Electric cars

Martyn1981

sweetsand said:

Car going, vheiecles going 100% eletric will not really help the global air pollution stakes but it will help the bigger cities. London during lockdown had cleaner air and now its back to normal.
What worries me is though the gov is in denial is the fact we will not have the capacity to charge all eltric cars and eltric prices will shoot up in my jusgment as supply v demand will reuslt in price hikes if supply is hard to get.

If you do the maths quick you will find that 30m cars at an average of 2,000kWh pa (7,900 mile pa average, and ~4 miles/kWh) works out at 60TWh or approx 17% (gross) increase in leccy demand. That's not a problem, we can add more supply, that's simply supply and demand economics. In reality, after you deduct the reduced energy demand by refineries, the net increase is probably closer to 10%, or 20%-25% if we include all light and heavy goods vehicles too.
As for price rises, that seems highly unlikely given the rapidly falling costs of renewable energy, especially now that even off-shore wind contracts are coming in below the UK average wholesale price, and UK national waters have the potential to supply 10 to 100 times our future energy needs (alone).
More likely, BEV charging will create an excellent market for the low demand period, where leccy has to be sold off cheap (E7) to create a market for it.

Martyn1981

facade said:

onlyfoolsandparking said:

Don't know about eltric cars but GOOD NEWS we definitely do have the capacity to charge all ELECTRIC cars so don't worry yourself about this. Maybe just treat your brain to a workout and concentrate (if it's not too difficult for you of course) on getting your facts straight.

We only have 142,000 electric cars at the moment (https://www.nextgreencar.com/electric-cars/statistics/). However, if they all go for a 50kw fast charge at once, that works out to 7,100 MW, or 7.1GW, and the National grid maxes out at 50GW.

There is going to be an awful lot of charge management required if we get upto 10% of the cars in the UK  all electric (there are 38 million running about https://www.racfoundation.org/motoring-faqs/mobility), i.e. we had 3.8 million of them, and they were all on 7kw chargers that would be 50% of the grid capacity going into charging- bear in mind we get it to the high 40s in Winter, and that is burning a lot of gas for heating, we are really going to be In Trouble when they ban the use of fossil fuels for domestic heating & transport.

I think you've built a conclusion based on a whole raft of assumptions.
I appreciate that your 'all BEV's charging at 50kW' now example is supposed to make us think about a future with many more, but it is an extreme and unlikely scenario. The average car drives 7,900 miles pa, or 150 miles per week, or 22 miles per day, so a 50kW charger would provide a 'day's worth' in ~11 mins. I struggle to understand why all the BEV's would want to use fast chargers (when the majority of charging is done slowly overnight), and all during the same 11 mins on a particular day.

You can of course escalate the example up to perhaps 30m BEV's, with a smaller and smaller % of them needing fast charging, but even that argument would be silly, since if you think about it, fast charging at any specific time point will be limited by the number of fast chargers in existence.

Then we can further interrogate your assumptions by asking how many of those fast chargers will have on-site battery storage, for the specific purpose of spreading peak loads across a wider (and cheaper) supply period.

Moving on to your charge management if we reach 10% BEV's. Well first off that is already happening as the home chargers (7kW) being rolled out are 'smart' and therefore charge management can be deployed. But more importantly we need to go back to real demand, rather than panic over theoretical extremes.

I've previously suggested that cars will add (gross) about 60TWh to the UK's leccy consumption. I think it's fair to assume that the bulk of that will be spread across the low demand period (8pm to 8am), so 60TWh / (365 x 12) = 13.7GW.
Given that the grid already supplies between 20GW and 55GW (typically) varying from lows in summer nights, to highs in winter evenings (5-7pm peak as part of 4-8pm high demand), we can see that adding 13.7GW during the low demand period is not a problem and remains well down on the grids average peak, and its actual higher potential peak capacity.

To think of it a different way, and based on the assumption that 30m cars means we can safely assume averaging, then an average car will consume ~5kWh per day, and I'll cheat a bit and simply say there will be 1.5 cars per residence. So that's 7.5kWh per day, drawn from 8pm to 8am, is an equivalent average load of 625W per residence.

Obviously you can point to the need for fast charging for some vehicles, but that (as explained earlier) will be managed naturally, and will in fact reduce load a small bit on the average overnight figures I have given.

And now for the best bit. If you really are concerned about peak demand periods then don't worry there is a great solution on its way, and almost as a side effect. That solution is V2G (vehicle to grid) where plugged in BEV's can be used to help manage the grid by mopping up cheap excesses or adding supply when demand/prices rise. 30m BEV's would contain about 1,500GWh of batteries. The estimate for intra-day storgae in a 100% RE future is approx 500GWh, so BEV's could actually provide the excess absorption and peak load support we need. [Note - Intra-day storage will manage daily RE fluctuations. For longer term storage to meet larger RE cycles, we will of course need larger amounts of storage, most likely H2, CAES/LAES, flow batts etc. etc..]

It's almost as if BEV's are part of the solution, not the problem.