GRID RELIABILITYPredicting, Managing EV Charging Growth to Keep Electricity Grids Reliable, Affordable

Published 24 March 2022

With a growing fleet of EVs on the road, grid planners depend on accurate estimates of charging patterns to calculate electricity demand. A team of researchers at Stanford University assembled a scalable probabilistic model for charging demand that can be applied to a flexible array of populations and account for a wide range of factors.

One day, the demand for electricity to charge electric vehicles may overwhelm the power grid, unless the electricity sector is prepared for the challenge.

With a growing fleet of EVs on the road, grid planners depend on accurate estimates of charging patterns to calculate electricity demand. A team of researchers at Stanford University assembled a scalable probabilistic model for charging demand that can be applied to a flexible array of populations and account for a wide range of factors. Within California, the model found that by 2030 – in a scenario where most EV owners opt to charge their vehicles when they get home every evening – peak charging demand would be more than twice as high as if drivers charged throughout the day at home, work and public stations. By 2030, EV charging will comprise a significant proportion of electricity demand in advanced economies, so keeping peak demand as low as possible would curb the need for new generators and transmission lines.

“We wanted to create a model framework for long-term planning that captures real drivers’ charging patterns and accounts for uncertainty,” said Ram Rajagopal, senior author of the study, which was published in the March 1 edition of Applied Energy, Rajagopal is an associate  professor in Stanford’s Department of Civil & Environmental Engineering.

Today’s 7 million EVs globally are expected to swell to 400 million by 2040. In order to support that almost 60 fold increase, the world must make substantial updates to EV-supporting infrastructure, including the generating capacity, transmission and distribution, smart grid technologies and an estimated 300 million readily-accessible charging stations.

The switch from gasoline powered vehicles to electric ones is key to decarbonizing human activity. Drivers’ opportunities to charge EVs must be convenient and plentiful for that switch to happen. Future policy decisions can facilitate easy, reliable and affordable charging.

“We foresee this being used by people in the utilities industry, as well as in government, who want a data-driven approach to studying future scenarios,” said Siobhan Powell, co-lead researcher of the study and a PhD candidate in Stanford’s Department of Mechanical Engineering.

The researchers’ model aims to give grid planners and policymakers just that information: where, when, how, how much and how often drivers will charge. On a regular laptop computer, the model could simulate charging data for 100 million EVs in around 10 minutes, the researchers said.

More Diverse Population
Today, the majority of California’s EV charging occurs at single-family homes. However,