How a lack of joined-up thinking could block EV charging expansion


Interesting, very good article.

the fuse in the LV substation will be rated typically between 200A and 300A

Wow, I didn’t realise the sub-station fuse could be as low as 200A per phase shared between 100 houses, That’s really not very much!

Getting three-phase into properties would help solve the imbalance issue and lower the phase current, e.g 11kW is only 16A per phase when using a three-phase charge point. I think in Germany, households are limited to 16A per phase for EV charging, hence why most German EVs support three-phase since single-phase EVs would only be able to get 3.7kW.

Another issue which the article didn’t touch on is the issue of DNO approval for rapid charging stations. Everyone I speak to who works in the industry complains about how long it takes to get DNO connection for rapid chargers. There is a hub of 4x 150kW rapid chargers installed not far for me at a motorway services on the A55, the units were installed last year but are still awaiting DNO connection.

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This article doesn’t mention it, but obviously there is a push to electrify other things too, most notably heating. Tens of heat-pumps running simultaneously - perhaps a few electric boilers - isn’t going to improve that margin.

Will there be a need to retrofit 3-phase to existing residential properties in the UK?

Undoubtedly, in the fullness of time. But can you imagine the scale of that - there are something like 25 million in England, about 1½ million in Wales, 2½ million in Scotland and 0.8 million in Northern Ireland. It could take some considerable time.

When sizing those transformer/house ratios around these parts, I think they budget an ADMD (After Diversity Maximum Demand) of about 4.5kVA for a standard residence and 7kVA for “prestige housing”, and like you guys, most houses here are historically single phase - although 3 phase is not uncommon.

Where I live in SEQ, EVSEs are restricted to 20A (4.6kVA - assuming single phase) but you can go to 32A (7.4kVA) if you give them some control over when charging is permitted, which is what I’ve done.

The fact that substations are or are going to be a constraint is indeed something that has been totally ignored and clearly will become a bigger issue however it is NOT the main issue.

What EV zealots both - existing owners, the government and car makers repeatedly fail to address is the fact that 40% or more of the population has no off-street parking. This renders the substation issue meaningless since that 40%+ cannot charge at home anyway.

Where I live in London there are literally just two on-street chargers within a mile of my house. I am fairly certain these are not high power ones either.

By the way, the electricity via on-street, or other commercial chargers is subject to VAT at 20% and not the 5% applied to home electricity bills.

As a result it is totally impractical for me and millions of others to consider getting a pure EV even if I want to.

Clearly these issues could be improved by -

  1. A vast increase in the number of on-street chargers (not going to happen to the levels needed, you would ultimately need one for almost every parking space)
  2. A reduction of VAT on commercial charging to 5% (also not going to happen with Sunak running the treasury)
  3. Theoretically you could have your home electricity account linked to on-street chargers so that when you use an on-street charger it is billed via your home electricity account, this could then be charged at 5% VAT and take advantage of any battery capacity or feed-in power if you have solar etc., (again not going to happen in reality :frowning: )
  4. The scheme being trialled to a limited extent of swapping out the entire battery pack on special designed EV cars is a potential solution in that it gives you a full charge in a similar time scale to traditional refueling, it also potentially solves the other elephant in the room - batteries age and die - ask the man in Norway who received a $25,000 bill for new batteries from Tesla and instead blew up his car with dynamite.

So whilst EV zealots are right that hydrogen is a less efficient solution being that you have to use electricity to make hydrogen to make electricity, it is a practical solution for the very large number of people with no off-street parking.

I do not see a particular problem with this . as the vast majority of people drive about 50km per day average - so that is about 9kw per day so roughly 3 hrs for charging … also a lower charge rate lengthen the life of the battery… I personally charge at 10amp

I don’t see why this can’t happen, especially with some of the great street charging ideas seen abroad, and surely nowhere near almost every car needs charging every night, as most cars go days or weeks between recharges with petrol or diesel, as most cars only do short journeys or stand idle most of the time.

A couple of the other things would help a lot too but by far the biggest problem is the good old British “the sky is falling” can’t-do/won’t-do change-hating attitude.

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Not good… shocking it’s only 200 A for so many households. I thought with 100 A per household it would be something like 8x for 10 households.

I’m getting my second EV, becoming a NICE household (no internal combustion engine). Plus the battery I plan to install in the mid-future to off-set 100% of my usage to off-peak / solar. That means I may wish to pull 16 Amps for Leaf, 32 Amps for Tesla, 20 odd Amps for the battery => ~70 Amps during the short and cheap off peak period. That’s not including eventual heat pump.


Perhaps with more and more EV / home batteries. Cheap off-peak bulk period would slowly disappear? No doubt we still need smarter way to match demand to renewables. But perhaps cheaper tariff can be found by smartly charge batteries based on substation load? Eg. houses along the street get a different price tariff schedule each day, smart chargers take care of the rest.

Let’s face it, cars are parked 90% of the time, so why not put those batteries to use? Roll out something similar to DemandShaper nationally for people who want cheapest power?

With batteries, we need to stop think like refuelling a car. Plug it in when parked, it’s an asset to help smooth out demand. Eventually V2G type products will be an integral part of the solution, perhaps even a way to slowly pay for parts of car ownership!


Re lack of driveways, I personally can’t sympathise with this. I live in London, near N Circular and driveway was one of my top requirement many years before EV were a thing. It offers numerous benefits beyond charging the car. No driveway space = cannot take advantage of cheaper tariff, it’s the price you have to pay for choosing to clutter up the road. :stuck_out_tongue_winking_eye: … I mean lifestyle.