Power produced from hot dry rock geothermal resources: a case study for the Imperial Valley, California

The case study described here concerns an HDR system which provides geothermal fluids for a hypothetical electric plant located in California's Imperial Valley. Primary concern is focused on the implications of differing drilling conditions, as reflected by costs, and differing risk environments for the potential commercialization of an HDR system. Drilling costs for best, medium and worst drilling conditions are taken from a recent study of drilling costs for HDR systems. Differing risk environments are presented by differing rate of return requirements on stocks and interest on bonds which the HDR system is assumed to pay; rate of return/interest combinations considered are 6%/3%, 9%/6%, 12%/9% and 15%/12%. The method used for analyzing the HDR system involves a two-stage process. In stage 1, the maximum amount that the electric plant can pay to an HDR system for geothermal fluids is calculated for alternative busbar prices of electricity received by the electric plant. In stage 2, costs for the HDR system are calculated under differing assumed risk environments and drilling conditions. These two sets of data may then be used to analyze the minimum busbar price of electricity - which defines a maximum fuel bill that could be paid to the HDRmore » system by the electric plant - which could result in the HDR system's full recouperation of all production and drilling costs.« less