Effect of solar panel orientation and EV charging profile on grid design

Abstract

The implementation of solar coupled with daytime electric vehicle (EV) charging, aligns seamlessly with the broader goal of transitioning to a decarbonized grid and clean energy future. This paper explores how fixed-tilt solar arrays coupled with daytime EV charging would affect a future renewable-energy-driven grid in California. We use capacity-expansion modeling to identify the lowest-cost grid design for 40 scenarios that compare two solar panel mounting configurations (east–west versus south-facing), two EV charging profiles, five tilt angles ranging from 15°to 35°, and two assumptions about a long-duration energy storage (LDES) candidate resource. We then evaluate and discuss the mix of generators selected by the model for the various scenarios, the associated curtailment, and the implications about the best approaches for adding fixed-tilt solar arrays as part of transitioning to a new energy system. Although the east–west-facing solar orientation is expected to reduce the need for diurnal storage by being able to charge EVs early and late in the day, it appears that the better matching between seasonal supply and demand for the south-facing orientation is more important.