National Transmission Planning Study - Chapter 5: Stress Analysis for 2035 Scenarios

Summary

The U.S. Department of Energy's National Transmission Planning Study, Chapter 5, analyzed the Western Interconnection's grid resilience under extreme weather by 2035, applying high demand growth (21% peak increase) and a 90% decarbonization target. It compared a Limited transmission expansion scenario with an Alternating Current (AC) interregional scenario across four stress cases. The study found that compounded heatwaves and droughts significantly increase unserved energy, with the AC scenario reducing unserved energy in California by 1.5% and the Pacific Northwest by 1.9% during combined California heatwave and Pacific Northwest drought events. The AC scenario also offered $0.7 billion to $0.9 billion in avoided generation costs and up to $45 billion in reduced cumulative value of lost load in some scenarios, although the Limited scenario performed better with $16 billion less C-VOLL during the Pacific Northwest heatwave + Pacific Northwest drought due to higher local dispatchable capacity in California (7.5 GW more than AC scenario).

Key Facts

Source Document

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