At the American Geophysical Union meeting on Friday, December 13, scientists from Ohio State University, University of Minnesota, and Lawrence Livermore National Laboratory (LLNL), debuted a geothermal power plant that will lock away unwanted carbon dioxide underground and use it as a tool to boost electric power generation by at least 10 times that of conventional geothermal power.
Heat Mining Company, LLC, a start-up derived from endeavors from the University of Minnesota, expects to have an operational pilot project based on an initial incarnation of this new approach in 2016.
Traditional geothermal power plants use take the heat from hot water buried deep in the earth and use the heat to generate electricity and return the cooler water to the earth’s subsurface. This new approach partly replaces the water with CO2 and/or another fluid.
CO2 is beneficial because it mines heat from the subsurface more efficiently from the subsurface. Martin Saar at the University of Minnesota originally developed this approach, and it is doubly effective conventional geothermal approaches.
There is a downside: the geothermal plant would most likely have to be connected to a large CO2 source, like a coal-fired power plant, which was scrubbing the CO2 from its own emissions and they would have to be joined by a pipeline. Scientists might design the pilot plant to be powered solely by nitrogen injection, in order to prove the economic viability of using CO2.