Public-Private Collaboration Yields Potential Solar Silicon Game-Changer

Developing a cheaper, more efficient means of fabricating solar photovoltaic (PV) cells could revitalize U.S. solar PV manufacturing, a technology invented here in the U.S. That's in addition to helping realize the Department of Energy's (DOE) SunShot Initiative goals of driving the cost of installed solar power capacity under $1 per watt -- a level competitive with fossil fuel-fired electricity generation.

U.S. solar silicon manufacturing startup Crystal Solar -- with the help of the U.S. DOE's National Renewable Energy Laboratory (NREL) -- has developed a new method for fabricating high-quality, high-efficiency monocrystalline solar silicon wafers at 100 times the throughput and half the cost of traditional methods.

Crystal Solar's innovative approach to fabricating silicon solar wafers garnered it an “R&D 100” award as one of the top technology innovations of 2013. If Crystal Solar can scale-up production, the new method “could be a game-changer, creating American jobs and stemming the flow of solar cell manufacturing overseas,” CEO T.S. Ravi of the Santa Clara, California-based company stated in an NREL news release.

Cooking with gas

Rather than fabricating solar silicon wafers by sawing thin slices from an ingot of silicon – the standard industry approach – Crystal Solar has developed a much more efficient and less costly direct gas-to-wafer method that entails growing layers of semiconducting silicon directly on reusable silicon substrates.

As NREL explains, Crystal Solar's new gaseous-deposition method offers “several advantages, including eliminating the waste incurred in the traditional approach, which involves sawing thin slices from a large ingot or block of silicon. In the new approach, wafers can be made thinner without compromising their quality or efficiency.”

Overcoming a hurdle to similar R&D efforts, Crystal Solar's gaseous deposition process also speeds up solar silicon fabrication. That also lowers manufacturing costs. Crystal Solar can produce as many as 500 wafers per hour and sells for less than $5 million. That translates to a cost per wafer of around 13 cents per watt -- “less than half the typical cost of 30 cents per watt for high-end wafers,” Ravi highlighted.

Critical government support

Government support has always been critical to guiding market forces toward new technologies that could prove socially, environmentally and economically beneficial. Just three years into the decade-long SunShot Initiative, the U.S. solar industry is more than 60 percent of the way towards realizing the SunShot goal to reduce the cost of utility-scale solar to a cost-competitive 6 cents per kilowatt-hour, as well as drive the cost of installed solar power systems down to under $1 per watt by 2020.

The rapid decline in costs and technological advances in U.S. solar and renewable energy technology have come despite the comparative paucity of private-sector, as well as government, investment in energy research and development (R&D), much less the investments in clean energy. As Bill Gates noted in a blog post on the need for “energy miracles”:

• Sixty percent of the federal government's R&D spending is on defense; about 25 percent is on health. Energy spending? 2 percent.


• The U.S. ranks 11th in overall percentage of gross domestic product that goes to energy research. (Finland and China are the top two, respectively.)


• R&D spending on energy isn't just a government problem. It's also a serious problem in the private sector. The energy industry invests less than half of one percent (0.42 percent) of its revenue in research. In contrast, the pharmaceutical industry puts 20.5 percent of sales into R&D, and aerospace and defense spends 11.5 percent.

Currently at the pilot-manufacturing stage, Crystal Solar is planning to build a factory here in the U.S. The company is “struggling to keep up with the people who want our wafers,” Ravi stated. "We believe this technology will probably thrive in the United States, that it will be cheaper to do it here than anywhere else in the world."

That would be a boon in terms of reviving the U.S. manufacturing base, which currently accounts for around 13 percent of economic activity. The success of Crystal Solar and NREL's collaboration is also a testament of the effectiveness and triple bottom line benefits that can result from public-private partnerships.

*Image credits: 1), 2) Crystal Solar/NREL; 3) NREL; 4) National Science Foundation