Evaluating Cross-Sectoral Impacts of Climate Change and Adaptions on the Energy-Water Nexus
Our article distills findings from the fragmented literature into a generalized framework identifying how climate change affects coupled electricity and water systems, and the cross-sectoral implications of measures taken to balance resource supplies and demands. The framework is then applied to California to quantify the best- and worst-case range of climate change impacts on water and resource supply and demand quantities, and the magnitude and energy requirements for water adaptation measures that may be needed in the event of water shortage.
This framework provides a first-order, system-level assessment tool for identifying the biggest potential climate stressors, the range and order of magnitude of climate adaptation measures that may be needed, the possible compounding vulnerabilities due to cross-sectoral feedback effects, and key uncertainties and knowledge gaps for further analysis. The framework applied in a California case study illustrates that the energy implications of water adaptation measures could significantly compound the direct effect of climate change on the electricity system, suggesting the need for grid planning to incorporate not only direct impacts (such as future air-conditioning growth and hydropower reductions), but to also coordinate with water resource planners.
Electricity and water systems are inextricably linked through water demands for energy generation, and through energy demands for using, moving, and treating water and wastewater. Climate change may stress these interdependencies, together referred to as the energy-water nexus, by reducing water availability for hydropower generation and by increasing irrigation and electricity demand for groundwater pumping, among other feedbacks. Further, many adaptation measures to augment water supplies—such as water recycling and desalination—are energy-intensive. However, water and electricity system vulnerabilities and adaptations are often studied in isolation, without considering how multiple interactive risks may compound. This paper reviews the fragmented literature and develops a generalized framework for understanding the implications of climate change on the energy-water nexus. We apply this framework in a case study to quantify end-century direct climate impacts on California’s water and electricity resources and estimate the magnitude of the indirect cross-sectoral feedback of electricity demand from various water adaptation strategies. Our results show that increased space cooling demand and decreased hydropower generation are the most significant direct climate change impacts on California’s electricity sector by end-century. In California’s water sector, climate change impacts directly on surface water availability exceed demand changes, but have considerable uncertainty, both in direction and magnitude. Additionally, we find that the energy demands of water sector climate adaptations could significantly affect California’s future electricity system needs. If the highest projected water shortage occurs under climate change, water-conserving adaptation measures can provide large energy savings co-benefits, but other energy-intensive water adaptations may double the direct impacts of climate change on the state’s electricity resource requirement. These results highlight the value of coordinated adaptation planning between the energy and water sectors to achieve mutually beneficial solutions in response to changing stressors.