Silicon Valley renewable-energy company SolarCity has started installing lithium-ion battery packs to help companies cut their utility bills. Those Tesla Motors lithium-ion battery packs aren’t just powering electric luxury sports sedans for the 1 percent any more.
They’ve started appearing in a small number of California homes to store electricity generated by rooftop solar panels, and beginning today SolarCity, the Silicon Valley solar installer, will start providing Tesla batteries for businesses that want to cut their utility bills. A big box retailer like Walmart could charge up a Tesla battery pack with cheap energy produced by its SolarCity rooftop photovoltaic array and then tap that power when demand—and electricity rates—spike. . . .