Geothermal energy has been used since the Roman times for space heating and some countries, like Iceland, almost run entirely on geothermal. Geothermal is extremely cost effective, reliable and sustainable but usage is unfortunately fairly limited. Fortunately, two University of Minnesota researchers have come up with a new geothermal technique that makes the process much more efficient and can help combat climate change.
Martin Saar and U of MN student Jimmy Randolph created the CO2 plume geothermal technique (CPG) that uses high pressure CO2 instead of water as the heat-carrying liquid. CO2 holds many advantages over traditional water including:
- Traveling easier through porous rocks allowing for geothermal power access in areas not traditionally viable for geothermal power
- Preventing CO2 from entering the atmosphere by sequestering it underground
- Reducing the risk of a geothermal plant “short-circuiting” or plugging the flow of fluid through rock due to CO2’s lessened ability to dissolve materials around it
- Boosting fossil fuel production in pushing natural gas and oil from partially depleted reservoirs.
The idea for CPG began three years ago in 2008 when Saar and Randolph were traveling around Northern Minnesota. They received a $600,000 grant from the U of MN Initiative for Renewable Energy and the Environment (IREE) and later received a $1.5 million grant from the U.S. Department of Energy to explore subsurface chemical interactions of the process.
There are many geothermal techniques that promise more efficiency or better access to geothermal across the globe. CPG may not only provide clean, stable energy (and temporarily boost fossil fuel production) it could be the only renewable energy that could actually effectively combat climate change in the near future.
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