Made in the U.S.A. Photovoltaic Energy Solutions
John P. Benner Executive Director
Bay Area Photovoltaic Consortium Stanford, California
Institute for Materials Research Colloquium
Ohio State University March 6, 2012
Bay Area Photovoltaic Consortium
BAPVC
Bay Area Photovoltaic Consortium 2
Electricity from Photovoltaic Solar Energy Conversion
•Reliable •Bankable •Growing •Improving •Subsidized
Solar Electric Energy Today
Silicon Feedstock Ingot Growth Slicing Wafers
Cell Fabrication Module Encapsulation Photovoltaic System
Cash purchase. Includes all Federal, state, and local (utility) incentives, as of Q4 2010. State average retail electricity rates.
Principal Analyst: Sean Ong, NREL SEAC
$5/Watt
Cost Projections
BAPVC
Original Source: Deutsche Bank, January 2011; Systems are global (i.e., blended across geographies) My source: R. Swanson, IEEE PV Specialists Conf., June 2011
Installed System Price per Watt, 2008-2011
5
3Q10 Breakout
$3.17
$2.83
$3.72
$5.92
PV Learning Curve ($2010) Historical to 2002 with projection from Silicon Roadmap
6 R. Swanson, IEEE PV Specialists Conf., June 2012
Comparison to Actual
7
PV Learning Curve ($2010) Projected vs Realized
R. Swanson, IEEE PV Specialists Conf., June 2012
2011 $1.25/W
8 R. Swanson, IEEE PV Specialists Conf., June 2011
Wire saws
Wafer thickness 300
Wafer thickness 200
Wafer thickness 150
First Solar
PV Learning Curve ($2010) Projected vs Realized
BAPVC Photovoltaic Module Shipments (MWp)
0
5000
10000
15000
20000
25000
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
U.S. Europe Japan ROW China & Taiwan
9 Source data: Paula Mints, Principal Analyst, Navigant
BAPVC U.S. PV Production:
Supply Chain Perspective
PV Supply Chain 2010 Sales ($B)
PV Poly Silicon (exported) 2.5
Encapsulation -- Glass, EVA, Backsheet ~2
PV Equipment 1.4
PV Modules 1.6
U.S. % of Global PV Product Sales ~25%
Bay Area Photovoltaic Consortium 10
Source: SEIA/GreenTech Media. U.S. Solar Energy Trade Assessment 2011
BAPVC
• Re-gain U.S. Leadership in PV manufacturing • Establish significant PV generating capacity
The DOE SunShot Initiative
Bay Area Photovoltaic Consortium
“ The SunShot Initiative accelerates and advances existing DOE research efforts by refocusing its solar energy programs — valued at approximately $200 million per year — to make large-scale solar energy systems cost competitive without subsidies by the end of the decade.”
BAPVC Objective: Dollar-per-Watt Price for Utility Scale Systems
To achieve $1/W installed system, it is critical to get the module cost below $0.50/W.
Bay Area Photovoltaic Consortium 12
BAPVC The DOE SunShot Initiative
Bay Area Photovoltaic Consortium
Inst
alle
d S
yste
m P
rice
($/
Wp)
Cash purchase. Unsubsidized. State average retail electricity rates.
$1/Watt
Principal Analyst: Sean Ong, NREL SEAC
Note: Change to legend from previous slide.
Cost Projections
BAPVC Photovoltaic Manufacturing Initiative (PVMI)
• Industry-led consortium, SEMATECH – PVMC $62.5M Copper indium gallium selenide (CIGS) pilot line, in partnership with CNSE cSi metrology and wafering technologies, in partnership with UCF in Florida
• PV manufacturing development facility – SVTC $30.0M Baseline silicon solar cell tool set Development services Specialized tool bays & characterization
• Bay Area Photovoltaic Consortium – BAPVC $25.0M University Focus – Industry Led Stanford/Berkeley Host Support for University Research Nationwide Full Module Approach
Absorber photon management Contacts Substrate Characterization Module packaging Reliability
Bay Area Photovoltaic Consortium
Bay Area Photovoltaic Consortium (BAPVC) $25M funded within the DOE SunShot Initiative
Bay Area Photovoltaic Consortium
Co-Director: Yi Cui Stanford University
Co-Director: Ali Javey UC Berkeley
Executive Director: John Benner Stanford University
Industry Liaison: Stephen Eglash Stanford University
BAPVC Internal Research Partners
Bay Area Photovoltaic Consortium 17
Lead Institutions
Partner Institutions
BAPVC Initial Industry Members Reflect Full Supply Chain
Bay Area Photovoltaic Consortium 18
BAPVC DOE PVMI: Objectives
- Perform industry-relevant R&D to facilitate high-volume PV manufacturing - Establish scope of research with explicit industry support - Manage open and competitive solicitations - Develop highly trained workforce - Speed up commercialization of cutting-edge PV technologies
BAPVC plans to achieve all these objectives
Bay Area Photovoltaic Consortium 19
BAPVC Organization
Bay Area Photovoltaic Consortium
Executive Board Richard Swanson, Chair
BAPVC Management
Yi Cui, Co-Director Ali Javey, Co-Director
John Benner, Exec Director Steve Eglash, Industry Liaison
U.S DOE Sunshot PVMI
Industry Board • Executive • Members • Participating
Research Participants Internal
Research Participants Nationwide
Separate RFPs
Cost-Share Technology Guidance
Funding $5M Annually Program Guidance
BAPVC Operations Led by Industry Members
Bay Area Photovoltaic Consortium
InternalWorkshopCall ReleasedProposal Prep.Review January 12-13EvaluationExec. BoardNegotiation
NationwideIndustry BoardCall ReleasedConcept PapersDown SelectRFPProposal Prep.ReviewEvaluationExec. BoardNegotiation & Award
Apr May June JulyNov Dec Jan Feb Mar
Stanford Berkeley Nat'l Labs
BAPVC Our Whole Module Approach to Reach $0.50/W Modules
Transparent electrode
Antireflection
Absorber and junction
Substrate
Transparent electrode
Encapsulation
Bottom contact
Nanoscale photon management
Nanocone substrate
500nm
Substrates
50 µm
Metal nanowire transparent electrode
Novel electrodes
Substrate
H2O, O2, H2other active chemical
species
photochemical reactions
cracking and debonding
UV Exposure
defect evolution in nanomaterial
layers
surface weathering
Substrate
H2O, O2, H2other active chemical
species
photochemical reactions
cracking and debonding
UV Exposure
defect evolution in nanomaterial
layers
surface weathering
Reliability
Advanced materials characterization
Thin film absorber
Encapsulation
BAPVC Downward Trending Costs of PV Electricity Can Be be Sustained
Crystal Solar -- Vapor to Wafer Lift-Off
- single crystal film silicon; high rate epitaxy
Group 4 – much less than 50 µm
25 25
Rolling &
Heating
Solution-based
buffer growth
HW-CVD Si deposition (replacing numerous and
costly Si-processing steps)
Module Fabrication (common techniques for light trapping, top contacts, etc.)
Even thinner Silicon – Ampulse Manufacturing Process crystalline-silicon manufactured with thin-film economies
Ampulse “c-Stack”
BAPVC January 12 Industry Board Meeting $0.50/Wp @ 20% Module Efficiency
Topics particular relevance to industry • Thinner wafers – 50 um
(mechanical stress, breakage) • Low cost ingots compatible
with high efficiency • Direct wafer generation –
kerfless • Kerf loss reduction • Bulk passivation (hydrogen
passivation of multicrystalline wafers)
• Mono cast and other absorbers
Issues/Approach specific to Universities • Cleaning and texturing of 50 um thick
wafers (dry, black silicon etc) • Low cost cleaning (environmentally
friendly cleaning) • Inline emitters (HIT structure) – dry
(plasma doping, ion implant etc) • Simultaneous surface passivation and
light trapping – Light management – Bulk & surface defects – n-type Si
• Metallization - less Ag and new metallization scheme eg Cu etc
• Low cost methods for inline metrology • Better understanding of mono cast
(absorber)
Alta Devices 28.2% efficient thin-film cell
Source: B. Kayes, IEEE PVSC, June 2011
Voc = 1.13 V near perfect photon recycling
BAPVC III-V and CPV Concentrator Optics High Performance and Ultra-low Cost
Substrates and Absorbers
Measuring and Analyzing System Efficiency Novel low-cost substrates (e.g. not Si) Broadband cell ARC – incl low temp on acrylic Low-cost growth Non-fouling High Performance Mirror Designs (e.g. coatings)
Strategies for High Efficiency Cells (e.g. 2.2 eV Top Cell)
Eliminating the secondary 45% efficiency
Optics Reliability Non-incremental technolgies
High Performance and Low Cost Thermal Management
Test and measurement
Ultra-low cost packaging Indoor testing system for the module level
Novel Passive Cooling Measurement of optical efficiencies Reliable packaging Reliable packaging
ZnO, ITO 2500 Å
CdS or ZnS 500 Å
Mo 0.5-1 µm
Glass, Metal Foil,
Plastics
CIGS 1-2.5 µm
CIGS Device Structure
29
Higher Cell Efficiency through Higher Photo Current
30
•Record Jsc << Best Si
•Window materials – TCO and CdS – dominate losses.
•Improve buffer/emitter layers and photon management without sacrifice of Voc and FF values
Potential for efficiency = 20.3% x (40.5/35.4) = 23.2%
31
Coevaporated CIGS (on glass): road map
• Assumes current (2011) In and Ga prices (historic highs)
Goodrich, A.; Woodhouse, M.; Noufi, R. “CIGS Road Map”. NREL Technical Report (In preparation), 2011
BAPVC Transparent Metallic Electrodes
• Line width: Smaller than light wavelength 40 nm • Separation: ~ equal to light wavelength 400 nm
Bay Area Photovoltaic Consortium 32
J.Y. Lee, S.T. Connor, Y. Cui, P. Peumans,Nano Lett. 8, 689–692 (2008).
BAPVC Electrospinning of Nanofibers for
Transparent Electrodes
Bay Area Photovoltaic Consortium
(Pioneer: Y. Xia) http://www.youtube.com/watch?v=87uRQ7KwbB0
20 um
Pathways to increase CIGS Short Circuit Current Density from commercial (30 mA/cm2) to best lab cell (36 mA/cm2)
Slide 34
Action
Potential Current Increase
(mA/cm2)
Technical Risk
Pathways
Reduce CdS window layer thickness
1.5 Medium Develop 20 nm thick continuous CdS layer without shunting.
Larger band gap junction partner
2.5 Medium Replace CdS ( e.g. 2.5 eV) with wide bandgap emitter (i.e., ZnS (3.1 eV))
Improved TCO 1.5 Medium Develop TCO with high conductivity, transparency, environmental stability (i.e., a-InZnO)
Minimize reflection off CIG surface
1.5 Medium Develop a suitable low cost anti-reflection coating
BAPVC
Interconnects cost 12% of active area. - boost Jsc by 3 mA/cm2?
Advanced Scribe and Print
BAPVC Thin-Films 20% Module Efficiency Developing manufacturing process
Understanding the materials doping, defects, microstructure, boundaries, etc.
Controls and diagnostic tools for materials
Enabling next generation of thin-films Achieving high deposition rates/high throughput
TCO issue (coatings)
Uniform deposition of thin film
earth abundant new materials
High Performance Reliability
Photon management
Accelerated life tests for new materials
High deposition rate Identification of failure mechanisms
Improve CdTe champion cell efficiency Standardization of testing
Novel packaging
BAPVC U.S. Manufacturing Drivers
• Market – Competitive Without Subsidies
• Investment – R&D – Expansion Capital
• Time to cash flow positive • Advantage
– Production Cost – Shipping – Reduced Risk
• Supply, Inflation, Exchange Rates, IP Control – Great ideas
Bay Area Photovoltaic Consortium 37
BAPVC Summary
- The PV industry delivers significant amounts of high-value electricity, with improving technology replacing declining incentives.
- PV modules prices have been cut 10-fold in the past 20 years; cut in half during the past 18 months; and, are or will soon be competitive in most electricity markets.
- BAPVC provides a forum for industry and universities to jointly and creatively set direction and priorities for research in PV manufacturing technologies.
- We will find and fund the best university teams to deliver solutions in 3 to 5 years to our industry.
- Industry membership from full supply chain expedites technology transfer and we intends to generate abundant IP to exploit this benefit.
Bay Area Photovoltaic Consortium