H. Thorsteinsson, C. Augustine, B.J. Anderson, M.C. Moore, P.R. von Rohr, J.W. Tester
EGS, drilling, geothermal, economic feasibility, carbon emissions
The publication of “The Future of Geothermal Energy” in 2006, which resulted from a comprehensive assessment of US geothermal potential, brought renewed interest in Engineered Geothermal Systems (EGS) worldwide. The magnitude and accessibility of the resource within a continuum of grades, coupled with its ability to provide baseload renewable electric power at scale without carbon emissions makes it a particularly attractive alternative to fossil-fuel fired electricity production. Calculations based on projections of future energy demand show that widespread deployment of geothermal energy would significantly lower carbon emissions in the US, as well as globally. However, for EGS to be deployed widely, it has to be both technically and economically feasible at commercial production rates for a wide range of geothermal resource grades. This paper reports the results of a parametric study of the effects of resource quality, reservoir performance, and drilling technologies on the economic feasibility of EGS and identifies areas for intensified research and development. Specifically included are the effects of drilling depth, average geothermal gradient, reservoir production flow rate, and thermal drilling and advanced well casing approaches.