Electric cars being charged at night making America’s power grid unstable

STANFORD, Calif. — Leaving your electric car charging overnight so it’s ready in the morning sounds like a good idea in theory. But in fact, research suggests it does more harm in the long run. Stanford scientists say it costs more to charge your electric car at night and could stress your local power grid.

Instead, the researchers suggest drivers switch to charging their vehicle at work or at public charging stations. Another added benefit of daytime charging at a public station is that it reduces greenhouse gas emissions.

With the effects of climate change more apparent than ever — frequent wildfires, widespread flooding and more severe hurricanes — automakers expect people to start investing in electric cars in the future. For example, California residents should buy more electric cars, as the state plans to ban sales of gas-powered cars and light trucks in 2035.

“We encourage policy makers to consider utility rates that encourage daily charging and incentivize investment in charging infrastructure to move drivers from home to work for charging,” says the co-lead author of the study, Ram Rajagopal, associate professor of civil and environmental engineering at Stanford University. , in a report.

So far, electric cars account for a million or 6% of auto sales in California. The state’s goal is to increase that number to five million electric vehicles by 2030. However, the study’s authors say the switch from gasoline to electric will put a strain on the grid electric when there are 30% or 40% of cars on the road.

“We were able to show that with less home charging and more daytime charging, the western United States would need less generation and storage capacity, and it wouldn’t waste as much solar power. and wind turbines,” says Siobhan Powell, PhD in mechanical engineering and lead author of the study. “And it’s not just California and the western states. All states may need to rethink electricity pricing structures as their EV charging needs grow and their grid changes.

If half of the vehicles in the western United States are electric, the team estimates that it would take more than 5.4 gigawatts of stored energy, the equivalent of five large nuclear reactors, to charge the cars . However, if people charged their electric car at work rather than at home, electric demand would drop to 4.2 gigawatts.

California currently uses hourly rates to encourage people to use electricity at night, such as running the dishwasher and charging cars. However, the authors claim that with the growing demand for electric cars, this strategy is outdated and will soon result in high demand with low supply. Specifically, the teams say that if a third of households charged their electric cars at 11 p.m. or whenever electricity rates drop, the local grid would become unstable.

“The findings of this paper have two profound implications: The first is that price signals are not aligned with what would be best for the network – and for ratepayers. The second is that it calls for considering investments in charging infrastructure where people work,” says Ines Azevedo, associate professor of energy science and engineering and co-lead author.

“We need to move quickly toward decarbonizing the transportation sector, which accounts for the bulk of emissions in California,” Azevedo adds. “This work provides insight on how to get there. Let’s make sure we pursue investment policies and strategies that allow us to do so in a sustainable way.

The study is published in natural energy.

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