When it comes to opening the market for battery-backed solar homes, hitting the right price point will be critical. But getting the right combination of services will be equally important.
Tesla set the bar for low-price home energy storage in May, when it announced a $3,500 wholesale price for its 10-kilowatt Powerwall home battery system, with key partner SolarCity offering the unit as part of new solar installations. There’s been some confusion about final pricing, but Tesla CEO Elon Musk said in June that it’s targeting a purchase and installation price of about $4,000.
That’s a lot lower than the prices coming from competitors in the home solar-battery space. Take Sonnenbatterie, the startup that’s sold thousands of batteries for solar homes in Germany, and has launched a U.S. partnership with solar company Sungevity. The company is pricing its 4-kilowatt battery system for $10,000.
But that $10,000 retail price includes a lot more than Sony’s Fortelion lithium-ion cells and inverters from U.S. partner Outback Power, said Boris von Bormann, CEO of Sonnenbatterie’s U.S. operations.
It also includes an energy management system -- one that comes with circuit panel controls to tie certain household loads to the battery’s backup power, and just as importantly, leave non-critical loads unpowered when the grid goes down. And it comes with several “smart plugs,” networked via HomePlug powerline carrier (PLC) signals, to allow control over all the appliances, consumer electronics and other household stuff that plug into wall outlets, not the home circuit panel, he said.
“We truly believe in the all-in-one integrated package, because it makes it really easy for the installer,” von Bormann said. “We’re doing a whole-home backup, and driving critical devices with the Smart Home platform. No one else is offering that.”
That’s not to say that Sonnenbatterie’s competitors lack these capabilities. For example, SolarCity has installed control systems at its customers’ homes to give it remote monitoring and management capabilities, and its MySolarCity app offers customers information about their energy generation and consumption trends. In April it announced a partnership with Nest to connect solar data (and potentially storage data) with the Google-owned company’s smart thermostats and networked home platform.
Likewise, Stockton, Calif.-based startup Sunverge has been installing control systems in a Sacramento, Calif. storage-grid integration pilot project, and is partnering with SunPower on integrated systems, including a 1.8-megawatt “virtual power plant” for Consolidated Edison in New York.
Microinverter maker Enphase has a battery offering and partnerships with Nest and Trane’s Nexia home control platform. And Japanese inverter giant Tabuchi is working with lithium-ion battery maker Panasonic and battery control system vendor Geli on a residential solar-storage system that comes with home energy management.
The question is how much of this advanced home energy integration and management capability comes with the home energy storage prices being quoted today. If it isn’t -- and if homeowners want to have it -- that could add some significant costs to the final price tag, von Bormann noted.
“If you look at whole-home installation costs, just looking at equipment costs, it will probably be equal,” he said. But with installation included, “That cost is not even comparable.”