The Role of Polycrystalline Th

Technologies in Competitive 

National Center for Photovoltaics

National Renewable Energy Laborator

Golden, Colorado USA

33rd IEEE PVSC, San Diego, CA 5/12-16/

Bolko von Roedern and Harin S

NREL/PR-520-43311Presented at the 33rd IEEE Photovoltaic Specialist Conference held May 11-16, 2008 in S
Acknowledgemen

• Past Thin Film program and interactio

subcontractors

• Martha Symko Davies for SAI materia• Long-time SERI/NREL support and fe
Presentation Outli

Update on comparing different PV technologiesIssues for Commercializing CdTe a

PV technologiesCommercial PV developments
The US PV companies i

• (1) First Solar: shipped: 120 MW, cap 08: 15• (2) Uni-Solar Ovonics: 48 MW, cap 08: 120 

• (3) Solar World (Shell): 35 MW, cap 08: 10• (4) Evergreen Solar: 16.4 MW, cap 08: 86 M

• US total: 266 MW, cap 08: 616 MW • Slide considers MW produced in US only
DOE/NREL PV contract p

• In the past: Thin Film Partnership and 

• Since 2006: Solar America Initiative
President’s Goal for the Solar America Init

Making Solar Cost-Competitive Nationwi
PV R&D pipeline will support technologies/co

with funding opportunities calibrated to matur
PV Technologies

• Following slide shows all of them

• Will come back to ordinate (not abscis

• Need to see where technologies are an

relative value

Near-term PV technol

“standard” wafer/ribbon Siamorphous silicon-----------------------------------------------

“Non-standard” wafer Si

a-Si (nc-Si) spectrum splitting multijunctionsCdTeCIGS------------------------------------------------

Next generation OPV and DSC------------------------------------------------Concentrators at all of the above levels
A Rigorous Scheme for Comparin

Term Potential of Different PV 

Technologies

• We needed to asses real efficiency n

knowing that champion cell results acommercial product are well docume

• Define the c/c ratio as the ratio betw

(stabilized) champion cell efficiency commercial product efficiency

• Assume that at some point in the fut

of 0.8 will be achieved for all technol

• Project cost effectiveness ($/W

p) ass

thin-film module will avoid Si wafer ccost the same as Si modules.
Web Survey of (“best”) Flat Plate Commerc

Eff. (%) Module T.coeff (%P/oC) Technolo

19.3 SunPower 315 -0.38 FZ-Si, ‘p

17.4 Sanyo HIP-205BAE -0.30 CZ-Si, ‘H

15.1 BP7190 -0.5 CZ-Si, ‘P

14.2 Kyocera KC200GT Only for Voc MC-Si 

14.2 SolarWorld SW 185 Only for Voc CZ-Si 

13.4 SolarWorld SW 225 Only for Voc MC-Si, 

13.4 Suntech STP 260S-24V/b MC-Si, 

13.3 Sharp ND-216-U1 not given MC-Si 

11.0 WürthSol. 11007/80 -0.36 CIGS 

10.4 First Solar FS-275 -0.25 CdTe 

8.5 Sharp NA-901-WP -0.24%/C a-Si/nc-S

6.3 Mitsubishi H. MA100 T2 -0.2 a-Si (1-j) 

6.3 Uni Solar PVL-136 (-0.21) a-Si (3-j) 

6.3 Kaneka T-SC Not given a-Si (1-j) 
Future commercial module perform

on today’s champion cell results an

of 80%

Technology Future commercial 

performance

Relative Performance (s.p. Si =1)

Relatiperforfilm c

Silicon (nonstand) 19.8% 1.18 0.85 (

Silicon (standard)

17.0% 1.00 1.00 (

CIS 15.9% 0.94 0.53 (CdTe 13.2% 0.78 0.64 (a-Si (1-j) 8.0% 0.47 1.06 (

a-Si (3-j) (or aSi/nc-Si) 9.7% 0.57 0.88 (
Summary:

• Champion cell results can predict commerci

performance

• Without a 15% efficient total-area stabilized 

be no commercial 10% low-cost module pro

• a-Si/nc-Si will need greater laboratory effic

competitive with competing technologies in 

• Near term, all technologies are competitive, 

modules with efficiencies >9% will lead the 

lower module prices.

• Concentrator systems, technically ready, wo

if a PV growth rate >~40%/per year was ma
Technical Issues (gen

• Efficiency value to be understood in c

efficiency, pilot, commercial)

• Better knowledge when to further opti

when to substitute or add new process

• Better knowledge as to what creates a 

instable module
Technical issues (CI

• How can very high efficiencies be ach

large areas under manufacturing condi

• What deposition processes are most pr

• What factors afflict module stability?

• How can we reduce In usage?
Technical issues (Cd

• What deposition processes are most pr

• What factors afflict module stability?

• Do we require improved back-contact

• How can we reduce Te usage?

• (Will there be customer acceptance of 

module?)
40 MW – Thin Film CdT

Field

Under Construction

Total Project Price: Euro – 130 Million

PV System Price: Euro – 3.25 / Watts

Completion Date: December 2008
US-owned, US manufactured modules by te

crystalline Si and Thin Films (incl. a-Si) 19
PVNews reported US production 

US production

0

20406080

100120140160180200

2001 2002 2003 2004 2005 2006 2007

year

MWp
Conclusions

• Who will win the PV race, non-standard Si, standard • U.S.-based commercial thin-film PV module product

of 29% in 2005, 45% in 2006 in the U.S., 65% in 200more rapid growth than crystalline Si PV

• Commercial module performance is increasing based 

knowledge. Today’s R&D will lead to future product 

• A sustained growth of PV technology >~40%/year w

resources than are currently available world-wide.