Efforts to transform energy systems have focused on reducing greenhouse gas (GHG) emissions, yet the energy systems technologies may also have major impacts on water resources. This thesis reports on a meta-analysis of life cycle assessment studies for both GHG emissions and water uses associated with the production of electricity and transportation fuels. The water use of various energy pathways were classified by type and assigned an impact factor (IF) to ‘weigh’ the environmental cost or benefit of water use assuming regional differences in water availability. This allowed the calculation of a ‘water equivalent’ footprint (H2Of) associated with energy pathways that could be used with CO2 equivalents (CO2e) to assess the larger environmental footprint implications of energy systems choices to include both GHG and water use perspectives. With stakeholder input on IF values for a given region, calculations of H2Of should provide a useful tool for informing energy systems choices.