Heliovolt is Making Cheaper Solar Cells with the $77 million in venture capital it has received:
Heliovolt is one of several startups developing a type of thin-film solar cell that converts light into electricity with a micrometers-thick layer of a copper-indium-gallium selenide (CIGS) semiconductor. Thin-film solar cells are attractive because they could produce electricity cheaper than conventional silicon solar cells. Although thin-film cells produce less electricity per square meter than conventional silicon solar cells do, they make up for this by using orders of magnitude less active material per square meter. This can result in significant savings. For example, generating one watt of electricity requires about 80 cents’ worth of silicon, but it only requires a penny’s worth of a semiconductor used in a thin-film cell, says John Benner, who manages electronic materials for photovoltaics research at the National Renewable Energy Laboratory (NREL), in Golden, CO. (Heliovolt is working with NREL to further develop its cells.)