[cmdkeen]

I live in Edinburgh, one of the more car-unfriendly cities in the UK and recently bought a Model 3. I park on the street, the city has gone nowhere with its plans to provide on street chargers. Yet it isn't a problem, despite a relative lack of public chargers compared to elsewhere in the country it is still perfectly feasible. I've tweaked my habits to go to the supermarket that has a charger in the car park, when planning what to do at the weekend I check nearby charging locations.

Business locations can acquire visitors by offering them, and there's all sorts of upsell benefits. A garden centre that has one might get me to stay and visit their cafe if I know I'm going to be there for an hour for instance.

[leoedin]

Is this strategy still going to work if everyone is doing the same thing?

My local supermarket has a couple of electric car charging points, amongst perhaps 200+ car parking spaces. On a busy saturday most of those spaces are full.

Certainly it's possible to install a charging point at every parking space, but it requires both a large scale building project to lay all those wires (the existing charge points are right by the supermarket - where the power is already available), and also potentially an upgrade to the local power network.

If each of those cars is fast charging at 50 kW, the supermarket carpark will suddenly be consuming 10 MW. Assuming a constant cycle of people, that's equivalent to the average power usage of 20,000 houses.

Just in one supermarket car park.

Fortunately it's unlikely everyone will charge every time they pop in, but it's something that has to be considered carefully. The electric grid has to be sized for peak load - most of the time it's not near capacity. If we're going to slot electric cars into the existing grid we have to manage demand very carefully - which means only charging cars when electricity supply is high or demand is low. Everyone rapid charging whenever they feel like it (eg during the Saturday shop) will cause huge stability issues.

The most straightforward way to manage it is to try to get as many cars as possible charging overnight (or charging whenever they're idle) and then manage when they actually draw power centrally based on electricity supply. That means extensive kerb side charging points.

[mcjiggerlog]

How do these public charging stations work in terms of payment? Do you have to activate it using a credit/debit card first and then just leave it plugged in?

[cmdkeen]

The supermarket ones are free - though only 7kW, as they're for customer use. I park up and go for a walk round the local park then do my shopping.

For the rest I use Charge Place Scotland - it's a scheme where you pay £20 a year and get free unlimited charging at various locations around Scotland, they do have some separate locations you have to pay, usually for faster charging. Certainly amongst my friends with electric vehicles it's a point of pride to never pay for charging beyond that £20.

[mcjiggerlog]

Wow ok, surprised that they are unmetered! Surely that can't scale? What is an estimate £ cost in electricity for filling an average battery?

[ourlordcaffeine]

Assuming ~75KWh batteries, £7.50 if the supermarket pays 10p per KWh.