Firm buys U’s new energy technology

The technology makes geothermal power using carbon dioxide instead of water.

by Julia Marshall

University of Minnesota researchers have developed a new energy technology that removes carbon dioxide from the air while generating electricity.

Energy firm Heat Mining Company recently bought the rights to the system, called Carbon Dioxide Plume Geothermal technology or CPG.

The new technology is about twice as efficient as traditional methods of generating geothermal electricity, said Martin Saar, the lead researcher on the project and an associate professor in the department of earth sciences,

Kenneth Carpenter, the firm’s managing partner, said Heat Mining Company plans to build its first power plant using the CPG technology in June. He said he expects the technology to expand, and the plant is set to open in early 2016.

“Ultimately, there’ll be hopefully hundreds of plants, but initially we’re looking at this first site in Canada,” he said.

Even though geothermal energy isn’t as popular as solar or wind power, it’s more reliable and flexible, said Thomas Kuehn, a University mechanical engineering professor who helped create the CPG system.

“With the CPG geothermal system, we can run it 24/7 if need be,” he said. “Or we could run it to supplement the wind systems when the wind doesn’t blow or supplement the solar systems when the sun doesn’t shine.”

Because CPG plants could run constantly, Kuehn said, they’re more efficient than other renewable energy generators.

“A typical [CPG] plant might put out on the order of 15 megawatts, which would be equivalent to 10 large wind turbines running at full wind speed, and maybe closer to 40 or even 50 of them at normal wind conditions,” he said.

Before developing the CPG system, Saar saw potential for energy in heated carbon dioxide stored deep underground. The heat could be used to
generate electricity if harnessed correctly.

Traditional methods of generating geothermal energy use water heated by the earth to turn turbines and generate electricity.

The CPG system
instead takes in hot carbon dioxide from coal-burning power plants and other sources to create electricity. The system then injects the carbon dioxide underground.

Saar said negative effects on the environment “are not a concern” because the carbon dioxide goes into saline formations — permeable rocks that are saturated with water.

“These saline aquifers are very salty waters; we’re not talking about any kind of usable fresh water,” he said. “There’s not anything that would be polluted or made unusable.”