University of Utah researchers will pump cool water and pressurized water into a “dry” geothermal well during a five-year, $10.2 million study aimed at boosting geothermal power plant productivity and making them feasible nationwide.

Energy & Geoscience Institute (EGI) geologist Joe Moore—who will head the research effort at U.S. Geothermal Inc.’s Raft River power plant in southeast Idaho—says most geothermal power in the U.S. is produced west of the Rocky Mountains, where hot rocks are found closest to the surface.

But hot rock is present across the United States and new methods must be developed to produce geothermal power, he says. “We want to use oil and gas industry techniques to create pathways in the rock so that we can use the heat in the rocks to generate electricity.”

The U.S. Department of Energy will pay almost $7.4 million of the project’s cost. Moore says DOE did geothermal research for three decades at the Raft River site, 11 miles from Interstate 84. Raft River is now a U.S. Geothermal power plant producing 10.5 to 11.5 MW of electricity. Some estimate the site may be capable of producing 110 MW of power.

The Raft River plant currently has five “production” wells that produce geothermal energy and four “injection” wells where water from the production wells is returned to the geothermal reservoir to maintain pressure in a geothermal power system. One well drilled in recent years failed to produce enough hot water for production because it did not connect with enough of the underground cracks that carry the hot water.

“Geothermal wells are like oil wells— some wells produce and some don’t,” Moore says. “Drilling wells is expensive. That is why we need to develop low-cost techniques to improve their productivity.”

If the experiments work, U.S. Geothermal eventually will operate the test well and put it into service.

Reflector Could Cut Solar Cost

A solar company has teamed with scientists at the National Renewable Energy Laboratory to develop curved sheets of metal that have the potential to be one-third percent less expensive than some of today’s best concentrated solar power collectors.

The SkyTrough Parabolic Trough Solar Concentrating Collectors will be longer than football fields and look like fun-house mirrors. But they could be game-changers in solar energy’s bid to provide electricity.

NREL senior scientist Gary Jorgensen and SkyFuel Chief Technology Officer Randy Gee developed a thin silver polymer film to substitute for glass mirrors on solar-collecting troughs.

“Glass is highly durable, but is heavy

“Glass is highly durable, but is heavy and hard to shape without added cost,” Jorgensen said. “Once industry sees the advantages of the silver polymer and is convinced the product is durable in an outdoor environment, the sky is the limit.”

Gee said the film, trademarked ReflecTech Mirror Film, has the same performance as glass mirrors, but at about a 30 percent lower cost and lower weight.

A prototype SkyTrough is capturing the sun’s rays at NREL’s Golden, Colo., campus; a larger pilot system also is at SkyFuel’s location in Arvada, Colo. In commercial use, a SkyTrough would measure 375 feet long and 20 feet high. One SkyTrough could supply enough electricity for 50 homes.

Algae for Biofuels and Carbon Capture

Salt-loving algae could be the key to the successful development of biofuels as well as being an efficient means of recycling atmospheric carbon dioxide, says professor John Cushman of the University of Nevada.

One current limitation of biofuel production is the lack of adequate feedstocks for biodiesel and ethanol production. Halophytic (salt-loving) micro-algae can be grown on marginal lands with brackish or salt water unsuitable for traditional agriculture. Their growth is non-seasonal, making them 10 to 30 times more productive than land-based crops. They can be grown on municipal wastewater and have widespread potential for recycling carbon dioxide from biomass-, coal- and gas-fired power plants.

Algae are adapted to a wide range of water sources but grow year-round in warm, tropical or sub-tropical climates. Using geothermal heat, professor Cushman extended the growing season for algae production from three months to nine months in colder climates.

“Our work aims to find suitable algal strains to use for biofuel production,” said professor Cushman. “We need to identify the key components of the biosynthetic pathway to learn how to improve oil production and alter desirable oil characteristics with immediate and significant impact on the emerging algal feedstock biofuels industry.”