Gaps, Challenges, and Pathways Forward for Superhot Rock Geothermal: Summary Report

Abstract

Research suggests that 2% of the geothermal energy within 3 to 10 km of Earth’s surface could provide the equivalent of 2,000 times the current energy demand of the United States.[1], [2] This energy is harnessed by circulating water through hot rocks to capture heat energy and bring it to the surface. It is continually regenerating and considered virtually inexhaustible, but for too long has been limited to low-temperature rocks in only a few areas of the world. Superhot rock energy (SHR) is a new form of geothermal that leverages next-generation geothermal technologies in very hot rocks (374°C or above). With innovation, SHR could have the potential to provide long-term, scalable, renewable baseload power in many more places around the world at a scale and cost equivalent to fossil fuels. However, SHR energy is still developing, and more work is needed to help it reach its full potential at a cost that is competitive with mature energy technologies. To better understand what’s needed to make SHR successful at a commercial scale, Clean Air Task Force commissioned a collection of flagship gap analysis reports from independent international experts. Each report dives into a distinct technology essential for the success of end-to-end superhot rock energy projects: drilling, heat extraction, well construction and design, and power production. The primary goal of these reports is to evaluate the state of the technology, pinpoint remaining technological gaps, and identify where future research, development, and testing efforts should be concentrated. By doing so, these reports aim to ensure that no critical areas are neglected and to define a clear path forward for each segment of the technology. This report serves as a summary of each flagship report. Each section reviews a category of technologies—drilling, well construction, heat extraction, and power production—for accessing superhot rock energy, identifies existing technology gaps within each of these technology areas, and suggests strategies to overcome the technology gaps identified. A fifth report, to be added as an addendum, will focus on site characterization. The Bridging the Gaps reports illuminate two key insights. First, the technology to enable SHR energy is within reach, and targeted investments could rapidly accelerate its development. Second, the most pressing need is for facilities—both laboratories and field sites—where equipment and methods can be tested under SHR conditions. [1] Petty, S., Uddenberg, M., Garrison, G. H., Watz, J., & Hill, B. (2020). Path to Superhot Geothermal Energy Development. [2] Tester, J. W., Anderson, B. J., Batchelor, A. S., Blackwell, D. D., DiPippo, R., Drake, E. M., Garnish, J., Livesay, B., Moore, M., & Nichols, K. (2006). “The Future of Geothermal Energy.” Prepared for the U.S. Department of Energy by the Idaho National Laboratory.