Sunrun Inc., one of the top 10 largest U.S. solar installers, today announced it completed its first installation of a Sunrun BrightBox energy storage system, which is based on Tesla's Powerwall lithium-ion battery.
The BrightBox energy storage system combines rooftop solar panels with the Powerwall wall-mounted lithium-ion battery. Sunrun's is also the first ever to be installed under Hawaiian Electric Company's (HECO) new Customer Self-Supply (CSS) Program.
Hawaii's CSS Program allows residents to install solar systems that do not export power back to the grid -- known as net metering. Customers are not compensated for any export of energy.
Late last year, after net metering became too successful and too much energy was sold back to utilities from residential installations, Hawaii's Public Utilities Commission (PUC) issued a ruling and adopted the CSS Program instead. Hawaii's PUC also initiated new tariffs for distributed systems, both residential and business-based rooftop solar, which offered residents the option to continue selling solar power to utilities. But the PUC capped the maximum at 25mW and cut the rate paid by utilities for the power to half that of the retail price.
Under the program, Hawaii homeowners can install a rooftop solar system with a battery so they can use solar energy day and night, with power priced below utility prices today.
"Sunrun's commitment to affordability means homeowners can get BrightBox now through an affordable monthly or prepaid lease for little to no money down," the company said in a statement.
Sunrun did not list its pricing for the Powerwall battery installation. SolarCity spokesman Jonathan Bass, however, said the company offers battery storage as a service for $4,250, including the battery pack, advanced hybrid inverter, monitoring and control systems and warranty and nine-year service agreement.
SolarCity, co-founded by Tesla CEO Elon Musk, was the first reseller of the Powerwall home battery systems. SolarCity was co-founded by Musk's cousin, Lyndon Rive, who is the company's CEO.
SolarCity began taking preorders for the batteries a year ago.
Musk announced earlier this year that Powerwall batteries were being produced at the company's Gigafactory outside Reno, Nev. The Gigafactory is expected to produce 500,000 lithium-ion batteries every year.
Tesla's battery systems originally included two consumer-grade batteries -- the Powerwall line -- that store 7 kilowatt hours (kWh) and 10kWh worth of power and cost $3,000 and $3,500, respectively.
The 10kWh Powerwall would have been optimized for backup and the 7kWh battery is meant for daily use. Both can be connected to rooftop solar panels or the grid to provide power, either during blackouts or periods of lower energy generation. Earlier this year, after removing references to the 10kWh Powerwall from its website, Tesla said it would no longer be building the 10kWh Powerwall.
The 7kWh Powerwall battery, which is 51.3-in x 34-in x 7.2-in, is scheduled for release this summer by Tesla Energy, a subsidiary of Tesla Motors.
Up to nine batteries can be daisy-chained together, providing up to 63kWh capacity (with the 7kWh version). The batteries come with a 10-year warranty.