Climate change and its influence on water systems increases the cost of electricity system decarbonization

Abstract

Abstract The electricity sector faces a dual challenge: decarbonization and adaptation to climate change. In many regions, this challenge is complicated by interdependence of electricity and water systems, through hydropower and energy-intensive water resources. By coupling detailed water and electricity system models, we evaluate how climate change alters pathways to carbon-free generation across the Western Interconnect, emphasizing water interactions. We find that grid planning that ignores climate projections and water linkages underestimates the capacity and investment needed to achieve decarbonization and maintain grid reliability. By 2050, electricity use could grow by up to 2% annually but up to 8% in July from cooling and water-related electricity demand, while hydropower generation could decrease annually by 23%. To adapt, the region would need to build up to 139 GW of capacity between 2030 and 2050, which is equivalent to nearly thrice California’s peak demand and adds up to $150 billion (7%) in costs.