Local to Regional Energy System Impacts of Water Management and Agricultural Decisions in the Southwest: The Importance of Scale.

In the US Southwest, limited water availability and water management decisions can affect power system operations and agricultural production. Changes in water use in one sector can have dramatic impacts on other sectors. Historically, modeling these interdependencies has been challenging due to differences in sector-specific models and the incompatibility of least-cost optimization models of the energy sector and rule-based simulation models in the water and agricultural management sectors. Here we present a novel integrated modeling framework that combines high resolution power system modeling with rule-based water and agricultural management models to assess how these systems respond to varying levels of water availability. We use the San Juan River Basin in the US Southwest as a case study to demonstrate how water availability could affect shortage sharing agreements among energy, agricultural, and other water users. We consider multiple climate scenarios, water demand scenarios, and power system scenarios to demonstrate the tradeoffs among sectors. To further highlight the importance of including water management decision-making in power system model frameworks, we perform sensitivity analyses using varying levels of detail in the water management model. Results show how water and agricultural management decisions can substantially affect power system outcomes, and how having higher resolution and detail on water management can lead to fewer disruptions to power system operations. This suggests that coupled model frameworks that do not incorporate water and agricultural management decisions could be overestimating the impacts of drought on power system operations.