A Roadmap for Strategic Development of Geothermal Exploration Technologies

Abstract

Productive geothermal systems occur in diverse geologic settings, often without clear surface manifestations of the underlying resource. Characterizing these hidden systems is challenging and costly, with resource confirmation relying on the drilling of multimillion-dollar wells with varying success rates. Reducing this risk through improvements in exploration technologies is critical to the identification and ultimate development of an estimated (USGS, 2008) 30 gigawatts electric (GWe) of undiscovered hydrothermal resources in the western U.S. In July 2011 the Geothermal Technologies Office (GTO), U.S. Department of Energy (DOE), convened a workshop in Berkeley, California, to outline needs and opportunities for advancing exploration technologies on annual to decadal timescales. Geothermal community members identified critical technologies within traditional disciplinary foci categorized as geology, geophysics, geochemistry, and remote sensing. In this paper we summarize these needs through technical pathways that target the key geothermal signatures of temperature, permeability, and fluid content. We develop the time evolution of these pathways, tying the past and current status of each to the active GTO exploration Research and Development (R&D) portfolio. We discuss metrics that existing GTO exploration initiatives could help to realize on a five-year timescale. Technologies that could accelerate the confirmation of 30 GWe are further projected to 2030. The resulting structure forms the basis for a Geothermal Exploration Technologies Roadmap, a strategic development plan to help guide GTO R&D investments that will lower the risk and cost of geothermal prospect identification.