RE: MINI Cooper E
Discussion
As a reference point, a 200bhp petrol car with a 50 litre tank running flat out at 25% efficiency would drain its tank in 50 minutes.
200bhp in a mini would surely be 140ish mph though, and this is limited to 95. Assuming P is proportional to v^3 (i.e. dominated by aero drag) the mini would require 47kW at 95mph so should run for 36 minutes flat out giving a range of 57 miles. Reduce the speed to 75mph and it'll run for about 70 minutes and 90 miles.
On average we drive about 30 miles a day, I'd be interested to know the actual distribution of daily mileages. I think it's pretty clear that electric cars will initially make most sense for people commuting in cities, not those doing long motorway journeys.
200bhp in a mini would surely be 140ish mph though, and this is limited to 95. Assuming P is proportional to v^3 (i.e. dominated by aero drag) the mini would require 47kW at 95mph so should run for 36 minutes flat out giving a range of 57 miles. Reduce the speed to 75mph and it'll run for about 70 minutes and 90 miles.
On average we drive about 30 miles a day, I'd be interested to know the actual distribution of daily mileages. I think it's pretty clear that electric cars will initially make most sense for people commuting in cities, not those doing long motorway journeys.
dcb said:
AlpineWhite said:
But you're probably right. Perhaps it will be the next Prius. The wider public will probably miss the fact that they're plugging it into the end of a coal power station anyway.
At best, any electric car can only move the supposed problem upstreamto the local electric power station.
A few weeks back I was speaking to a guru on alternative piston engine technology who hates the idea of battery powered electric cars (and indeed fuel cells), but still concedes they'd be good in town.
Myths about electric cars:
1) "Electricity comes from oil-power stations and is therefore at least as bad as the internal combustion engine"
It doesn't have to come from any particular type of power station at all. We have been making renewable electricity since it was first discovered, and the future will see us looking away from fossil-fuel stations anyway. On top of that, controlling pollution-centres is that much easier if you have one big polluter (the power station) instead of thousands of smaller polluters (car engines). CO2 aside, the air we breathe in cities is in an appalling state and causes breathing problems, damage to buildings... and doesn't smell nice.
2) "Batteries stop working and then cause more pollution"
Batteries are in most cases quite easy to disassemble and then recycle. Once a standard has been settled on, we can expect to see recycling happening totally as a matter of course.
3) "Electric cars are slow and can't go very far"
This Mini E is the Benz Velo of 2008. The first of their type. Cast your mind back to 1894, and you'll remember those were pretty shit too. Every evolution will bring better power, range, efficiency, weight and usability.
4) "Where can I charge an electric car? This will never work if I park in the road"
There was once a time when we had no petrol stations. Providing the infrastructure for electric points in the road is a far easier ask than petrol refineries, pipelines, pumps etc. As soon as someone sees they can make money from it, it will come.
1) "Electricity comes from oil-power stations and is therefore at least as bad as the internal combustion engine"
It doesn't have to come from any particular type of power station at all. We have been making renewable electricity since it was first discovered, and the future will see us looking away from fossil-fuel stations anyway. On top of that, controlling pollution-centres is that much easier if you have one big polluter (the power station) instead of thousands of smaller polluters (car engines). CO2 aside, the air we breathe in cities is in an appalling state and causes breathing problems, damage to buildings... and doesn't smell nice.
2) "Batteries stop working and then cause more pollution"
Batteries are in most cases quite easy to disassemble and then recycle. Once a standard has been settled on, we can expect to see recycling happening totally as a matter of course.
3) "Electric cars are slow and can't go very far"
This Mini E is the Benz Velo of 2008. The first of their type. Cast your mind back to 1894, and you'll remember those were pretty shit too. Every evolution will bring better power, range, efficiency, weight and usability.
4) "Where can I charge an electric car? This will never work if I park in the road"
There was once a time when we had no petrol stations. Providing the infrastructure for electric points in the road is a far easier ask than petrol refineries, pipelines, pumps etc. As soon as someone sees they can make money from it, it will come.
Edited by Mr Gear on Thursday 18th December 13:53
astrsxi77 said:
Ah yes and the safe recycling of batteries will, no doubt, use absolutely no energy whatsoever!
And the recycling of internal combustion engines doesn't (when it's done at all)?And petrol takes no energy to extract, refine and ship?
Edited by kambites on Thursday 18th December 14:04
AlpineWhite said:
kambites said:
I think an internal combustion powered car is about 20% efficient under normal driving conditions.
More like 35% I'm lead to believe; but if your figures on power stations are right then they still appear to better the IC engine.supercritical plants get up into the low 40's
ultrasupercritical plants, and for the best and latest designs there are some pressure part material issues that have not yet been fixed can be around 48% and there it is believed this can get up to 50+
Gas fired CCGT (ie a gas turbine which directly drives a generator, plus the exhaust gas from the gas turbine generates steam in a boiler which then drives a steam turbine) these are about 60% but then maybe gas is a much more limited supply long term than coal, hence the focus on clean coal technology.
Then you have CHP systems, where you generate electricity from some fuel, which could be coal, gas or municipal waste, and waste heat from the boiler is used for district or process heating. These can be 90% thermally efficient.
Basically if you increase the electricity demand because of a fundamental change, eg by a shift to electric cars, then the efficiency of those cars can only be as good as the efficiency of the worst plant you have to put online in order to meet the total demand. The eco-mentalists somehow always want to ring fence the power produced by green generation in these cases, and say that electric cars will be powered by windmills. It's a complete fallacy.
So what I'm saying is, if you have to put some old coal fired plant at 38% efficiency on line because of the overall demand increase with electric cars, then the efficiency is actually 38% minus the transmission loses, minus the losses due to storage and efficiency of the car itself. You end up worse than a petrol car and much much worse than a modern diesel.
If somebody has said all this in the thread before me, I apologise for posting before reading the whole thread.
HTH
FiF
edited due to multitudinous typos
Edited by F i F on Thursday 18th December 15:02
F i F said:
AlpineWhite said:
kambites said:
I think an internal combustion powered car is about 20% efficient under normal driving conditions.
More like 35% I'm lead to believe; but if your figures on power stations are right then they still appear to better the IC engine.supercritical plants get up into the low 40's
ultrasupercritical plants, and for the best and latest designs there are some pressure part material issues that have not yet been fixed can be around 48% and there it is believed this can get up to 50+
Gas fired CCGT (ie a gas turbine which drives a generator, the exhaust gas from the gas turbine generates steam in a boiler which drives a steam turbine) these are about 60% but then maybe is a much more limited supply long term than coal, hence the focus on clean coal technology.
Then you have CHP systems, where you gerenrate electricity from some fuel, which could be coal, gas or municipal waste, and watse heat from the boiler is used for district or process heating these can be 90% thermally efficient.
Basically if you increase the electricity demand because of a fundamental change, eg by a shift to electric cars, then the efficiency of those cars can only be as good as the efficiency of the worst plant you have to put online in order to meet the total demand. The ec-mentalists somehow always want to ring fence the power produced by green generation in these cases, and say that electric cars will be powered by windmills. It's a complete fallacy.
So what I'm saying is, if you have to put some old coal fired plant at 38% efficiency on line because of the overall demand increase with electric cars, then the efficiency is actually 38% minus the transmission loses, minus the losses ude to storage and efficiency of the car itself. You end up worse than a petrol car and much much worse than a modern diesel.
If somebody has said all this in the thread before me, I apologise for posting before reading the whole thread.
HTH
FiF
What it all comes down to, is that there is no obvious solution. However, advances in technology of this kind rarely do any harm. I suppose in the case of electric cars, one would have to assume that the extra power was generated by new power stations, probably a combination of nuclear and "renewable fuels".
Edited by kambites on Thursday 18th December 15:00
F i F said:
So what I'm saying is, if you have to put some old coal fired plant at 38% efficiency on line because of the overall demand increase with electric cars, then the efficiency is actually 38% minus the transmission loses, minus the losses due to storage and efficiency of the car itself. You end up worse than a petrol car and much much worse than a modern diesel.
Don't forget that electric cars are not only more efficient than ICE-powered cars, but (primarily in 'urban' stop-start driving) have lower energy demand thanks mainly to regenerative braking.Real-world experience shows that 15kWh/100km is a reasonable figure for electric car energy consumption (some claim as little as 6kWh/100km). If this energy is supplied by a fossil-fuel powered generation and distribution system which is 40% efficient, the total energy consumption is 37.5 kWh/100km. Petrol contains ~10kWh/L so that's 3.75L/100km or 74mpg.
Mr Gear said:
3) "Electric cars are slow and can't go very far"
This Mini E is the Benz Velo of 2008. The first of their type. Cast your mind back to 1894, and you'll remember those were pretty shit too. Every evolution will bring better power, range, efficiency, weight and usability.
The electric car has been around since the late 1800's. For the 20 years up to around 1910, it held it's own against steam and gasoline powered automobiles. The benefits of 'clean' emmissions, quiet operation and rechargeable batteries were appreciated over a century again. Electric powered cars achieved a land speed record of 65 mph. Another model could run for 13 hours at 14mph. Range varied from 20 to 60 miles before recharging.This Mini E is the Benz Velo of 2008. The first of their type. Cast your mind back to 1894, and you'll remember those were pretty shit too. Every evolution will bring better power, range, efficiency, weight and usability.
Article here: http://www.geocities.com/Athens/Crete/6111/electca...
Progress? Ha...
Go this the Honda Clarity site and then look at the "Home Energy Station" section. That's the real future.
automobiles.honda.com/fcx-clarity/
automobiles.honda.com/fcx-clarity/
Charge time = 240V@48A 2.9 hours = 120,268,800 joules = 33.408 KWh
One KWh "costs" 537g of CO2, from standard grid electricity; http://www.carbontrust.co.uk/resource/conversion_f...
So one charge will produce 33.4KWh * 537g/KWh = 17936g
Range is 150 miles, or 240km
17936g/240km = 74.3g CO2/km.
74.3g CO2/km is very good indeed, the 1.6 diesel Mini only manages 104.
One KWh "costs" 537g of CO2, from standard grid electricity; http://www.carbontrust.co.uk/resource/conversion_f...
So one charge will produce 33.4KWh * 537g/KWh = 17936g
Range is 150 miles, or 240km
17936g/240km = 74.3g CO2/km.
74.3g CO2/km is very good indeed, the 1.6 diesel Mini only manages 104.
NiallOswald said:
* G-Wiz, Tesla or anything in between - they're pretty much all in the region of 10-20 kWh/100km and our current electricity mix produces about 500g/kWh giving 50-100g/km which compares pretty well to the current average of ~180g/km for new cars.
I can imagine 10kWh/100km for the G-Wiz, but 20 for the Tesla doesn't sound right to me. I would have expected probably double that consumption smply because the car is heavier and people will be accelerating quicker and reaching higher speeds. Do you know the energy required to charge the car and the real world mileage? I don't mean Tesla's figures obviously.herewego said:
NiallOswald said:
* G-Wiz, Tesla or anything in between - they're pretty much all in the region of 10-20 kWh/100km and our current electricity mix produces about 500g/kWh giving 50-100g/km which compares pretty well to the current average of ~180g/km for new cars.
I can imagine 10kWh/100km for the G-Wiz, but 20 for the Tesla doesn't sound right to me. I would have expected probably double that consumption smply because the car is heavier and people will be accelerating quicker and reaching higher speeds. Do you know the energy required to charge the car and the real world mileage? I don't mean Tesla's figures obviously.tomkandy said:
herewego said:
NiallOswald said:
* G-Wiz, Tesla or anything in between - they're pretty much all in the region of 10-20 kWh/100km and our current electricity mix produces about 500g/kWh giving 50-100g/km which compares pretty well to the current average of ~180g/km for new cars.
I can imagine 10kWh/100km for the G-Wiz, but 20 for the Tesla doesn't sound right to me. I would have expected probably double that consumption smply because the car is heavier and people will be accelerating quicker and reaching higher speeds. Do you know the energy required to charge the car and the real world mileage? I don't mean Tesla's figures obviously.herewego said:
NiallOswald said:
* G-Wiz, Tesla or anything in between - they're pretty much all in the region of 10-20 kWh/100km and our current electricity mix produces about 500g/kWh giving 50-100g/km which compares pretty well to the current average of ~180g/km for new cars.
I can imagine 10kWh/100km for the G-Wiz, but 20 for the Tesla doesn't sound right to me. I would have expected probably double that consumption smply because the car is heavier and people will be accelerating quicker and reaching higher speeds. Do you know the energy required to charge the car and the real world mileage? I don't mean Tesla's figures obviously.David McKay said:
Manufacturers always quote the best possible performance of their products. What happens in real life? The real-life performance of a GWiz in London is shown in figure 20.21. Over the course of 19 recharges, the average transport cost of this G-Wiz is 21 kWh per 100 km – about four times better than an average fossil fuel car. The best result was 16 kWh per 100 km, and the worst was 33 kWh per 100 km. If you are interested in carbon emissions, 21 kWh per 100 km is equivalent to 105 gCO2 per km, assuming that electricity has a footprint of 500 gCO2 per kWh.
David McKay said:
The Tesla Roadster 2008 has a range of 220 miles (354 km); its lithium-ion battery pack stores 53 kWh and weighs 450 kg (120Wh/kg). The vehicle weighs 1220kg and its motor’s maximum power is 185 kW. What is the energy-consumption of this muscle car? Remarkably, it’s better than the G-Wiz: 15 kWh per 100 km.
If the real-world range was as bad as 105 miles, that'd be ~30 kWh/100km which still compares pretty well to the G-Wiz.Gassing Station | General Gassing | Top of Page | What's New | My Stuff