3 November 2010


DOW POWERHOUSE becomes first solar shingle to gain UL certification

The Dow Chemical Company of Midland, MI, USA says that its DOW POWERHOUSE Solar Shingle has become the first residential solar roofing shingle with an integrated connection system to receive Underwriters Laboratories (UL) safety certification.

In 2007, Dow received a $20m grant from the US Department of Energy as part of its Solar America Initiative to develop building-integrated photovoltaic (BIPV) arrays for the residential and commercial markets. Subsequently, in October 2009, Dow Solar unveiled DOW POWERHOUSE Solar Shingle as the first in a portfolio of building-related solar energy generating products.

Dow chose thin-film copper indium gallium diselenide (CIGS) as the PV material in the solar shingle, and Global Solar Energy (GSE) of Tucson, AZ was selected as the preferred supplier in support of the product launch. Dow says that CIGS offers the best balance of low cost and highest sunlight conversion efficiency of the commercialized thin-film technologies currently available, and the flexible foil substrate of GSE’s CIGS cells provides the necessary level of flexural durability to allow the solar shingle to perform reliably in a demanding application environment.

DOW POWERHOUSE panels hence come in the form of a solar roofing shingle that can be installed by a roofer along with standard asphalt shingle materials. The firm says that it reduces installation time and complexity by using a system design that eliminates on-roof wiring, minimizes through-roof penetrations, and allows installation in the same manner as a standard roofing shingle.

“The receipt of UL safety certification represents the successful completion of a rigorous and comprehensive multi-test process,” says Dow Solar VP Jane Palmieri. “This is another important milestone towards the planned 2011 commercialization of Dow’s solar shingles, and represents a crucial third-party validation of the safety of this product,” she adds.

Given the new nature of the solar shingle, Dow Solar worked closely with UL to indentify a series of rigorous tests to assess the safety of the unique design and of all the elements of the combined solar and roofing product. The final listing that was awarded represents compliance to a diverse sequence of UL’s safety and building standards, specifically UL 746, 1703, 1897, 790, 486 and 514. More than 50 individual tests were conducted to assess the safety of the solar shingle against building code standards, including wind and fire resistance, and electrical code requirements, such as proper wiring and photovoltaic (PV) connections.

“UL has been leading the development of PV equipment testing methodologies and standards since the 1980s, and has contributed to the safe operation of PV equipment by providing safety testing and certification services for PV equipment manufacturers worldwide,” says Jeff Smidt, VP & general manager for UL’s Global Energy business. “In the case of Dow’s solar shingles, we had to take a unique approach in order to test the product as both a roofing shingle and a PV system,” he adds.

In addition to the design and material safety tests performed by UL, Dow says that it will continue with its own reliability and durability testing in support of commercialization. The firm is currently performing tests on installed systems in addition to individual shingles in order to assess the product's durability, using Design for Reliability and Physics of Failure methodologies to measure performance against weather, extreme temperatures and more.

Dow says that, by breaking the traditional barriers to residential solar adoption (complexity, affordability and aesthetics), solar shingle offers the missing link needed by the energy industry to drive solar adoption across the US, and will bring the possibility of safe and reliable solar power to households. The product is expected to be commercially available in select US markets by mid 2011.

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