Kunal Girotra is the former head of the Tesla’s residential energy business. Now he is off on his own and heading a new company called Lunar Energy that promises an “end-to-end home battery system” that eliminates the confusion of dealing with one company for your rooftop solar system, another for your residential storage battery, and possibly a third company to make the two systems play nice with each other. He says the mission of Lunar Energy is to “transform homes to 100 percent clean energy.”
Girota must be onto something. The company has just completed two investment rounds totaling $300 million led by US residential solar leader Sunrun and South Korean battery giant SK Group. Other investors include Japanese trading conglomerate Itochu and automaker Honda, both of which have taken a minority stake in the company. That stake comes as part of Lunar Energy’s acquisition of Moixa, a UK-based software provider that is managing a fleet of 35,000 residential battery systems in Japan, according to Canary Media.
Lunar Energy has hired about 250 employees and completed a 35,000 square foot manufacturing facility in Mountain View, Girotra says. Its first product will be “a combination of battery modules, power electronics, and software, all designed from the ground up,” rather than the cobbled-together systems common today that combine “this component from this company, that component from that company.” Lunar Energy expects to start marketing the integrated platform by the end of this year.
“There are competitors in this space,” Girotra says. “But the home battery system market is still an expensive proposition for homeowners,” with costs compounded by the market’s complexity. “There are a lot of boxes on the wall, they’re not integrated, they come from different manufacturers.”
Lunar Energy Residential Solar & Storage System
This mix-and-match ecosystem can confuse homeowners and installers. It’s not always clear which combination of systems is best suited to provide backup power during grid outages, or how much electricity batteries need to store to keep different combinations of home loads running over extended periods of time.
Nor is it always clear which vendor is in charge of managing the interplay of solar power, battery storage capacity, and household loads. Managing those tasks is necessary to maximize the savings homeowners expect and to allow them to earn money by making their battery’s capacity available to utility or energy market grid services programs.
Lunar Energy hopes to win over customers and partners by “designing architecture that will be super easy to install, looks compact and elegant in your home, and does grid interaction and microgrid formation in a very seamless manner,” Girotra said. Tesla has been promising much the same thing for years, with only limited success, which illustrates how complex the challenges can be.
Dan Finn-Foley, an energy transition and storage expert for PA Consulting, tells Canary Media, “You could make a compelling argument that the majority of residential storage on the grid today has no economic reason for existence. A large proportion of these storage systems bought by early adopters have been more emotional decisions. They’ve been driven by the ‘cool factor,’ or spending money on non-monetary factors like using your own solar power or having clean backup power.”
The situation is “changing pretty dramatically,” he says. The cost of solar and batteries have continued to fall, although supply chain constraints have slowed the downward trend significantly. And yet, virtual power plants composed of many homes with rooftop solar, batteries, smart thermostats, and internet-controlled electric …….