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PV Manufacturing R&D Project 

Status and Accomplishments 

under "In-Line Diagnostics and 

Intelligent Processing" and 

"Yield, Durability and Reliability" 

Preprint 

D.J. Friedman, R.L. Mitchell, and B.M. Keyes 

National Renewable Energy Laboratory 

W.I. Bower 

Sandia National Laboratories 

R. King and J.A. Mazer 

U.S. Department of Energy

Presented at the 2006 IEEE 4th World Conference on 

Photovoltaic Energy Conversion (WCPEC-4) 

Waikoloa, Hawaii 

May 7–12, 2006 

Conference Paper 

NREL/CP-520-39904 

May 2006 
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PV MANUFACTURING R&D PROJECT STATUS AND ACCOMPLISHMENTS UNDER 

“IN-LINE DIAGNOSTICS AND INTELLIGENT PROCESSING” AND “YIELD, 

DURABILITY AND RELIABILITY”* 

D.J. Friedman1, R.L. Mitchell1, B.M. Keyes1, W.I. Bower2, R. King3, J.A. Mazer3

1

National Renewable Energy Laboratory, Golden, CO 80401 USA 2

Sandia National Laboratories, Albuquerque, NM 87123 USA 

3

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

ABSTRACT 

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

conducts cost-shared research and development 

programs with U.S. PV industry partners. There are 

currently two active industry partnership activities. “In-line 

Diagnostics and Intelligent Processing,” launched in 2002, 

supports development of new in-line diagnostics and 

monitoring with real-time feedback for optimal process 

control and increased yield in the fabrication of PV 

modules, systems, and other system components. “Yield, 

Durability and Reliability,” launched in late 2004, supports 

enhancement of PV module, system component, and 

complete system reliability in high-volume manufacturing. 

A second key undertaking of the PVMR&D Project is the 

collection and analysis of module production cost-capacity 

metrics for the U.S. PV industry. In the period from 1992 

through 2005, the average module manufacturing cost in 

2005 dollars fell 54% (5.7% annualized) to $2.74/Wp, and 

the capacity increased 18.6-fold (25% annualized) to 253 

MW/yr. An experience curve analysis gives progress ratios 

of 87% and 81%, respectively, for U.S. silicon and thin-film 

module production. 

INTRODUCTION 

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

conducts cost-shared research and development 

programs with U.S. PV industry partners. The goals of this 

partnership are to accelerate manufacturing cost 

reductions for PV modules, balance-of-systems 

components, and integrated systems; improve 

performance and reliability of commercial products; 

improve U.S. PV industry module manufacturing 

processes and equipment; and develop manufacturing 

technology to enhance investment opportunities for scaleup of U.S. PV manufacturing capacity. The Project 

monitors progress toward these goals by gathering data 

on U.S. PV manufacturing cost, and production capacity 

and level. 

There are currently two active industry partnership 

activities. “In-line Diagnostics and Intelligent Processing 

(IDIP)” supports development of new in-line diagnostics 

and monitoring with real-time feedback for optimal process 

control and increased yield in the fabrication of PV 

modules, systems, and other system components. This 

activity was launched in 2002 and currently has four active 

subcontracts. “Yield, Durability and Reliability (YDR),” 

supports enhancement of PV modules, system 

components, and complete system reliability in highvolume manufacturing. The first subcontracts in this 

activity were launched in late 2004 and the final ones in 

April 2006, for a total of 11 subcontracts, itemized below. 

SUBCONTRACTOR ACTIVITIES 

Subcontracts are selected by competitive 

procurements. The two procurements currently active are 

described below. 

In-line Diagnostics and Intelligent Processing (IDIP) 

The IDIP procurement is directed at improvements in 

module manufacturing processes; system and 

manufacturing flexibility; and balance-of-system 

development. These subcontracts emphasize new and 

improved in-line diagnostics and monitoring with real-time 

feedback for optimal process control and increased yield 

in the fabrication of PV modules, systems, and other 

system components. Subcontracts active as of April 2006 

are listed in Table I. 

Yield, Durability and Reliability (YDR) 

The YDR procurement is directed at enhancing 

module, system-component, and complete-system 

reliability. Focus areas for these goals are improvement of 

module-manufacturing processes; system and systemcomponent packaging, integration, manufacturing, and 

assembly; product manufacturing flexibility; and balance-

*This work has been authored by an employee or employees of

the Midwest Research Institute under Contract No. DE-AC36-

99GO10337 with the U.S. Department of Energy. The United 

States Government retains and the publisher, by accepting the

article for publication, acknowledges that the United States 

Government retains a non-exclusive, paid-up, irrevocable, 

worldwide license to publish or reproduce the published form of

this work, or allow others to do so, for United States Government 

purposes. 

1
Table II. YDR subcontractors, listed in alphabetical order 

by company name.

Subcontractor Title of Subcontract 

BP Solar International, Inc Development of Large High-Voltage 

PV Modules with Improved 

Reliability and Lower Cost 

Dow Corning 

Corporation 

High Performance Packaging 

Solutions for Low Cost, Reliable PV 

Modules 

Evergreen Solar Low-Cost Manufacturing of HighEfficiency, High-Reliability String 

Ribbon Si PV Modules 

First Solar, LLC Implementation of Reliable 

Manufacturing of Higher Efficiency 

First Solar Modules 

GE Energy Solar Cell Design for 

Manufacturability 

PowerLight 

Corporation 

Accelerating PV Cost Effectiveness 

Through Systems Design, 

Engineering, and Quality Assurance 

Schott Solar, 

Inc. 

High Performance Multicrystalline 

Modules and Products 

Shell Solar 

Industries 

Photovoltaic Module Manufacturing 

Technology 

Shingleton 

Design 

One-Axis Trackers - Improved 

Reliability, Durability, Performance, 

and Cost Reduction 

SunPower 

Corporation 

Automated Manufacturing of High 

Efficiency Modules 

Xantrex 

Technology 

Advanced, High Reliability, System 

Integrated 500kW Photovoltaic 

Inverter Development 

Table I. IDIP subcontractors during FY 2006, listed in 

alphabetical order by company name. 

Subcontractor Title of Subcontract 

BP Solar International, Inc. *Large-Scale PV Manufacturing 

Using Ultra-Thin Polycrystalline 

Silicon Solar Cells 

Energy 

Conversion 

Devices, Inc. 

Implementation of a Comprehensive On-Line Closed-Loop Diagnostic System for Roll-to-Roll Amorphous Silicon Solar Cell Production 

Evergreen Solar, 

Inc. 

*Innovative Approaches to Low 

Cost Module Manufacturing of 

String Ribbon Si PV Modules 

ITN Energy 

Systems 

*Trajectory-Oriented and Fault 

Tolerant Based Intelligent Process 

Control for Flexible CIGS PV 

Module Manufacturing 

Schott Applied 

Power, Inc. 

Plug and Play Components for 

Building-Integrated PV Systems 

Schott Solar, 

Inc. 

*EFG Technology and Diagnostics 

R&D for Large-Scale Manufacturing 

Specialized 

Technology 

Resources, Inc. 

Development of New Low-Cost, 

High-Performance, PV Module 

Encapsulant/Packaging Materials 

Spire 

Corporation 

Development of Automated 

Production Line Processes for 

Solar Brightfield Modules 

*Research completed as of April 2006. 

of-systems development. The YDR subcontracts are 

shown in Table II. 

Selected Highlights of Subcontractor Activities 

BP Solar developed a process to use thinner wafers to 

decrease Si consumption and cost. For this effort they 

completed process equipment specifications for sawing, 

demounting, and handling 100 μm wafers cut on 290 μm 

centers, and reduced wafer thickness in production from 

250 to 220 μm. They have also introduced lead-free 

interconnects on all BP Solar multicrystalline Si modules, 

and new junction boxes on all commercial products. 

Dow Corning Corporation is developing prototype 

encapsulant materials with fast lamination speed, 20% 

faster than typical EVA lamination times, and the potential 

for non-laminator assembly methods such as pinch rollers. 

They have completed initial prototype laminations to 

determine minimum thicknesses for the adhesive and 

encapsulant layers by demonstrating bubble-free 

laminates and suitable samples for cut and voltage breakthrough testing. 

Energy Conversion Devices has completed testing of 

an on-line PV capacitive diagnostic system to stabilize and 

optimize a-Si deposition, improving both solar cell 

efficiency and production yield. They have also developed 

optical reflection spectrometers for online QA/QC and 

closed-loop control of film thickness and cross-web 

uniformity of several of the critical layers in their cell 

structure. 

Evergreen Solar has designed and bench-tested a 

new in-situ ribbon cutting apparatus for their string 

ribbon® Si-based PV modules. Because of the success of 

tests, implementation of a pilot phase has been 

accelerated. A move to thinner 170 μm wafers is under 

development, focusing on process yield improvement in 

the glass etch, decal application, and tabbing and 

stringing steps. 

First Solar is currently ramping up activity on their 

subcontract, which will develop advanced front contact 

window layers, an enhanced semiconductor vapor 

transport deposition system, and improved post-deposition 

processing. 

GE Energy is currently ramping up activity on their 

subcontract, which will develop a set of improvements to 

their silicon-film cells and also a low-cost silicon-film 

module. 

2
ITN Energy Systems has implemented improved 

process controls and fault-tolerance procedures on the 

Global Solar production line, resulting in an 85% increase 

in yield and a 13% increase in cell efficiency. 

PowerLight has improved their PowerGuard product 

manufacturing, including a reduction in the cost of the 

mortar coating of the foam backer-boards, as a result of 

input from accelerated testing. They have completed 

design of a prototype foamless PV roof tile and 

implemented production of PowerGuard tiles for 

customers without the need for added insulation. 

Schott Applied Power has developed a new design for 

a free-standing mounting system bracket, allowing the 

module to be completely free to rotate to shallower angles 

in response to wind forces and to prevent it from overrotation; this design has been rigorously validated, 

including wind tunnel testing on scale-model array design. 

Schott Solar has raised the production yield for their 

EFG (Edge-defined Film-fed Growth) wafers, 

demonstrating high-yield processes for 250-μm EFG 

wafers, implementing a higher cutting speed laser (+60%), 

and cutting cycle time reduction (~20%). They have 

integrated diagnostic equipment and statistical methods 

for high-speed monitoring of wafers, cells, and processes 

in their 60-MW manufacturing facility, resulting in a 15% 

increase in wafer and cell operational throughput. 

Shell Solar has introduced a thin 125 μm wafer-cutting 

wire to their pilot production mode, giving an increase of 

almost 8% in watts out per kg of silicon input for a 

significant cost improvement and demonstrating a 

production increase of over 6% for over 500 saw runs. 

SunPower Corporation, a new member of the PV 

Manufacturing R&D Project, introduced an antireflective 

glass to their module design, resulting in a module with a 

223 W power output and a corresponding 17.9% total-area 

efficiency, as verified by NREL. SunPower also developed 

and successfully tested a lead-free interconnect system, 

finding an additional benefit of increased resistance to 

fatigue failure. 

Specialized Technology Resources Inc. developed a 

new thin-film encapsulant formulation which is thinner and 

has improved glass adhesion. 

Spire Corporation built and tested an automated 

module lay-up process system for large-area modules, as 

well as a robotic string busing system, which automatically 

connects solar cell strings together and installs bypass 

diodes in the cell circuit before lamination. They also 

demonstrated a method for forming shallow, fine-pitch 

corrugations in copper ribbon to relieve stress and 

maintain high yield in the cell string soldering process. 

Xantrex Technology is currently ramping up activity on 

their subcontract, which will develop the architecture, 

system components, software, and control circuits for a 

500-kW system-integrated PV inverter. 

PROGRESS IN MANUFACTURING COST, CAPACITY 

AND PRODUCTION LEVEL 

To track the progress of these activities in meeting the 

project objectives, and to monitor the state of U.S. PV 

manufacturing as a whole, the PVMR&D Project annually 

gathers data from a variety of industry contributors. The 

data aggregate a significant majority of the U.S. PV 

industry on manufacturing cost ($/Wp) and production 

capacity (Wp/yr). Other company cost centers or costs not 

directly related to manufacturing, such as marketing, 

administration and sales, are excluded. Cost data include 

all manufacturing costs and manufacturing-related 

overhead costs associated with the actual manufacturing 

of modules and cells/wafers. The cost values represent 

the actual cost of producing modules at each year's 

specific capacity level. 

Production capacity data represent the actual capacity 

of the manufacturing facility, as determined by the ratelimiting processes. Regularly scheduled maintenance and 

down time are included, assuming a fully staffed 

production line. Production level data represent the actual 

megawatts of modules produced on the production/pilot 

lines, including cells/wafers and modules that were not 

used for sale but were of product quality. Finally, 

projections five years into the future were solicited from 

the contributors for cost/capacity/production. 

Figure 1 shows the progress in combined crystallineSi/thin films/concentrator module manufacturing 

production cost vs. capacity from 1992 to 2005, as well as 

the projections to 2010. From 1992 to 2005, the average 

module manufacturing cost decreased 54% to $2.74/Wp 

(in 2005 dollars), an average 5.7%/year decrease, while 

the production capacity increased 18.6-fold to 253 MW, an 

average 25%/year increase. These numbers represent a 

slight slowdown in cost decrease and capacity increase 

reported previously [1] for the 1992-2003 data set. This 

change is attributable to a recent temporary shortage in 

silicon feedstock as discussed further below. 

Figure 2 shows the production levels and 

manufacturing plant utilization (production/capacity) over 

the same time period, for both thin-film and silicon 

6

5

4

3

2

1

10 2 3 4 5 6 7 8

100 2 3 4 5 6 7 8

1000 2

Total PV Manufacturing Capacity (MW/yr)

"Average" Module

Manufacturing Cost ($/Wp)

13 PV Manufacturing

R&D participants with

active manufacturing

lines in 2005.

Direct module manufacturingcost only

(2005 Dollars)

Overall PV Industry:

Crystalline Silicon, Thin Films,

and Concentrators

1992

1993

1994

1995

1996

1998

1999

2000

2001

2002

2005

2010

2006

2007

2008

2009

2005 Data 2003

2004

Fig. 1. U.S. PV module manufacturing cost vs. capacity. 

3
modules. Also shown is the fraction of production due to xSi vs. thin films. The manufacturing plant utilization for Si 

modules have to date been quite stable from year to year, 

while thin-film manufacturing plant utilization has 

fluctuated much more. There was a pause in the growth of 

Si production in 2003-2005, attributable to a silicon 

feedstock shortage. This growth pause is projected to 

continue into 2006, but a return to normal growth is 

anticipated in 2007. 

1.0

0.5

0.0

Plant Utilization

1995 2000 2005

Year

1

10

100

1000 Production (MW)

 x-Si

 Thin Film

Production

Manufacturing Plant Utilization 2005 data

1.0

0.8

0.6

0.4

0.2

0.0

Production Ratio

1995 2000 2005

Year

Production Ratio

x-Si/(x-Si+Thin Films)

x-Si

thin films

Fig. 2. Manufacturing production levels, plant utilization 

(production/capacity), and production ratio for crystalline 

silicon and thin-film PV. 

The relationship between production level and cost is 

shown in Fig. 3 in the form of “experience curves.” In this 

analysis, the dependence of cost upon cumulative

production (i.e. “experience”) is considered. It is often 

observed empirically that cost decreases according to an 

inverse exponent of the cumulative production. The value 

of the exponent determines the “progress ratio,” the 

fraction by which the cost falls for each doubling in 

cumulative production. Figure 3 shows that over the 1992-

2003 period, silicon module production cost has followed a 

fairly stable learning curve with an 87% progress ratio. In 

2004-2005 the cost actually rose, attributable to the silicon 

feedstock shortage as previously noted. This rise in cost is 

projected to be only a temporary anomaly, and the overall 

trend of costs falling with a roughly 87% progress ratio is 

forecast to continue through 2010. For thin-film production, 

the data are less well described by a learning curve due to 

an anomalous rise in costs in 2001-2003 due to redesigns 

of the modules during that time period. The fit to a learning 

curve is shown in Fig. 3 as the dashed line, with a 

progress ratio of 81% from 1992 to 2010. 

6

7

8

9

1

2

3

4

5

6

7

8

9 10

Module Manufacturing Cost (2005$/Wp

100 101 102 103 104

Cumulative Production (MW)

 x-Si

 Thin Film

 PR=87%

 PR=81%

1992

1993

2005 2010

2005

2010

2005 data

Fig. 3. Experience curve plot of module cost vs. 

cumulative production for x-Si and thin-film modules. The 

solid line represents a progress ratio=87% fit to the 1992-

2003 x-Si data. 

ACKNOWLEDGMENTS 

This work is supported or funded under DOE Contract 

No. DE-AC36-99GO10337. The core of the PV 

Manufacturing R&D Project is the participation of the 

industry partners. We are especially grateful to the 

companies for providing their production cost-capacity 

data to the industry survey presented here. We also thank 

S. Pedigo and A. Hicks for their many contributions to the 

Project. 

REFERENCES 

[1] K.E. Brown, R.L. Mitchell, W.I. Bower, and R. King, “PV 

Manufacturing R&D Project Status & Accomplishments 

Under In-Line Diagnostics & Intelligent Processing”, 

Proceedings of the 31st IEEE Photovoltaic Specialists 

Conference, 2005, pp. 1671-1674. 

4