Chapter 22 – Enhanced Geothermal Systems—Projects and Plants

This chapter investigates new potential systems for exploiting certain types of geothermal resources, starting with a definition of these concepts (hot dry rock (HDR), enhanced geothermal systems (EGS), and deep hydrothermal systems (DHS)). Two programs that began in the 1970s and 1980s aimed to develop the HDR concept to the commercial stage: the Fenton Hill and Rosemanowes projects. These two experimental projects are described in detail, along with later projects in Japan at Hijiori and Ogachi. A project in Basel, Switzerland, was also developed but was derailed by seismic events that caused concern and put an end to the project in 2009. The chapter continues with the discussion of the history and development of recent EGS projects in France and Germany, and then looks forward to proposed projects in Australia, Germany, and the United States. The success or failure of the Newberry Volcano project in the United States is critical to the future growth of EGS projects elsewhere in the United States.