SOLAR TODAY - April 2011

advances

solar technology | analysis | markets

D.C. Reneges on Incentive Grants 13 Fire Safety in PV Systems 14 Clean Air Act Under Attack 15

SunShot: Is a Buck a Watt Feasible?

Energy Secretary Steven Chu in February launched the SunShot initiative, with the goal of bringing the installed cost of utility-scale solar down to $1 per watt by 2020. The program awards $27 million to nine new solar projects, tasked with reducing supply chain costs and opening new markets.

It sounds ambitious. Ken Zweibel, who was program director for thin film at the National Renewable Energy Lab before founding PrimeStar Solar (now a GE subsidiary), calls it a “stretch goal.”

Back in 1999, while at NREL, Zweibel published a paper laying out a roadmap to 33
cents per watt, positing 15 percent efficiency. “That’s not realistic on the 2020 timeframe,”
Zweibel said. “Manufactured cost at First Solar is now about 75 cents per watt, for mod-
ules with efficiency around 11 percent. To deliver modules at 33 cents per watt we need
to see significant improvements in both efficiency and production costs. We can do it with
the technology we have today — we don’t need big breakthroughs. It will come through
a thousand cost cuts. The effort will be very good for PV [photovoltaics].”
Inverters need to make progress, too. Richard Thompson, CEO of Power-One, said
“The goal is extremely ambitious, considering prices today are in the $3.50 to $4.00

range for installations.” He noted that utility-scale inverters are now selling for about 20 to 22 cents per watt. “The overall price on the inverter will have to drop even further, say to 10 or 12 cents per watt, in order to meet the SunShot goal,” he said. “That can be accomplished through higher-density products and production-scale economies when PV reaches parity with other sources of energy. Grid parity is reached as we approach the $1.50 range. I’ve read reports recently that estimate the cost of the inverter in a $1.50 system at 15 cents per watt.”

The best available price for thin-film modules today stands at $1.25 per watt, so meeting the goal requires about a 75 percent reduction (as opposed to a 50 percent cut for inverters). An installed cost of $3.50 implies $2.00 for construction and financing. When PV modules sell for 33 cents and inverters for 10 to 12 cents, the SunShot goal will need construction-related costs to drop more than 70 percent. At $1.50 a watt, construction costs need to come down about 65 percent. —SEth MaSia

SunShot Grant Recipients 1366 Technologies — $3 million, Lexington, Mass. Develop the “direct wafer” process, which avoids sawing individual wafers from blocks of silicon. 3M — $4.4 million, St. Paul, Minn. Commercialize a flexible topsheet, enabling production of flexible photovoltaic modules. Caelux — $1 million, Pasadena, Calif. Develop a flexible PV-manufacturing process that minimizes the amount of semiconducting material used. Crystal Solar — $4 million, Santa Clara, Calif. Commercialize single-crystal silicon wafers, four times thinner than standard cells. PPG — $3.1 million, Cheswick, Pa. Develop a new glass article for the cadmium telluride module-manufacturing industry. Solexant — $1 million, San Jose, Calif. Develop a new printable nanoparticle thin-film ink from common nontoxic substances. Stion — $1 million, San Jose, Calif. Develop a technology consisting of two stacked high-efficiency thin-film devices, offering improved absorption of light. Varian Semiconductor — $4.8 million, Gloucester, Mass. Reduce the cost of manufacturing interdigitated back-contact cells. Veeco — $4.8 million, Lowell, Mass. Commercialize a low-cost multi-stage thermal deposition production process for CIGS modules.