Last week, as millions of his fellow Texans were plunged into unrelenting darkness and cold, Nicholas Littlejohn considered himself lucky. In the area outside Austin where he lives, the power first went out early Monday morning, and then flickered on and off, all week long, for 20 minutes at a time. Littlejohn decided to make the most of those minutes. When the power was on, he charged up his 2011 Nissan Leaf, parked outside under a layer of snow. Then, when the lights went out again, he connected his car to an inverter, pushing electrons out of its 24-kilowatt-hour battery and into other things that were, at the time, more essential: lights, a space heater, an electric blanket, and his Wi-Fi router. He skipped plugging in the fridge.
How many cars like Littlejohn’s would it take to replace the energy that was missing last week from the Texas power grid? Emily Grubert, an energy infrastructure expert at Georgia Tech, posed the question last weekend on Twitter. Her thought was sparked by a dispiriting reality: “The idea was that a lot of people during these outages have been climbing into their cars for heat,” she later told WIRED. In a way, car engines were doing at least some of the work that should have been done by the power grid. What if, she wondered, all the cars were electric? And what if that energy could be redistributed not just into homes, but onto the grid itself, powering up everyone’s lights and heaters? Assuming the grid lost 1 terawatt-hour of energy overall, and also assuming a bigger car battery, such as the one in a Tesla Model S, it would take perhaps 10 million electric vehicles to make up the total energy lost, she figured. Which sounds like a lot of cars. But as she points out, there are 22 million vehicles registered in Texas alone. And soon, many more of them will be electric.
A grid backed by 10 million Teslas is unlikely to be the top priority of most energy experts thinking about how to prevent future Texas-style crises. Yes, people need to drive. And yes, it would be impractical, if not impossible to coordinate. Experts have identified plenty of sensible ways to make the Texan grid better: weatherization of existing power plants and lines, improved connections to other grids, and regulations that encourage various forms of resilience as well as low prices. Better planning, basically. But as Grubert puts it, the crisis pointed to many possible futures for a more reliable electric grid. Batteries, both large and small, are becoming more ubiquitous, whether we consciously tie them into the power grid or not. So how could we harness them to make the grid more nimble and keep the power on? “What I was getting at was, there are many ways we could think about planning for the future,” she says.
In states like California, finding ways to store energy has long been on the minds of regulators and utility operators. The primary reason is the state’s goal of relying on 100 percent clean energy by the year 2045. The problem with that is that the sun doesn’t always shine and the wind doesn’t always blow—at least not everywhere across the state and not all at once. And so, since 2013, utilities have been required to procure energy storage systems that suck up otherwise wasted power when renewables produce more than is needed, and disburse it when there’s a gap in supply. It’s a matter of balancing a load that’s uneven, but often predictably so, such as when solar panels go offline at night.
There’s a basic business proposition in that: Storage operators make money because they can store energy when it’s cheap and sell it when it’s in demand and prices are higher. In many places, including Texas, that’s driven a battery boomlet, helped along by the growth of variable renewable energy sources and falling battery prices. In California, that’s been eased by clean energy goals and rebates. Those batteries themselves often take the form of large, utility-scale installations attached to solar and wind plants. But in some cases those are augmented by a battalion of smaller ones enlisted to share power with the grid, including batteries nestled into neighborhoods or hung inside garages—and, yes, even sitting in private cars.
The other possible use is in a crisis. In California, that occurred last August, when Death Valley sizzled past 130 degrees and lingering overnight heat across the state meant people kept running air conditioners long after solar farms had stopped harnessing rays. Natural gas plants that should have stepped in to handle the mismatch of supply and demand didn’t run as efficiently in the heat, and others that should have been on standby were unexpectedly offline. And so, the grid started to fritz. Millions of people lost power. That left some wondering why there shouldn’t be more energy stored to make up the gaps, after gas had failed to do its job as a last-ditch savior.
“Diversifying into storage is something that we need everywhere,” says Daniel Kammen, a professor of energy at the University of California, Berkeley, who helped craft the law requiring energy storage in California. He points to similar issues last week in Texas, where gas plants, unable to source the fuel they needed to keep running, represented the bulk of the energy supply lost during the cold weather. Even without a renewable energy goal similar to California’s, Kammen thinks the Texas crisis should invite a discussion in that state about how to install more storage.
Batteries alone would not be able stave off a Texas-style crisis. The scale and the duration of the outage, with over 4 million homes in the dark and about half of the usual energy supply missing, was far too large. “Even if you took all the storage assets everywhere in the United States, it wouldn’t be enough,” says Michael Craig, a professor of energy systems at the University of Michigan. The essential problem is that batteries do not produce any energy themselves. At full blast, lithium-ion batteries can distribute power back to the grid for only a few hours at a time. When the grid goes down for a week, as it did in some parts of Texas, you’re out of luck. Even with shorter outages, the batteries themselves would also need their own special protections in cases of extreme weather—as anyone who’s taken their iPhone out on a cold winter day can attest.
There are ways, in theory, to store energy for longer periods. In California, for example, where a lull in the wind in late summer happens to coincide with hot weather—a seasonal mismatch of supply and demand—utilities have begun to explore other technologies, like compressing air or hydrogen, to smooth the gaps. Those fuels can be produced using excess energy from solar or wind plants earlier in the summer, and then generate energy during the doldrums later on. In Texas, Kammen envisions offshore wind farms on the Gulf of Mexico that would provide the energy to produce hydrogen that could be stored in salt caverns buried along the coast. That hydrogen could then be tapped when the power goes off during a hurricane or a deep freeze.
Consider that an eventuality. “If you had week-long storage, that would’ve been a great contributor in Texas,” says Wesley Cole, an energy economist at the National Renewable Energy Laboratory. “But is it worth the cost? There are probably cheaper ways to do that, like winterizing the plants you have.” In time, the costs of long-term storage will come down, Cole adds, aided by more research and potential pilot projects that help make the technology’s case. But in the meantime, he suggests a more diverse repertoire of renewables that includes plans for shorter-term storage. He points out that last week solar panels did well, even as the rest of the energy supply collapsed. “It happened to be a very sunny week in Texas,” he says.
Perhaps the biggest question, Grubert says, is how to make power grids nimble enough to make energy reserves useful, without going overboard. In California, the strategy has involved redesigning portions of the grid to operate with more flexibility and independence. That way, when there’s a supply crunch, it’s easier to avoid large-scale outages. It’s a step in the direction of Grubert’s electric car battery scenario—maybe not involving millions of cars, or even cars specifically, but involving enough distributed resources to help. Doing that isn’t simple. Grids designed for big coal and gas plants are structured in ways that mean one portion cannot be shut off without affecting others, and they are often governed by baroque rules about who exactly can sell power to the grid and when. It’s a system that needs to be rebuilt, in many cases, from the ground up.
But that is worth doing, Grubert says. People are installing solar-to-battery systems in their homes and buying electric cars because they want them, and because they make financial sense, she points out. So batteries are becoming more distributed, naturally. In the past, the response to crises may have been to build more capacity among energy sources, like gas, that were more familiar and seen as reliable. And that may still be true. Even last year in California, state regulators, skeptical that enough battery storage would be ready in time for another possibly dry and hot summer, decided to hold on to natural gas plants that the state had previously planned to phase out to curb emissions. But over time, batteries will be an equally ubiquitous resource, as familiar as the fossil fuels we know so well now. The question is how prepared we’ll be to make use of them.