Life Cycle Approach to Understanding Impacts of EGS

Abstract

Estimates that enhanced geothermal system (EGS) technology is capable of providing at least 100,000 MW of electricity to the U.S. within 50 years suggest substantial opportunity for widespread adoption. Energy and environmental analyses that characterize the economics, energy and environmental impacts are critical to the development and deployment of EGS. Life cycle analysis (LCA) tools can quantitatively assess energy and emission benefits of EGS to aid decisions for resource development according to proximity to infrastructure, lithologies of resource, and tradeoffs associated with well depth and resource temperature. While impacts at a single EGS power plant may be localized and small relative to other base load power plants, when considering widespread adoption of a technology, it is important to understand the cumulative effects at a large scale. One such effect is water consumption. An EGS power plant requires water both to stimulate the resource and to produce electricity. Depending upon the location and characteristics of the formation, individual EGS facilities can have very different water resource requirements and water quality implications. The cumulative effects can be assessed through the development of EGS scenarios that consider regional differences in the U.S., depth of operation wells, operation temperature, and water infrastructure for EGS operation. This life cycle approach for understanding impacts of EGS is part of an ongoing project, and preliminary study results will be discussed with an emphasis on water consumption and quality concerns.