How Electric Cars and Trucks Improve Grid Reliability

EVs aren't straining the electric grid and can improve grid reliability.

An electric pickup truck with its front trunk open is parked in front of a home that is under construction

Courtesy Ford

With the Western U.S. facing a record September heat wave that is stressing its electric grid, some have asked if the region—and the entire nation—can handle an increasing number of electric cars and trucks. Some of this, of course, is just bloviation from ideologues who want to keep American addicted to oil.

Putting the misleading hyperbole aside, it’s a reasonable question to ask if our electric grid can handle  all the electric vehicles (EVs) we need to address the climate crisis (which is what’s actually responsible for the heat emergency that’s straining the electric grid today).

The short answer is: Yes, EVs can easily be charged when there’s spare capacity on the grid.

The longer answer is: EVs can improve the resilience and reliability of the grid, especially if we put in place commonsense policies and technologies. This means encouraging EV owners to charge when electricity is plentiful and cheap, and deploying technologies so the batteries in EVs can not only draw power from the grid but provide back-up power to homes and supply the grid during times of severe stress.

EVs aren’t a problem, but a solution to support the grid

EVs can soak up solar and wind generation when it’s abundant, easily be programmed to avoid peak hours when the grid is strained, and have to potential to put electricity back onto the grid when demand peaks, supporting the grid and preventing blackouts.

Policies that advance EV adoption are not in conflict with efforts to continue to move to renewable energy, but a means to achieve those goals and improve reliability. For example, California’s recently adopted Clean Car Standards will put about 14 million zero-emission vehicles on the road by 2035. If those were all battery-electric vehicles capable of putting electricity back onto the grid, that would represent a collective battery that could theoretically power all of the homes in California for three days.

Realizing that vision would require the deployment of technologies to allow EVs to supply electricity to the grid that have already been proven but that haven’t yet been deployed at scale. But this isn’t science fiction. For example, the electric version of the Ford F-150 pick-up truck (which has been the best-selling vehicle in America for decades) is now being delivered to customers across the country with the ability to power a home for 3 to 10 days (or power the tools needed to build a home). And even just providing back-up power to one home yields systemwide benefits because that’s one less home that needs grid electricity when others do.

How electric vehicles are like pumpkin pie

When skeptics ask about the viability of more EVs on the grid, they start from an overly-simplistic premise: With the grid Western grid under strain, won’t adding an additional source of electricity demand overwhelm it?

This premise misses two important facts about the grid and EVs:

  • First, EVs are a very small part of overall electricity demand and won’t become a significant share of electricity use even with millions more EVs on the road. Even in California, which already has over a million EVs on the road, those EVs currently account for less than 1% (to be precise, 0.4%, based on the underlying analysis done by the California Energy Commission) of overall demand for electricity. Saying they’re what’s straining the grid ignores 99.6% of today’s challenge. And even if there were 5.4 million passenger EVs plus another 193,000 commercial trucks on California’s roads by 2030, they would still only account for 4% of demand for electricity during the evening peak (4PM-9PM).
  • And, second, the electricity system is built for the most demanding hour of the year, but every other hour there’s excess capacity. And, in almost all cases, electric vehicles don’t need to draw power during those times of strain.

Think of an electric grid like your oven. It’s more than big enough to cook a typical meal. But, on Thanksgiving the oven is going to be on most of the day and face competing demands in the hours before dinner to cook the turkey, the brussel sprouts, the stuffing, etc. But EVs are more like pumpkin pie, which can be baked the day before to keep the oven available for the stuff you need to serve hot at dinnertime.

EVs don’t need to be charged during the hours of the year when demand for electricity peaks; they can easily be charged when there is plenty of excess grid capacity. Much has been made of California’s grid operator asking consumers to help avoid potential blackouts by setting their thermostats at 78⁰F and avoiding uses of electricity like charging EVs during the hours of 4 p.m. and 9 p.m., but during this extreme heat emergency, that still leaves another 19 hours of the day for EV owners to “fill up” their cars.

That’s exactly what EV drivers on “time-of-use” electric rates (which reflect the fact electricity is abundant and cheap during off-peak hours) are already doing on an everyday basis. We know from hundreds-of-thousands of real-world data points that EV drivers on such time-of-use rates do 90 percent of their charging during off-peak hours.

Widespread EV adoption can support the electric grid while saving all utility customers money

Researchers at the Pacific Northwest National Laboratory found sufficient spare capacity in the nation’s electric grid to power nearly 200 million light-duty passenger vehicles if charging is properly managed. That means we could potentially electrify 73% of the U.S. passenger vehicle fleet without building a single new power plant.

And because EV charging takes advantage of spare capacity in electrical infrastructure we’ve already paid for while bringing in new revenue (money that would otherwise go to oil companies), they save all electricity customers money on their bills. In the years from 2012 to 2019, California EV drivers contributed $806 million more in revenues than associated costs, money that was automatically returned to utility customers in the form of rates and bills that were lower than they otherwise would have been. (And, of course, electric vehicles are cheaper to own and operate than a similar gasoline-powered vehicle.)

But what if everyone had an EV? NRDC partnered with researchers from Lawrence Berkeley National Laboratory to model what would happen if every household in the San Francisco Bay Area had an EV. That analysis showed that, if only 30% of EV owners shift to time-of-use utility rates, that would slash the need for grid investments. Happily, nearly that many customers in the area with EVs are already on such time-of-use rates. The analysis also demonstrated that more comprehensive adoption of smart charging strategies could entirely obviate the need for grid upgrades.

An electric vehicle is a battery on wheels that can support the grid

Using electric vehicles like the batteries they are would help the overall electricity grid during times of strain. As Axios put it: “As more cars plug in, EVs could actually make the grid more resilient by supplying electricity back to the network when it's needed most.”

A separate Lawrence Berkeley National Laboratory study found that just programming vehicles to charge when there is spare capacity could save costs of $1.5 billion for stationary batteries. And enabling so-called “vehicle-to-grid” technology, when electric vehicles would actually supply power back to the grid during times of stress could save $13-15 billion in stationary battery costs.

“By displacing the need for construction of new stationary grid storage, EVs can provide a dual benefit of decarbonizing transportation while lowering the capital costs for widespread renewables integration,” the researchers concluded. Put simply, it’s cheaper to pay individual utility customers to use batteries on wheels they’ve already bought-and-paid-for than it is to pay corporations to buy big batteries and park them on the grid.

A change is gonna come

Let’s be clear: The climate crisis is upon us—this record heat wave in the West is just the latest manifestation of it. In order to address this crisis, we need to zero-out tailpipe pollution by powering our cars, trucks and buses with an increasingly clean, nimble, and resilient electric grid. Using the right policies and technologies, electric vehicles will help bring about this transition—and put more money in our wallets along the way, too. That's why we need more, not less electric cars, trucks, and buses, and why we need policies like California's Prop 30 that will accelerate EV adoption.

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