Climate change will impact electricity generation and demands directly, as well as indirectly through the interdependent water sector. In the Western US, the electricity grid faces both reduced hydropower and increased demand from air-conditioning and water use due to climate change. Water adaptation strategies, such as desalination and recycling, may further increase electricity use. Despite recognition of such cross-sectoral risks, electricity planning models typically do not account for either climate impacts or water adaptation pathways. Similarly, water resource models rarely consider the energy implications of those adaptive actions.

To address these gaps, we integrate a climatically-driven water resource model based on the Water Evaluation and Planning (WEAP) system, with an open-source grid planning model (SWITCH), to simulate water system operations and grid infrastructure investment under different climate change projections and adaptation scenarios. Our analysis includes the full range of interacting components between energy and water systems (hydropower, and energy consumption for water conveyance, treatment) at relevant spatial scales (watershed boundaries and electric utility planning areas) to represent the Western US water system and electric grid out to 2050. WEAP combines physical hydrology and water management, matching calculated supply by watershed with urban and agricultural demands and hydropower reservoirs. SWITCH co-optimizes operations and investment in generation and transmission capacity, subject to energy demand for water and hydropower availability under climate change from WEAP.

We evaluate the energy implications of various adaptation strategies that conserve water, prioritize local sources, or augment supplies. We examine how these strategies simultaneously affect water system reliability, as well as the generation and transmission capacity and cost for the grid’s Western Electricity Coordinating Council (WECC) region. Through this cross-sectoral modeling approach, our results highlight water management strategies that both stabilize deliveries under numerous climate projections and have co-benefits for electricity grid operations, thereby informing how the water and electricity sectors can jointly become more climate resilient.