A Roadmap for Strategic Development of Enhanced Geothermal Systems Technologies

Abstract

Roughly 90% of the geothermal power resource in the United States is thought to reside in Enhanced Geothermal Systems (EGS) (USGS, 2008). While realization of EGS development on the 100+ gigawatts electric (GWe) scale would make geothermal a significant component of the renewable energy portfolio, hurdles to commercial development still remain in accessing and characterizing, creating and monitoring, and operating and sustaining engineered reservoirs. In August 2011 the Geothermal Technologies Office (GTO), U.S. Department of Energy, convened a workshop in San Francisco, CA, to outline opportunities for advancing EGS technologies on five- to 20-year timescales. Community input charted technology needs categorized within the functional stages of Characterizing, Creating, and Operating EGS reservoirs. In this paper we present technical pathways - identifying, creating, and managing fractures and flow paths; monitoring flow paths and fracture evolution; zonal isolation; drilling; models; and tools - that encompass the underlying technology needs identified at the workshop as critical to optimizing and ultimately commercializing EGS. We develop the time evolution of these pathways, tying the past and current status of each to the active GTO EGS R&D portfolio, anticipating milestones that strategic initiatives could help to realize on a five-year timescale, and projecting to target capabilities for 2030. The resulting structure forms the basis for an EGS Technologies Roadmap to help guide priorities for GTO R&D investments.