Geotechnical Environmental Aspects of Geothermal Power Generation at Heber, Imperial Valley, California. Topical report 1

This report presents a portion of the results from a one-year feasibility study sponsored by the Electric Power Research Institute (EPRI) to assess the feasibility of constructing a 25-50 MWe geothermal power plant using low salinity hydrothermal fluid as the energy source. The impact of power generation from hydrothermal resources on subsurface water flow, seismicity and subsidence are of acute interest in the determination of the environmental acceptance of geothermal energy. At the same time, the experience and data bases in these areas are very limited. The objective of the project was to assess the technical, geotechnical, environmental and economic feasibility of producing electricity from hydrothermal resources like those known to exist in the US. The objective of this part of the study was to investigate the geotechnical aspects of geothermal power generation and their relationship to environmental impacts in the Imperial Valley of California. This report discusses geology, geophysics, hydrogeology, seismicity and subsidence in terms of the availability of data, state-of-the-art analytical techniques, historical and technical background and interpretation of current data. it also discusses estimates of the impact of these geotechnical factors on the environment in the Imperial Valley, if geothermal development proceeds