Environmental Assessment -- Hydrothermal Geothermal Subprogram

This environmental impact assessment addresses the design, construction, and operation of an electric generating plant (3 to 4 MWe) and research station (Hawaii Geothermal Research Station (HGRS)) in the Puna district on the Island of Hawaii. The facility will include control and support buildings, parking lots, cooling towers, settling and seepage ponds, the generating plant, and a visitors center. Research activities at the facility will evaluate the ability of a successfully flow-tested well (42-day flow test) to provide steam for power generation over an extended period of time (two years). In future expansion, research activities may include direct heat applications such as aquaculture and the effects of geothermal fluids on various plant components and specially designed equipment on test modules. Construction-related impacts would be relatively minor. Construction of the facility will require the distance of about 1.7 ha (4.1 acres). No further disturbance is anticipated, unless it becomes necessary to replace the seepage pond with an injection well, because the production well is in service and adjacent roads and transmission lines are adequate. Disruption of competing land uses will be minimal, and loss of wildlife habitat will be acceptable. Noise should not significantly affect wildlife and local residents; the most noise activities (well drilling and flow testing) have been completed. Water use during construction will not be large, and impacts on competing uses are unlikely. Socio-economic impacts will be small because the project will not employ a large number of local residents and few construction workers will need to find local housing