Two birds with one stone

Science rarely works the way it does in the movies – with a flash of inspiration followed by a musical montage of furious scrawling in notebooks and laboratory hijinks:

But a pair of University of Minnesota researchers recently had one of those screen-worthy epiphanies that could lead to more widespread use of geothermal power.

The scientists, Martin Saar and Jimmy Randolph, were working separately on geothermal energy and CO2 sequestration. While traveling to northern Minnesota together to do field work, the scientists started swapping ideas.

“We connected the dots and said, ‘Wait a minute – what are the consequences if you use geothermally heated CO2?'” Saar said in a news release. “We had a hunch in the car that there should be lots of advantages to doing that.”

The idea, basically, is to use compressed CO2 instead of water to capture geothermal heat from deep in the ground. The key advantage is that CO2 moves more easily through rock, making it more efficient than water, which could make geothermal energy viable in places it wouldn’t otherwise make economic sense. In addition, it’s a means of sequestering CO2 in the ground, and could also be combined with secondary oil and natural gas recovery operations.

“It’s combining proven technology in a new way,” Saar said in the news release. “It’s one of thos things where you know how the individual components work. The question is, how will they perform together in this new way? The simulation results suggest it’s going to be very favorable.”

Saar and Randolph developed the technology with the help of $600,000 in renewable energy innovation funds from the University’s Institute on the Environment, and published their findings in the latest issue of Geophysical Research Letters. They’ve applied for a patent and plan to start a company to market the technique.

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