SunPower offers batteries to hold homes’ solar power until night

By Ehren Goossens
Bloomberg News

SunPower Corp., the second-largest U.S. solar manufacturer, is offering energy-storage systems to California homeowners that will power houses at night with electricity generated from sunlight during the day.

The company is testing systems that combine rooftop solar panels with battery storage in new homes built by KB Home, San Jose, California-based SunPower said in a statement today.

Such systems will reduce consumers’ reliance on electric utilities and the grid, cutting power bills and providing electricity during blackouts, Chief Executive Officer Tom Werner said yesterday in an interview. Though the technology isn’t widely used today, and SunPower only expects to install about 10 of the systems in KB Home houses this year, Werner expects it to become standard in less than five years.

“The cost of storage is going to come down rather dramatically over the five-year period,” said Werner. “We think of storage as where solar was five to 10 years ago.”

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KB Home is initially offering the systems at communities in Irvine, El Dorado Hills and San Diego, California, and will expand the program into additional areas next year.

Homeowners will own the power systems and the costs will be incorporated into their mortgages, said Steve Ruffner, president of KB’s Southern California unit.

Standard feature

The builder already includes a 1.4-kilowatt solar system as a standard feature at its Vicenza community in Irvine, saving an average of about $216 a month, or roughly $25,600 over ten years. Storage systems will lead to higher savings.

“When we incorporate the battery with that they’re going to see that the savings are significant,” Ruffner said. He couldn’t estimate how much more.

SolarCity Corp., the largest installer of rooftop solar panels, offers similar storage systems. The company has said it’s faced hurdles imposed by California utilities that are reluctant to connect the systems to the grid.

SunPower is also planning to test power-storage systems in Australia this year and in Germany next year. The company has installed about 15,000 rooftop solar systems in the U.S., including almost 3,000 with KB Home. First Solar Inc. is the largest U.S. solar manufacturer.

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