Live in the suburbs with a garage? Good news: Charging an electric vehicle couldn’t be cheaper. Live in the city center and park on the street? Tough luck, you could be paying more than the cost of diesel to keep your EV running.

That’s a small problem now—but it’s getting bigger by the day. EV sales doubled in the past year and now make up 8.6 percent of global sales. And though the vehicles often remain more expensive to buy than gas or diesel cars, the high cost of fuel means they’re cheaper to run in the longer term. But there’s a catch: Despite record fuel prices in the US and Europe, topping up the battery at a fuel station rapid charger can cost almost 80 percent more than charging it in your driveway or garage—if you even have one.

That high cost isn’t just bad for individuals. It could also stall the EV rollout across the cities—or city districts—suffering from some of the worst air pollution. “This isn’t just unfair, it’s a policy mistake,” says Nana Osei Bonsu, a research fellow focusing on sustainability at Birmingham Business School. “People living in flats are being left out of the transition to EVs.”

Consumer organization Which? tracks and compares the cost of charging specific EVs using a range of methods: At-home charging costs 28 pence (34 cents) per kWh on average, using a slower AC public charge point costs 35p per kWh, and a rapid DC charge point costs 50p per kWh. This means that recharging a Hyundai Ioniq at home costs 7.3p per mile at current electricity prices, versus 13.1p per mile at the most expensive rapid charging points, a difference of more than £500 ($600) a year if you drive 9,000 miles annually.

That gap widens for more inefficient cars or those that require more power, such as SUVs. The Polestar 2, for example, would cost 13.2p per mile to charge at home versus 23.5p per mile using a rapid charger.

The gap gets even bigger if you compare the cost of charging from wall-mounted smart chargers, which cost around £900 to install, with the cost of a basic cable. Smart chargers let you take advantage of overnight electricity rates, which can drop prices by almost a third.

And while EVs generally remain cheaper to run than gas or diesel equivalents, if you were to only use a DC rapid charger, that may not be the case. If you plug in your EV at home or use on-street charge points, you’ll likely be drawing down alternating current, or AC. Rapid chargers use direct current, or DC, which is faster and more expensive. Charging that Hyundai Ioniq at an average AC point would cost £826 a year versus £1,180 on a 50kW DC charge point—and as that’s an extremely efficient EV using 16.3kWh per 100km, it’s the best-case scenario.

Data from the International Council on Clean Transportation, an environmental nonprofit, shows rapid chargers can cost three to five times as much as residential electricity. “Relying on more expensive and likely also less convenient charging removes one of the primary benefits of an electric car: lower ongoing cost of driving,” says senior researcher Dale Hall. “Those in apartments, including those with lower incomes, may end up either paying more or simply not purchasing an electric vehicle and continuing to spend money on fuel.”

Homes in cities are less likely to have off-street parking than those in rural or suburban areas, and 78 percent of resident-owned American homes have a garage or carport, versus just 37 percent for those that are rented, according to US census data. “This burden is certainly felt more heavily by those living in urban areas, as in the US private garages with electricity access are almost universal outside of the dense city centers,” says Hall. “Even in cities in the US, off-street parking is relatively common, but these are frequently in shared garages where there may not be electricity access.”

In short, cities with the greatest need for EVs are the most hostile to them, and low-income residents who would most benefit financially by ditching gas can end up paying a premium. Installing an abundance of charging points throughout cities—on streets, in housing estate car parks, in retail locations and offices—can address the first challenge, but ensuring EV charging is equitable is a harder problem to solve.

In the meantime, city dwellers with lower incomes will either pay more for an EV or not drive one at all. “Either of these options reinforces economic inequality, and may also contribute to a popular perception of electric vehicles as a technology for wealthy people and not for broader society, hampering efforts to accelerate adoption,” says Hall.

To help close the gap, the rates for EV electricity could be reduced through regulation or enticements to utilities. The UK should reconsider the value-added tax (VAT), as home electricity has a VAT of 5 percent, while electricity sold at charging points has a VAT of 20 percent.

There are other solutions. Bonsu calls for more rapid chargers in communities, rather than just gas stations, while Hall suggests EV points be required in all new buildings or those undergoing major renovations, be they shops, homes, or office blocks. Hall warns against assuming only white-collar workers want chargers, which should be installed at industrial parks, retail locations, and anywhere else people work. “Although this will take a while to have an impact, it can help to ensure that once electric vehicles make up the majority of the fleet, far more drivers will have access to affordable, convenient charging,” Hall says.

But there’s more to the problem than availability of infrastructure—charging networks are too complicated, adding extra burdens beyond the financial. There are dozens of suppliers, each with their own payment app, subscription systems, and prices, not to mention connection fees and other add-on costs and different chargers. “The user experience that comes with using public chargers versus a home charger is night and day,” says Patrick Reich, the CEO and cofounder of charging aggregation and payment app Bonnet.

Another complaint is reliability: Drivers show up to charging points to find they’re in use, out of service, or not compatible with their car. “People are not so worried about range anymore, but they do have charger anxiety—when they turn up to charge, they want to be confident that it’s working and available for use,” says Melanie Shufflebotham, COO and cofounder of Zap-Map.

Apps like Bonnet and Zap-Map help by including reliability and availability data, as well as aggregating payments for as many networks as possible, but not all operators make it easy. “While we have 70 percent of charge points on the map with live data, there are still some networks who don’t want to share their market—that’s not great for the market,” says Shufflebotham.

All of this adds up to people without off-street parking—those living in cities and on lower incomes—not only facing higher costs than their suburban, often wealthier counterparts, but spending time, effort, and anxiety to keep their EV battery charged. And that means they’re less likely to make the switch to electric, leaving them paying more and breathing more polluted air. “If we want more people to switch to an EV, particularly those who cannot charge from home, charging must be easy, accessible, and affordable,” says Natalie Hitchins, head of home products and services at Which.

In addition to reducing charging network chaos, EV prices, and rates for away-from-home charging, another solution involves funding mass transit systems that benefit everyone. EVs are necessary for many people, as cars can’t yet be fully replaced, says Hall, but they’re just one piece of the puzzle. “Alternatives to car ownership, including walking, biking, and public transport, have great benefits in terms of climate, air pollution, safety, and social inclusion,” Hall says. “Given the scale of the climate crisis, we will need a number of solutions—electric vehicles are a part, but certainly not all, of the solution.”