Choosing a power plan when you drive an EV

An EV changes the power question more than almost anything else you can put in a house. Not because of how much electricity it uses — a heat pump and a hot water cylinder are both substantial — but because you decide when it uses it.

That is the whole basis of time-of-use pricing, and it means an EV household is choosing between plan shapes that a household with nothing movable can safely ignore.

Work out your number first

Before comparing anything, get the size of the load:

Annual kilometres ÷ efficiency (km per kWh) = kilowatt hours a year.

Efficiency is on the car's spec and in its own trip computer. Add the result to your existing annual usage from a power bill. That total is what any plan should be priced against, and it is usually a significant step up, which cuts both ways: it makes a better rate worth more, and it makes a badly shaped plan cost more.

What to look for in a plan

A genuinely cheap off-peak window, and one you can actually use. Overnight is the usual one and it suits an EV perfectly: the car is home, plugged in and not needed until morning. Check what the window is and what the rate in it actually is, not just that one exists.

What the peak rate is. Time-of-use plans buy the cheap window by charging more at peak. If the rest of your household is a classic six-o'clock spike, the peak rate is applied to that too. Work out roughly what share of your non-EV usage falls in the peak before assuming the plan wins.

Whether you can schedule reliably. Most EVs and most dedicated chargers can start charging at a set time. If you are charging from a standard socket and plugging in when you get home, an off-peak plan does nothing for you.

The daily charge. An EV household is usually a high-usage household, which generally means a standard-user plan shape rather than a low-user one. Worth checking, because a lot of people never revisit the plan they signed up to before the car.

Spot pricing and EVs

Spot plans reward the same behaviour more aggressively, and an EV is the ideal load for one — entirely shiftable, and easy to skip for a day. The risk is unchanged: occasional periods where the wholesale price is far above a fixed retail rate. It is a reasonable choice for someone who watches prices and could absorb an expensive month, and a poor one otherwise.

What we can show you

The table above is the plan types we have confirmed for each of the 8 companies we compare. We do not publish rates, because we hold no verified rate files, and an EV comparison built on assumed rates and an assumed charging pattern would compound two guesses. Take your annual figure to the shortlist and ask each for a written quote against it.