[alancalverd]

If we are prepared to pay a premium then we can import renewables.

From? The UK has by far the greatest potential for wind generation of any nation in Europe, and the others are at least as determined to electrify their road transport. We've discussed the politics and economics of a dedicated cable to supply the UK exclusively  from the Sahara. 

[alancalverd]

And I apologise for using Wolfekeeper's recharging figure of 3 kW when he later says he meant 300W.

Whatever the average utilisation may be, the diversity of demand is irrelevant for liquid fuels because you can recharge at 33 MW (UK limit is 50 liters/minute at ~40 MJ/l) from a car pump, any time you happen to be passing a garage. Not the case for electric cars.

It is likely (as asserted by Wolfekeeper and Hamdani)  that there will be an electric vehicle demand surge around 6 - 7 pm  when between 3 and 30 million vehicles will all demand 300 or 3000 watts at the same time from their 13A sockets. But anyone able to shell out £30 - 50k for a new car will almost certainly install a standard 7.2 kW home fast charger (because as Wolfekeeper says, everyone has a private driveway) so the peak demand will actually be between 25 and 250GW.  If you live in a city, it's often quite cheap to access a 3-phase supply, where the home charger will deliver 22 kW. So to avoid "cup final brownouts", the Powers that Be will have to assign  your recharging time slot.

[wolfekeeper]

I did the arithmetic here
https://www.thenakedscientists.com/forum/index.php?topic=81292.msg637211;topicseen#msg637211

 " the average power is about 58 GW"
That's the average power delivered by diesel and petrol in the UK- almost all of it is used in vehicles.

Even allowing for the poor efficiency of ICE, dropping power to 9GW would require a sacrifice in something- probability spurious acceleration and the ability to massively exceed the speed limit.

But it does indicate that 90GW for much more efficient electric vehicles is a silly number.

I apologise for thinking that Alan might have got it right. I should know better.

Yes, and even then you rather messed up the calculation. Electricity is low entropy energy which can be converted to motion extremely efficiently (equivalently, electric motors and lithium ion batteries are extremely efficient). Wherea petrol is thermal, high entropy, energy. You can only convert petrol to motion with incredible waste (Carnot's theorem).

But let's look at the figures. An electric car gets about 0.25 kWh to the mile.

Meanwhile, a UK car on average gets about 39 miles to the gallon.

Let's convert that into energy:

0.25 kWh = 3.6e6 *0.25 = 900e3 J

One gallon of fuel = 4.5 * 35E6 J = 157 MJ
Energy per mile = 157E6/39 = 4e6 J.

That's a factor of 4.5 lower energy (in the form of electricity) needed for electric cars per mile. And no, you don't have to sacrifice anything very much. Electric drive trains can be very powerful.

The only thing you really do lose is range at very high speed. At high speed the aerodynamic losses drain the battery faster because the useful energy in the battery is lower than you can get in a petrol tank, even allowing for the much greater efficiency. So you have to recharge more often at high speed. But most people average about 50-60 mph on motorways under real traffic conditions. But an electric car barrelling down an autobahn at full tilt is going to have to recharge after an hour.

And I apologise for using Wolfekeeper's recharging figure of 3 kW when he later says he meant 300W.

NO! BOTH ARE CORRECT.

If you plug an electric car in, it will usually take at least 3kW. But it's only going to charge for a few hours to top off the battery and then switch off.

But that 3kW matters because it sizes the local wiring.

What is the AVERAGE current draw? Around 300 watts.

That 300 watts matters, because it sizes the total grid demand across the whole country.

Whatever the average utilisation may be, the diversity of demand is irrelevant for liquid fuels because you can recharge at 33 MW (UK limit is 50 liters/minute at ~40 MJ/l) from a car pump, any time you happen to be passing a garage. Not the case for electric cars.

No, because you set the car to charge overnight, or whenever the electricity is cheap.

It is likely (as asserted by Wolfekeeper and Hamdani)  that there will be an electric vehicle demand surge around 6 - 7 pm  when between 3 and 30 million vehicles will all demand 300 or 3000 watts at the same time from their 13A sockets.

No, I never said that. People WILL NOT be usually charging their cars at peak demand. People are using economy 7 or 10 because the electricity is half the price.

But anyone able to shell out £30 - 50k for a new car will almost certainly install a standard 7.2 kW home fast charger (because as Wolfekeeper says, everyone has a private driveway) so the peak demand will actually be between 25 and 250GW.

Every single little bit of this is absolute and complete bullshit. I NEVER said that, and nobody would ever do that. Even the vehicle chargers would probably notice the grid frequency dropping and cut off their charging and wait for it to recover.

If you live in a city, it's often quite cheap to access a 3-phase supply, where the home charger will deliver 22 kW. So to avoid "cup final brownouts", the Powers that Be will have to assign  your recharging time slot.

Right, so in your imaginary world, EVERYBODY decides, they need to charge their cars, at exactly the same time, paying twice or more the cost per kWh, to charge their cars at 22 kW, and every car has a 22 kW charger.

Are you off your meds? Because absolutely nothing you're claiming makes any sense at all. Not a single thing.

[hamdani yusuf]

No, because you set the car to charge overnight, or whenever the electricity is cheap.

And it can be done automatically, without human intervention, and gives us profits from price difference.

[Bored chemist]

The UK has by far the greatest potential for wind generation of any nation in Europe,

Due to monumental stupidity, we are no longer part of the EU. While Europe is still conveniently "near", it's not the only option.

We've discussed the politics and economics of a dedicated cable to supply the UK exclusively  from the Sahara. 

It would need protection- just like the oil supply.
Of course the sensible thing to do would be to transport something like hydrogen or whatever- just like we do with oil.

[Bored chemist]

Yes, and even then you rather messed up the calculation.

If you think that 58 divided by 4.5 is 9, I'm in good company.

The point of my calculation was that it provides good reliable data on two important things.
What energy is used in transport and also how much CO2 is produced.

As I said...

Even allowing for the poor efficiency of ICE,

Powers that Be will have to assign  your recharging time slot.

Or they could use the existing system of monitoring the mans frequency and shedding loads when the grid is under pressure.
Just like they already do.
Or, as has been pointed out by someone sensible, they could get people to use economy 7 style systems - just like they already do.

[alancalverd]

Quote from: alancalverd on Yesterday at 23:15:25
The UK has by far the greatest potential for wind generation of any nation in Europe,
Due to monumental stupidity, we are no longer part of the EU. While Europe is still conveniently "near", it's not the only option.

The cross-channel electricity trade predates the EU and continues today. Problem is that the cable capacity is pretty small =- it was intended to soak up  night-time excess nuclear capacity from France, nobody is building nukes in Europe these days, and our neighbors are even more enthusiastic to use the wind they don't have, than we are. .

[alancalverd]

Or, as has been pointed out by someone sensible, they could get people to use economy 7 style systems - just like they already do.

So your car ceases to be a personal convenience and becomes a state-monitored privilege that can be withdrawn. The communist dream: electric Trabants!

People WILL NOT be usually charging their cars at peak demand. People are using economy 7 or 10 because the electricity is half the price

Surely they will want to charge their cars as soon as they get home? My point is that this will create a new peak demand.

Of course the sensible thing to do would be to transport something like hydrogen or whatever- just like we do[ with oil.

Agreed.

[wolfekeeper]

Or, as has been pointed out by someone sensible, they could get people to use economy 7 style systems - just like they already do.

So your car ceases to be a personal convenience and becomes a state-monitored privilege that can be withdrawn. The communist dream: electric Trabants!

So what you're saying is that your fossil car is not licensed? Because your car already is a state-monitored privilege that can be withdrawn.

People WILL NOT be usually charging their cars at peak demand. People are using economy 7 or 10 because the electricity is half the price

Surely they will want to charge their cars as soon as they get home? My point is that this will create a new peak demand.

If they need their car to be topped up because they're making a long journey and they're willing to pay a premium, sure. Just like people pay more for petrol on motorways and A-roads. And, it's still cheaper than paying for petrol!

But most people prefer to pay less, and the car capacity is sufficiently large that it's not worth it. The whole point of Economy 7 etc. is to move demand to the early hours where electricity is plentiful and greener.

Of course the sensible thing to do would be to transport something like hydrogen or whatever- just like we do[ with oil.

Agreed.

Except that's not actually sensible for cars because hydrogen costs a lot more all round, and there's heavy conversion losses.

This seems to be roughly the state of the art, the hydrogen fuel costs four times as much per mile as electric vehicles:

https://cleantechnica.com/2019/04/26/hydrogen-cars-have-4x-annual-fuel-cost-2-70-times-the-carbon-debt-as-electric-vehicles/

[alancalverd]

So what you're saying is that your fossil car is not licensed? Because your car already is a state-monitored privilege that can be withdrawn.

Taxed, not licensed. I can have as many cars as I like, and drive as far as I like. The privilege is only withdrawn if I am demonstrably incompetent.

[alancalverd]

This seems to be roughly the state of the art, the hydrogen fuel costs four times as much per mile as electric vehicles:

If you buy petrol at £1.20 per liter, deduct VAT at 20% leaving
£1 per liter,  deduct fuel tax at 60 p/liter to give
fuel cost 40 p per liter

10 miles per liter is pretty normal, so the actual fuel cost is 4p/mile.

250 Wh/mile for an electric car at 12p/unit works out at....4p per mile.

So the "cost saving" for an electric car is simply tax avoidance.

How long before the Treasury notices that tax receipts have fallen by £20 billion per year? And what will they do about it? Tax everyone else to subsidise my business mileage? Tax electricity at the same rate as petrol and freeze a few pensioners to death?

[wolfekeeper]

250 Wh/mile for an electric car at 12p/unit works out at....4p per mile.

So the "cost saving" for an electric car is simply tax avoidance.

You know that bit where I said that most people charge their car on economy 7, because economy 7 is about half the price, and you totally didn't get it? Yeah, about that, imagine I'm still laughing in your face about that because I am.

[alancalverd]

Economy7 night tariff is about 10.8p per unit, say 3.6 p per mile. But if you happen to top up the car at the E7 day rate of 18.8p you will probably exceed the 4p/mile benchmark.

E7 dates from the days of expanding nuclear and coal plant. It is preferable to keep reactors and very large (> 100 MW) coalfired generators working 24/7. Fewer companies are offering the tariff nowadays and it is likely to disappear in the foreseeable future.

[wolfekeeper]

It doesn't matter, the point is that there are, and will continue to be cheap tariffs available for off-peak at times where there is a glut of electricity on the UK grid.

[alancalverd]

Watch out for flying pigs.

[wolfekeeper]

Oh really, so you're claiming that low price tariffs that have existed for about 40 years, don't exist? On the contrary, the National Grid have stated they want demand side flexibility, which implies variation in pricing, otherwise the demand side won't be bothering.

[alancalverd]

No, I'm quoting the current tariff prices from EDF, and expert opinion (Moneysupermarket and others) on the future of cheap electricity.

Recharging 30,000,000 cars every night at the same time as people are cooking dinner and firing up their new non-gas boilers, is almost the antithesis of flexiblity. Problem is that Members of Parliament are all in the bar or having sex with pigs  by 6 pm so there's no source of hot air and flatulent language to drive the windmills.

[Bored chemist]

Recharging 30,000,000 cars every night

Is not what anyone is suggesting.

It has already been pointed out a few times that they don't need charging every night.
Why are you banging on about it?