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Conference Proceeding

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National Renewable Energy Laboratory

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The fields of well construction and engineering, power plant construction and engineering, and reservoir engineering often proceed independently of one another. Yet the subsystems of a geothermal plant with which each of these fields is concerned need to be integrated in order to create a viable geothermal power system and make enhanced (or engineered) geothermal systems (EGS) a technical and an economic reality. Furthermore, each of these subsystems need to be examined in the context of the overall power system to aid with plant construction, and–more salient to the U.S. Department of Energy–to help determine best investment of research dollars.

In further development of a high-level model begun in collaboration between the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories (SNL), refinements of the Geothermal System Scoping Model (GSSM) are presented. GSSM uses a lumped-parameter approach to examine the interactions among the several subsystems of a putative EGS. This effort will provide a means for performing a variety of trade-off analyses of surface and subsurface parameters, sensitivity analyses, and other systems engineering studies in order to better inform R&D direction and investment for the development of geothermal power into a major contributor to the U.S. energy supply.

GSSM is not a design tool, but rather is intended to search over broad parameter spaces to determine the technical, and to a more limited extent, economic feasibility of a wide range of geothermal power configurations. The model does not make any assumptions as to the type of geothermal power being used. Thus, whether the system considered is hydrothermal, EGS, or co-produced fluids is not explicitly considered, although the inputs to the model should be aligned with known characteristics of the type(s) of plant under consideration. This allows GSSM to be more broadly applied. The model is complementary to ongoing work at SNL, which is more strongly focused on EGS.

Early results of the application of GSSM to the Geothermal Technologies Program’s technical baseline are also presented.


EGS; Geothermal engineering; Geothermal modeling; Geothermal power plants; Geothermal resources; Geothermal systems


Oil, Gas, and Energy | Power and Energy




Presented at the Geothermal Resources Council 2010 Annual Meeting, October 24-27, 2010, Sacramento, California.

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