California’s EV Push Hinges on More Power—and Help From Drivers

This summer, the state faced the threat of rolling blackouts during an extended heat wave and asked people to avoid charging and using major appliances during critical hours, raising questions of whether its electrical grid can handle the added demand from charging EVs.

The state’s success depends on a range of factors, which include influencing the behavior of many consumers who are used to accessing gasoline at any time and unaccustomed to thinking about curtailing electricity use outside of weather emergencies.

“Are people going to top off every night? Are people going to wait every few days and then charge up all at once?” asked Dan Bowermaster, senior program manager for electric transportation at EPRI, a nonprofit research group. “There are a lot of questions about customer behavior.”

To help manage the demand on the electrical grid, utilities and auto makers are offering incentives for owners to charge up at certain times and in different ways. Charging usually takes place at home over several hours, with similar kinds of chargers available at places like offices where people are parked for long periods.

Ultimately, vehicle-to-grid technology that can use EV batteries to back up power to homes or send electricity back to the grid will be adopted, analysts say.

In California, managing the stresses on the grid is important because of the expected demand added by charging. The state’s energy commission estimates that in 2030, California will have 5.4 million passenger EVs and 193,000 medium- and heavy-duty EVs, resulting in charging approaching 5% of the electric load during peak hours from less than 1% currently. 

California’s strategy includes adding renewable energy supplies and limiting power demand, such as asking people not to charge EVs during critical hours, as it did this month amid the heat wave, said Liane Randolph, chair of the California Air Resources Board, the agency that sets air quality and vehicle emissions standards.

Ms. Randolph said EV charging isn’t going to break the grid because consumers can control when they charge and avoid busier times. “The reality is the grid is only stressed in a limited period, a few hours in the early evening on certain types of days. Most of the time it’s fine.” 

A Stanford University study published Thursday found daytime public or workplace EV charging, instead of the more common at-home charging, would be the least stressful for the grid in Western states. With current electricity rate designs, the study also found the grid could face problems late at night—when EV drivers typically charge in home garages—because too many cars could start charging at once and create a demand spike. 

“If everyone were doing that, it would cause really big problems,” said Siobhan Powell, the study’s lead author.

California is rapidly overhauling its electricity supplies, retiring older fossil fuel plants and adding more renewable resources such as solar, wind and battery projects, but the addition of new power isn’t coming fast enough to avoid potential problems.

Heat waves, drought and the slow pace to site and permit projects have made setting a target to decarbonize the power grid challenging. A crunchtime arrives on hot evenings when the West’s abundant solar power drops but demand for air conditioning remains high. California lawmakers voted in August to keep the state’s last nuclear plant online in a bid to ease anticipated electricity supply shortages.

“There’s some energy challenges in how we’re bringing on new resources to meet this new growth of electricity demand,” said

John Moura,

director of reliability assessment and performance analysis at the North American Electric Reliability Corp., a nonprofit that develops standards for utilities and power producers.

Mr. Moura said at-home charging sessions draw about the power of 2.5 air conditioners. He doesn’t expect the increased demand to create a problem with delivering reliable power to homes and businesses, mainly because utilities will manage the connection of new EV chargers. If they had to, utilities would delay charger connections until they could make grid reliability improvements to provide more power. It is an outcome to avoid, Mr. Moura said, because it would anger and inconvenience customers who would have EVs as their only new-car option.

“The disaster kind of comes from the rally cries from the public that utilities aren’t connecting their EVs fast enough,” Mr. Moura said. “And now that bumps up against EV mandates. That’s the train-crash scenario.”

EVs won’t arrive all at once, or even by 2035. Cars typically last more than 15 years, which means the fleet turnover in California will take place over many years, analysts say. The state’s mandate also allows the sale of so-called strong plug-in hybrids, which get about 50 miles of range on batteries before switching over to a gasoline engine.

“We are doing a ton of planning to make sure that the grid is ready,” said Katie Sloan, vice president of customer programs and services at utility Southern California Edison Co. That includes grid upgrades and building infrastructure so that commercial customers can add chargers at places like shopping centers and hospitals.

Auto makers are also involved.

BMW

has about 1,000 U.S. vehicles enrolled in a program that works with local utilities to tell vehicles when to charge, including one with California’s

PG&E Corp.

that signals when large amounts of renewable energy are on the grid, said Adam Langton, BMW’s U.S. energy services manager.

“There’s an opportunity there,” Mr. Langton said. “But you’ve got to have customers that are wanting to be a part of that.”

—Timothy Puko contributed to this article.

Write to Jennifer Hiller at [email protected]