Dow Chemical has developed a roof shingle that contains thin-film solar power cells and can be integrated into asphalt roofs, which are used in 90 percent of American homes. Dow executives said the solar shingles can be handled like a regular asphalt shingle and can be nailed right onto a roof and
walked on by roofers. The company will begin test-marketing the shingles in mid-2010 and the company will initially target new home construction. By 2015, Dow estimates that the market for the solar shingles could be $5 billion a year as builders increasingly make the solar roofs standard on new construction. The thin-film solar cells, made by Global Solar of Tucson, are less efficient than traditional photovoltaic arrays, but a Dow researcher that with the solar shingles covering large portions of a roof they could meet 40 to 80 percent of a homeowner’s electricity demand. Electricians are not needed to install the solar shingles but do have to connect the completed array to the home’s electrical system.