Dow Chemical has dropped its line of building-integrated photovoltaic (BIPV) roofing shingles, reports Green Building Advisor's Scott Gibson.

The company will stop accepting orders for its Powerhouse Solar System on July 28. The product, introduced five years ago, integrates low-cost, thin-film PV cells into a proprietary roofing shingle that can be interwoven into standard asphalt roofing. Gibson has the low-down on what has caused Dow to pull it from the market:

The solar shingles are manufactured with flexible solar cells made with copper indium gallium selenide (CIGS) produced by NuvoSun, a wholly owned subsidiary acquired by Dow in 2013. As Greentech Media notes, NuvoSun is one of many companies that have ventured into CIGS technology with hopes it would be an efficient, less obtrusive, and lower-cost alternative to conventional crystalline silicon solar panels.

That hasn't quite worked out. The shingles have a low profile, but the thin-film CIGS cells aren't as efficient at generating electricity as standard solar modules, and they're difficult to manufacture. In the end, investing in building-integrated solar "amounts to paying a premium for less of a return," as Greentech Media's Julian Spector put it.

Pricing information posted at the Dow website seems to bear that out. The company says that if a typical residential roof using conventional materials costs $10,000, the same roof incorporating enough Powerhouse shingles to generate 3 kilowatts of electricity would be $25,000, after federal and utility incentives.

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