Geothermal takes a technological step forward

Still to come at Newberry is drilling one or two production wells to show whether these reservoirs can provide enough steam to run a commercial geothermal power plant.

"If we can demonstrate that we can create a geothermal reservoir here, then we can have more confidence in our ability to move to similar locations, maybe near other Cascades volcanoes," Petty said.

The Newberry project is one of 230 funded by Department of Energy to create a pathway for private industry to develop geothermal energy into a major source of homegrown power, said Doug Hollette, program manager for the Geothermal Technologies Office at Energy.

The effort is similar to one started by the department in the 1970s, which is now bearing fruit with cheap natural gas from shale deposits, he said.

Commercial production with EGS is still a long way off, because it depends on developing new technologies, he said. In the near term, the department is developing maps of potential new areas to develop conventional geothermal power, including areas that show no signs on the surface. They are expected to be ready in a few years. In the medium term, the DOE is financing development of low-temperature geothermal, and tapping abandoned oil and gas wells for their heat, known as coproduction. Other projects involve adopting horizontal drilling techniques, now common in oil and gas, to connect multiple geothermal reservoirs in a field.

There are 3.2 gigawatts of geothermal power connected to the U.S. grid, less than 1 percent of the grid's capacity. Government estimates put the potential for new discoveries of conventional geothermal power at about 30 gigawatts, and EGS at more than 100 gigawatts over the next 50 years. That would be 10 percent of the grid's current capacity.

"We are big believers that EGS will be a successful part of the energy mix once we show the pathway," Hollette said.