Predicting, Managing EV Charging Growth to Keep Electricity Grids Reliable, Affordable

the researchers predict that people with less access to in-home charging – like apartment renters and condominium owners – will transition to EVs and the fraction of in-home charging will sink. At the same time, workplaces could install more charging stations and electric utilities could incentivize charging at varying times of the day. The model can account for several factor changes.

“In the model, we capture driver behavior, which includes when they charge, the timing of their charge, and how much energy they use. We also capture location, like home or the workplace,” said Gustavo Cezar, the other co-lead researcher. Cezar is a PhD candidate in civil and environmental engineering, and a staff engineer at Stanford’s SLAC National Accelerator Laboratory.

Some of today’s drivers also use automatic timers to dictate when their cars charge. The timers track electricity prices, and charge vehicles when it is cheapest to do so. However, if a large number of timers were utilized, they could cause a surge in electricity demand on the grid. At 11 pm, California’s EV charging demand could peak on the order of 8.725 GW in 2030. The typical daily peak demand for all electricity in California currently is on the order of 25 GW, so charging EVs would comprise a large proportion of all electricity demand.

This could create a number of issues, especially if the grid is not equipped to handle this level of demand. By comparison, scenarios without timer control and where charging was spread throughout the day led to a smaller peak demand of under 4 GW.

“Grid operators have to worry about reliability and cost. Without planning, in the worst case they could end up with an outage, or even if they can serve all the demand, end up with high costs for the electricity,” said Powell.

Policy decisions made with this in mind could incentivize charging at a more distributed pace, which could curb electricity infrastructure investments while maintaining the reliability of the grid. The framework created by the researchers can also be augmented to include other factors like day of the week, season, holiday or region.

But, said Cezar, simply switching to EVs from fuel-burning  cars, motorcycles and small trucks may not be enough on its own to decarbonize light-duty vehicles. He said that, among all the talk about switching to EVs, the pollution from the production of electricity that charges them gets too little attention.

“Here in California, we primarily use solar during the day, so we’re going to need to procure fossil fuel generation to supply the charging load overnight, in particular if the focus is on residential charging,” he said “The next step is figuring out how to sustainably increase the number of EVs.”

Cezar said the team is working to disaggregate their model and apply it to narrower locations, like neighborhoods and campuses, to help planners avoid overwhelming local electricity distribution systems.