@Adrian I think your last sentence is correct. The savings come with every mile you drive and I think that for many (especially buyers rather than leasers) you do need to drive many miles for it to pay.
I’m sure you’ll do the sums before switching to an EV tariff but you will likely be better off staying on your current one if you are “fixed” on a good tariff. I did the following sums, which clearly show that for a low mileage driver, such as myself since covid, I would be better staying on my current tariff (even the standard price cap one).
I only drove 2450 miles between last 2 MOTs.
Fuel at todays prices (140.7p) would cost me £412/year
EV charging cost based on current cheapest rate and only ever charging during 0030 and 0430 on a home charger costs just £75/year…a saving of £336/year.
BUT to obtain this cheap EV night rate I need to change from my current Octopus standard tariff (I was moved across from AVRO) which increases my day rate from 19.89p/Kwh to 29.82p/Kwh. My annual usage is 4060.5 Kwh. This means an increase of £403.20 in my daytime electricity. Giving me a yearly negative of £67.20 if I drove an EV over an ICE on an EV tariff.
It makes more sense to stick with a standard tariff for me as it would cost £194.92/year to charge the EV, a saving of £217.08/year over ICE. BUT the price-cap of gas and electricity prices are due to rise in April and this could be up to 50% I’m rather certain that a 50% increase would mean I’d be better off in my ICE car even with petrol rising in price (highly unlikely to rise by 50%).
If I return to driving around 5000 miles/year then EV starts looking more attractive……except for one important thing. I already have a ICE vehicle fully paid for and there’s no way that I’d be better off selling my car and purchasing an EV. There could be an option of me selling my car and re-joining Motability, but to get a similar vehicle as mine (but EV version) would either not be available or the AP would make it unrealistic. BUT I would never re-join Motability again unless I had another vehicle as back up. I just don’t trust DWP with their assessments and I could end up without any car.