Life Cycle Water Consumption and Water Resource Assessment for Utility-Scale Geothermal Systems: An In-Depth Analysis of Historical and Forthcoming EGS Projects

This report is the third in a series of reports sponsored by the U.S. Department of Energy Geothermal Technologies Program in which a range of water-related issues surrounding geothermal power production are evaluated. The first report made an initial attempt at quantifying the life cycle fresh water requirements of geothermal power-generating systems and explored operational and environmental concerns related to the geochemical composition of geothermal fluids. The initial analysis of life cycle fresh water consumption of geothermal power-generating systems identified that operational water requirements consumed the vast majority of water across the life cycle. However, it relied upon limited operational water consumption data and did not account for belowground operational losses for enhanced geothermal systems (EGSs). A second report presented an initial assessment of fresh water demand for future growth in utility-scale geothermal power generation. The current analysis builds upon this work to improve life cycle fresh water consumption estimates and incorporates regional water availability into the resource assessment to improve the identification of areas where future growth in geothermal electricity generation may encounter water challenges.

本报告为美国能源部地热技术项目资助的一系列报告中的第三份。该系列报告旨在评估围绕地热发电的水相关问题的各个方面。首份报告首次尝试量化地热发电系统的生命周期淡水需求，并探讨了与地热流体地球化学组成相关的运行和环境问题。对地热发电系统生命周期淡水消耗的初步分析表明，运行用水需求占生命周期中消耗水资源的绝大多数。然而，该分析依赖于有限的运行用水消耗数据，且未考虑增强型地热系统（EGS）的地下运行损失。第二份报告对未来大规模地热发电增长所需的淡水需求进行了初步评估。本次分析在前人工作的基础上，进一步优化了生命周期淡水消耗的估算，并将区域水资源可用性纳入资源评估，以改善对地热电力生成未来增长可能面临的水资源挑战区域的识别。