Tesla, Inc.’s CEO Elon Musk has made his company’s mission to help the world to transition away from reliance on fossil fuels and toward the embrace of sustainable energy sources. Now a U.K. energy-storage startup called Powervault is now in competition with Tesla, Inc. to outfit homes with affordable backup battery power across the pond.

Tesla Powerwall 2

Powerwall 2 stories are becoming commonplace, in which a consumer captures energy during daylight off-peak hours with SolarCity photovoltaic solar panels stored in a Powerwall home battery unit. When energy rates are higher during evening hours, the consumer powers the home with energy stored captured earlier in the day.

Powerwall uses an internal inverter to convert DC energy to the AC energy required for a home or small business. A liquid thermal control system regulates Powerwall’s internal temperature to maximize battery performance in any climate. The most affordable home battery in terms of cost per kWh, the company argues that the Powerwall economically meets the daily energy needs of most homes. With usable capacity of 13.5 kWh, the Powerwall system has a 100% depth of discharge and 7kW peak / 5kW continuous power. Floor or wall mounted, indoor or outdoor, the Powerwall has a ten year warranty and is scalable up to nine Powerwalls. Its operating temperature ranges from -4° to 122°F / -20°C to 50°C. The system is certified to meet North American and international standards.

One 14 kWh Powerwall battery costs $5,500, with installation and supporting hardware adding $1,500, or a total estimate $7,000. U.S. installations are beginning in February, 2017, according to company data.

There’s no doubt Elon Musk sees solar as the future for electricity generation, just as he views electric cars as the future of transportation. “The primary means of energy generation is going to solar,” he said in 2015 prior to the merger with SolarCity, in which the issue of utility-based versus independent energy generation still seemed futuristic. “It will at least be a plurality, and probably be a slight majority in the long term.”