This report documents a part of a broad assessment of energy-water-related issues in the western United States. The full analysis involved three Department of Energy national laboratories: Argonne National Laboratory, Los Alamos National Laboratory, and Sandia National Laboratories. Argonne's objective in the overall project was to develop a regional power sector expansion forecast and a detailed unit-level operational (dispatch) analysis. With these two major analysis components, Argonne estimated current and future freshwater withdrawals and consumption related to the operation of U.S. thermal-electric power plants in the Western Electricity Coordinating Council (WECC) region for the period 2005-2025. Water is withdrawn and used primarily for cooling but also for environmental control, such as sulfur scrubbers. The current scope of the analysis included three scenarios: (1) Baseline scenario as a benchmark for assessing the adequacy and cost-effectiveness of water conservation options and strategies, (2) High nuclear scenario, and (3) High renewables scenario. Baseline projections are consistent with forecasts made by the WECC and the Energy Information Administration (EIA) in its Annual Energy Outlook (AEO) (EIA 2006a). Water conservation scenarios are currently limited to two development alternatives that focus heavily on constructing new generating facilities with zero water consumption. These technologies include wind farms and nuclear power plants with dry cooling. Additional water conservation scenarios and estimates of water use associated with fuel or resource extraction and processing will be developed in follow-on analyses.