Why the solar-​​plus-​​battery revolution may be closer than you think

The Washington Post
June 24, 2015

By Chris Mooney

In late April, Tesla Motors took a step toward upend­ing home energy when it announced the Pow­er­wall, a bat­tery for homes that can pro­vide backup power, and that was paired with higher capac­ity ver­sions for busi­nesses and even power companies.

Within about a week of the announce­ment, Bloomberg reported, the com­pany had already pulled in $800 mil­lion worth of orders, with the vast major­ity of rev­enue not for indi­vid­ual home bat­ter­ies but rather for larger, com­pany or util­ity scale appli­ca­tions called Pow­er­Packs. With num­bers like that, the energy stor­age rev­o­lu­tion may already be here.

[Why Tesla’s announce­ment is such a big deal: The com­ing rev­o­lu­tion in energy stor­age]

It’s not entirely clear yet how it will play out, though. In par­tic­u­lar, a big ques­tion mark con­cerns when a much touted pair­ing of home energy stor­age with rooftop solar power — so that peo­ple can power their homes at night with solar energy gath­ered dur­ing the day, and need only min­i­mal amounts of power from the grid — will become widely avail­able, not to men­tion affordable.

Some skep­tics have argued that it’s still very costly to buy the Pow­er­wall — the cost is $3,500 for 10 kilowatt-​​hours worth of energy or $3,000 for 7 kilowatt-​​hours — and have also objected that at least at first, it appears its chief usage will be sim­ply to pro­vide backup power dur­ing a power out­age. Indeed, SolarCity announced it was offer­ing the Pow­er­wall with home solar instal­la­tions for an added cost, but described it as a “bat­tery backup ser­vice,” to replace “noisy, dirty fos­sil fuel gen­er­a­tors with zero-​​emission stor­age technology.”

Nonethe­less, the solar plus bat­tery rev­o­lu­tion is com­ing in very much in the form many have envi­sioned, argued Nancy Pfund, the founder and man­ag­ing part­ner of DBL Investors, a San Fran­cisco based ven­ture cap­i­tal firm that has invested in Tesla and SolarCity, at a Tues­day Wash­ing­ton Post event enti­tled Amer­i­can Answers: Pow­er­ing Cities (I mod­er­ated the panel).

It is a rev­o­lu­tion,” Pfund said, adding that “it isn’t that far away.” When asked how much solar energy capac­ity and bat­tery stor­age capac­ity peo­ple would need to fully power their homes with solar energy at night and also charge their elec­tric vehi­cles overnight, she com­mented, “remem­ber your cell­phone, how unfunc­tional and expen­sive and huge it was in those early days. Obvi­ously there’s a cost curve that’s com­ing down…there’s a long wait­ing list of peo­ple want­ing to do this.”

To read the full arti­cle, visit The Wash­ing­ton Post.