Solar Industry: No Breakthroughs Needed  

Technology Review has an article on the state of play in the solar power industry, with the industry declaring "incremental advances have made transformational technologies unnecessary" - Solar Industry: No Breakthroughs Needed.

The federal government is behind the times when it comes to making decisions about advancing the solar industry, according to several solar-industry experts. This has led, they argue, to a misplaced emphasis on research into futuristic new technologies, rather than support for scaling up existing ones. That was the prevailing opinion at a symposium last week put together by the National Academies in Washington, DC, on the topic of scaling up the solar industry.

The meeting was attended by numerous experts from the photovoltaic industry and academia. And many complained that the emphasis on finding new technologies is misplaced. "This is such a fast-moving field," said Ken Zweibel, director of the Solar Institute at George Washington University. "To some degree, we're fighting the last war. We're answering the questions from 5, 10, 15 years ago in a world where things have really changed."

In the past year, the federal government has announced new investments in research into "transformational" solar technologies that represent radical departures from existing crystalline-silicon or thin-film technologies that are already on the market. The investments include new energy-research centers sponsored by the Department of Energy and a new agency called ARPA-Energy, modeled after the Defense Advanced Research Projects Agency. Such investments are prompted by the fact that conventional solar technologies have historically produced electricity that's far more expensive than electricity from fossil fuels.

In fact, Energy Secretary Steven Chu has said that a breakthrough is needed for photovoltaic technology to make a significant contribution to reducing greenhouse gases. Researchers are exploring solar cells that use very cheap materials or even novel physics that could dramatically increase efficiency, which could bring down costs.

But industry experts at the Washington symposium argued that new technologies will take decades to come to market, judging from how long commercialization of other solar technologies has taken. Meanwhile, says Zweibel, conventional technologies "have made the kind of progress that we were hoping futuristic technologies could make." For example, researchers have sought to bring the cost of solar power to under $1 per watt, and as of the first quarter of this year one company, First Solar, has done this.

These cost reductions have made solar power cheaper than the natural-gas-powered plants used to produce extra electricity to meet demand on hot summer days. With subsidies, which Zweibel argues are justified because of the "externalities" of other power sources, such as the cost from pollution, solar can be competitive with conventional electricity even outside peak demand times, at least in California. And projected cost decreases will make solar competitive with current electricity prices in more areas, even without subsidies.

Representatives of the solar industry say the federal government should do more to remove obstacles that are slowing the industry's development. One issue is financing for new solar installations, which can be much more expensive if lending institutions deem them high risk. A recent extension of federal tax credits and grants for solar investments is a step in the right direction, many solar experts say. But more could be done. A price on carbon would help make solar more economically competitive and more attractive to lenders.

Stirling Energy Systems (SES), based in Phoenix, has decreased the complexity and cost of its technology for converting the heat in sunlight into electricity, allowing for high-volume production. It will begin building very large solar-power plants using its equipment as soon as next year.

The company is currently building a 1.5-megawatt, 60-unit demonstration plant that will use the company's latest design. Stirling expects to finish that project by the end of the year. It also has contracts with two California utilities to supply a total of 800 megawatts of solar power in Southern California. The first of the plants that will supply this power could be built starting the middle of next year, pending government permits and loan guarantees from the U.S. Department of Energy (DOE).

The projects are part of a resurgence in what's known as solar thermal power. Various solar thermal technologies were developed starting in the 1970s, but a breakdown in government funding and incentives caused them to stall before they reached a scale of production large enough to drive down costs and allow them to compete with conventional sources of electricity. "It was a classic problem with solar. The market support to bring solar to high volume wasn't there," says Ian Simington, the chairman of SES and chief executive of the solar division of NTR, a company based in Dublin, Ireland, that bought a controlling share of SES last year.

Recent state mandates and incentives for renewable energy have led to a new push to commercialize the technology. There are over six gigawatts of concentrated solar power under contract in the southwestern United States right now, says Thomas Mancini, program manager for concentrated-solar-power technology at Sandia National Laboratory in Albuquerque, NM. That's equivalent to about six nuclear-power plants. BrightSource Energy has contracts to provide 2.6 gigawatts of solar power with concentrated solar power (a previous version of this story cited only one of two 1.3 gigawatt contracts), and Solar Millenium has announced a project that would generate nearly one gigawatt of power.

Stirling Energy Systems technology uses 12-meter-wide mirrors in the shape of a parabolic dish to concentrate sunlight onto a Stirling engine. The difference in temperature between the hot and cool sides of the engine is used to drive pistons and generate 25,000 watts of electricity. The first phase of the company's large-scale projects will use 12,000 of these dishes to generate 300 megawatts of power. Simington expects electricity from the systems to cost between 12 and 15 cents per kilowatt hour, higher than the cheapest sources of electricity--such as coal-fired power plants--but competitive in many markets, especially in the afternoon, when prices are highest.

Earlier this month the company unveiled its production design. Compared to several prototypes that have been tested for several years at Sandia National Laboratory, the new design cuts about two metric tons from the weight of each dish and reduces the number of mirrors in each from 80 to 40. The simplified design can be built in large quantities using equipment in existing factories for automobiles.