Energy Storage

Public power utility taps Tesla, SolarCity for remote island microgrid

In an effort to slash its dependence on diesel fuel to produce electricity, the American Samoa Power Authority has begun operating a new microgrid on a remote island.

The microgrid, built by SolarCity, includes 1.4 megawatts from a solar panel array and a set of Tesla utility-scale Powerpack batteries that can provide 6 megawatt-hours of storage.

The project is expected to provide all the electricity needed by the roughly 600 residents of the island of Ta'u, which is about 87 miles from American Samoa's main island.

The system will be less expensive and more reliable than the island's diesel generators, which use about 109,500 gallons of diesel a year, according to SolarCity.

"Solar and storage systems also eliminate expenses and issues associated with shipping diesel and provide stable power costs for decades, unlike fluctuating fossil fuel prices," Peter Rive, SolarCity cofounder and chief technology officer, said in a blog posted on the company's website Nov. 22.

The microgrid project is a key element of the American Samoa Energy Action Plan, which calls for a group of three islands, including Ta'u, to get all their electricity from renewable sources, according to the Department of Interior's Office of Insular Affairs. The office coordinates federal policy for the territories of American Samoa, Guam, the U.S. Virgin Islands and the Commonwealth of the Northern Mariana Islands.

As part of the effort, the American Samoa Power Authority, a public power utility, is replacing sodium vapor streetlights on the three islands with light-emitting diode, or LED, lights to cut energy use, according to the office. The switch is expected to cut overall electric use by 15 percent.

Ta'u uses about 1,460 MWh a year, according to the American Samoa Power Authority.

The project was funded by the American Samoa Economic Development Authority, the Environmental Protection Agency and the Department of the Interior.

The market for remote microgrids, also called off-grid microgrids, is expected to grow from about $11 billion last year to about $197 billion in 2024, according to an August report by Navigant Research, a consulting firm.

The American Samoa Energy Action Plan, adopted in August, calls for the territory to get half of its energy from renewable resources by 2025 and all its energy from renewables by 2040.