Naked Science Forum
General Discussion & Feedback => Just Chat! => Topic started by: Petrochemicals on 01/06/2021 06:06:40
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The big one. I've put it here because it will run to politics and tax.
If cost is almost certainly the governing element in the effi iency of things, is a combustion engine more efficient or an electric car or a hybrid.
Electricity is not taxed, car fuel is plus other costs Even though electric cars appear cheaper, in the UK petrol costs an extra 58p per litre in a levvy plus 20 percent. Happily petrol is around the 1.20 mark at the minute and has been for a few years, forgetting the downward blip during corona. So a litre of petrol is costing to the pump 42 p per litre. So for a gallon that is 1.89 sterling. In a 40pmg car that is 4.725p per mile.
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Forecourt fast chargers are charging up to 45p per kWh - about 9.5 p per mile.
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Fast charging
Best mileage
Low Cost
no noise
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Fast charging
Best mileage
Low Cost
no noise
That sounds like you should start a seperate thread entitled "what qualities should you desire in an electric car.
Forecourt fast chargers are charging up to 45p per kWh - about 9.5 p per mile.
That sounds like it it commercially balanced. You would have to take 20 percent tax from that, so 7.6p
Edit
Around the 7.9 mark
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In order to compete with liquid fuel for convenience, a car needs to recharge at 40 MW and have a "tank" capacity of at least 2GJ. Anything less, and it becomes an encumbrance.
If it uses the same fuel as an "essential" process like cooking and lighting, the supply must be differentiated and separately taxed. If not, either the Treasury will lose billions, or you will have to tax domestic electricity or gas at 300% of the cost of production.
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Or you could have a mileage tax.
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In order to compete with liquid fuel for convenience, a car needs to recharge at 40 MW and have a "tank" capacity of at least 2GJ. Anything less, and it becomes an encumbrance.
If it uses the same fuel as an "essential" process like cooking and lighting, the supply must be differentiated and separately taxed. If not, either the Treasury will lose billions, or you will have to tax domestic electricity or gas at 300% of the cost of production.
As I've said elsewhere, the government make an excess over tax of around 60p a litre on vehicle fuel and 100 pounds plus on most cars road tax. If you pay the 30,000 plus for an EV at present this is offset by tax breaks and fuel savings, when the EVs become the majority HMs treasury will have to find the cash from other sources.
The charging rate I think is down to the battery, they are far harder to put energy into than draw it from.
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The charging rate I think is down to the battery,
Never mind the battery. 40 MW is 90,909 amps at 440 volts That's one hell of a hefty cable. Or a one-inch petrol hose.
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. 40 MW is...
... a made up number; unrepresentative of the real charge rates for vehicles.
It would require a very heavy cable to deliver that power- But nobody cares, because the charging systems do not deliver that power.
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A standard fuel pump delivers 1 liter per second of petrol or diesel. At 40 mJ per liter that's 40 MW in my book. If you are in a hurry you can go to the HGV lane where the pumps run at 80 MW but the nozzle may not fit. Aircraft refuel at 20 - 40 liters/second - not sure if you can get a 20 minute turnround with an electric plane!
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A standard fuel pump delivers 1 liter per second of petrol or diesel. At 40 mJ per liter that's 40 MW in my book.
We know.
That is what they can do, but not what they "must" do.
Have you heard anyone complaining that we couldn't use methanol as a fuel because it would "only" deliver about 20 MW at that flow rate?
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A standard fuel pump delivers 1 liter per second of petrol or diesel. At 40 mJ per liter that's 40 MW in my book. If you are in a hurry you can go to the HGV lane where the pumps run at 80 MW but the nozzle may not fit. Aircraft refuel at 20 - 40 liters/second - not sure if you can get a 20 minute turnround with an electric plane!
50mmx50mmx pi x 10amps/mm2 = 80,000ish
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Have you ever tried to lift a 3 x 100 mm diameter cable to plug it in to a car? it weighs about 230 kg per meter and a 10m length (in case you have parked the car the wrong way round to the pavement in a one-way street) will cost you about £20,000. You need to derate it to prevent core overheating, but I grant you it will carry around 32 MW for a short period - almost as long as it will take someone to saw it off for scrap.
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Have you heard anyone complaining that we couldn't use methanol as a fuel because it would "only" deliver about 20 MW at that flow rate?
Being very old and stuck in my conventional ways, I think there is a big difference between 20 MW and 20 kW. It's like the difference between an asset and a burden. But the young have more time on their hands, I guess.
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Have you ever tried to lift a 3 x 100 mm diameter cable to plug it in to a car? it weighs about 230 kg per meter and a 10m length (in case you have parked the car the wrong way round to the pavement in a one-way street) will cost you about £20,000. You need to derate it to prevent core overheating, but I grant you it will carry around 32 MW for a short period - almost as long as it will take someone to saw it off for scrap.
I have no belief that the health and safety people will let anyone near 80000 amps AC. Whether you can make a battery to take 80000 amps at 500v is another question
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The 40MW figure is still silly.
It assumes stat the electric vehicle has the same energy storage as conventional one, but, as people like Alan are noted for whining, you don't get the same power or range in an electric car- they simply don't have the energy density.
(It obviously helps that, being rather more efficient, the electric car doesn't need the same stored energy anyway.
And because there's less stored energy, you don't need as large an energy transfer rate to top it up.
There is, of course, also the fact that, while we are used to filling our cars almost instantly, there's no reason why you can't take a few minutes over it.
If you accept that a fuel stop also gives you time to go to the bathroom, it's an asset.
So, as I said before, the 40MW rate is meaningless.
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So, as I said before, the 40MW rate is meaningless.
It has a precise meaning in this context. It is part of what determines the utility of a liquid-fuelled car. A small car can carry a 2 GJ energy store and recharge it in less than a minute, so you don't need many charging stations to keep everyone moving. If you run out of "juice" in the middle of nowhere the nice man from the AA can bring you 200 MJ in a can, ready for immediate use.
I refuse to wear a £20 "smart watch" because I object to a machine telling me when to stand up or breathe. BC, on the other hand, wants to spend £30,000 on a machine that tells him when and where to pee. We are very different.
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It has a precise meaning in this context. It is...
The product of an arbitrary choice of 1 l/m and the heat of the reaction of oxygen with an oily hydrocarbon.
I refuse to wear a £20 "smart watch" because I object to a machine telling me when to stand up or breathe.
I have a rather more expensive smart watch- with those functions switched off. I'm prepared to pay for ironic humour, but mainly it's a heart rate monitor + step counter.
BC, on the other hand,...
in reality, as he has pointed out before, doesn't drive. One consequence of this is that he is never stupid enough to run out of fuel. It seems Alan differs.
We are very different.
Yes.
I don't post nonsense like Alan does.
. If you run out of "juice" in the middle of nowhere the nice man from the AA can bring you 200 MJ in a can, ready for immediate use.
If the nice man from the AA turned up, he wouldn't need to bring as much energy with him to get you home, because electric cars waste less.
That's the point Alan keeps missing.
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Quote from: alancalverd on Yesterday at 21:50:15
It has a precise meaning in this context. It is...
The product of an arbitrary choice of 1 l/m and the heat of the reaction of oxygen with an oily hydrocarbon.
1 liter per second, not per minute. The use of petroleum hydrocarbons as fuel seems rational: non-corrosive, low toxicity, stable, easily vaporised, high energy density, controlled burn....which is why the lighter hydrocarbons are used as primary fuel for the power stations that we will have to build to charge all the electric cars.
If the nice man from the AA turned up, he wouldn't need to bring as much energy with him to get you home, because electric cars waste less.
At the point of use, about 50% less. But instead of a gallon can, poured into the spout in a few seconds, he will have to bring a 400V battery that happens to fit your car, or a 30 kW (diesel, i.e. 60 kW) generator and connecting lead and spend over an hour charging your car so you can drive to the next motorway charging station.
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1 liter per second, not per minute.
Oops; typo.
The use of petroleum hydrocarbons as fuel seems rational: non-corrosive, low toxicity, stable, easily vaporised, high energy density, controlled burn.
Which are the reasons for choosing those hydrocarbons (along with price).
Nobody said " we need to deliver 40MW- what fuel can we use?"
The 40MW is just the number you happen to end up with of you pump petrol. It's not a design parameter.
Even if the man from the AA has to turn up with a diesel engine (and generator) occasionally, that's better than lugging the diesel engine around all the time belching fumes.
BTW, you do realise that all the arguments you have put forward for not going electric, are the same as you could have used a hundred years ago for why ICE vehicles couldn't be practical, don't you?
It turns out that we are quite good at solving problems.
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spend over an hour charging your car so you can drive to the next motorway charging station.
It will not take an hour to provide the energy for a 28 mile/ half an hour journey
"Current government policy is that the interval between core motorway service areas should be no more than 28 miles or 30 minutes travelling time, whichever is the lesser."
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Standard consumption figure is 300Wh/mile. Just over 30 MJ. So it takes 17 minutes at 30 kW to get enough charge to each the next charging station. :Let's do it at the most economical speed of 50 mph or thereabouts - say 30 minutes to get there, 15 minutes to recharge enough to get to the next one.....If every charging station delivers 30 kW your average speed over a long journey will be 33.3 mph.
Please don't get me wrong. In a perfect world I'd love to have an electric car. But not in the real world.
BTW, you do realise that all the arguments you have put forward for not going electric, are the same as you could have used a hundred years ago for why ICE vehicles couldn't be practical, don't you?
Electric vehicles cars were indeed on the road 100 years ago. The reasons I give explain why they have not superseded ICE vehicles to date, and why the infrastructure and environmental costs of rapid adoption of electric cars are unacceptable.
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But not in the real world.
In the real world, you would start by charging the car overnight.
For most journeys, that would get you to your destination.
For longer journeys you would charge when you stopped for lunch.
If we accept the number you pulled out of the air of 30KW as a charging rate then an hour's lunch gives you about another 120 miles.
Why do you post such a silly figure as 33 MPH?
You must realise that electric cars exist, and that they go- on average- faster than that.