Charging an EV at €0.068/kWh: what the math leaves out

The car's kWh at €0.068, but the rest of the home pays a different rate

In July 2026, a 10% discount promotion on Octopus Energy's electricity tariff is still running — the same company advertising €0.068/kWh for charging your electric car with its smart charging system. The app connects to the vehicle or charger via API and decides on its own when to plug in, during the cheapest hours, with no input needed from the driver. You arrive, plug in and forget about it. The brochure arithmetic is flawless.

How much does it cost to fill a 60 kWh battery?

The calculation that keeps coming up is two lines long. A 60 kWh battery fills up for about €4, enough for 300 to 400 kilometres. Fuel at the price of two coffees, and on top of that, anyone who signs up through another customer's referral gets €50 in credit that the company pays to both parties. For anyone who drives a lot and always charges at home, the savings compared to the petrol pump are hard to argue with. That's the hook, and it works. The referrer, moreover, turns the customer into their own salesperson: every signup through their link splits another €50 between the two.

The bill that doesn't appear in the brochure

From there, the calculation twists. The cheap tariff covers the car; the fridge, washing machine, air conditioning and electric heating keep paying something else. Household consumption of 1,000 kWh outside the vehicle, at a price some estimates put close to €0.30/kWh, can eat up a good chunk of the savings. Some sum it up with a smirk: the bargain is for the car, not for the house. And that's where the real tug-of-war begins, because the headline only tells half the story.

Can the utility know how much electricity the car uses?

That's the question running through the whole debate. The claim is that utilities already have the technology to separate household consumption from what goes to the vehicle, and that the latter will eventually be taxed like petrol so the tax authority doesn't lose revenue. It should be said clearly: this argument circulates without a single source to back it up. It's a suspicion, not a fact. The only verifiable thing is that the company identifies the charging because its app reads it via API. Without that connection, the technical separation is unproven.

Batteries, heat and inspections

The conversation also brings up the usual antiestéticars: batteries that catch fire more easily in summer and accidents that require a technical inspection. These are claims nobody quantifies. The seasonal risk comes with no figure, no study, no specific case. They remain what they are: anticipatory antiestéticar.

The brochure math is true for the car. The doubt begins right on the other side of the meter, and there, nobody has put a number on it yet.