Sunrun Buys Mainstream’s Rooftop Solar Installer Business

Sunrun Inc., a closely held rooftop solar-power provider, acquired the residential installation and racking units of Mainstream Energy Corp. to add in-house construction capabilities.

Mainstream’s top two executives are joining Sunrun, Chief Executive Officer Lynn Jurich said in an interview. She wouldn’t provide terms for the deal.

Sunrun provides financing for residential solar plants and typically hires local contractors to build them. Acquiring an installation operation brings Sunrun closer to becoming a full-service home solar supplier such as rival SolarCity Corp. as demand for rooftop power surges.

“We’re buying into the installation area,” Jurich said. The deal “will help us better understand the installation business.”

About 31,000 systems were installed on U.S. homes in the third quarter, the fastest growing segment of the the U.S. solar industry, according to the Solar Energy Industries Association. That brings the cumulative total to 360,000 homes. Sunrun, SolarCity and other rooftop solar providers typically offer power systems at little to no upfront cost to customers, who sign long-term contracts to buy the electricity.

The deal includes the residential operations of Mainstream’s REC Solar unit; its SnapNrack business, which makes mounting systems that hold panels in place and reduce installation times; and the AEE Solar distribution unit, San Francisco-based Sunrun said in a statement today.

Mainstream Energy CEO Paul Winnowski is becoming Sunrun’s chief operating officer and Chairman Tim Ball will join Sunrun’s board. Mainstream is based in Sunnyvale, California.

Sunrun co-CEO and co-founder Ed Fenster will shed that role to become chairman as Jurich becomes sole CEO.

Mainstream will continue to provide commercial solar systems through its REC Solar Commercial unit.

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