we cover 12,000 miles per year.
Not true - the average UK car
covered 7,400 miles in 2019.
We own more than 20,000,000 cars. Then there's trucks, busses, bikes.
According to the RAC :
31.6 million cars
4.1 million LGVs
0.47 million HGVs
1.3 million motorcycles
0.12 million buses & coaches
0.74 million other vehicles
But just look at the cars for the moment.
Then there's the fact that 300Wh per mile means you have to drive very slowly all the time.
Most of the cars doing the What Car? test route which is 20 miles simulating everything from urban to motorways range from 275Wh to 500Wh per mile, but most of the "average" ones seem to be a bit over 300Wh/mile on that test which I think we can assume to be representative of the average driver.
The Kona could do 3.6 miles/kWh (278Wh/mile), the Tesla 3 Performance (capable of 0-60 in 3.5s) could do 2.8 miles/kWh (357Wh/mile). Call it 330Wh average by the time we're at 100% electric cars.
So call it 330*3600*7400 = 8.79GJ per car annually=279W on average, or 8.8GW on average 24/7.
Tesla are quoting <2000Wh per mile for their truck, let's say that LGVs do 600Wh/mile.
In the year to March 2020, the UK HGV fleet did 17.2 billion miles, the LGV fleet did 54.9 billion and cars and taxis did 272.1 billion. In comparison 120k buses and a million motorbikes are rounding errors.
But if that lot was 100% electric (some time after 2045 or so) then we're looking at
HGVs - 34,400GWh
LGVs - 32,940GWh
Cars/taxis - 89,973GWh
Total - 157,133GWh
So 100% electric trucks, vans and cars together require a 24/7 average of 17.93GW.
We need to treble generating capacity
No we don't.
Current generation capacity is 77.92GW, compared to
last year's peak of 48.815GW. We do not need 234GW of capacity.
.....everyone will expect to charge in one hour between 6 and 7pm
Why on earth would they want to do that? All people care about is that their car is ready for work the next morning, they'll just plug it in (or park over an induction coil or whatever) and leave it to the car computer to talk to the charger. If anything the electric car fleet will be net contributors to the grid at teatime, then they'll charge overnight.
If
you look at the charts, you'll see that we use less than 30GW from ~10pm to 7am. So if all the trucks, vans and cars in the UK were electric, had efficiencies similar to current vehicles and were charging only between 10pm and 7am, then they'd be using 47.8GW in those 9 hours, implying a total demand of <77.8GW during that period - less than our current generation capacity.
Now obviously you can't run your entire generation system that close to full capacity in the real world, you need way more slack in the system than that. At least the numbers aren't so wildly out. But we aren't talking about 100% electrification overnight, it won't happen until 2045 or so - and a lot of electrical kit only has a 25 year lifespan, so we'll have to replace much of it anyway by the time it's needed. And for instance, much of the cost of a wind farm is actually in all the startup costs - planning permission, building roads and the bases, which don't need to be done again if you're just replacing the turbine heads when they get too old. In just the next 6 years it's planned to install another 17GW of offshore wind and 10GW of onshore wind capacity - and Carrie is talking about another 13GW of offshore wind by 2030.
(and yes, capacity is not the same as actual contribution, but last year UK offshore wind managed
a load factor of 40.4%, compared to 26.6% for onshore).
So we will need a bit more capacity, but it's within plausibility - the issue is more on the transmission side and last mile.