SunPower to sell energy storage, potentially lithium ion batteries

Solar company SunPower (s spwr) plans to roll out its first energy storage product, possibly lithium-ion batteries, in a bid to expand its share of the rooftop solar market, company executives said on Wednesday during the company’s analyst day. CEO Tom Werner told analysts that selling energy increasingly will require more comprehensive solutions, including energy storage technologies, and explained “this is a fundamental change in how solar companies compete.”

Adding energy storage reflects the evolution of the company, which started off as a solar cell and panel maker before it entered the power plant development business. SunPower has carried out pilot energy storage projects in recent years and worked with different energy storage technologies, including advanced lead acid and zinc bromide batteries.

But lithium-ion batteries “will likely be the first technology to have an impact,” said Jack Peurach, executive vice president of products. The emergence of electric cars plays a role in making lithium-ion battery the front runner for being paired with solar, he added.

SunPower & Flextronics Factory in Milpitas, CA

SunPower & Flextronics Factory in Milpitas, CA

SunPower executives didn’t provide details, such as the timing and battery suppliers, for its energy storage plans. But the discussion puts SunPower on a growing roster of solar energy companies that are offering or plan to offer energy storage.

SolarCity (s SCTY), for example,  has been bundling lithium-ion batteries from Tesla Motors (s TSLA) with its solar energy systems and applying for a California program that subsidizes energy storage installations. One Roof Energy is working with battery maker Silent Power to roll out products. Korean conglomerate Hanwha Group, which runs a solar panel manufacturing subsidiary, is an investor in both OneRoof and Silent Power. SunEdison has done a pilot project with a battery system from startup Seeo.

Energy storage will be part of SunPower’s plan to expand its reach in the commercial and residential market, where it sells power purchase agreements or leases via its dealers or its own project development business. The company designs the power purchase agreements for its commercial and government customers and leases for homeowners. Power purchase agreements and leases work in similar ways: business or home owners sign a long-term contract of up to 20 years and pay a monthly fee for the solar electricity from the SunPower solar energy systems on their rooftops.

PHOTOS: SunPower Factory Tour, 25 Years to 1 GWSunPower’s foray into the energy storage business will prompt more comparison with SolarCity, which started in 2006 as purely a solar installer. SolarCity is most active in the residential and commercial markets, but it scored the first utility project last year. As a result, the two companies have been competing more intensely in recent years.

In fact, a lawsuit filed by SunPower against SolarCity and five people last year highlighted that rivalry. The lawsuit accused five former SunPower employees of stealing confidential data and brought the data with them when they went to work for SolarCity. The two companies settled on Dec. 31, 2012, and a judge dismissed the lawsuit in January, SolarCity said in its 2012 annual report. It didn’t disclose the amount of the settlement.

SunPower executives didn’t say whether they will sell energy storage in the United States first or in other regions. Werner said that, for now, energy storage makes financial sense only in markets that offers government incentives. That would include California, Germany and Japan.