Pre-production Activity Impacts of Enhanced Geothermal Systems

Research into the sustainability of geothermal energy previously focused on the management and use of the resource (Rybach and Mongillo, 2006) and the environmental impacts during geothermal energy production (Bloomfield et al., 2003; Reed and Renner, 1995). Within these constraints, studies have shown that there will be less impact on air emissions (including greenhouse gases), water consumption, and land use from geothermal electricity generation than from traditional fossil-fuel–based electricity generators. However, the environmental impacts from the construction of geothermal energy production facilities are less well understood, especially for enhanced geothermal systems (EGSs). With the U.S. Department of Energy’s commitment to support research and development of EGS and the potential total production capacity for EGS in the United States expected to exceed 100,000 MW, the life-cycle impacts of the technology must be explored (Tester et al., 2006). This paper discusses potential impacts and factors associated with EGS transportation, construction, drilling, and production. Including the impacts from pre-production activities allows us to more accurately assess and compare EGSs to fossil fuel-based electricity generators.