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Operated for the U.S. Department of Energy 

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by Midwest Research Institute • Battelle 

Contract No. DE-AC36-99-GO10337 

K.E. Brown and R.L. Mitchell 

National Renewable Energy Laboratory 

W.I. Bower 

Sandia National Laboratories 

R. King 

U.S. Department of Energy 

Prepared for the 31st IEEE Photovoltaics Specialists 

Conference and Exhibition 

Lake Buena Vista, Florida 

January 3–7, 2005 

February 2005 • NREL/CP-520-37381 

PV Manufacturing R&D Project 

Status & Accomplishments 

Under “In-Line Diagnostics & 

Intelligent Processing” 
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PV MANUFACTURING R&D PROJECT STATUS & ACCOMPLISHMENTS UNDER 

“IN-LINE DIAGNOSTICS & INTELLIGENT PROCESSING” 

K.E. Brown,1

 R.L. Mitchell,1 W.I. Bower,2 and R. King3 1

National Renewable Energy Laboratory, Golden, CO 80401 2Sandia National Laboratories, Albuquerque, NM 87123 3

U.S. Department of Energy, Washington, D.C. 20585 

ABSTRACT

In 1991, the U.S. Department of Energy (DOE), 

National Renewable Energy Laboratory, and Sandia

National Laboratories embarked on a research partnership

with the U.S. photovoltaic (PV) industry by cost-sharing

industry-based R&D efforts.1

 The PV Manufacturing R&D

(PVMR&D) Project, an extension of the earlier PV

Manufacturing Technology (PVMaT) Project, aims at 

streamlining and improving the current PV manufacturing

technology to enable U.S. manufacturers to compete in

the global marketplace. Currently, PVMR&D has ten active

subcontracts with manufacturers working in several facets

of the U.S. PV industry; four subcontracts were completed

within the past year. 

BACKGROUND

The PV Manufacturing R&D (PVMR&D) Project is a

partnership with the U.S. photovoltaic (PV) industry in 

cost-shared manufacturing research and development

activities. The overriding PVMR&D mission is directed at

facilitating R&D to improve PV manufacturing processes

and equipment; accelerate manufacturing cost reductions

for PV modules, balance-of-systems components, and

integrated systems; increase commercial product

performance and reliability; and enhance the investment

opportunities for substantially scaling up U.S. 

manufacturing capacity and increasing U.S. market share.

Progress toward achieving these objectives is tracked by

analyzing the trends in direct module manufacturing costs, 

existing PV production capacity, and estimated cost

savings. 

A sampling of the achievements under the current “InLine Diagnostics and Intelligent Processing” (IDIP) 

procurement includes the development of an innovative

wafer molding manufacturing process, the implementation

of in-situ measurements of individual cells in a triple

junction during deposition, and the fabrication of sloped, 

insulated tiles for PV systems integration. Future work in

PVMR&D will be focused on improvements related to

yield, durability, and reliability. 

PROJECT IMPACT 

As part of its mission, PVMR&D is tasked with

facilitating manufacturing cost reductions and significant 

production capacity scale-up. To track progress toward

these goals, PVMR&D collaborates with its industry 

partners to compile a database of both historical and

projected values for manufacturing cost and capacity

figures, as well as estimated cost savings directly related

to project participation. 

Cost-Capacity Achievements

The overriding goals of PVMR&D are directed at

accelerating manufacturing cost reductions and enhancing 

the investment opportunities for substantially scaling up

U.S. manufacturing capacity. Figure 1 shows continued

progress toward meeting these goals: total PV

manufacturing capacity increased from 14 MW at the

project’s inception to 201 MW at the close of 2003, while

direct manufacturing costs, in 2003 constant dollars, 

decreased from $5.55 to $2.49 over the same time period. 

In this context, direct manufacturing costs is defined

as those costs directly associated with module production

and do not include research, sales, marketing, or general

administrative expenses. The cost shown here are 

calculated as a weighted average based on manufacturing

capacity. Production capacity represents the potential 

production if operating at full capacity.

Recapture of R&D Funding for PV Manufacturing R&D 

PVMR&D module manufacturing partners have

provided the Project with manufacturing cost reductions

that can be directly attributed to the efforts completed 

Fig. 1. U.S. PV manufacturing cost-capacity for 2003

1
under their cost-shared subcontracts. In addition to the

raw cost-savings data, manufacturers have also provided

information related to how those cost reductions will be

allocated. The recapture of the money invested by both

the U.S. DOE and the companies themselves can be

determined by analyzing how much of the cost reductions

will be passed on to consumers through lower prices and

how much will be retained by the company as increased

profits, debt reduction, or capital investment. 

Figures 2 and 3 show the recapture of public and

industry investment, respectively. This analysis shows that 

the public and industry both recaptured funds by mid1998, including all investments through 2003. 

IN-LINE DIAGNOSTICS & INTELLIGENT PROCESSING 

In 2001, PVMR&D launched IDIP solicitation with the

goal of improving process control on current production 

technology. Under this procurement, PVMR&D awarded a

total of fourteen subcontracts, ten of which are ongoing to 

date. The work to be performed under these subcontracts 

represents a broad range of activities throughout the PV 

industry, from encapsulant development to wafer

fabrication to complete system integration. 

Module Manufacturing & Support

AstroPower, Inc., focused efforts on improvements to

its Silicon-Film products and associated manufacturing

line. Under its recently completed PVMR&D subcontract, 

“High Volume Manufacturing of Silicon-Film Solar Cells

and Modules,” AstroPower developed a breakthrough

wafer-molding process to increase silicon utilization and 

throughput. Previously using a continuous-sheet method, 

AstroPower recently implemented a process that produces 

individually molded wafers, thus drastically reducing

waste. This process alone has reduced the amount of

silicon feedstock used per wafer by 30%, significantly

accelerating manufacturing cost reductions for

AstroPower’s APx-8 cell. Considerable gains in yield and

efficiency have resulted from implementing this process. 

Under the PVMR&D subcontract, “Large-Scale PV

Module Manufacturing Using Ultra-Thin Polycrystalline

Silicon Solar Cells,” BP Solar is developing a process to

produce and handle silicon wafers 100-μm thick on 290-

μm centers.2

 This effort includes the development of

models to explore changes to device parameters, an

examination of cutting media, as well as the development

of processes and equipment for demounting and 

subsequent handling of very thin silicon wafers. BP Solar

proposes to use thinner wafers to reduce silicon

consumption and cost. 

Fig. 2. Recapture of public investment in PVMR&D Fig. 3. Recapture of industry investment in PVMR&D

Energy Conversion Devices, Inc. (ECD), has

continued to advance the amorphous silicon (a-Si)

manufacturing technology of lower-tier subcontractor 

United Solar Ovonic. Under the “Implementation of a

Comprehensive On-Line Close-Loop Diagnostic System

for Roll-to-Roll Amorphous Silicon Solar Cell Production”

subcontract, ECD developed a comprehensive set of

diagnostic systems that provide continuous online quality 

monitoring for each cell in the triple junction device, 

closed-loop thickness control systems for the ZnO and

ITO deposition processes, and plasma monitoring systems

to optimize the deposition process.3

 Using this foundation,

ECD is now developing systems for continuous online

optimization and closed loop control of the a-Si thickness

and properties. 

Energy Photovoltaics, Inc. (EPV), achieved 

milestones related to productivity improvement and the

stabilization of PV module power output under its 

subcontract, “Productivity Enhancement for Manufacturing

of Amorphous Silicon PV Modules.” Through this work,

EPV substantially improved the automated RF matching 

network by implementing active feedback capabilities to

continuously tune conditions during deposition. In addition, 

EPV worked to improve the uniformity by employing an 

optimal combination of process conditions and

improvements in the deposition systems. 

Evergreen Solar, Inc., recently completed the second

phase of its subcontract, “Innovative Approaches to LowCost Module Manufacturing of String Ribbon Si PV

Modules.” During this subcontract, Evergreen has 

developed a means of growing two silicon ribbons from a 

single crucible.

4

 This breakthrough technology enabled

Evergreen to double silicon manufacturing capacity 

without requiring additional production space. Evergreen

2
focused on improving this dual-ribbon growth technique to

bring this technology into the production line.

Implementation of this silicon growth technique resulted in

significant cost reductions due to increased production

scale and savings on consumable goods. To date, 

Evergreen has demonstrated a 14.6% cell made from the

dual-ribbon material. 

Under the "Trajectory Oriented and Fault Tolerant

Based Intelligent Process Control for Flexible CIGS PV 

Module Manufacturing" subcontract, ITN Energy Systems,

Inc., in collaboration with Global Solar Energy (GSE), has 

developed trajectory-oriented predictive/control models,

fault-tolerance control, control platforms, and in-situ

sensors for implementation on GSE's CIGS production

line.5

 To date, ITN's focus on CIGS processing has led to 

physics-based and empirical models of CIGS deposition,

as well as the application of model-based control for CIGS

processing and predictive models for constructing new 

evaporation sources. Process improvements resulted in 

significant increases in CIGS uniformity, yield, throughput, 

and thickness control, including a 71% reduction in copper

variability. Further developments include in-situ sensor 

development and the potential for enhanced process

status monitoring and control of all deposition processes. 

RWE Schott Solar, Inc. (RSSI), focused on improving

the manufacturing processes for its edge-defined film-fed

growth (EFG) ribbon technology to boost yield, quality, 

process control, and throughput. RSSI is developing

Statistical Process Control (SPC) techniques and a

Computer Maintenance Management System (CMMS) 

under its current PV Manufacturing R&D subcontract, 

“EFG Technology and Diagnostics R&D for Large-Scale

PV Manufacturing.”6

 To date, RSSI has developed and 

installed the CMMS, enabling routine use of high-level

SPC on equipment performance throughout all three areas

of wafer, cell, and module manufacturing. These 

developments support RSSI in capacity scale-up for both

wafer and cell production. 

Under its “Development of an In-line Minority-Carrier

Monitoring Tool for Process Control During Fabrication of

Crystalline Silicon Solar Cells” subcontract, Sinton

Consulting, Inc., implemented improvements for its in-line

minority-carrier monitoring tool.7

 The instrument uses

quasi-steady-state photoconductance measurements to 

predict final cell efficiencies. When incorporated into the 

production setting, this tool has the potential to

significantly decrease manufacturing costs as lower

efficiency materials can be removed from production

during early processing stages. Due to the 0.4-s 

measurement time, the tool has a capacity of 30 MW per

year. In addition, Sinton has also designed a variety of tool 

configurations, enabling users to measure both boules 

and wafers. 

During the "PV Manufacturing R&D - Integrated CIS 

Thin-Film Manufacturing Infrastructure" subcontract, Shell 

Solar Industries, Inc. continued advancement of CIS 

production through development of high-throughput CIS 

absorber formation reactors and implementation of 

associated safety infrastructure, XRF measurement for 

process feedback, bar-code scribed serial numbers, and

intelligent processing functions for production.

8

 This work

addressed multiple production bottlenecks, thereby 

exercising the overall process at higher production rates

and laying the groundwork for evaluation of near- and

long-term manufacturing scale-up. 

Specialized Technology Resources, Inc. (STR), is

collaborating with U.S.-based PV manufacturers to 

develop and complete qualification testing on an

expanded line of high-performance, engineered

encapsulation for constructing PV modules under a 

subcontract entitled, “Development of New Low-Cost,

High-Performance, PV Module Encapsulant/Packaging

Materials.”9

 To date, STR has evaluated PV manufacturer 

input, identified formulation strategies, and developed

analytical models, all of which have contributed to the

manufacture of new encapsulants. The company improved

the performance of the new Super Fast Cure and Flame

Retardant EVA encapsulants and scheduled lamination

trials and IEC qualification testing. 

Under the “Development of Automated Production 

Line Processes for Solar Brightfield Module” subcontract, 

Spire Corporation designed a large-area, 800-W module

for utility-scale PV arrays and began development work for

the manufacturing equipment required to implement an

automated production line for such modules.

10 As part of

this effort, Spire recently completed fabricating and testing

a full-scale prototype automated string inspection system

for solar cells. The inspection system is capable of

detecting large, visible defects, as well as imperceptible

microcracks. This detection method, when incorporated 

into a production line, has the potential to decrease

current labor hours spent performing visual inspections

and to increase module yields by removing damaged cells

from production at an earlier stage. The implementation of 

this automated string inspection system has the potential 

to accelerate manufacturing cost reductions and to 

increase commercial production reliability.

Balance of Systems & System Integration

PowerLight Corporation has made many

improvements to the production of PowerGuard tiles 

during the “PowerGuard Lean Manufacturing” subcontract. 

Most significantly, the development of two new tile designs

greatly improved the manufacturability of PowerGuard,

creating the potential for drastic reductions in cost.11

Additionally, the production launch of the Gen II sloped tile

proved the manufacturing advantages of a continuous flow

process and the benefit of applying lean manufacturing

techniques to PowerGuard production. The Gen II flat tile

shows great promise for taking advantage of the 

improvements gained from lean techniques. Under its 

subcontract, PowerLight has been able to make significant

progress in reducing the cost of integrated PV systems. 

Over the course of the "Plug and Play Components

for Building-Integrated Systems" subcontract, RWE Schott 

Solar, Inc. (RSSI), is enhancing its systems for mounting

and wiring PV arrays on both flat and pitched roofs, in

addition to developing a 300-W AC module.12 A novel 

grid-interconnection device for residential PV applications 

has also been prototyped. A major accomplishment of this 

effort has been the development of the company's new

free-standing system for mounting large PV arrays on flatroof buildings, allowing for penetrationless installation. 

3
Efforts on the AC-module design to date have resulted in

the determination of the preliminary specifications for the

SunSine AC module and the design of the inverter

packaging and integration with the PV module. 

Xantrex Technology recently completed the work

effort under its PVMR&D subcontract, “PV Inverter 

Products Manufacturing and Design Improvement for Cost

Reduction and Performance Enhancements.” In the first 

phase of this subcontract, Xantrex developed the 

hardware for three advanced, high-impact PV inverter

products for grid-tied applications.13 The weight, size, cost, 

and conversion losses of these new inverters were

reduced by nearly 50% compared to current technology. In

addition, the effort resulted in cost-reduced, higherreliability, high-impact, PV products to market by

improving development, procurement, and manufacturing

efficiencies of the Xantrex inverter products. 

YIELD, DURABILITY & RELIABILITY 

The FY2003 procurement, “PV Manufacturing R&D—

Large-Scale Module and Component Yield, Durability, and 

Reliability,” is a continuation of the PV Manufacturing R&D

Project, which focuses on further accelerating the PVMaT

achievements and is designed to be impartial to various

PV technologies and manufacturing approaches. The 

goals are to improve PV manufacturing processes and

products while reducing costs, provide a technology 

foundation that supports significant manufacturing scaleup (500 MW total U.S. capacity), and position the U.S. 

industry to meet rapidly emerging large-scale deployment

and other markets. 

In response to the solicitation, the U.S. PV industry 

submitted an unprecedented 29 Letters of Interest (LOI): 

nine addressed non-module aspects of PV systems 

component manufacturing processes under Category A, 

“PV System and Component Technology,” whereas the

remaining twenty primarily addressed aspects of module

manufacturing processes under Category B, “PV Module

Manufacturing Technology.” Upon review, seventeen of

the LOIs were determined to be within the competitive

range. Negotiations are underway with potential

subcontractors under this procurement. 

CONCLUSIONS

To date, PVMR&D has made substantial contributions

to the U.S. PV manufacturing industry through cost-shared

research efforts. Based on an analysis of the current

trends in PV manufacturing, PVMR&D is facilitating

research activities that result in cost savings for both the

consumer and manufacturer, as demonstrated by both the

recapture analysis and demonstrated cost reductions. The 

current IDIP subcontracts have resulted in improved

manufacturing methods throughout the U.S. PV sector. 

REFERENCES 

[1] D. Mooney, R.L. Mitchell, C.E. Witt, R. King, and D.

Ruby, “PV Manufacturing R&D Accomplishments and

Status,” NCPV and Solar Program Review Meeting, 2003, 

pp. 964-7. 

[2] J. Wohlgemuth, and S.P. Shea, “Large-Scale PV

Module Manufacturing Using Ultra-Thin Polycrystalline

Silicon Solar Cells: Annual Subcontract Report,” NREL 

Report No. SR-520-35887, 2004. 

[3] T. Ellison, “Implementation of a Comprehensive OnLine Closed-Loop Diagnostic System for Roll-to-Roll

Amorphous Silicon Solar Cell Production: Phase I Annual

Report,” NREL Report No. SR-520-36610, 2004. 

[4] J.I. Hanoka, “Innovative Approaches to Low Cost

Module Manufacturing of String Ribbon Si PV Modules: 

Phase II, Annual Technical Progress Report,” NREL

Report No. SR-520-36908, 2004. 

[5] L. Simpson, “Trajectory Oriented and Fault Tolerant

Based Intelligent Process Control for Flexible CIGS PV 

Module Manufacturing Scale-Up: Phase II, Annual 

Technical Report,” NREL Report No. SR-520-36983, 

2004. 

[6] J. Kalejs, P. Aurora, B. Bathey, J. Cao, R. 

Gonsiorawski, B. Heath, J. Kubasti, B. Mackintosh, M. 

Ouellette, M. Rosenblum, S. Southimath, and G. Xavier,

“EFG Technology and Diagnostic R&D for Large-Scale PV

Manufacturing, Annual Subcontract Report,“ NREL Report

No. SR-520-37347. 

[7] R. A. Sinton, T. Mankad, S. Bowden, and N. Enjalbert, 

“Evaluating Silicon Blocks and Ingots with Quasi-SteadyState Lifetime Measurements,” 19th European PVSEC, 

2004, pp. 520-3. 

[8] D. E. Tarrant and R. R. Gay, “PV Manufacturing R&D –

Integrated CIS Thin-Film Manufacturing Infrastructure, 

Final Technical Report,” NREL Report No. SR-520-36982, 

2004. 

[9] S.C. Agro and R.T. Tucker, “Development of New LowCost, High-Performance, PV Module Encapsulant/ 

Packaging Materials: Annual Technical Progress Report,”

NREL Report No. SR-520-35683, 2004. 

[10] M. Nowlan, J. Murach, S. Sutherland, D. Miller, S. 

Moore, and S. Hogan, “Development of Automated

Processes for Utility Scale Photovoltaic Module

Production,” 19th European PVSEC, 2004, pp. 2149-52. 

[11] L. Hargis and J. Botkin, “PowerLight Corporation Lean

Manufacturing, Final Subcontract Report,“ NREL Report

No. SR-520-35881. 

[12] M.C. Russell, “Plug and Play Components for

Building-Integrated PV Systems: Phase I--Final Report,” 

NREL Report No. SR-520-36246, 2004. 

[13] R. West, “PV Inverter Products Manufacturing and

Design Improvements for Cost Reduction and

Performance Enhancements: Final Subcontract Report,” 

NREL Report No. SR-520-35885, 2004. 

4
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PV Manufacturing R&D Project Status and Accomplishments Under 

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NREL/CP-520-37381 

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In 1991, the U.S. Department of Energy (DOE), National Renewable Energy Laboratory, and Sandia National 

Laboratories embarked on a research partnership with the U.S. photovoltaic (PV) industry by cost-sharing industrybased R&D efforts. The PV Manufacturing R&D (PVMR&D) Project, an extension of the earlier PV Manufacturing 

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U.S. manufacturers to compete in the global marketplace. Currently, PVMR&D has ten active subcontracts with 

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