbon Nanotubes Grown by a Cold-Walled 

Radio Frequency Chemical Vapor Deposition 

Process”, Chemistry of Materials, 20(10), 

3466-3472, 2008. 

•	 R.B. Little, et al. “On the dynamical 

ferromagnetic, quantum Hall, and relativistic 

Systems Integration and Coordination 210
 

 

 

 

 

 

 

 

 

 

 

effects on the carbon nanotubes nucleation 

and growth mechanism”, J. of Magnetism and 

Magnetic Materials, 320(3,4), 540-547, 2008. 

•	 A.R. Biris, et al. “Hydrogen influence on the 

growth process and properties of single wall 

carbon nanotubes”, Physics Letters A, 

372(17), 3051-3057, 2008. 

•	 Z. Li, et al. “Effects of the Fe-Co Interaction on 

the Growth of Carbon Nanotubes”, J. of 

Chemical Physics, 129(7), 074712/1­

074712/6, 2008. 

•	 S. Bourdo, et al. “Structural, electrical, and 

thermal behavior of novel graphite-polyaniline 

composites with increased crystallinity”, 

Advanced Functional Materials, 18(3), 432­

440, February, 2008. 

•	 A.R. Biris, et al. “Multiwall carbon nanotubes 

synthesized from acetylene by RF-CCVD on 

novel CaO supported catalysts”, Physics 

Letters A, 372(42), 6416-6419, 2008. 

•	 A.R. Biris, et al. “Hydrogen Storage in CarbonBased Nanostructured Materials”, Particulate 

Science and Technology J., 26(4), 297-305, 

2008. 

•	 Four papers, Annual Meeting of the American 

Chemical Society, New Orleans, 2008. 

•	 Two papers presented at the annual meeting 

IEEE-IAS, 2008. 

UNLV 

•	 E. Dimakis, et al. “Growth and properties of 

near-UV light emitting diodes based on 

InN/GaN quantum wells”, Phys. Stat. Sol. (a) 

205, No. 5, 1070 (2008). 

•	 C. Thomidis, et al. “InGaN-based LEDs grown 

by plasma-assisted MBE on (0001) sapphire 

with GaN QDs in the nucleation layer”, Phys. 

Stat. Sol. (c) 5, No. 6, 2309 (2008). 

6. University and Industry Partners 

Organization/ 

Principal Investigator Location Description/Title of Research Activity FY 2008 

($K) 

Cost 

Share 

($K) 

Eikos, Inc. 

NREL Golden, CO Expertise, device fabrication, 

characterization, and materials. 

492 37 

NIREC: 

Desert Research Institute 

Dr. H. Kuhns 

University of Nevada, Reno 

Dr. Andrzej M Trzynadlowski 

UC Davis, Dr. Mark Mascal 

University of Nevada, Reno 

D. K. Kim 

Reno, NV 

Reno, NV 

Davis, CA 

Reno, NV 

Developing Utility Accountant – tool to 

help manage utility costs. 

Power electronic converter-controller for 

off-grip wind-turbine systems. 

Direct conversion of sugars, cellulose, 

and cellulosic biomass into fuels. 

Condenser for geothermal applications. 

90 

97 

60 

70 

50 

NDSU: 

UC-Riverside 

Dr. R. Haddon 

University of Toledo 

Dr. Marsillac 

Riverside CA 

Toledo OH 

Evaluate novel electro catalyst 

materials for fuel cells 

Liquid silane-derived films. 

533 

200 

33 

50 

RPI/Harvard 

CVM 

Don Schneider Sr. 

Syracuse University 

Jianshun Zhang 

Island Bay Window and 

Curtain Wall 

Cambridge, NY 

Syracuse, NY 

Long Island, NY 

Value engineering/optimization of 

system components. 

System testing. 

Curtain wall panel fabrication 

50 

0 

0 

50 

0 

100 

* Funded with prior year funds 

** Continuation of existing Congressional Earmark 

211 Systems Integration and Coordination
Systems Integration and Coordination 212
 

 

 

 

Solar Energy Technologies Program 

Total FY 2008 Budget ($K) 

NREL Sandia Other Solar 

Total Total Total Total 

Solar Energy Technologies 69,754 15,983 84,264 170,000 

Photovoltaics 64,064 11,309 62,628 138,000 

Applied Research 29,024 818 7,358 37,200 

Exploratory Research 7,218 470 7,019 14,707 

Silicon Center of Excellence 0 0 712 712 

Thin Film Center of Excellence 600 0 0 600 

Future Generation Projects 156 0 6,000 6,156 

MURA Projects 292 0 7 299 

Industrial CRADAs 2,100 0 0 2,100 

Fundamental R&D 1,706 0 300 2,006 

Seed Fund Projects 1,870 470 0 2,340 

Exploratory Project Management 494 0 0 494 

Electronic Materials & Devices 10,149 250 0 10,399 

Silicon Materials & Devices 3,541 0 0 3,541 

Processes & Advanced Concepts 2,605 250 0 2,855 

Thin-Film Polycrystalline Compounds 2,225 0 0 2,225 

Concentrator Crystalline Cells 1,578 0 0 1,578 

EMD Project Management 200 0 0 200 

Measurements & Characterization 9,492 0 0 9,492 

Analytical Microscopy 2,462 0 0 2,462 

Electro-Optical Characterization 2,455 0 0 2,455 

Surface Analysis 1,670 0 0 1,670 

Cell and Module Performance 2,125 0 0 2,125 

M&C Project Management 780 0 0 780 

M&C Project Management 780 0 0 780 

Process Develop Integrate Lab 1,830 0 0 1,830 

PDIL Hardware Development 1,125 0 0 1,125 

PDIL Project Management 336 0 0 336 

PDIL Software Integration 369 0 0 369 

Operations & Planning 335 98 339 772 

Program Management - AR 335 98 0 433 

Rescission - AR 0 0 339 339 

Earmarks – AR* 0 0 12,900 12,900 

Systems Development 21,216 871 42,713 64,800 

PV Systems Development 160 0 39,300 39,460 

Technology Pathway Partnerships 0 0 35,500 35,500 

University Process & Product Dev 0 0 3,500 3,500 

SAI Project Monitoring 160 0 300 460 

PV Component Development 20,089 0 0 20,089 

PV Incubator Solicitation 11,598 0 0 11,598 

Industry Thin Film Partnerships 2,435 0 0 2,435 

University Thin Film Research 1,591 0 0 1,591 

PV Manufacturing R&D 3,032 0 0 3,032 

213 Appendices
 

 

 

 

 

 

 

 

PV Comp Project Mgmt 1,434 0 0 1,434 

PV Systems Project Mgmt - CR 600 0 0 600 

PV Systems Project Mgmt - Plus 834 0 0 834 

Operations & Planning 967 871 3,413 5,251 

Program Management -SD 967 511 695 2,172 

PV Capital Equipment 0 360 0 360 

PBA Activities - SD 0 0 2,118 2,118 

Rescission – SD 0 0 600 600 

Test & Evaluation 10,736 8,305 2,659 21,700 

Modeling & Analysis 2,490 730 250 3,470 

System Modeling 1,140 730 0 1,870 

Systems Analysis 1,350 0 250 1,600 

Market - Solar Annual Report 300 0 0 300 

Market - PV Roadmap Support 100 0 0 100 

Market - Solar DS Model 100 0 0 100 

Value - GPRA Analysis 100 0 0 100 

Value - PNNL/NEMS Model 50 0 100 150 

Value – PV Value Clearinghouse 50 0 0 50 

Policy - General Analytic Support 300 0 0 300 

Policy - Topical Reports 150 0 150 300 

Financial Analysis 200 0 0 200 

Grid Integration 400 4,404 0 4,804 

PV Grid Integration 400 400 0 800 

Inverter/BOS R&D 0 775 0 775 

Inverter/EMS Solicitation 0 3,229 0 3,229 

Inverter Awards 0 3,000 0 3,000 

Lab Support 0 229 0 229 

Reliability R&D 4,625 2,040 0 6,665 

Module Screening & Field Eval 1,945 320 0 2,265 

Industry Reliability & Codes 475 445 0 920 

SLP Models & Failure Modes 270 645 0 915 

Accelerated Lifetime Testing 1,935 630 0 2,565 

Accelerated Lifetime Testing 1,935 630 0 2,565 

Systems Engineering 1,775 1,070 1,750 4,595 

Module, Array & Systems T&E 1,575 840 0 2,415 

PV Module Database 0 180 0 180 

Energy Ratings Method Validations 200 0 0 200 

Regional Experiment Stations 0 50 1,750 1,800 

Thin-Film Hot/Humid Exposure 0 25 875 900 

Thin-Film Hot/Humid Exposure 0 25 875 900 

Resource & Safety R&D 1,380 0 470 1,850 

Solar Radiometry and Modeling 800 0 0 800 

Resource Assess & Character 580 0 0 580 

ES&H/Lifecycle Research 0 0 470 470 

Operations & Planning 66 61 189 316 

Program Management - TE 66 61 0 127 

PBA Activities - TE 0 0 1 1 

Rescission – TE 0 0 188 188 

Appendices 214
 

 

Market Transformation 3,087 1,315 9,898 14,300 

Codes & Standards 200 100 750 1,050 

Solar America Board of Codes & Standards 200 100 750 1,050 

Training & Certification 0 0 485 485 

PV Installer Training 0 0 300 300 

PV Installer Certification 0 0 185 185 

Building Integration & Finance 2,155 0 65 2,220 

Solar Decathlon 1,155 0 65 1,220 

Solar Decathlon Pro 1,000 0 0 1,000 

Technical Partnerships 0 1,140 5,766 6,906 

Solar America Showcases 0 190 800 990 

Solar America Cities 0 870 4,416 5,286 

Government Solar Installation Program 0 80 550 630 

Integrator 0 0 400 400 

RES Support 0 0 150 150 

Lab Support 0 80 0 80 

Technical Outreach 497 0 1,889 2,386 

Utility Tech Outreach 0 0 45 45 

Builder Tech Outreach 0 0 63 63 

State Technical Outreach 115 0 1,465 1,580 

MT Support Activities 382 0 316 698 

Market Data & Surveys 270 0 0 270 

SETP Annual Conf/CPS 0 0 165 165 

MT Communications/NBM 112 0 26 138 

ASES Solar Home Tour 0 0 125 125 

Operations & Planning 235 75 943 1,253 

Core Communications – PV 110 50 25 185 

IEA PV Activities 125 25 0 150 

PBA Activities – MT 0 0 569 569 

Rescission - MT 0 0 130 130 

Earmarks – MT* 0 0 5,320 5,320 

Solar Thermal 5,690 4,674 21,636 32,000 

Concentrating Solar Power 4,400 4,574 21,026 30,000 

Parabolic Trough R&D 648 75 2,351 3,074 

Trough Solar Field 183 75 0 258 

Power Cycle & BOP 84 0 0 84 

Trough Systems Integration 216 0 0 216 

CSP FOA – Trough 165 0 2,351 2,516 

Next Generation Trough 0 0 500 500 

Advanced Polymeric Reflector 0 0 439 439 

All Aluminum Trough 0 0 406 406 

FOA - Analysis & Engineering Support 165 0 150 315 

Phase II Awards 0 0 856 856 

Dish/Stirling R&D 70 0 920 990 

Dish Solar Field 30 0 0 30 

CSP FOA – Dish 40 0 920 960 

30kW Free Piston Dish/Stirling 0 0 321 321 

200kW Dish/Brayton w/Storage 0 0 300 300 

FOA Adv Dish Engine Support 40 0 0 40 

215 Appendices
 

 

 

 

 

 

 

Phase II Awards 0 0 299 299 

Thermal Storage R&D 489 379 7,593 8,461 

Storage Components 0 93 0 93 

Storage Systems 79 130 0 209 

Advanced HTF Development 110 56 0 166 

CSP FOA – Storage: Phase 1 0 100 2,593 2,693 

2nd Rnd (HTF, Tower, CLFR) 300 0 5,000 5,300 

Advanced HTF Solicitation 0 0 5,000 5,000 

Advanced HTF Support 300 0 0 300 

Advanced CSP Concepts 460 3,333 2,256 6,049 

Advanced Concepts R&D 210 233 400 843 

CSP FOA - Advanced Concepts 250 100 1,856 2,206 

Thermo-Chemical H2 Earmark 0 3,000 0 3,000 

Heliostat Field Upgrades - Hardware 0 1,500 0 1,500 

Heliostat Field Upgrades - Software 0 500 0 500 

Advanced Heliostat Development 0 1,000 0 1,000 

CSP Market Transformation 1,720 56 1,425 3,201 

Southwest Stakeholder Outreach 160 56 25 241 

CSP Resource Assessment 650 0 0 650 

Market Analysis & Grid Integration 535 0 0 535 

Solar Advisor Support 250 0 0 250 

Programmatic Support for EIS 125 0 1,400 1,525 

Programmatic EIS on BLM Lands 125 0 400 525 

Additional Funding 0 0 1,000 1,000 

Operations & Planning 1,013 731 6,482 8,226 

Program Management - CSP 295 656 838 1,789 

CSP Capital Equipment & Facilities 283 0 0 283 

IEA SolarPACES 45 25 0 70 

CSP Communications 390 50 0 440 

PBA Activities – CSP 0 0 3,259 3,259 

SBIR – CSP 0 0 2,110 2,110 

Rescission – CSP 0 0 273 273 

Earmarks – CSP* 0 3,000 0 3,000 

Solar Heating & Lighting 1,290 100 610 2,000 

SHC Systems Development 1,100 100 0 1,200 

Solar Electric/Thermal Pathways to ZEH 400 100 0 500 

Low-Cost SWH for ZEH 500 0 0 500 

Solar Heating & Cooling for ZEH 200 0 0 200 

PV Thermal Systems 20 0 0 20 

Lab Support 180 0 0 180 

SWH Market Transformation 0 0 530 530 

Solar Water Heating Barriers 0 0 500 500 

NABCEP - SHL 0 0 30 30 

Operations & Planning 190 0 80 270 

Program Management - SHL 150 0 18 168 

SHL Communications 40 0 0 40 

PBA Activities - SHL 0 0 21 21 

SBIR - SHL 0 0 23 23 

Rescission - SHL 0 0 18 18 

* Earmarks were funded outside of the Solar Program. 

Appendices 216
 

 

 

Acronyms and Abbreviations 

A2LA American Association for Laboratory Accreditation 

AC alternating current 

AES Auger electron spectroscopy 

AFM atomic force microscopy 

AIC aluminum-induced crystallization 

ALT accelerated lifetime test 

AOP Annual Operating Plan 

APD antiphase domain 

APS Arizona Public Service 

AR antireflection 

ASES American Solar Energy Society 

ASHRAE American Society of Heating, Refrigeration, and Air-conditioning Engineers 

a-Si amorphous silicon 

ASOS Automated Surface Observing System 

ASRC Atmospheric Sciences Research Center (at State University of New York) 

ASRM advanced solar reflective mirror 

ASSET Analysis of State Energy Tradeoffs Databank 

ASTM American Society for Testing and Materials 

ASU Arizona State University 

BES Basic Energy Sciences (within U.S. DOE Office of Science) 

BEW Behnke, Erdman & Whitaker Engineering 

BIPV building-integrated photovoltaics 

BLM Bureau of Land Management 

BNL Brookhaven National Laboratory 

BOS balance of systems 

BSC Basic Sciences Center (within the National Renewable Energy Laboratory) 

BSF back-surface field 

Btu British thermal unit 

BU Boston University 

CAD computer-assisted design 

C-AFM conductive atomic force microscopy 

Caltech California Institute of Technology 

CBD chemical bath deposition 

CdTe cadmium telluride 

CEC California Energy Commission 

CEG Clean Energy Group, Inc. 

CET Center for Ecological Technology 

CIGS copper indium gallium diselenide 

CIGSS copper indium gallium sulfur selenide 

CIS copper indium diselenide 

CL cathodoluminescence 

CNT carbon nanotube 

COP coefficient of performance 

COSE cost of saved energy 

COTS commercial off the shelf 

CPS Corporate Planning System 

CPUC California Public Utilities Commission 

CPV concentrating photovoltaics 

CRADA Cooperative Research and Development Agreement 

Csave cost of saved energy 

CSDS Concentrating Solar Deployment System 

c-Si crystalline silicon 

217 Appendices
 

CSR Climatological Solar Radiation 

CSS close-spaced sublimation 

CSP concentrating solar power 

CU University of Colorado 

CVD chemical vapor deposition 

CY calendar year 

CZ Czochralski 

DC direct current 

DEG/SE Davis Energy Group/SunEarth 

DETL Distributed Energy Technologies Laboratory (at Sandia National Laboratories) 

DFMA design for manufacturing and assembly 

DFMECA design failure mode effects and criticality analysis 

DFR design for reliability 

DJ dual junction 

DLR German Aerospace Center 

DLTS deep-level transient spectroscopy 

DMA dynamic mechanical analysis 

DNI direct normal incident 

DoD Department of Defense 

DOE Department of Energy 

DSC differential scanning calorimetry 

DSP digital signal processing 

EAO Energy Analysis Office 

EBSD electron backscatter diffraction 

EERE Energy Efficiency and Renewable Energy (U.S. Department of Energy office) 

EFG Edge-defined, Film-fed Growth 

Eg bandgap energy 

EH&S environmental health and safety 

EIA Energy Information Administration 

EM&D Electronic Materials and Devices 

ENEA Italian National Agency for New Technologies, Energy and the Environment 

EPA Environmental Protection Agency 

EPAct Energy Policy Act 

EPC Engineer, Procure, Construct 

EPS environmental portfolio standard 

EPV Energy Photovoltaics 

EUL enhanced use leasing 

EVA ethylene vinyl acetate 

EVMS Earned Value Management System 

FAQ frequently asked questions 

FF fill factor 

FFPT fixed focal point trough 

FIB focused ion beam 

FOA Funding Opportunity Announcement 

FOUP Front-Opening Unified Pod 

FR flame retardant 

FSEC Florida Solar Energy Center (at University of Central Florida) 

FTIR Fourier transform infrared 

FY fiscal year 

FZ float zone 

GB grain boundary 

GE General Electric 

GIS geographical information system 

GMS gas management system 

GO Golden Field Office (U.S. Department of Energy) 

GOES Geostationary Operational Environmental Satellite 

Appendices 218
GPRA 

GPS 

GSE 

GSIP 

GW 

HALT 

HCE 

HBCU 

HEM 

HFSF 

HFSS 

HIPSS 

HiPerf PV 

HQ 

HRII 

HRTEM 

HSL 

HTF 

HVAC 

HWCVD 

IBAD 

IC 

ICP 

ICS 

IDIP 

IEA 

IEC 

IEC 

IEEE 

IEP 

IMA 

IPO 

IPP 

IR 

IREC 

IRR 

ISES 

ISET 

ISIS 

ISO 

ISP 

IST 

ITN/ES 

ITO 

I-V 

JEDI 

JGCRI 

Jsc 

J-V 

KIESD 

kW 

kWhe 

kWht 

LACSS 

LBNL 

LCA 

Government Performance and Results Act 

Global Positioning System 

Global Solar Energy 

Government Solar Installation Program 

gigawatt 

highly accelerated lifetime testing 

heat collection element 

Historically Black Colleges and Universities 

heat exchanger method 

High-Flux Solar Furnace 

high-flux solar simulator 

high-intensity pulsed solar simulator 

High-Performance Photovoltaics Project 

headquarters 

High-Reliability Inverter Initiative 

high-resolution transmission electron microscopy 

hybrid solar lighting 

heat transfer fluid 

heating, ventilating, and air-conditioning 

hot-wire chemical vapor deposition 

ion-beam-assisted deposition 

integrated circuit 

inductively coupled plasma 

integral collector storage 

In-Line Diagnostics and Intelligent Processing 

International Energy Agency 

Institute of Energy Conversion (at University of Delaware) 

International Electrotechnical Commission 

Institute of Electrical and Electronics Engineers 

Independent Energy Producer 

impact-modified acrylic 

initial public offering 

independent power producer 

infrared 

Interstate Renewable Energy Council 

internal rate of return 

International Solar Energy Society 

International Solar Electric Technologies 

Integrated Surface Irradiance Study 

International Standards Organization 

Institute for Sustainable Power 

Industrial Solar Technology 

ITN Energy Systems 

indium tin oxide 

current voltage 

Jobs and Economic Development Impact 

Joint Global Change Research Institute 

short-circuit current 

current density voltage 

Kentucky Institute for the Environment and Sustainable Development 

kilowatt 

kilowatt hour electric 

kilowatt hour thermal 

large-area, continuous-solar simulator 

Lawrence Berkeley National Laboratory 

life-cycle analysis 

219 Appendices
 

 

 

LCOE levelized cost of energy 

LD laser diode 

LED light-emitting diode 

LEED Leadership in Energy and Environmental Design 

LIPA Long Island Power Authority 

LOI letter of interest 

LP QCM liquid-phase quartz crystal microbalance 

MBE molecular beam epitaxy or mean bias error 

MBMDPE metallocene-based multi-density polyethylene 

mc multicrystalline 

MDC McDonnell Douglas Corporation 

MEG Multiple-exciton generation 

MLTE module long-term exposure 

MOCVD metal organic chemical vapor deposition 

MPP model power plant 

MPPT maximum power point tracking 

MSR Million Solar Roofs 

MT market transformation 

MTBF mean time between failure 

MURA Minority University Research Associates 

MW megawatt 

MYPP Multi-Year Program Plan 

MYRP Multi-Year Research Plan 

MYTP Multi-Year Technical Plan 

NABCEP North American Board of Certified Energy Practitioners 

NAHB National Association of Home Builders 

NARUC National Association of Regulatory Utility Commissioners 

NASA National Aeronautics and Space Administration 

NCPV National Center for Photovoltaics 

nc-Si nanocrystalline silicon 

NEC National Electrical Code 

NEMS National Energy Modeling System (of the International Energy Agency) 

NEPA National Environmental Policy Act 

NETL National Energy Technology Laboratory 

NGO non-governmental organization 

NIR near infrared 

NIST National Institute of Standards and Technology 

NMSU New Mexico State University 

NOCT normal operating cell temperature 

NRCC Northeast Regional Climate Center 

NREL National Renewable Energy Laboratory 

NSRDB National Solar Radiation Data Base 

NSTTF National Solar Thermal Test Facility (at Sandia National Laboratories) 

NTUA Navajo Tribal Utility Authority 

NWS National Weather Service 

NYSERDA New York State Energy Research and Development Authority 

OATS Outdoor Accelerated-weathering Testing System 

O&M operations and maintenance 

OMB Office of Management and Budget 

OMCVD organometalic chemical vapor deposition 

OPV organic photovoltaics 

ORC Organic Rankine Cycle 

ORNL Oak Ridge National Laboratory 

OTF Outdoor Test Facility (at National Renewable Energy Laboratory) 

OWIP Office of Weatherization and Intergovernmental Programs 

PAE planning, analysis, and evaluation 

Appendices 220
 

PBA Office of Planning, Budget, and Analysis 

PC polycarbonate 

PCD photoconductive decay 

PCU power conversion unit 

PDIL Process Development and Integration Laboratory 

PEC photoelectrochemical 

PECVD plasma-enhanced chemical vapor deposition 

PED pulsed electron-beam deposition 

PERT Performance and Energy Ratings Testbed 

PET polyethylene terephthalate 

PI principal investigator 

PIER Public Interest Energy Research (program of the California Energy Commission) 

PLD pulsed laser deposition 

PMMA polymethyl methacrylate 

PNNL Pacific Northwest National Laboratory 

PP polypropylene 

PPA power purchase agreement 

PPR polypropylene random copolymer 

PTL Photovoltaic Testing Lab (at Arizona State University) 

PV photovoltaics 

PVD physical vapor deposition 

PVME polyvinylmethylether 

PVMR&D PV Manufacturing R&D 

PVPS Photovoltaic Power Systems Programme (of the International Energy Agency) 

PVSAC Photovoltaic Systems Assistance Center 

PVSAM PV Systems Analysis Model 

PVSC Photovoltaic Specialists Conference 

PVSOL PV System Optimization Laboratory (at Sandia National Laboratories) 

QCM quartz crystal microbalance 

QD quantum dot 

QDLED quantum dot light-emitting diode 

QE quantum efficiency 

QSSPC quasi-steady-state photoconductance 

RCPCD resonant-coupled, photoconductive decay 

R&D research and development 

REAP Renewable Energy Academic Partnership 

REC renewable energy certificate 

RES Regional Experiment Station 

RFP request for proposal 

RFQ request for qualifications 

RITH roof-integrated thermosiphon 

RMOTC Rocky Mountain Oilfields Testing Center 

RMSE root mean square error 

RO reverse osmosis 

ROI return on investment 

ROWPU reverse osmosis water purification unit 

RPS renewable portfolio standard 

RSI renewable systems integration 

RSM reciprocal space map 

RT room temperature 

RTA rapid thermal annealing 

RTSE real-time spectroscopic ellipsometry 

RUS Rural Utilities Service (of the U.S. Department of Agriculture) 

SAC Solar America Cities 

SAI Solar America Initiative 

SAIC Science Applications International Corporation 

221 Appendices
 

 

 

 

SAM	 Solar Advisor Model 

SAS	 Solar America Showcases 

SBC	 systems benefit charge 

SBIR	 Small Business Innovation Research 

SDA	 Systems-Driven Approach 

SDHW	 solar domestic hot water 

SDSU	 South Dakota State University 

SEGIS	 Solar Energy Grid Integration Systems 

SEIA Solar Energy Industries Association 

SEM	 scanning electron microscope 

SEPA	 Solar Electric Power Association 

SERES Southeast Regional Experiment Station (at University of Central Florida) 

SERF	 Solar Energy Research Facility (at National Renewable Energy Laboratory) 

SETP	 Solar Energy Technologies Program 

SES Stirling Energy Systems 

SHC solar heating and cooling 

SHGR	 Solar Hydrogen Generation Research 

SHJ	 silicon heterojunction 

SHW	 solar hot water 

SIF	 stress intensity factor 

SIMS	 secondary ion mass spectrometry 

SKPM	 scanning Kelvin probe microscopy 

SLP	 service life prediction 

SMIF	 Standard Mechanical InterFace 

SMUD	 Sacramento Utility District 

SNL	 Sandia National Laboratories 

Solar PACES Solar Power and Chemical Energy Systems 

SolarDS	 Solar Deployment Systems (model) 

SOW	 statement of work 

SPC	 solid-phase crystallized 

SPIE International Society for Optical Engineering 

SRCC Solar Rating and Certification Corporation 

SRP	 Salt River Project 

SSE	 Surface Meteorology and Solar Energy (a NASA project) 

SSI	 Shell Solar Industries 

STC	 Standard Test Conditions 

STCH solar thermochemical hydrogen 

S&TF	 Science & Technology Facility (at National Renewable Energy Laboratory) 

SUNY State University of New York 

SURFRAD	 Surface Radiation Budget Network 

SWH	 solar water heating 

SWRES Southwest Regional Experiment Station (at New Mexico State University) 

SWTDI	 Southwest Technology Development Institute (at New Mexico State University) 

TA technical assistance 

TBD	 to be determined 

TCA	 thermal cycle annealing 

TCC	 transparent conductive coating 

TCDF	 Technology Commercialization Development Fund (at Sandia National 

Laboratories) 

TCO	 transparent conducting oxide 

TDMS	 thermal-desorption mass spectrometry 

TEM	 transmission electron microscopy; also technical exchange meeting 

TEP	 Tucson Electric Power 

TES	 thermal energy storage 

TIO	 Technology Improvement Opportunity 

TMY typical meteorological year 

Appendices 222
 

TOP 

TOU 

TPD 

TPP 

TRNSYS 

TRPL 

TVA 

TW 

UHV 

UL 

ULRF 

UN 

UNLV 

UNM/ME 

U of L 

UPS 

USAID 

USDA 

USGBC 

UV 

VASE 

VB 

VBM 

Voc 

VSHOT 

VTD 

WCPEC 

WGA 

WIP-I 

WMO 

WOM 

WREC 

WRR 

WVTR 

XPS 

XRD 

YDR 

ZEH 

theoretical overlay photographic 

time of use 

temperature-programmed desorption 

Technology Pathway Partnership 

TRaNsient SYstem Simulation Program 

time-resolved photoluminescence 

Tennessee Valley Authority 

terrawatt 

ultrahigh vacuum 

Underwriters Laboratories 

University of Louisville Research Foundation 

United Nations 

University of Nevada Las Vegas 

University of New Mexico Mechanical Engineering Department 

University of Louisville 

ultraviolet photoelectron spectroscopy 

U.S. Agency for International Development 

U.S. Department of Agriculture 

U.S. Green Building Council 

ultraviolet 

variable-angle spectroscopic ellipsometry 

valence band 

valence band maximum 

open-circuit voltage 

Video Scanning Hartmann Optical Test 

vapor transport deposition 

World Conference on Photovoltaic Energy Conversion 

Western Governors' Association 

Weatherization and Intergovernmental Program-International 

World Meteorological Organization 

weatherometer 

World Renewable Energy Congress 

World Radiometric Reference 

water vapor transport rate 

X-ray photoelectron spectroscopy 

X-ray diffraction 

yield, durability, and reliability 

zero energy homes 

223 Appendices
NOTICE

This report was prepared as an account of work sponsored by an agency of the United States government. 

Neither the United States government nor any agency thereof, nor any of their employees, makes any 

warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or 

usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not 

infringe privately owned rights. Reference herein to any specific commercial product, process, or service by 

trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, 

recommendation, or favoring by the United States government or any agency thereof. The views and opinions 

of authors expressed herein do not necessarily state or reflect those of the United States government or any 

agency thereof. 

Available electronically at http://www.osti.gov/bridge 

Available for a processing fee to U.S. Available for sale to the public, in paper, from: 

Department of Energy U.S. Department of Commerce 

and its contractors, in paper, from: National Technical Information Service 

U.S. Department of Energy 5285 Port Royal Road 

Office of Scientific and Technical Information Springfield, VA 22161 

P.O. Box 62 phone: 800.553.6847 

Oak Ridge, TN 37831-0062 fax: 703.605.6900 

phone: 865.576.8401 email: orders@ntis.fedworld.gov 

fax: 865.576.5728 online ordering: http://www.ntis.gov/ordering.htm 

email: mailto:reports@adonis.osti.gov 

Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste 
Prepared by the National Renewable Energy Laboratory (NREL)

NREL is a national laboratory of the U.S. Department of Energy

Office of Energy Efficiency and Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC

DOE/GO-102009-2662 • May 2009

Printed with renewable source ink on paper containing at

least 50% wastepaper, including 10% post consumer waste.