The United States has a large, domestic source of lithium in geothermal fluids, especially at the Salton Sea region of southern California, where estimates of lithium pass-through at geothermal plants exceed 24,000 metric tons per year, based on 2019 geothermal plant operations. Lithium extraction from geothermal brines offers the potential to provide the United States with a secure, domestic supply of lithium to meet the increasing demands of electric vehicles, grid energy storage, portable electronics, and other end-use applications. Additionally, the use of direct extraction technologies allows for a more sustainable lithium supply relative to current evaporative brine and hardrock mining operations in terms of land use, water use, time to market with lithium products, and carbon intensity of operations. This report is part of an effort to assess geothermal brines as a source of commercial lithium supply for the United States. In this study, the National Renewable Energy Laboratory (NREL) reviews and summarizes public technoeconomic analyses of lithium extraction technologies. The work was coordinated with the Critical Minerals Institute at the Colorado School of Mines who focused on supply chain analysis of lithium.Mineral extraction from geothermal brines in the Salton Sea and elsewhere has a decades-long history, but there have been few pilot-scale field tests focused on extraction of lithium from geothermal brines. There are also limited publicly available cost and performance data to fully evaluate the techno-economics of lithium extraction from geothermal brine. There are, however, demonstrations in progress that will more fully inform future analyses. For this report, technical and economic data are reviewed from projects focused on lithium extraction from geothermal and other brine types to assess the technologies being deployed and estimated costs to produce end products lithium carbonate (Li2CO3) and lithium hydroxide monohydrate (LiOH•H2O). A review of these projects indicates expected production costs (i.e., operating expenses or OPEX) near $4,000/metric ton of lithium carbonate equivalent (LCE) and reported internal rates of return suggest this production cost target is economically feasible with estimated prices of