Reduced grid operating costs and renewable energy curtailment with electric vehicle charge management

Widespread adoption of plug-in electric vehicles (PEVs) and renewable energy (RE) can help to jointly decarbonize the transportation and electricity sectors. Previous studies indicate strategies to manage PEV charging facilitate integration of RE into electricity grids, but the value of such strategies at scale is unclear because electricity markets and PEV charging have been inadequately represented together. This analysis focuses on the state of California in 2025, and improves on prior work by linking high-resolution mobility and grid dispatch models to quantify the value of managed charging under a 50% RE grid and PEV adoption scenarios up to California's 5 million vehicle target. Even after accounting for practical charging and grid constraints, 0.95 to 5 million “smart” charging PEVs avoid $120 to $690 million in California grid operating costs annually (up to 10% of total costs) and reduce RE curtailment up to 40% relative to unmanaged PEVs. Overnight time-of-use (TOU) charging provides similar cost savings but increases curtailment. Both of these managed strategies defer system infrastructure expansion at the 5 million PEV deployment. The results suggest residential smart charging complemented by TOU tariffs with added daytime periods are policies with most potential to advance California's dual PEV and RE goals. •This paper values California grid impacts with electric vehicle charge management.•Smart charging lowers grid costs and curtailment relative to unmanaged vehicles.•Overnight electric vehicle charging saves grid costs but increases curtailment.•Managed electric vehicle charging can defer investments in grid capacity expansion.•Residential smart charging and adjusted time-of-use rates are favorable policies.