Geothermal energy developers working on the flanks of an ancient Oregon volcano say they have taken an important technological step toward expanding geothermal energy from a small niche into a potential major source of homegrown power.

Geothermal energy developers plan to pump 24 million gallons of water into the side of a dormant volcano in Central Oregon this summer to demonstrate new technology they hope will give a boost to a green energy sector that has yet to live up to its promise.