Can solar concentrating photovoltaic (CPV) technology, which uses a hybrid of solar cells and solar thermal technologies to generate electricity, ever become mainstream? A new project shows it just might: Tenaska Solar Ventures will develop 150 MW of CPV systems that will produce electricity for San Diego Gas & Electric, the companies said Thursday.
The 150 MW project, which will use gear from CPV tech maker Concentrix Solar, dwarfs the previous largest planned CPV project of 30 MW project announced last year. Project developer Cogentrix Energy said it would use equipment from California-based Amonix to build that 30 MW power plant and sell electricity to Utility Public Service Co. in Colorado.
A CPV system relies on mirror and lenses to concentrate and direct sunlight onto solar cells, which typically use multi-layers of gallium arsenide, germanium and other materials in the III-V semiconductor group. These multi-junction solar cells are expensive but much more efficient at converting sunlight into electricity than silicon solar cells that are common in solar panels on the market today. The use of optics to concentrate the sunlight makes it possible to use only slivers of the multi-junction solar cells.
Although CPV technology sounds promising, it has struggled to attract project developers. One key reason is the competing solar technologies, such as solar panels using silicon solar cells, have become much cheaper in the last two years than they were five years ago when CPV seemed like a cost-effective alternative. Plus, project investors tend to shy away from new technologies until they see proof that the new technologies can deliver good returns.
“CPV is an example of a type of technology that the (U.S. Department of Energy’s) loan guarantee program can help to bring projects to fruition and reduce risks perceived by the private sector,” said Tom Kimbis, director of policy and research at the Solar Energy Industries Association.
The largest CPV installation in the U.S. currently is the 1 MW project completed by SolFocus at Victor Valley College in Southern California last year. CPV technology is more suitable for sunny and dry climates because its equipment works best in cloudless days. Large-scale projects that serve utilities are more likely to be built in the southwestern region of the country, said Shayle Kann, managing director of solar practice at GTM Research.
The Tenaska project is set to rise on 1,057 acres in Southern California’s Imperial County and will be named Imperial Solar Energy Center West. The company expects to complete the power plant in 2015 and has signed a 25-year power sales agreement with SDG&E, which lags behind two other main utilities in the state in meeting a mandate to buy 20 percent of its electricity from renewable sources by 2010 (the utilities have until 2013 to meet that requirement).
SDG&E was able to get to 11.9 percent of its electricity from clean power in 2010, compared with 19.4 percent by Southern California Edison and 17.7 percent by Pacific Gas and Electric, according to the California Public Utilities Commission. The three utilities also have been signing power purchase agreements or planning their own projects to meet a 2020 requirement to raise that clean power level to 33 percent.
Concentrix’s parent company, France-based Soitec, plans to build a CPV equipment factory in the San Diego area that will have 200 MW of annual production capacity, the company said. The factory will make the equipment for the 150 MW Imperial project, and Soitec expects to start delivering equipment in early 2013. But the factory project appears to be contingent on Tenaska getting an Energy Department loan guarantee for the power plant project. Neither Tenaska nor Soitec disclosed the cost of the power plant or the power plant project.
Photo courtesy of Concentrix