Silicon PV vs. thin film vs. concentration – The Future of Solar

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Silicon PV vs. thin film vs. concentration The
Future of Solar
featuring
co-sponsored by
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Your Presenters

• SolarWorld's Terry Jester is Director,
  Engineering and Operations of SolarWorld
  Industries America. She's been with the company
  for 28 years, and developed the standard Cz
  module the company has in production today.
• Global Solar's Mike Gering, President, joined the
  company in October, 2001 after an 18-year career
  at Litton Industries. Gering previously served 25
  years as a U.S. Marine.
• NuEdison's Joe Lichy, President and CEO, has 15
  years of experience in RD with Intel, QED, and
  PMC-Sierra, and is the inventor of NuEdison's
  upcoming flat-plate concentrator.

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Agenda

• Introduction to issues
• Presentations
• Silicon photovoltaics SolarWorld
• Thin film Global Solar
• Concentration NuEdison
• Questions from moderator
• Questions from audience

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History - 1975
Wafered silicon too expensive
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History - 1975
Wafered silicon too expensive
What actually happened
Source SunPower
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40
Best Cell Efficiencies in Lab
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Multijunction Concentrators Crystalline Si
Cells Thin Film Technologies Emerging dye
organic PV
32
28
24
20
Efficiency ()
16
12
8
4
0
2000
1995
1990
1985
1980
1975
2005
Source NREL
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Issues today

• Silicon panels
• Past accidental technology
• Present clear technology of choice, continued
  cost reduction
• Future crossroads, but not going away
• Thin film
• Efficiencies finally becoming competitive
• But theres more to the story than just
  efficiencies
• Best on big, commercial roofs with lots of space?
• Concentration
• No longer just thermal-only
• But installers dont want moving parts
• Predicated on silicon being expensive

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Benefits and drawbacks
Question becomes, what technology is best used
where, for what?
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Cost Development 2002 - 2010
Silicon
Wafer
Cell
Module
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Reduced wafer thickness over 10 years
Wafer thickness, produced industrially µm
main thickness 400 340
330 330 300 300 270 270 270 270 270
240 240 240 210 210 210 210 210
210 180 180

• 2000 2004 2005 2006 2007
• 100 125 156 156 156 156 / 210 mm
• length of wafer edge

100 200 300 400 Wafer thickness µm
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Silicon foil technology development
Silicon Sheet from Powder
Edge defined Film-fed Growth
String Ribbon
Ribbon Growth on Substrate
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What is CIGS?

• Polycrystalline Thin Film Photovoltaic Solar Cell
  Based on the Copper Indium Gallium Diselenide
  (CIGS) Material System
• Typical Structure
• Molybdenum/CIGS/Cadmium Sulfide/Indium Tin Oxide
• Formed on Substrates
• Glass
• Stainless Steel
• Polymer

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Process to Product

• Thin-Film deposition of 100 meter plus rolls
• Cell / Submodule Manufacturing
• Module Finishing
• Deployment

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Products to Market
Standard Solar Modules
Rugged Environment
Commercial Products
Silicon Cell Replacement
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Why thin-film CIGS?

• Higher efficiency
• Currently Global Solar Cells are 9-10
• NREL verified cells as high as 19
• Lower cost (in volume)
• Process costs are lower
• Manufacturing costs are lower
• Features
• Flexible substrate
• Cell size can be easily changed
• Benefits
• CIGS flexible cells are adaptable to the widest
  variation of solar power applications portable,
  glass PV, building integrated products
• In addition to portable applications, Global
  Solar cells are compatible with silicon industry
  manufacturing

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Concentration
Complementary technologies combine to yield
performance breakthroughs

• 1990s
• 1GHz Microprocessor
• Submicron lithography
• Planar processes
• Pipelined Architectures
• On-chip Caches
• Copper Interconnect
• Advanced Design Tools

• 2000s
• 1/Watt PV Module
• More Efficient Materials
• Thinner Wafers
• Concentrators
• Manufacturing Scale
• Yield Improvements

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Two Worlds of PV Concentrators

• High Concentration
• III-V Multijunction Cells
• Requires Tracking
• Requires Arid Climate
• Utility Scale Installations

• Low Concentration
• Si and CIGS
• Stationary
• Distributed Generation (rooftops, 5x energy
  value)
• Can accept diffuse light

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Concentrator Ecosystem
Thermodynamic Limit of Stationary Concentrators
Diminishing Economic Returns for Si
III-V MultiJunction Becomes Economical
Si, CIGS
Valley of Death
GaInP/GaAs/Ge
Vendor F
Vendor B
Vendor E
Vendor A
Vendor C
Vendor D
2X
5X
10X
100X
1000X
500X
1X
Concentration Factor
19
Future of Concentrators
With each new material generation, new
performance milestones will be reached. Each new
technology will struggle to meet the cost of the
older, more mature existing devices. Concentrators
are cell technology agnostic. Higher performance
materials benefit more from concentration. Concent
rators will provide the vehicle for accelerating
new materials into the market.
Source Martin Greene, The future of thin film
solar cells
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Questions
Terry Jester, Director, Engineering and
Operations SolarWorld (silicon PV) Mike Gering,
President Global Solar Energy (thin film) Joe
Lichy, President and CEO NuEdison (concentration)
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Silicon PV vs. thin film vs. concentration The
Future of Solar

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