But that's assuming we're just running power plants off of petrol and fuels. Coal is much cheaper than petroleum in some cases. There's also a lot of people who get their power from nuclear, hydro, solar, and wind. In many cases, your electric prices are not at all affected by the increases in petrullium prices, because most of your electricity is coming from something else. In fact, I doubt there's any place in the world that all your electricity is coming from petroleum fuels. Even if that's the major input, there are almost undoubtedly other sources in the mix.
Over 25% of this is then lost in transmission and distribution[0] (down to 45%). Then 10-25% of that lost in charging the car[1] (down to 40%). Finally, the car itself loses about 10-15% of that[2] (down to 35%).
[0] https://www.statista.com/statistics/322834/transmission-dist...
[1] https://go-e.com/en/magazine/ev-charging-losses
[2] https://evreporter.com/understanding-the-complete-efficiency...
Furthermore, if you're going to include distributional losses, then let's also drop the available petrol by 10-15% to account for refining etc.
Finally, on anything resembling a sunny day, my car charges entirely of rooftop solar, so what efficiency do we assign to that?
25TWh annual distribution losses off of ~300TWh usage per year is 8% loss.
If you charge at home, and you don't have a car tariff, it'll be ~25-30p per kwhr
If you get a car charging tariff then you'll be paying ~9p a kwhr.
if you are brave then you can use an agile prices which depends on the weather you can be paid to charge (my record was -11p a unit) however in winter it can be a lot high, like 45p a unit.
Charging on the street can be around 50p a kwhr up to 98p a kwhr
In Canada most of that is pretty opaque. Electricity tariffs are not really something that most households would worry about. Businesses and Industrial usage do though
You can base it on the wholesale price, great if you have battery storage
https://octopus.energy/smart/agile/
Or just an overnight rate
https://octopus.energy/smart/intelligent-octopus-go/
Again if you put in a £5k 10kWh battery you are golden, as you put 8kWh into your car and 8kWh into your battery every night, dropping your electric cost to £38 a month (plus the standing charge, which is far higher)
Many people choose a single fixed or variable rate tariff, but there are also off-peak tariffs that are very cheap at night but slightly more expensive in the day (designed for EV users), or even tariffs where the rate changes every 30 minutes depending on what is being generated - in this case when there is excess solar and wind generation then sometimes the rate even goes negative and you are paid to use the excess power.
Most places I lived had this set up.
(Nowadays smart meters offer many more options.)
