Hydroclimate Risks to the Western US Electric Grid under a Warming Climate

Changing hydroclimate creates risks to the western U.S. electric grid, particularly when hydropower generation changes, but tools to characterize these risks are relatively new. Here, we ask: how is hydropower changing in a warming climate, and what are the consequences of hydroclimate change for the grid?

Climate projections of future hydropower generation are somewhat uncertain due to precipitation change uncertainties, but production is consistently expected to shift from summer towards winter, out of phase with changes in load. Interactions between hydrologic drought and hot temperatures are particularly problematic, yielding increased prices and greenhouse gas emissions, with uncertain shortfall risks.

Future work should continue stress-testing new tools, evaluate hydroclimate risks under a wider range of emissions scenarios, evaluate potential energy-hydroclimate feedbacks (including those with complex causal pathways), and consider the impacts of potential changes in non-energy water uses and reservoir operator adaptations.