Another odd feature of electricity pricing is demand charges. These charges are paid by operators of electric vehicle charging stations and are based on their highest usage in 15-minute to one-hour intervals during a payment period. These demand charges help utilities manage the various costs of building and maintaining an electric grid. In the context of electric vehicle charging, however, they are frustrating because some chargers are used very rarely – but when they are used, they use a lot of electricity in a short period of time. This leads to demand charges.

These performance fees can “amount to hundreds of thousands annually for a given location,” says Rachel Moses, who heads sales, marketing and business development at Electrify America.

Some utilities now charge “peak prices,” meaning more money when lots of other people are using electricity. This means that charging stations tend to cost more between 4 p.m. and 9 p.m. when everyone goes home, turns on their TVs, air conditioners or heaters, and maybe even plugs in their cars. This all leads to slightly unpredictable charging prices.

Electrify America says its pricing is “station-specific,” meaning customers have to pay more money to charge at stations that are more expensive to operate. But other electric vehicle charging companies take a broader approach, calculating the cost of operating their entire network to determine pricing for a larger area.

In addition, companies may dynamic Prices for charging electric vehicles, which means they can change. Fortunately, there is a limit to this strategy. The rules for funding the nation’s public charging infrastructure mean that chargers built with public money cannot change their prices while you are in the middle of charging your car – even if the price the company pays for its electricity changes.

All this means that it’s currently hard to predict what you’ll pay to charge at a public fast charger. No wonder drivers are frustrated.

New gas station?

But should Drivers frustrated? Not knowing exactly what you have to pay to charge your car at a public fast-charging station can be annoying. But it also doesn’t fully reflect most people’s experiences with electric vehicles.

The real advantage of owning an electric car is that while you can only get gas at gas stations, you can charge cars in many different places. At home, at the grocery store, at work: These places may not all have fast chargers, but many have outlets and slower “Level 2” chargers where drivers can get some juice.

Public charging stations are a big headline issue—and for some drivers, too. But about 90 percent of today’s electric car drivers have garages, driveways or other places where they can charge their cars overnight. One day, that won’t be the case, and public charging stations will have to fill the gaps for people who live in apartments or park on the street.

But now: Maybe you shouldn’t get too upset public Chargers that today mostly fill the gaps when drivers of electric vehicles undertake longer car journeys.

“We have this gas station model in mind,” says Kellen Schefter, senior director of electric mobility at the Edison Electric Institute, an association that represents American investor-owned power companies. “If our goal is just to copy the gas station model for electric vehicles, we’ve missed one of the real benefits of electric vehicles.”