[ifwinterco]

Houses in the UK typically have 100A supply and the whole local grid is sized assuming people use relatively small amounts of electricity. If everyone gets an electric car and a massive heat pump, lots of local transmission will need upgrading

[IshKebab]

Right but unless everyone is drawing large amounts of power at the same time it doesn't matter if you use 1kW for 10 hours or 10kW for 1 hour. To the grid they look the same.

One interesting case where "at the same time" actually does happen is overnight car charging. Some chargers are configured to start charging exactly when a cheaper tariff kicks in, which causes big transient issues for the grid. I think modern chargers have a random delay to help with that.

[footydude]

> Some chargers are configured to start charging exactly when a cheaper tariff kicks in, which causes big transient issues for the grid. I think modern chargers have a random delay to help with that.

Here in the UK some electricity providers offer 'smart' charging (e.g. Octopus Intelligent Go).

In that situation the energy provider controls when to charge the car - e.g. you say "I want the car at 80% by 7am tomorrow" and the energy provider controls the timing of charges.

That's how my EV charges - I plug it in, and Octopus control it.

Benefit for me is that whenever the car is charging my entire home's use gets the overnight rate (even if part of the schedule is charged during the day).

Benefit for Octopus is they can use my car to balance grid demand / schedule the charge when it is most financially effective for them.

I can - at any time - override that logic if I just want it to charge at a specific time for whatever reason.

(I presume this sort of arrangement is becoming more common in other countries too)

[ifwinterco]

Yep but while that is true at the level of the overall grid, actually the nearest part of "the grid" might be a local transformer that only serves 10-100 houses.

At that scale, it's definitely possible that you all plug in your electric cars and turn on your heat pumps more or less at once on a cold evening after work and start cooking your local transformer. Not my day job but I think it is a potential issue when everything is sized assuming ~2kW average demand or something