December 22, 2016

Last month, a new dawn rose over a small island in American Samoa. The island of Tau (also spelled Ta’u), home to less than 1,000 people, now gets all of its electric power from the sun. It is a small but significant step in the global push toward renewable energy. American Samoa is a United States territory in the Pacific Ocean, about 2,300 miles (3,700 kilometers) southwest of Hawaii. It consists of seven tropical islands with a combined population of about 55,000 people.

Solar panels and battery storage systems on the island of Ta’u, seen here, have provided all the island’s electric power since November 2016. Credit: © SolarCity

Tau worked with the company SolarCity, which was recently acquired by the electric car manufacturer Tesla, to convert its small electrical grid to run entirely on solar energy. (Both companies were founded by Elon Musk, a South African-born business developer.) About 5,000 solar panels and 60 battery storage systems were installed on the island over the course of two years. The battery systems store electric energy for nights and cloudy days. With the battery backups, the island can operate without sun for several days in a row.

Prior to the solar conversion, Tau’s power came from costly and polluting electric generators. Diesel fuel had to be shipped to the island over long stretches of ocean, an expensive process that itself used a lot of fuel. The new solar energy system will save some 110,000 gallons (415,000 liters) of diesel fuel each year, thereby preventing about 2.5 million pounds (1.1 million kilograms) of carbon dioxide emissions—a main cause of global warming and climate change—from entering the atmosphere.

The conversion is the latest step in the slow but steady trend toward renewable energy. Not only are such power systems better for the environment, but they are also becoming cheaper than fossil fuel-burning systems in a growing number of situations. Prices for solar cells continue to fall while their efficiency at capturing the sun’s energy slowly improves. Manufacturers are producing larger and more efficient wind turbines as well. Earlier this month, the first offshore wind farm in the United States began delivering power to an island within the state of Rhode Island. Offshore wind farms are more expensive and complicated to build than wind turbines on land, but they take advantage of strong, steady winds off the coasts to deliver cheap, consistent power.

Pacific islands like Tau are prime targets for switching to solar energy. Many are close to the equator and have few cloudy days. Therefore, they receive a strong, constant supply of sunlight year-round. Furthermore, the remote locations of these islands make shipping fossil fuels to them extremely expensive. Residents of Tau saw their electric bills remain the same after the switch and will now be insulated from oil’s fluctuating (rapidly changing) prices that, in the past, often caused energy costs to spike.

SolarCity is now working with the Hawaiian island of Kauai to improve distribution and storage of solar energy there. Kauai is significantly larger than Tau, with a population of over 70,000, but the Hawaiian state government is committed to switching to entirely renewable energy. Such islands as Kauai and Tau are likely to bear the brunt of global warming through rising sea levels and greater numbers of extreme weather events. Renewable energy, often considered the best environmental choice, may soon become the best economic choice as well.