With typical efficiency ratings for crystalline-silicon cell PV modules hovering for years in the mid-teen percentages, new technology that doubles that performance level could be a huge breakthrough for the solar industry and PV system developers.
According to Semprius, Inc., an innovator in high-concentration photovoltaics (HCPVs) based in Durham, N.C., cells made with its proprietary microtransfer printing process have achieved independent test efficiencies of 41%—with modules using these cells testing out at 33.9%. Testing was conducted by the Solar Energy Institute of the Polytechnic University of Madrid.
The transfer printing process allows the manufacturer to “grow” the cells, lift them with a rubber stamp off a substrate by the thousands, and then “print” or stamp them onto ceramic substrates used in the modules. This process is key to the cost efficiencies that Semprius claims will come with the technology.
Like other concentrated PV modules, Semprius’ HCPV modules rely on optics to increase their output, but due to the cell design, the company can combine a primary glass lens on the module with secondary ball lenses over each tiny cell, increasing output and making the module profile much thinner than its competitors. Because lens-concentration technology relies on direct sunlight for maximum performance, clear, dry, and sunny climates are the best locations for HCPV installations.
Semprius was founded in 2005 as an offshoot of research at the University of Illinois, and after further development with the National Renewable Energy Laboratory. The company’s module was named to MIT’s 2012 list of the 10 most important emerging technologies, and Siemens AG recently acquired 16% of the company.
Semprius’ target now is utility-sized installations, and within a few years the company expects to be able to produce systems that will generate electricity for around $0.08 per kilowatt-hour, less than the average retail price of about $0.10 per kWh in 2011.
Manufacturing at a new Henderson, N.C., facility will begin later this year. The company expects to manufacture enough panels to deliver 6 MW of electricity annually and expand that to 30 MW by the end of 2013. —Rick Schwolsky