A Very California Lesson on Just How Weird Electricity Is

The state’s record-smashing heat wave is a window into the future … and it’s okay.

The bear from the California State flag carrying a power cord in its mouth
Tyler Comrie / The Atlantic

Last week, Americans had a rare view into what the future might look like. It came from California, as usual, but it was not courtesy of Apple’s annual keynote, or indeed of any technology company. It came from the state’s electricity grid.

Wait—wait! Don’t click away yet. Electricity is, I hasten to add, extremely interesting. It is the energy source of the future. In basically any world in which America addresses climate change and zeroes out carbon pollution from its economy, we will have to use more electricity. Electricity will propel our cars, cook our food, and heat our homes. And that means we should start to cultivate the kind of commonsense understanding of the electricity system that many of us already have about, say, gasoline, or oil prices, or car engines. Because especially if you’re used to living in a world of physical commodities—and physical fuels—electricity is really, really weird.

Here’s an example. Last week, California broiled under one of its worst heat waves in written history. San Jose, Sacramento, and Redwood City recorded their hottest all-time temperatures, with the state capital hitting 116 degrees Fahrenheit. That record-smashing heat led to grid-straining demand for air-conditioning. Last Tuesday, California’s electricity use spiked to more than 52,000 megawatts, surpassing previous all-time records for peak power demand by more than 3 percent.

That’s one view of the future: To state the obvious, these unusually intense heat waves are going to become more common under climate change, which is making heat waves generally more frequent, more intense, and longer-lasting. More important, climate change is also expanding the spatial extent of heat waves, meaning that pockets of hot air in the atmosphere are now physically larger—and therefore cover a much larger land area—than they once did. That’s what happened this week. Although California got the brunt of the heat wave, record-setting warmth stretched across the West, knocking down nearly 1,000 records and enveloping Nevada, Utah, and Montana.

In the past, California could deal with surging power demand by importing electricity from nearby states. But if people across the West are cranking up their AC to fend off the warmth, then there’s simply less electricity to go around.

And here is the first lesson from this week: This particular problem is most acute in the early evening. California has one of the cleanest grids in the country, with more than 15,000 megawatts of installed solar capacity. (How much is a megawatt? While per capita electricity use varies widely from one region of the U.S. to another, one megawatt is enough to power about 750 California homes at once.) In the middle of the day, nearly all of that solar capacity pumps electricity into the grid. But in the afternoon, it begins to fade, literally, as the sun falls lower in the sky. And it shuts off, of course, with the arrival of dusk.

In other words, solar has almost entirely dropped off the grid by 7 or 8 o’clock at night. But that’s exactly when electricity demand peaks—especially on a very hot day. That creates a painful window, lasting from roughly 6 to 9 p.m., when it’s still hot outside, so people still have their air-conditioning on high, but when solar is no longer keeping the grid afloat. Engineers have to fill in the missing supply with any other source of power. This week, nearly all of California’s crunch times have come during this late-evening period.

When the state last suffered such a widespread heat wave two years ago, its grid lapsed into rolling blackouts. But this time, the grid held fast. State officials have said that an emergency cellphone alert that asked residents to reduce their power usage helped save it. Within 45 minutes of the alert going out, the state had cut more than 2,000 megawatts of electricity, roughly as much energy as it normally takes to power more than 1.5 million homes. And the grid was fine.

There’s the second lesson: A shortage of electricity doesn’t work like a shortage of a physical commodity. Imagine that a hurricane makes landfall and cuts off a city from receiving gasoline for a few days. At first, gas stations might sell off their inventory, perhaps rationing fuel as reserves dwindled. Eventually all of the city’s gasoline would be sold. But even after gasoline shipments started to flow in again, the city would remain crucially short on gasoline for a few days as drivers made “make up” purchases to fill their tanks. In other words, a brief stoppage of gasoline shipments can lead to a much longer-lasting shortage.

This is not how electricity shortages work. Because the electricity system must balance supply and demand at every instant, electricity shortages themselves are very brief. The grid operator can foresee a shortfall at 7 p.m. but know that everything will be all right by 8 p.m. Unless something really catastrophic happens, the grid will emerge unhurt. This is why it works to simply mass-text an entire population and ask them to solve a temporary grid problem by turning the AC a few degrees warmer or by shutting off their laundry machines.

The grid’s struggles have led some commentators to predict a clash with another aspect of California’s future: the state’s ban on the sale of new internal-combustion cars, which will take effect in 2035. “I did wonder how that same scenario might play out a few years hence, as California’s electric-vehicle mandate kicks in,” the columnist Megan McArdle wrote. “Can California’s infrastructure hold up under the strain?”

It just might. (That’s the final lesson we learned this week.) Electric vehicles may actually help the grid, Michael Wara, a scholar of climate and energy policy at the Stanford Doerr School of Sustainability, told me.

Once you use an EV, “you immediately begin to understand that the way the charging works on these cars is designed to avoid exactly the kind of impacts that people are talking about, and is actually very beneficial to the grid,” said Wara, who described himself as “lucky enough to own a Tesla Model 3.”

“The car won’t charge between 3 p.m. and 11 p.m.” unless you override it, he said. “The reality is either you charge at work, and then you’re done by 3. Or you get home, plug your car in, and it doesn’t draw from the grid until 11 o’clock. But you don’t care because you’re having dinner with your kids, then you go to sleep, and it charges.”

More and more appliances may soon work like this, especially if, as in California, time-of-use electricity rates become the default. (Under these plans, electricity is usually slightly more expensive in the early evening, when power demand is peaking but solar is beginning to fade.) Yesterday, Apple announced a new “Clean Energy Charging” feature that allows users to set their iPhones to charge during the parts of the day when the grid is most likely to be dominated by renewable sources.

But EVs will also cause demand for electricity to increase, Wara said, and that is likely to be a boon for utilities. For the past 15 years, electricity demand has been more or less flat. That has led overall investment in the basic infrastructure of the grid to lag. “We need to do all this grid investment because—forget about climate change—the grid is old and rickety,” he said. “But industries that don’t have growth can’t do investment.”

EVs will give utilities that opportunity for growth. The National Renewable Energy Laboratory has projected that U.S. power generation will need to rise at least 25 percent by 2050 even if Americans don’t switch to electric vehicles very quickly. If Americans do flock to EVs, then power demand could rise as much as 72 percent. The Inflation Reduction Act’s generous tax credits for new solar, wind, geothermal, and nuclear plants could also help spur utilities to turn over their fleets.

Electricity is the lifeblood of technical society. Two decades ago, the National Academy of Engineering ranked electrification as the greatest engineering feat of the 20th century, outranking the automobile (No. 2), the airplane (No. 3), and computers (No. 8). Yet of late the public’s understanding of energy has been treated as identical to its understanding of fossil fuels. That outlook must change: Nothing less than progress requires it.