There has been a spate of efficiency advances announced by upstart companies with thin-film solar technology, reflecting the large investments made in the field over the past decade. Last week, Stion announced that its solar modules, or panels, can convert 13.4 percent of sunlight into electrical energy. Miasole, which makes flexible solar cells from a combination of copper, indium, gallium, and selenide (CIGS), last month claimed the world record thin-film efficiency with 15.5 percent.
Improving cell efficiency is one of the most powerful levers thin film solar companies have in competing on price per watt against polycrystalline silicon panel manufacturers--and pushing down the price for solar, in general. Commodity silicon panels have an efficiency in the range 15 percent. Thin film solar panels can be substantially less efficient, but because the cost of materials is so much lower, they can come in cheaper per watt.