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The study finds that California can reliably meet an 85% clean electricity target by 2030 using portfolios primarily composed of wind, solar, and battery storage. Through 264 PLEXOS simulations, the authors tested three portfolios—Base Case, Diverse Clean Resources, and High Electrification—against stressors including gas and coal retirements, low hydro availability, and extreme weather. Results indicate the system remains robust even under simultaneous stressors, though it remains dependent on a strategic amount of in-state natural gas and economic imports. The report emphasizes that diversifying resources with offshore wind and geothermal reduces the need for solar and storage and improves grid stability by lowering instantaneous inverter-based generation. While demand flexibility can offset some storage needs, the study concludes that further nodal transmission and grid stability analyses are required for a complete reliability assessment.

The report analyzes the impact of raising California's Renewables Portfolio Standard (RPS) to 50 percent by 2024. It finds that while this transition reduces GHG emissions and production costs, it increases renewable curtailment, primarily driven by downward reserve and regional generation requirements. The study concludes that non-fossil flexibility—including electricity storage, advanced demand response, and allowing renewables to provide reserves—is significantly more effective at reducing curtailment and emissions than increasing the flexibility of natural gas power plants.

The document finds that reaching an 85% clean electricity target by 2030 is feasible and reliable for California, even under most simultaneous stress conditions. Analysis indicates that while solar and battery storage are primary drivers, a diverse portfolio including offshore wind and geothermal reduces dependence on imports and gas. Battery storage specifically reduces the 'duck curve' ramping requirements by an average of 42%. While the state can retire nearly a third of its in-state gas fleet under certain conditions, some gas remains necessary for reliability unless replaced by comparable firm clean resources. The study emphasizes that sharing power with the rest of the Western United States is more optimal than a 'go it alone' approach.