JAKARTA, Indonesia: Chevron Corp., the only foreign business currently developing geothermal energy in Indonesia, is expanding operations at one of its power plants on Java island to bring electricity to an additional 700,000 homes, the company said Tuesday.

The U.S. energy company, which has operated two geothermal fields on the seismically charged island since the 1980s, said in a statement it has started commercial production at its 110-megawatt (MW) Darajat III plant in Garut, West Java province.

The renewable energy produced there will bring the number of homes receiving electricity from Chevron's geothermal projects in Indonesia to 3.9 million up from 3.2 million at present, said John Watson, president of Chevron International Exploration and Production.

The sprawling archipelago sits on what is believed to be the world's largest geothermal resource base, with the potential to provide 21,000 megawatts — enough to supply all the energy needs for its 220 million people.

But existing plants have a combined capacity of just over 800 megawatts, or 4 percent of Indonesia's potential. Legal uncertainties, financial risks and government bureaucracy have kept international investors at bay.