Electric Cars and the Power Grid

by Brian Dunning
October 4, 2022

If it seems that there are too many Skeptoid episodes about electric cars this year, that's because it's a show about popular myths. And hardly any topic is more timely and popular as electric cars. We have states (and whole nations) requiring that increasing percentages of new car sales be for zero-emission vehicles. We have climate-driven heat waves putting extraordinary demand on power grids. We have an election year, when misinformation and disinformation tend to take over the news. So, yeah, electric cars are a hot topic right now. And they are the subject of one of the most common new claims: that as electric cars become more and more ubiquitous, power grids will not be able to keep up with the increased demand, and everything will go to heck. Or something. Is it true?

During an unprecedented heat wave in California in September of 2022, California issued a Flex Alert, which is a call to consumers to voluntarily reduce their energy usage. Flex Alerts are issued by an independent nonprofit called the California ISO, whose mission is to oversee the operation of the power grid to preserve its health. A typical Flex Alert asks people to reduce their use of electricity during the peak consumption period of 4 to 9pm. Normally this means requesting that people turn their air conditioning to no cooler than 26°C/78°F, to avoid the use of major appliances (washer/dryer, dishwasher, oven and stove), and to turn off unnecessary lights. After several days of Flex Alerts, one came out that had a new item added to the list: a fourth priority, and that was charging electric cars. If your car was low and you needed to charge it, the Flex Alert asked you to try and do so before 4pm or after 9pm.

Well, social media went crazy. It's no secret that electric cars are a political hot topic: many liberals love them; many conservatives hate them with a passion. What many people think about electric cars is not determined by anything about the cars themselves, but by those people's own tribal identity. A lot of those who hate electric cars were absolutely jubilant at this news; gleefully posting to social media that California's electric grid is now officially proven to be unable to support electric cars. And conservative media did exactly the same thing. If you don't particularly like chocolate ice cream, and then there's a chocolate ice cream shortage, do you go dancing in the streets celebrating that chocaholics can't have their favorite dessert? No. You probably wouldn't care. But it's different with electric cars, because their very existence cuts some people down to the bone.

Now, normally at this point in an episode, we'd say "Hey, let's look at the science and see what the facts are about electric cars and the power grid," but this little episode in California really had much less to do with the facts of the situation than with political tribalism. There's a gap between the facts of the power grid and the divisions that actually set people off. That's not good. What's better is when people care more about facts and what's best for everyone.

So today, we're going to set the political divisions aside (which is always a good idea no matter what) and focus instead on the science of this situation. If it turns out that supporting a carbon-free transportation network is not going to be practical, or will cause more harm than good, then I want to advocate against it. But if it is practical, then it's clearly in everyone's best interest so we should advocate for it. With that in mind, let's look at the power grid — most particularly at California's power grid, because that's the one in question, and it's also the world's biggest electric car market so far — the perfect test case.

It's worth noting that it wasn't until a single 5-hour spell during California's worst heat wave ever that a request was made to voluntarily reduce electric car charging, and then only after already asking people not to cook with appliances and to set their homes to uncomfortably warm temperatures. But there also aren't very many electric cars around yet. California has about 575,000 of them registered as of this writing, more than 40% of all electric cars in the United States. Right now about 12.5% of all new cars sold in California are electric. By 2026, California's new laws mean that percentage will triple to 35% by 2026, and triple again to 100% by 2035. That will be two million new cars every year added to California's grid: about four times as many as exist today, and that triggered that Flex Alert.

OK, does that sound pretty horrifying?

If I'd said California will be adding 2 million iPhones per year, nobody would blink. That's not a significant load on the grid. But what if I said 2 million new residential air conditioners per year? Would that worry you? Would you panic about the ability of California's grid to keep up? Most of us probably don't know, because we don't really have much of a sense of that. Also there's a huge range; there are new efficient air conditioners, old inefficient ones, some for big houses and some for small ones, and then everyone uses them differently, with some cranked super cold and some hardly touched. But we do know that the average American home spends 6% of its energy usage on air conditioning and uses 11,000 kWh per year. That comes to just under 2 kWh per day for air conditioning.

The average California driver logs 12,500 miles per year, or about 35 miles per day. That's about 8 kWh for a Tesla Model 3, and that's about four times what the average California house uses on air conditioning. Four times as much.

So, again, we have a conclusion that sounds horrifying. How could any grid possibly keep up with that kind of expansion?

The answer is — and it may sound hard to believe at this stage — quite easily. Since a home uses 11,000 kWh per year, that's 30 kWh per day, and the car adds only 8. Give every single home in California an electric car, and you're only increasing the residential power requirement by 27%. Not 400%, not 1000%; 27%. If you were to try and do that by 2035, residential grid capacity would only need to expand by 2% a year.

But there's more. Only a fifth of California's grid capacity is residential. Putting a new electric car into every single residential customer's garage by 2035 would require much less than a single percent increase annually.

Now of course, the picture is not as simple as that. There are countless complexities and variances. Many buyers of new electric cars won't be able to charge at home; they'll use public chargers at work or at stations. A lot of people won't buy electric cars at all; they'll hang onto their gassers (remember the regulations don't ask anyone to get rid of their existing cars, and used gas car sales will continue as always). Many of the cars sold to satisfy California's new regulations will be plugin hybrids, not all electric. Most of these factors ease that hypothetical 1% annual demand increase.

The basic fallacy that the alarmists rely upon, and that underlie their articles' enormously inflated power demand estimates, is the rather disingenuous assumption that every single electric car draws power from the grid at its maximum charging rate, 24 hours a day, every day. It assumes none are ever driven or parked, but require full-time charging. This is akin to claiming that gas cars need to constantly have gas pumped into them, all day every day, without ever using any of it. The truth is almost the exact opposite. At any given time, the majority of electric cars — like all cars — are parked and not being charged. Part of the rest of the time they are being driven. And only the small remaining part of the time are they being recharged; and of that, the vast majority is at a rate far lower than their maximum.

One anti-EV article by Reason says "If everybody in California went out and bought electric vehicles tomorrow, it would probably be an energy disaster" — a circumstance so absurd it scarcely warrants a reply. It then goes on to parrot other popular anti-EV falsehoods, such as "Millions of Californians won't and probably can't afford to transition to electric vehicles within the next 13 years" — as we discussed in episode #844 on anti-EV myths, Consumer Reports found that despite a higher initial purchase price, total cost of ownership of the average electric car is $6,000 to $10,000 cheaper than the average gas car, resulting in lower (not higher) monthly expenses. Make no mistake: the anti-EV lobby has few scruples when it comes to spreading propaganda to scare you away from going electric.

Regardless, it's a trivial matter for EV owners to not charge during peak hours — something they tend to avoid anyway because that's when rates are highest. You simply tell your car what hours to charge during, plug it in, and forget about it. Sometime during the night your car's charger will click on, and you're ready to roll in the morning, and you saved money doing it.

But moreover, it is the very fact that an electric car is basically just a giant battery on wheels that may turn out to be the healthiest thing for the grid. It's called bidirectional charging, and some electric vehicles, such as the Ford F-150 Lightning, already support this. What it means is that just as your house can power your car, so can your car power the house. If there's a blackout and you have the right equipment installed, your house instantly switches over from drawing power from the grid to drawing it from your car. You'd never even know anything had happened. When power is restored, it switches back. No more blackouts or brownouts ever, for anyone with an electric car so equipped.

But taking it one more step is where things get really exciting. It's called vehicle-to-grid, and it's already being tested around the world, in partnerships such as California's joint program between General Motors and Pacific Gas and Electric. In this scenario, if the grid gets close to maximum capacity, it can draw power from those plugged-in electric cars (whose owners opt in), as few or as many as are needed, and access all the additional capacity they want. Your electrical meter flows backwards, putting money in your pocket, and relieving everyone of any power grid concerns. This even covers the electric car owners who don't have garages and can't charge at home; the many that can will be more than enough to support everyone.

Can the grid support electric cars? In the very near future, it's the electric cars that will be supporting the grid.

It's true that installing the equipment in your house will cost money. It's true that upgrades to the grid infrastructure to support vehicle-to-grid will cost money. But none of this is new or unexpected. Everyone went through something similar when digital broadcasting replaced analog televisions; when personal computers took over the world and Wi-Fi was installed in every home and office; when we moved from land lines to cell phones; when air travel made us build expensive airports in every city; even going back to when cars replaced horses and the entire world had to be paved and equipped with traffic signals and painted lane lines, and freeways and interchanges were constructed. When the world first began to be electrified, its grids had to be built out and every home needed dramatic reworking to be electric. Is anyone ruing that progression? Every such investment throughout history has been more than worth it, and this one will be too.

Correction: An earlier version of this said the CAISO board was made up of representatives from the state's utilities. That's not correct; while many utility representatives are indeed advisors to CAISO, the board itself is appointed by the governor and most have public utility experience. —BD

By Brian Dunning
Follow @BrianDunning