Here's What EVs Are Doing to California's Energy Grid

If you’ve been outside lately in Southern California, you’ll know there’s an ongoing heatwave here. In something of an annual tradition, the electricity grid is under duress because of the heightened demand for power-hungry air conditioners.

In response, the California Independent Systems Operator, which oversees the state’s electric grid, has issued “flex alerts,” which are essentially pleas to residents to conserve power during peak usage (4 p.m. to 9 p.m.) by turning off appliances, air conditioning, setting thermostats to 78 degrees Fahrenheit, and refraining from charging electric vehicles.

This last item–don’t charge your EVs–has drawn some schadenfreude from some news outlets which point out that, just last week, the state announced plans to ban new gas car sales. How can California possibly hope to power a fleet of around 20 million electric vehicles in the future when it can hardly power around 1 million cars today?

Whether or not it’s being asked in good faith, it’s a valid question. So here’s an explainer about what exactly is going on with the grid and the role that EVs will likely play in the future.

The problem is that it’s too hot right now. As always, no one can claim that climate change caused this heatwave, but the overwhelming majority of scientists agree that human-caused climate change is making heatwaves like this one more common. The future will certainly have more such heat events than the present, especially if we don’t find a way to reduce or eliminate carbon emissions.

When it’s too hot, people use a lot more air conditioning. Air conditioning is especially energy-intensive. The result is that–all at once–there’s more demand for electricity. When demand outstrips supply, blackouts occur.

“People think of ‘the grid’ as this uniform system. But really, it's a bunch of electrical connections that have evolved over time,” says Cascade Tuholske, an assistant professor of Human-Environment Geography at Montana State University. “Some aspects of the grid are super antiquated. And you can't just pump more electricity into a system without upgrading it.”

You can imagine the electrical grid sort of like plumbing. Like water in pipes of different diameters, there’s a maximum amount of electronics that can flow through different grid architectures, so simply adding more energy into the system doesn’t necessarily solve the problem.

The California electric grid, in other words, has failed to keep pace with the increasing demand for air conditioning. Or, as California Gov. Newsom put it in a press conference yesterday, “All of us have been trying to outrun Mother Nature, but it’s pretty clear Mother Nature has outrun us.”

Even without the increased demand from electric vehicles, the grid needs upgrades. But EVs–even a whole state’s worth–don’t add as much demand to the grid as fossil fuel advocates might suggest. The main reason EVs aren’t likely to cripple the grid is that they don’t all charge at the same time and they don't usually charge when demand is high. Like with smartphones, most EV charging happens overnight, while the car sits in the garage, while people aren’t awake to use appliances, while demand for air conditioning is lowest.

Nationally, EV charging accounts for just .2% of energy grid consumption, by some estimates. Adding a nation of EVs will absolutely add demand for electricity to the grid–as much as 25% more, according to scientists–but this transition is going to happen slowly, over time. Even California, which has the most ambitious EV adoption policy, is allowing 13 years before banning gas-powered car sales. It will probably be 30 years or more before 90% of the cars on the road are electric. The demand for more power will ramp up slowly, just as it has historically as Americans bought refrigerators, air conditioners, computers, etc.

President Biden’s Inflation Reduction Act includes massive amounts of funding to address these exact issues, including $2.5 billion to “modernize and expand capacity of America’s power grid.”

Ironically, EVs actually may offer help to a stressed electrical grid if they’re used correctly. Cars with full batteries can be plugged in and used to supply energy to the grid – just as they did a month ago when Tesla pooled energy from its users’ vehicles to boost California’s supply. Of course this will drain your car’s battery, but you should be able to get paid for your troubles. A 50kWh battery like what’s found in an electric vehicle is more than enough to power the average house for a day.

“At least in theory, if they're integrated into the grid, you can draw the power off your EV battery during periods of excess demand,” says Tuholske.