Electric vehicles are a fixture of many a transportation utopia, and for good reasons. In a world still reliant on private transportation, they promise everything from lower pollution to higher torque. However, at least one counterpoint mars the dream of exhaust-free street racing: Today’s grid would likely fail catastrophically if the entire US car fleet immediately made the switch to running on electricity.

Let’s call this scenario of massive, simultaneous electric vehicle uptake the Pluggening. “If every customer starts buying electric vehicles, obviously that would cause a big impact on utilities,” says Mohammed Beshir, a professor of electrical engineering at USC’s Viterbi School of Engineering. Picture transformers spewing sparks like they were celebrating Chinese New Year. That scenario, though, is pure fantasy. Current EV trends show low to moderate uptake rates. And sure, if utilities don’t pay attention, they could wind up like proverbial frogs in simmering pots, not realizing they’re being boiled alive until it’s too late to hop to safety.

The good news is that massive—if not immediate—EV uptake could be a boon to the grid, by leveling out daily electricity demand and possibly even storing renewable energy in cars’ batteries, to be discharged when needed.

The utilities have plenty of time to plan ahead. Beshir, who has been researching how EVs might impact the grid for the better part of a decade, says he doesn’t see any real impact to the grid until around 15 percent of vehicles on the road go electric. A Bloomberg New Energy Finance report released last summer projects that level of uptake will happen by 2035.

Even if utilities are paying attention to the broad trends, they need to watch out for a patchwork Pluggening that could hit cities, towns, or neighborhoods where electric cars catch on quicker than elsewhere. Let’s call this scenario Keeping Up With the Muskses. “If each home on a block gets one electric vehicle, that’s probably equivalent to double that block’s existing power load,” says Beshir.

That’s a problem, because utilities traditionally dole out electricity in hub and spoke fashion. Power plants make the juice and ship it out over high voltage wires. The lines that send power to your lights, refrigerator, and Tesla Model 3 do the same for your neighbors. If demand surges in one EV-happy neighborhood, it could cause flickering lights—or worse—in nearby areas. Like politics, problems with the grid may seem national—but most begin locally.

The first sign the local grid has reached is limit will come from pole-top transformers, those cylindrical metal things you can hear humming loudly on hot, summer days, when everyone’s blasting the A/C. These spin down high voltage electricity from the transmission wires to the relatively tame 120V and 240V suitable for residential use.

Unlike the intractable complications of politics, girding the grid for an uptick in demand is straightforward. Utilities can start by installing more transformers, so more high voltage electricity can come down to residential levels. Eventually, as more people replace their internal combustion engined cars with Teslas and Chevy Bolts, the utilities will need to transmit more power.

The fix in this case is to add new wires capable of transmitting more power. This stuff isn’t hard to explain, it’s just expensive. By the way, those expenses are something you and every other electricity user will likely pay for a share of, regardless of whether you’ve bought an EV.

But Beshir and other experts think EVs will provide enough benefits to at least balance out at least some of the cost of those upgrades. So long as the electrification of personal transportation doesn’t completely restructure the American Workday. This is due to every economist’s old pals: supply and demand.