Most US electricity-sector models do not have sufficient data when it comes to analysing water-related impacts in different regions in the country, which means it is difficult to make informed decisions related to future electricity and water use. The research outlined in this article attempts to overcome this challenge by using the National Renewable Energy Laboratory's Regional Energy Deployment System (ReEDS) model to project detailed electricity results for 134 regions in the US through to 2050, and link these results with basin-level water modelling.

As described in Environmental Research Letters as part of the ERL Focus on Electricity, Water and Climate Connections, we modelled four scenarios in ReEDs to analyse the impacts of different future electricity technologies on US water consumption. These included a business-as-usual (BAU) scenario and three low-carbon scenarios that assume that the country as a whole will reduce electricity-sector carbon-dioxide emissions 83% below 2005 levels by 2050 using different low-carbon techniques.

In the BAU scenario, national water consumption is 34% lower than 2010 levels by 2050, since high-water-use coal and nuclear generation will reduce and electricity demand will be met primarily with natural gas. Under a low-carbon scenario, in which new nuclear facilities and new coal plants with carbon capture and storage that use recirculating cooling replace existing coal and nuclear plants that use once-through cooling, national water consumption is 22% higher than 2010 levels by 2050. Electricity prices are also 25% higher here by 2050 than in BAU models.

Under a low-carbon scenario in which energy efficiency reduces electricity use by 35% compared to BAU and renewable energy provides 80% of remaining US electricity generation by 2050, national water consumption is 85% lower by 2050 compared to 2010 levels. Significant reductions in electricity use thanks to investments in energy efficiency more than offset modest increases in electricity prices, lowering consumer electricity bills 31% by 2050 compared to BAU.

This research is part of the Energy and Water in a Warming World (EW3) Initiative, a collaborative effort between the Union of Concerned Scientists and a team of more than a dozen independent experts, which aims to build and synthesize policy-relevant research on the water demands of energy production in the context of climate variability and change.

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