Perhaps as a means of celebrating the acquisition of SolarCity by Tesla, today SolarCity announced that it has completed a PV and battery-powered microgrid on the island of Ta’u, in American Samoa. While the exact date when the system was commissioned was not known at the time of publication, SolarCity says that it completed the project over the course of one year.
The 1.4 MW PV plant that provides power for the system is accompanied by 60 Tesla Powerpack batteries, which together provide 6 megawatt-hours (MWh) of storage capacity. SolarCity states that this system will allow the island to stay powered for three days without sun, and recharge fully in seven hours.
The project received funding from the American Samoa Economic Development Authority, the U.S. Environmental Protection Agency, and the U.S. Department of Interior. It will replace the diesel generators which were previously used to provide power, which required fuel which was shipped in from ports thousands of miles away. According to SolarCity, these generators used an estimated 109,000 gallons of diesel fuel annually.
Additionally, given issues with shipping fuel and thus power was at times limited on Ta’u, which resulted in rationing.
Due to the high and unpredictable cost of electricity generation using imported fossil fuels, islands like Ta’u are leading the transition to 100% renewable energy. SolarCity is also currently installing a 13 MW PV plant and 52 MWh battery system on the island of Kaua’i in the Hawaiian chain, which will allow the island to get 25% of its power from solar in 2018 even though peak demand on Kaua’i comes after sunset.