Can distribution grid infrastructure accommodate residential electrification and electric vehicle adoption in Northern California?

Abstract

In this paper we ask: in what ways will utilities need to upgrade the electric distribution grid to accommodate electrified loads, and what will those upgrades cost? Our study focuses on the PG&E service area in Northern California, which serves 4.8 million electricity customers and is subject to aggressive targets for both EV adoption and electrification of residential space and water heating. We create spatio-temporally detailed electricity demand forecasts, and compare that demand to distribution infrastructure limits across a range of technology adoption scenarios. We find that electrification of residential space and water heating will lead to fewer impacts on distribution feeder capacity than EV charging, but that both transitions will require an acceleration of the current pace of upgrades. We also find that timing and location have a strong influence on total capacity additions in important ways: for example, scenarios that favor daytime EV charging have similar impacts to those with managed nighttime residential charging, but uncontrolled nighttime residential charging could have significantly larger impacts. We project that these upgrades will add at least $1 billion and potentially over $10 billion to PG&E’s rate base. We conclude that measures that enable the completion of a high number of upcoming upgrade projects—including addressing workforce and supply chain constraints, and pursuing non-wires alternatives like energy storage and demand response—are critical to successful electrification.