GRANTS PASS, Ore. (AP) - Geothermal energy developers working on the flanks of an ancient Oregon volcano say they have taken an important technological step toward expanding geothermal energy into a major source of homegrown power.

AltaRock Energy, Inc., of Seattle says the data is still being analyzed, but they are confident they have created three geothermal reservoirs from a single well where none existed before, a key to development of the next level of geothermal energy development, known as Enhanced Geothermal Systems.

AltaRock President Susan Petty says still to come is showing these reservoirs can power a commercial geothermal power plant.

The U.S. Department of Energy is paying half the $43.8 million cost of the project as part of its efforts to do for geothermal energy what it did for shale gas.

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