Economic Modeling of HDR Enhanced Geothermal Systems

Abstract

Hot Dry Rock (HDR) geothermal energy has the potential to become an important energy supply technology due to its environmental amenities and ubiquitous distribution. However, in order for HDR technology to successfully penetrate the electricity market, its cost needs to decline. The MIT Energy Laboratory, under the sponsorship of the US Department of Energy's Office of Geothermal and Wind Technologies, has created an economic model for evaluating the cost of electricity generation from HDR power systems. The model synthesizes engineering parameters (e.g., well depth, geothermal fluid flow rates, etc.) with resource characteristics (e.g., geothermal temperature gradient), reservoir performance (e.g., impedance, thermal drawdown rate), cost data, and financial parameters to calculate the cost of power production from HDR geothermal systems. The model also has the capability to optimize several engineering parameters in order to minimize costs. In this paper, we first describe the model and then discuss several case studies we have performed. We have applied the model to analyze the behavior of the experimental HDR sites at Fenton Hill, USA, at Soultz, France, and a proposed site at Hunter Valley, Australia. Based on our case studies, we identify key areas where more research is required for the improvement and, ultimately, the commercialization of HDR technologies. Finally, we develop a set of criteria in terms of resource conditions for the selection of favorable sites for future HDR development.