Fig.1 Geothermal resource favorability and identified hydrothermal sitesFig.2 A cross-section of the Fervo Enhanced Geothermal System. Horizontal drilling and hydraulic fracking allows for larger extraction of energy from a hot zone near the surface. Water flows from an injection well through the fractured rock to a production well running parallel.
Geothermal energy is energy extracted from the heat stored beneath the Earth's surface by means of water (or steam) circulating in deep wells. The threat of global warming from CO2 emissions has stimulated great interest in generating electricity from this clean, steady, and unlimited source of heat energy. The heat can also be used directly to replace fossil fuels in heating homes and buildings. Nations like Iceland, with favorable geology have made geothermal energy their primary source of heat and electricity. The problem for other areas of the world is that the heat is buried too deep. Recent progress in drilling technology has revived hope that geothermal energy may become a big part of the world's energy solution.
Commercial-Scale Demonstration of a First-of-a-Kind Enhanced Geothermal System Jack H. Norbeck and Timothy M. Latimer, White Paper, Fervo Energy, 2023. See Figure 2. This is a test well intended to demonstrate the economic feasibility of generating power using the latest drilling and fracking technology. Can it provide energy cheaper than coal? That is the question they must answer.
2022 GETEM Geothermal Drilling Cost Curve Update, Robins, Jody C., Devon Kesseli, Erik Witter, and Greg Rhodes. 2022. National Renewable Energy Laboratory. NREL/CP-5700-82771. "Despite advancements in [drilling performance] over the last 10 years, drilling costs have remained relatively constant." - about $375 per foot in shale.