Tesla is to power the Hawaiian island of Kauai with solar panels and giant battery packs.
The Kapaia installation includes a 13MW solar system with more than 54,900 panels as well as 52MWh of batteries that can store power during the day and dispatch it after the sun goes down.
Tesla has installed 272 of its large commercial batteries, called Powerpack 2, to store the solar energy.
It has signed a 20-year contract with Kauai Island Utility Co-operative to deliver clean electricity and reduce the amount of fossil fuels needed to meet demand.
The project is expected to save around 1.6 million gallons of fuel a year.
Last year Tesla bought solar panel installer SolarCity to help the company expand its clean energy business.
The company also announced plans to develop solar roof glass tiles, which it claims would cost less than a traditional concrete roof.