Vulnerability of the US Western Electric Grid to Hydro-Climatological Conditions: how bad can it get?

Abstract:

Little is known about the operational, rather than potential, impacts of droughts on the electric system. Vulnerability assessments are usually performed for a baseline water year or a specific drought, which do not provide insights into the full grid stress distribution across the diversity of climate events. In this presentation we estimate the impacts of the water availability on the electricity generation and transmission in the Western US grid for a range of historical water availability combinations. We softly couple an integrated water model, which includes climate, hydrology, routing, water resources management and socio-economic water demand models, into a power flow model and simulate 30 years of historical hourly power flow conditions in the Western US grid. The experiment allows estimating the grid stress distribution as a function of inter-annual variability in regional water availability. Results indicate a clear correlation between grid vulnerability (as quantified in unmet energy demand and increased production cost) for the summer month of August and annual water availability. There is a 3% chance that at least 6% of the electricity demand cannot be met in August, and 21% chance of not meeting 0.1% or more of the load in the Western US grid. The regional variability in water availability contributes significantly to the reliability of the grid and could provide trade off opportunities in times of stress. We discuss joint water-energy management opportunities under historical conditions and address equivalent assessments under future climate and socio-economic changes.