Marubeni Corp. is working on how to jump-start the geothermal industry and tap the heat that powers volcanoes as an alternative to nuclear reactors.

The biggest investor in electricity generation among Japan's trading houses hopes to draw pools of underground heat with potentially twice the current capacity of geothermal projects operating worldwide.

That would help Japan shift away from atomic reactors that provided 30 percent of the nation's power before the Fukushima crisis.