Status of Environmental Controls for Geothermal Energy Development

This report presents the initial findings and recommendations of the Environmental Controls Panel to the Interagency Geothermal Coordinating Council (IGCC). The Panel has been charged to assess the adequacy of existing environmental controls for geothermal energy systems, to review ongoing programs to develop environmental controls, and to identify controls-related research areas where redirection of federal efforts are appropriate to assure the availability of controls on a timely basis. In its deliberations, the Panel placed greatest emphasis on the use of geothermal resources for electricity generation, the application of geothermal energy receiving greatest attention today. The Panel discussed major known environmental concerns and their potential impact on the commercialization of geothermal resources, control options, regulatory considerations, and ongoing and planned research programs. The environmental concerns reviewed in this report include: air emissions, liquid discharges, solid wastes, noise, subsidence, seismicity, and hydrological alterations. For each of these concerns a brief description of the concern, associated legislation and regulations, control approaches, federal funding trend, and the Panel's recommendations and priorities are presented. In short, the Panel recommends that controls-related research efforts be rebalanced and enhanced, with the greatest emphasis placed on controls for hydrogen sulfide (H{sub 2}S) and non-H{sub 2}S gaseous emissions, injection monitoring methods, systems to treat and use nongeothermal waters for environmental control purposes, solid waste characterization and management methods evaluation, and subsidence controls