Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: sceptic-eng on 11/03/2018 08:40:34
-
The logistics look real scarry!!!
How many tons of batteries will a 7 ton truck need to drive 100 miles?
Are there sufficient materials in the planet earth to mine and produce billions of batteries?
How long will the driver need to waste time to change or charge his batteries?
How will the electric grid cope with producing enough power to eliminate CO2 emmissions?
If petrol and diesil are banned how will the power plants generate their power?
Power stations are only 50% efficient whereas diesel lorries are about 75%?
Hydrogen gas is not liquifiable economically; so what do we do now??
-
Thanks for starting an interesting thread. This interview with the Centre for Sustainable Road Freight's David Cebon about the carbon considerations of road freight (https://www.thenakedscientists.com/articles/interviews/carbon-costs-transporting-food) is a very interesting perspective and highlights some obvious - but oft-overlooked - issues about road freight.
-
Someone will have to invent the electric train.
-
Someone will have to invent the electric train.
Surely you aren’t suggesting containers could be loaded on to trains? Bit radical even for you!
-
Back in the 1950s Essex CC decided they didn't need to upgrade the road into Harwich, because it was a "rail port". Suffolk were more far-sighted, so Felixtowe took the bulk of the trade. Perhaps BC's ideas could rectify the situation.
On second thoughts, it's probably too late!
-
The main problem is "If petrol and diesil are banned how will the power plants generate their power?"
There is no way of producing sufficeint power at power stations to electrify the road transport fleet. Possibly one of the scientists on this forum has worked the gas/oil industry and can advise us on what percentage of their production goes into power plants and the percent into gas central heating/industry and percent that goes into petrol/diesel stations for transport use. Solar, hydro, tidal and wind energy should be exploited wherever possible for electric generation which can be used for domestic and industry but I am doubtful there are enough green sources to fuel transport as well and anyway the infrastructure and battery costs are totally OTT
-
Diesel lorries are nothing like 75% efficient. I doubt they're even over 50%. Electric drive trains are around 60+% and can be powered from renewables.
The amount of power to electrify the fleet is not in any way out of reach. The grid actually has significant capacity that it doesn't use, it averages perhaps 30 GW, but can supply at least 55 GW. The grid goes through a slump every night where they have to turn down the generation, having extra batteries to charge would be all to the good. And another factor is not the amount of energy used today for transportation- it's the amount of energy that would be needed if transportation was electrified- and it's a lot less- because electric power trains are a lot more efficient.
It's true that the up-front costs of electric trucks are somewhat higher, but not massively so, but the running costs are significantly lower. It's the total cost of ownership that matters, and they're already pretty favourable, and getting more favourable as the batteries are mass produced in ever greater numbers.
One minor issue is axle weight, many routes have a maximum, and trucks with reasonably large batteries are heavier, or equivalently, have smaller tonnage of freight. But it's only a few tonnes on a 20 tonne truck worth of difference.
Tesla's truck seems to have quite a few preorders; and other trucks are also already available. They're claiming up to 500 miles of range between charges, and rapid charging in about 20 minutes.The estimate is that a 3 tonne battery, in a 23 tonne truck, would be sufficient for that:
https://www.axios.com/elon-musks-semi-truck-battery-could-cost-70000-weigh-3-tons-1513301728-ecdf266d-a8f0-4ac9-9991-5fa2556ddfce.html
-
Look at the USA stats this month https://www.eia.gov/energyexplained/index.cfm?page=us_energy_home and immediately we see that amount of petrol/diesel used for transport is roughly the same as that used for generation at power stations with only 10% renewables at present. We are not going to double up on power stations to electrify long distance haulage transport ever are we? In cities hybrid electric cars are of great benefit to the environment but intercity is uneconomical.
-
I already addressed your points, doubling up is not required because electric cars need a lot less energy in the form of electricity to do the same thing that diesel and gasoline vehicles do, and the existing electricity equipment on the grids are not fully utilised. People are also adding a lot of solar panels on their roofs. Powering cars from solar panels can also be done; a typical car needs around 5-10 square metres of panels to do an average daily mileage, and households can export and import energy from the grid to balance out the variations in production and needs, but anyway electric cars handle variable power fairly well because they tend to have quite big batteries and battery sizes are getting rapidly larger, and costs are plummeting.
-
I agree that if the batteries are recharged using solar PV panels that would be ideal. So maybe all lorry depots should be required to instal solar panels which would be a start particularly those in built up areas.
However the cost of electricity per kWhour is 10 to 20 pence/cents and long haul diesel vehicles can easily achieve this without having to carry extra batteries. My little car engine generates 10 kWhr of energy for each litre of fuel I pump in
-
One could potentially install dynamic trolleybus lines. Just snap onto the line, and recharge in motion, then hop off the line when one needs to change course. That would significantly reduce the battery requirement. Then for a truck making multiple stops, it could also charge at each stop.
If one installed a power meter directly on the truck, then it really wouldn't make any difference where one recharged.
One could probably computerize the whole system, so no need to hop out of the cab and pull on the ropes for the trolley line hookup. One could probably make better pickups, not requiring individual arms to each cable.
As far as batteries... yes, a lot of raw materials needed, however, they would be 100% recyclable. Also, I think there is significant research into sodium batteries which should be dirt cheap to make, and perhaps use byproducts from desalination plants.
-
Interesting ideas. Ultimately it all comes down to better batteries, which are seriously holding things back at the moment...
-
Everyone always says that but anyone that's looked into Teslas know that physically speaking, existing battery tech can do it all already (even non-stop Land's End to John O' Groats is only 874 miles- whereas the electric vehicle range record now stands at slightly under a thousand miles). It would be nice if batteries were cheaper, but lithium ion batteries are dropping in price about 7% per annum anyway due to mass production; so they soon will be.
There's no infrastructure right now for fast-charging electric lorries, but that could be fairly easily installed; there's power lines all the way up the M1 apparently for example, and the National Grid have indicated there's plenty of capacity for electric vehicles (they pretty much welcome it- adding electric vehicles to our grid could potentially cut the cost of electricity for everyone by smoothing out the demand curve). One trick that will be necessary is to install fixed storage batteries at the fast charging stations. That way the grid can continuously charge them, and then they can deliver massive currents to the lorries when they need it (but lorries can also charge more slowly and cheaply when parked when they don't). Taking steady current from the grid cuts the cost of the electricity, whereas as consumers we normally pay ~9-20p per kilowatt hour, industrial users pay more like 7p, and solar is dropping in price ridiculously fast, and will be cheaper even than that.
It can all be done, already.
-
I cant see it taking off, especially in routes that are out in sparsely populated places, electric is expensive and so are batteries and to charge them is wasteful They have had electric trucks and buses for ages, round towns, probably more the target market. Very scary standing on the pavement waiting to cross and a silent 7.5t lorry comes from the blind side past you.
-
No, no. Electric drivetrains are MUCH more energetically efficient and cheap. The vehicles are currently somewhat more expensive to buy (but dropping in price rapidly), but a lot cheaper to run, total overall cost per mile is a fraction of the cost of diesel, and maintenance costs are negligible. And the UK is small enough that the somewhat limited range of electric trucks makes relatively little impact.
See:
http://www.bbc.co.uk/news/business-40715793
read to the bottom.
-
Diesel fuel has an energy density of about 48 MJ/kg. The best batteries store about 2 MJ/kg. There is much to be said for an electric drivetrain but the payload ratio is a serious problem for independent transport.
As far as running cost is concerned, the cost of manufacturing and delivering diesel fuel is about 60 cent/kg or 1.25 cent/MJ, about half the delivered cost of electricity. So if we allow 90% conversion efficiency for an electric vehicle and 45% for diesel, the running costs are about the same.
Depreciation is a key economic element. Relatively easy to assess for a diesel truck or bus, which can be written down at the standard 20%/annum tax allowance rate plus maybe one major engine overhaul at 400,000 miles. Battery performance claims are very variable, but scaling up from a small car suggests a major replacement every 100,000 miles for a truck or bus with current technology - arguably more frequently as peak current draw determines maximum payload.
An important question is the extent to which the taxpayer is prepared to continue subsidising the development of infrastructure for electric vehicles.
If renewable electricity really is free (or at least of negligible cost) it would make more sense to use it when and where available to manufacture liquid fuels from biogas and organic waste. The efficiency of that process is unimportant as the inputs are zero cost, and the resultant product can be used in all existing vehicles, so no need to manufacture new ones.
-
No, no. Electric drivetrains are MUCH more energetically efficient and cheap. The vehicles are currently somewhat more expensive to buy (but dropping in price rapidly), but a lot cheaper to run, total overall cost per mile is a fraction of the cost of diesel, and maintenance costs are negligible. And the UK is small enough that the somewhat limited range of electric trucks makes relatively little impact.
See:
http://www.bbc.co.uk/news/business-40715793
read to the bottom.
That is true but how do you get the electruc there in the first place. T9 my knowledge the most efficient engine is the electric hydrogen engine and they are clean, fast to recharge, problem is the size of the tank. The other fuel of angels as oppos3d to deisel wich is the fuel of satan, is LPG, very clean etc.
Heres the problem with electric efficiency
The electrical generating efficiency of standard steam turbine power plants varies from a high of 37% HHV4 for large, electric utility plants designed for the highest practical annual capacity factor, to under 10% HHV for small, simple plants which make electricity as a byproduct of delivering steam to processes or district heating systems.
From https://www.turbinesinfo.com/steam-turbine-efficiency/
Example a train elecrified being 60% efficient of 37% efficient generation gives 24% efficiency at the higher estimates, and 15% at the average, and thats before you charge and discharge, so about 12.5% to 8% for batteries, makes diesils 45% efficiency look briliant.
Dont forget you can synthesise hydrocarbons from renewables, and as someone stated fuels with the highest energy density are the fuels from petrochemicals !
-
FWIW a growing proportion of the UK's energy is wind turbines, and they have an efficiency of about 50%. Not that it matters, because, unlike diesel, you don't have to do anything except install the turbine to get the energy in the first place, and operationally the waste is zero pollution, whereas most of the diesel ends up as pollution.
But that's not even the point. Let's take cars, which are similar to lorries. A typical electric car gets 3-4 miles per kWh let's say 3. Whereas a diesel gets 60 mpg on a really, really good day? A litre of diesel costs ~£1.2, so a gallon costs 4.5*1.2 = £5.4, whereas a commercially sourced (or night rate) kWh costs ~£0.09
That means that to go one mile the diesel costs 5.4/60 = £0.09, whereas the electric costs 0.09/3 = £0.03
So the diesel is three times more expensive for running costs. For shipping they do a lot of miles, and that really, really matters.
Meanwhile your 'efficiency' argument doesn't really hold water. First we don't really care about efficiency per se. What we really care about is cost, and pollution. As I've shown diesel is much higher cost, and it turns out that it's significantly more polluting in every case except if you basically burn only coal or diesel for making your electricity.
Point of fact, the UK grid uses, for generating its electricity, mostly natural gas, which is low carbon and low for other emissions too. The grid also has significant amounts of nuclear, wind and has some solar and hydroelectricity and biofuels and some coal as also rans. So the UK grid is relatively clean, it's now one of the cleaner grids in the world, far, far cleaner than when it was running near 100% coal.
So, no, diesel is not better than electric drive trains, it's not even remotely close.
-
But we could not power even the vehicles fron green sources as is, so electric is a bad chouce. Gas to heat to turbine to electric to battery from battery to motor to road is not ecological. Gas to motor to road is far more sensible. Lpg all the way. As i said petrochemical fuels has the highest energy to content and can be synthesised from green sources.
And diesil costs 9p a litre before add ons (tax), but it is very dirty. Alcohol is a good fuel and so is petrolium. 4 miles from a kw hour is probably via the engine at 60% efficient, via the charger at 50% efficient so a kwh becomes 4 kwh from your socket. Ie 40 p a 4 mile. Its only taxes on petrochemicals and tax breaks on electric and subsidies that go to make it look any where near acceptable.
-
But we could not power even the vehicles fron green sources as is, so electric is a bad chouce.
Yeah, no, we could, no problem. There's enough wind resources around the UK to power most of Europe alone. In practice, you need something to act as backup for when the wind/solar drops out for more than a few days, that might be a biofuel.
Gas to heat to turbine to electric to battery from battery to motor to road is not ecological. Gas to motor to road is far more sensible. Lpg all the way. As i said petrochemical fuels has the highest energy to content and can be synthesised from green sources.
Yes, it's the most energy dense. But that doesn't make it the best overall choice because of its pollution. And the grid must be, and actually is, slowly phasing out even natural gas; most of the new generating capacity and output each year in the UK and globally, is now renewable.
Note that there's no practical scheme for making high energy-density hydrocarbon fuel right now, except for biofuels, which don't scale well, they use a lot of arable land.
And diesil costs 9p a litre before add ons (tax), but it is very dirty. Alcohol is a good fuel and so is petrolium. 4 miles from a kw hour is probably via the engine at 60% efficient, via the charger at 50% efficient so a kwh becomes 4 kwh from your socket. Ie 40 p a 4 mile.
No, nothing at all like that, don't forget quite a few people drive electric vehicles and that's not what they pay.
Although come to think of it the chargers and battery may well be only 80% efficient, so that's 3.6p/mile.
Its only taxes on petrochemicals and tax breaks on electric and subsidies that go to make it look any where near acceptable.
I believe that currently the tax is about 2/3 of the cost of diesel; so ignoring that they would be financially roughly equivalent- except for the environmental damage. And note that renewable energy, and the purchase cost of electric vehicles is still seriously dropping in price, wheres petrochemicals are only getting more expensive.
-
Note that there's no practical scheme for making high energy-density hydrocarbon fuel right now, except for biofuels, which don't scale well, they use a lot of arable land.
plants are 90 percent efficient, solar on the same area is 15% in a perpetual cloudless sky whilst the panels track the sun. Molten salt not withstanding
I believe that currently the tax is about 2/3 of the cost of diesel; so ignoring that they would be financially roughly equivalent- except for the environmental damage. And note that renewable energy, and the purchase cost of electric vehicles is still seriously dropping in price, wheres petrochemicals are only getting more expensive.
10 p is the cost to pour a litre of deisel from the ground into your tank, profeteering and taxation on petrochemicals aside.
-
? Plants are about 1-2% efficient at making biofuel. Solar panels are ~20% energetically efficient, they produce around 200 watts per square metre from a solar insolation of ~1kW per square metre.
And the cost of diesel doesn't seem to be anything like as low as that- indeed the cost of the crude oil is far bigger than 10p!!!
There's a breakdown of the various costs here:
http://www.bbc.co.uk/news/business-15462923
-
Ill be honest i made a mistake, plants are about 5 efficient per solar radiation area, but are 90 percent efficient to the radiation they absorb. A technical thing i picked up years ago reading about solar
https://www.economist.com/blogs/economist-explains/2014/12/economist-explains-1
https://en.m.wikipedia.org/wiki/Photosynthetic_efficiency
Ok then 20p a litre ? 0.5P a mile ? 1 p a mile ? Green energies and nuclear massivley subsidied, fossil massivley taxed.
-
Just to correct a couple of misunderstandings.
The cost of producing and delivering liquid fuels cannot be derived from the UK retail price of road fuel. You can get a bit closer by looking at the price of jet fuel or domestic heating oil (currently 40 p/liter), but JETA1 is at the posh end of oil refinement and domestic kerosene carries tax to subsidise renewables. The reason we use fossil fuels to generate electricity is because we can sell electricity for more than the cost of producing it - EDF, Centrica, or whoever owns your previously-national asset, is not a charity!
Direct extraction of biofuel from plant oils is a complete waste of land and sunshine.
But if renewable electricity really is free, the efficiency of whatever process we use to store and deliver it is irrelevant. Right now, it's cheaper than free, with windmill companies being paid to stop generating at times of low demand. So it makes scientific sense to investigate any processes, however inefficient, for turning organic waste directly into fuel rather than waiting millions of years for landfill and farm slurry to turn into coal or oil by themselves.
-
It will never be landfill for long enough, metal content in land fill is far bettter value for mining. Imagine how much copper is in them alone.
https://www.ft.com/content/0bf645dc-d8f1-11e7-9504-59efdb70e12f
-
Ok then 20p a litre ? 0.5P a mile ? 1 p a mile ? Green energies and nuclear massivley subsidied, fossil massivley taxed.
Nah. Just the crude oil alone costs 50p a litre. That's £2.25/gallon or 4p/mile @60 mpg in just crude costs. And that ignores all refining, distribution. Nevermind tax costs.
Compare that with the cost of the electricity, and electric cars come out ahead, we said just over 3p might be reasonable.
You could try arguing that a mile in an electric car wears the battery and try adding that to the cost per mile. But realistically that comes out of depreciation- fossil cars also have a large rate of depreciation. The second hand market seems to set depreciation for electric cars the same as fossil cars.
No, the bottom line is that electric cars are signficantly cheaper per mile than diesel cars and far less polluting. This isn't some taxation or subsidy conspiracy, even stripping taxation away completely, the electric car still wins, by a large margin.
At least, that's the case in the UK, other places may be less favourable. The UK has cheap night rate electricity, that's unavailable in many places in the United States for example.
-
Nah. Just the crude oil alone costs 50p a litre.
It's about half that.
http://markets.businessinsider.com/commodities/oil-price?type=wti
-
The cost of crude varies considerably over time. And that's actually not a good thing. And there are other costs are on top of that. Maybe on the rare occasions the price of crude is around the very bottom of its range the true cost per mile may be similar to electric vehicles.
-
The cost of producing and delivering liquid fuels cannot be derived from the UK retail price of road fuel. You can get a bit closer by looking at the price of jet fuel or domestic heating oil (currently 40 p/liter), but JETA1 is at the posh end of oil refinement and domestic kerosene carries tax to subsidise renewables. The reason we use fossil fuels to generate electricity is because we can sell electricity for more than the cost of producing it - EDF, Centrica, or whoever owns your previously-national asset, is not a charity!Direct extraction of biofuel from plant oils is a complete waste of land and sunshine. But if renewable electricity really is free, the efficiency of whatever process we use to store and deliver it is irrelevant. Right now, it's cheaper than free, with windmill companies being paid to stop generating at times of low demand. So it makes scientific sense to investigate any processes, however inefficient, for turning organic waste directly into fuel rather than waiting millions of years for landfill and farm slurry to turn into coal or oil by themselves.
" and domestic kerosene carries tax to subsidise renewables...."
Does kerosene tax subsidise ONLY renewables?
" So it makes scientific sense to investigate any processes, however inefficient, for turning organic waste directly into fuel...."
Except that lower efficiency processes demand more energy input (whether free or not), leading to greater demand on energy generation and distribution systems, fuelling concerns, as earlier in this topic, that "the grid will not be able to cope!"
-
But we could not power even the vehicles fron green sources as is, so electric is a bad chouce. Gas to heat to turbine to electric to battery from battery to motor to road is not ecological. Gas to motor to road is far more sensible. Lpg all the way. As i said petrochemical fuels has the highest energy to content and can be synthesised from green sources.And diesil costs 9p a litre before add ons (tax), but it is very dirty. Alcohol is a good fuel and so is petrolium. 4 miles from a kw hour is probably via the engine at 60% efficient, via the charger at 50% efficient so a kwh becomes 4 kwh from your socket. Ie 40 p a 4 mile. Its only taxes on petrochemicals and tax breaks on electric and subsidies that go to make it look any where near acceptable.
If you must stick to IC engines, at least use the hybrid transmission (preferably series) type. This allows the engine to run at constant speed and fairly constant load, which raises its actual efficiency towards the oft quoted figure obtained in dynamometer tests, rather than around 25% in a normal car.
My EV averages 3miles per KWh, over 4 in mild weather. This is the energy taken from my wall charger. You can use your electricity tariff to work out what that would cost you if you had an EV
-
..... So if we allow 90% conversion efficiency for an electric vehicle and 45% for diesel, the running costs are about the same.
I repeat, efficiency figures of 45 % for IC engines are always qouted as the peak measurable in dynamometer tests. For an IC engine, graph curves for power, torque and efficiency are far from straight lines. When operated over very variable load and speed ranges, as in a road vehicle, an engine performs far below its stated efficiency.
-
Interesting numbers. 1 kWh = 3.6 MJ, so 3 miles per kWh equates to 30 miles per US gallon of diesel, not bad for a very large family car, say a BMW 5 series 3 liter estate, driven harshly.
However you have measured 1 kWh at the retail supply point. The primary fuel that was required to generate that energy was at best 50% utilised, so if the electricity came from a gas, coal or oil-fired power station, your car is only managing 15 miles per gallon equivalent. A small aeroplane will do better, at an average speed of 120 mph. The only advantage to electric transport is that the pollution is generated many miles from your home, and everyone else subsidises your fuel costs..
-
Nah. Just the crude oil alone costs 50p a litre.
It's about half that.
http://markets.businessinsider.com/commodities/oil-price?type=wti
The price and the cost are 2 different things remember. The price of crude is inflated due to saudi wanting to profeteer, and is kept in line by the *cost* of shale oil production being 50 dollars a barrel.
Peak oil was calculated by easily extracted oil, a *price* of 10 pounds a barrel still creates the required profit from easily extracted sources to cover the cost. Its why they called it black gold, cheap production that powers its own distillation, and fools will pay 1.50 pounds a litre ! If oil hits *price* 100 dollars a barrel and production is costed accordingly, canadia has the biggest reserves on the planet through there very expensicve to extract tar sands. But saudi will make far more money!
10 p is the cost from a well on a big field of light crude to a refinery and to your fuel tank, market fluctuations tax profit etc not counted. Easily extracted light crude is becoming rarer though, and most have been found and largley explited.
-
But we could not power even the vehicles fron green sources as is, so electric is a bad chouce. Gas to heat to turbine to electric to battery from battery to motor to road is not ecological. Gas to motor to road is far more sensible. Lpg all the way. As i said petrochemical fuels has the highest energy to content and can be synthesised from green sources.And diesil costs 9p a litre before add ons (tax), but it is very dirty. Alcohol is a good fuel and so is petrolium. 4 miles from a kw hour is probably via the engine at 60% efficient, via the charger at 50% efficient so a kwh becomes 4 kwh from your socket. Ie 40 p a 4 mile. Its only taxes on petrochemicals and tax breaks on electric and subsidies that go to make it look any where near acceptable.
If you must stick to IC engines, at least use the hybrid transmission (preferably series) type. This allows the engine to run at constant speed and fairly constant load, which raises its actual efficiency towards the oft quoted figure obtained in dynamometer tests, rather than around 25% in a normal car.
My EV averages 3miles per KWh, over 4 in mild weather. This is the energy taken from my wall charger. You can use your electricity tariff to work out what that would cost you if you had an EV
A petrol is about 33 percent, deisel about 45. If you add hybrids and super chargers to the mix they go up. The recent upswing in efficiency was due to the installation of superchargers to engines.
-
Nah. Just the crude oil alone costs 50p a litre.
It's about half that.
http://markets.businessinsider.com/commodities/oil-price?type=wti
The price and the cost are 2 different things remember. The price of crude is inflated due to saudi wanting to profeteer, and is kept in line by the *cost* of shale oil production being 50 dollars a barrel.
Peak oil was calculated by easily extracted oil, a *price* of 10 pounds a barrel still creates the required profit from easily extracted sources to cover the cost. Its why they called it black gold, cheap production that powers its own distillation, and fools will pay 1.50 pounds a litre ! If oil hits *price* 100 dollars a barrel and production is costed accordingly, canadia has the biggest reserves on the planet through there very expensicve to extract tar sands. But saudi will make far more money!
10 p is the cost from a well on a big field of light crude to a refinery and to your fuel tank, market fluctuations tax profit etc not counted. Easily extracted light crude is becoming rarer though, and most have been found and largley explited.
Yeah, so, which bit of the economics don't you understand?
You've just explained that some, largely imaginary 'cost' of diesel would be very cheap, but the real world economics prevent you from ever getting a price anywhere remotely near that. they're never going to sell at that price to the trucking industry.
And you asked the question: "Are the economics of battery-driven lorries a non starter?" whereas the true question seems to be more: "Are the economics of diesel-driven lorries a non starter?". And the answer seems to be: wherever humanly possible you should use electric vehicles, because they're almost always cheaper for heavily used vehicles.
-
A very good point. Electric vehicles will continue to be economically advantageous until there are enough of them to damage the tax revenues on liquid fuels, whereupon the government will impose huge licence fees on EVs to subsidise the electricity industry and the dwindling market for liquid road fuel will lead to rapidly increasing costs for this "niche" product.
-
Interesting numbers. 1 kWh = 3.6 MJ, so 3 miles per kWh equates to 30 miles per US gallon of diesel, not bad for a very large family car, say a BMW 5 series 3 liter estate, driven harshly.
However you have measured 1 kWh at the retail supply point. The primary fuel that was required to generate that energy was at best 50% utilised, so if the electricity came from a gas, coal or oil-fired power station, your car is only managing 15 miles per gallon equivalent. A small aeroplane will do better, at an average speed of 120 mph. The only advantage to electric transport is that the pollution is generated many miles from your home, and everyone else subsidises your fuel costs..
I didn't mention the primary fuel because the post I replied to seemed to be concerned with cost to the user. I am well aware of the losses involved in transmission and generation
Re my EV only achieving 30 miles per US gallon, or 15 miles per energy at source:-
I am on record as admitting to being a sums dummy, but my thinking is thus:-
I have claimed that 3 miles per KWh is my average. Assuming that 1Litre of fuel contains 10 KWh, then 1 US gallon will contain 37 KWh. At 3 miles per KWh my EV then manages 111 miles, or 111 mpg. The energy consumed to provide this, using your 50% efficiency, would equate to 55 mp(US)g.
Not that good, but if the UK grid moves away from fossil fuel (government permitting) this figure will improve.
Incidentally, the meter used to measure my consumption gives me an all year average of 3.6 miles per KWh, but I am unsure of its accuracy, so I try to err on the pessimistic side.
-
Out of interest, 3miles pkwh, is it the energy utilised by the engine, energy removed from the battery, or energy from the socket into to the battery ?
-
Interesting numbers. 1 kWh = 3.6 MJ, so 3 miles per kWh equates to 30 miles per US gallon of diesel, not bad for a very large family car, say a BMW 5 series 3 liter estate, driven harshly.
However you have measured 1 kWh at the retail supply point. The primary fuel that was required to generate that energy was at best 50% utilised, so if the electricity came from a gas, coal or oil-fired power station, your car is only managing 15 miles per gallon equivalent.
How'd you figure that? The thermal energy in a US gallon of diesel is around 38 kWh. If we assume ~33% thermal conversion to electricity including delivery losses ot the consumer, that's 12kWh delivered, then allowing the charger to be 80%, that's about 10kWh into the battery. That's enough to go over 30 miles. I don't know where you got 15 miles from, that's not happening.
But using diesel for generating electricity is rare; it's expensive-the only places that do that much are pretty cut-off places like Hawaii and Alaska.
-
Apologies! Diesel is 36 MJ/liter, not gallon! Mea culpa.
-
Out of interest, 3miles pkwh, is it the energy utilised by the engine, energy removed from the battery, or energy from the socket into to the battery ?
3KWhour is from the socket, into the battery.
-
Interesting numbers. 1 kWh = 3.6 MJ, so 3 miles per kWh equates to 30 miles per US gallon of diesel, not bad for a very large family car, say a BMW 5 series 3 liter estate, driven harshly.
However you have measured 1 kWh at the retail supply point. The primary fuel that was required to generate that energy was at best 50% utilised, so if the electricity came from a gas, coal or oil-fired power station, your car is only managing 15 miles per gallon equivalent.
How'd you figure that? The thermal energy in a US gallon of diesel is around 38 kWh. If we assume ~33% thermal conversion to electricity including delivery losses ot the consumer, that's 12kWh delivered, then allowing the charger to be 80%, that's about 10kWh into the battery. That's enough to go over 30 miles. I don't know where you got 15 miles from, that's not happening.
But using diesel for generating electricity is rare; it's expensive-the only places that do that much are pretty cut-off places like Hawaii and Alaska.
Just nit-picking, but my 3KWh is from the socket, the charger is built into the car so its efficiency is irrelevant. And 38KWh x 3miles per KWh is 114 miles.
-
Out of interest, 3miles pkwh, is it the energy utilised by the engine, energy removed from the battery, or energy from the socket into to the battery ?
3KWhour is from the socket, into the battery.
Sorry Petrochemicals, 3miles per KWh is from the socket, so each KWh from the socket gives 3miles (average).
-
Interesting numbers. 1 kWh = 3.6 MJ, so 3 miles per kWh equates to 30 miles per US gallon of diesel, not bad for a very large family car, say a BMW 5 series 3 liter estate, driven harshly.
However you have measured 1 kWh at the retail supply point. The primary fuel that was required to generate that energy was at best 50% utilised, so if the electricity came from a gas, coal or oil-fired power station, your car is only managing 15 miles per gallon equivalent.
How'd you figure that? The thermal energy in a US gallon of diesel is around 38 kWh. If we assume ~33% thermal conversion to electricity including delivery losses ot the consumer, that's 12kWh delivered, then allowing the charger to be 80%, that's about 10kWh into the battery. That's enough to go over 30 miles. I don't know where you got 15 miles from, that's not happening.
But using diesel for generating electricity is rare; it's expensive-the only places that do that much are pretty cut-off places like Hawaii and Alaska.
Just nit-picking, but my 3KWh is from the socket, the charger is built into the car so its efficiency is irrelevant. And 38KWh x 3miles per KWh is 114 miles.
Sorry Wolfekeeper, my 3 miles per KWh is from the socket, meaning that each KWh gives me 3 miles(average).
-
So is the conclusion, possible if it is forced on us, even against better advice ?
https://www.statista.com/statistics/204169/retail-prices-of-diesel-fuel-in-the-united-states-since-2009/
So thats about 2 quid a gallon. At shale oil prices, with a bit of tax too.
Go for about 20 miles a pound, 5p a mile. Versus 3p for electric it does seem like this will be a future tech choice as oil goes up in costand EV come down ie batteries and subsudies via tax from oil to others.
But truthfully it will be a bubble like the deisel car subsidised by tax on others and pushed by governments, it will be cosing alot to drive lorries on national transit routes on batteries, hardwear and inefficiencies in charging, there are cheaper electric drive being proposed. Direct drive electric will obviously be on a par with an electric train, induction drive vehicles, overhead cables
-
Interesting numbers. 1 kWh = 3.6 MJ, so 3 miles per kWh equates to 30 miles per US gallon of diesel, not bad for a very large family car, say a BMW 5 series 3 liter estate, driven harshly.
However you have measured 1 kWh at the retail supply point. The primary fuel that was required to generate that energy was at best 50% utilised, so if the electricity came from a gas, coal or oil-fired power station, your car is only managing 15 miles per gallon equivalent.
How'd you figure that? The thermal energy in a US gallon of diesel is around 38 kWh. If we assume ~33% thermal conversion to electricity including delivery losses ot the consumer, that's 12kWh delivered, then allowing the charger to be 80%, that's about 10kWh into the battery. That's enough to go over 30 miles. I don't know where you got 15 miles from, that's not happening.
But using diesel for generating electricity is rare; it's expensive-the only places that do that much are pretty cut-off places like Hawaii and Alaska.
Just nit-picking, but my 3KWh is from the socket, the charger is built into the car so its efficiency is irrelevant. And 38KWh x 3miles per KWh is 114 miles.
Sorry Wolfekeeper, my 3 miles per KWh is from the socket, meaning that each KWh gives me 3 miles(average).
No, I don't think so. The kWh displayed in the car is the energy stored in the battery. The losses during the charging process are not included. So if you have an 85kWh Tesla Model S, and you charge your battery from empty, it will take 100kWh.
e.g.
https://www.greencarreports.com/news/1090685_life-with-tesla-model-s-one-year-and-15000-miles-later
So is the conclusion, possible if it is forced on us, even against better advice ?
There is no better advice. The use of fossil fuels has to phase out as soon as possible, or we will face catastrophic climate change that will cost us far more in other ways. This is not controversial in science circles, and this is a science-related board.
-
There is no better advice. The use of fossil fuels has to phase out as soon as possible, or we will face catastrophic climate change that will cost us far more in other ways. This is not controversial in science circles, and this is a science-related board.
This is a scifntific board, and to make a link between cost of electric battery driven vehicles, and global link for reasons on giving weight to the pro side, is clearly unscientific. More political id say
-
No, I don't think so. The kWh displayed in the car is the energy stored in the battery. The losses during the charging process are not included. So if you have an 85kWh Tesla Model S, and you charge your battery from empty, it will take 100kWh.
Interesting article you linked to. My car (sadly not a Tesla, just a Leaf) displays average miles per KWh on the dashboard. At the moment this shows 4.3Mile/Kwh. I don't take notice of this. It shows the energy remaining in the battery as percentage state of charge, and estimated miles remaining, not KWh. The consumption figures I provide are taken from a "smart" (?) energy meter which monitors the energy taken by the car, only, from the domestic socket. As far as I can see, losses in the on-board charger are accounted for in the supply readings. So I can say that for each KWh taken from the mains, I average 3 miles (well over 4 in mild weather). So far, the car has been charged almost entirely from this supply. As I said previously, I err on the pessimistic side because I can't vouch for the accuracy of the meter.
I don't notice a "vampire" effect, but I recognise the reduced range in cold weather, due to a drop in battery performance, and heavy use of the heater.
-
[
There is no better advice. The use of fossil fuels has to phase out as soon as possible, or we will face catastrophic climate change that will cost us far more in other ways. This is not controversial in science circles, and this is a science-related board.
[/quote]
Hear, hear!