Tapping Rocks for Power

A European consortium is drawing closer to building a megawatt-scale power plant that uses bedrock heat. By fracturing granite bedrock located five kilometers below the surface and pumping in super-saline water, a team of French, German, and Swiss engineers are extracting the rock’s thermal energy, and they plan to use it to produce pollution-free electricity. At least they will if the local residents put up with a little more shaking. The project is the most advanced effort to date to deliver on the promise of so-called hot-rock mining. Since the 1970s, geothermal engineers have tried many times to push enough fluid through hot rocks to capture energy at a commercial scale. Now the Soultz project has achieved the highest flow rates in the world through some of the hottest rocks. By this time next year, they expect to be transforming this heat into at least 1.5 megawatts of renewable power for the grid.

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