US Report Finds Sky Is the Limit For Geothermal Energy Beneath Us

An anonymous reader quotes a report from Ars Technica: Geothermal power sources come in many forms, and they’re typically much more subtle than steam shooting out of the ground. In reality, geothermal energy could be a big player in our future mix. That is made clear by the U.S. Department of Energy’s recently released “GeoVision” report. The report follows similar evaluations of wind, solar, and hydropower energy and leans on information from national labs and other science agencies. It summarizes what we know about the physical resources in the U.S. and also examines the factors that have been limiting geothermal’s deployment. Overall, the report shows that we could do a whole lot more with geothermal energy — both for generating electricity and for heating and cooling — than we currently do.

There are opportunities to more than double the amount of electricity generated at conventional types of hydrothermal sites, where wells can easily tap into hot water underground. That’s economical on the current grid. But the biggest growth potential, according to the report, is in so-called “enhanced geothermal systems.” These involve areas where the temperatures are hot but the bedrock lacks enough fractures and pathways for hot water to circulate freely — or simply lacks the water entirely. Advancing enhanced geothermal techniques alone could produce 45 gigawatts of electricity by 2050. Add in the more conventional plants, and you’re at 60 gigawatts — 26 times more than current geothermal generation. And in a scenario where natural gas prices go up, making geothermal even more competitive, we could double that to 120 gigawatts. That would be fully 16 percent of the total projected 2050 generation in the U.S. The report also estimates that installations of traditional ground-source heat pumps, which circulate fluid through loops in the ground to provide cooling in the summer and heating in the winter, could be increased 14 times over, to 28 million homes by 2050, “covering 23 percent of national residential demand.” When factoring in the limitations for how quickly the market could realistically change, the number only goes down to 19 million homes — still a massive increase.

Meanwhile, district heating systems, where a single, large geothermal installation pipes heat to all the buildings in an area, could be more widely deployed to more than 17,000 locations, covering heating needs for 45 million homes.

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