How much Fossil Fuel to Travel 200 Miles in a Model S?

How much Fossil Fuel to Travel 200 Miles in a Model S?

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politeperson

Original Poster:

544 posts

182 months

Tuesday 30th November 2021
quotequote all
I know there are some very clever people on this forum who might be able to answer this question.

I am only curious to know the answer, I liked my Model S very much over our time together.

Sitting in a traffic jam today looking at a "Zero Emissions" badge on the back of electric car, got me thinking about how some drivers think that their EV produces Zero Emissions!

Well I guess it does produce zero emissions from the tail pipe, the non- existent tailpipe.

So I tried to find factual study publishing where the electricity actually comes from in the UK

Very difficult to find out at the moment as the Government and the EV Green lobbyists seem to have have excellent PR and claim it comes from renewables whereas the good old coal and gas industries are hiding good and proper on line!

I gave up after 20 minutes, someone here might actually have dome some proper work on this.

From what I could glean, it seems that in the UK, the inputs for the electricity mix varies. At the moment it seems to be 50% gas + more for Coal, the rest nuclear, renewables and imported (a worse horror story in some places -especially China).

I know loads of talk is in the air about increasing the reliance on renewables. Great.

However, every KW that goes in seems to contain about 60% fossil fuel from source? Is that correct?

Not only that but 6-10% of the electricity produced is lost in distribution it would appear. That is alot of gas and coal burnt to make EV's work.

That must be wrong otherwise everyone wouldn't be so enthusiastic about them - would they?

So my question is- In the UK, How much fossil fuel is burnt to send a Model S 200 miles?- Would it be more that the 5 gallons I would burn in a Mercedes E220?

Finally, how much extra embodied energy is used in the production of an EV over the equivalent ICE car?

I would love to know the truth. It seems like a very complicated pair of questions though.

Sonemone must be able to put me right?

kambites

67,634 posts

222 months

Tuesday 30th November 2021
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The UK's energy mix in 2021 works out at about 200g of CO2 per Kwh delivered to a domestic supply (so after loses). EVs tend to average between 3 and 4 miles per kwh so you're looking at about 50-65 g/mile, or 30-40g/km.

But then to make that a fair comparison, you can't only look at the tailpipe emissions of the ICE you're comparing to, you need to take into account the electricity used to refine the petrol (the natural gas used to generate electricity doesn't require significant refinement) - about 5kwh per gallon. So if your car does 40mpg, that's an extra 5kwh per 40 miles for the petrol car; which is 125wh/mile which at the above is about 30g/km to refine the petrol. So if your 40mpg petrol car is about 160g/km at the tailpipe, or about 190g/km including refinement.

So for a 40mph petrol car and a typical EV running of the UK's energy mix, the ICE is producing roughly 5-6 times as much CO2 as the EV per mile. For a diesel that will could out at more like 4-5 times as much. Obviously the EV will have produced more in production but that's a whole other topic.


If you want to do it in petrol equivalent, a Model-S will do the equivalent of about 240mpg; so slightly under a gallon of petrol for your 200 miles.

Edited by kambites on Tuesday 30th November 19:13

RobDickinson

31,343 posts

255 months

Tuesday 30th November 2021
quotequote all
kambites said:
But then to make that a fair comparison, you can't only look at the tailpipe emissions of the ICE you're comparing to, you need to take into account the electricity used to refine the petrol
Its more complicated, Extract/mine, ship, refine, transport etc. Overall I think data shows at least 30% more co2 than the cars headline number, and lets face it no car ever hits its stated fuel efficiency - so dont use fantasy numbers for the fossil car and real numbers for the EV.

Then you have that but for wherever the fuel for the electricity generation comes from plus transmission etc.



One thing with EVs is you get to choose where your energy comes from though. Choose a renewable power provider and you're paying for low co2 electricity, or plug in to your own solar etc. Zero options for that with a petrol car.

kambites

67,634 posts

222 months

Tuesday 30th November 2021
quotequote all
RobDickinson said:
Its more complicated, Extract/mine, ship, refine, transport etc. Overall I think data shows at least 30% more co2 than the cars headline number, and lets face it no car ever hits its stated fuel efficiency - so dont use fantasy numbers for the fossil car and real numbers for the EV.
Yes but you have to do at least some of those things with the gas used for generating electricity as well.

And yes ICE vehicles rarely average their stated mpg, but there are plenty of petrol cars out there which do average 40mpg (well, some at least!).

RobDickinson

31,343 posts

255 months

Tuesday 30th November 2021
quotequote all
it also pisses me off when people post these kings of 'gotcha' questions when they've never ever given a single thought to the manufacturing or sourcing of anything they have ever bought in their lives before.


Very little we do is without some impact. And its impossible to build the future with the tools of the future, you have to use what you have now.


Is transport an environmental problem? Yes.

Is grid electricity an environmental problem? Yes.

Can we solve 1 without solving the other? Yes.

But we can and are working on both. That petrol car will never improve over time (it'll get worse..)

kambites

67,634 posts

222 months

Tuesday 30th November 2021
quotequote all
RobDickinson said:
But we can and are working on both. That petrol car will never improve over time (it'll get worse..)
One could argue that the transition from E5 to E10 should improve the net emissions of existing petrol cars. Albeit not by very much!

off_again

12,358 posts

235 months

Tuesday 30th November 2021
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And dont forget that almost all EV's are super slippery and optimized for higher speeds compared to many other ICE vehicles. A Model S has a very good cd rating and super efficient up to 60-70-80MPH compared to others, but clearly at lower speeds (around town being a good example) that advantage does drop. So 200 miles at 60MPH in an EV will be very efficient in comparison to an ICE.

SWoll

18,502 posts

259 months

Tuesday 30th November 2021
quotequote all
off_again said:
And dont forget that almost all EV's are super slippery and optimized for higher speeds compared to many other ICE vehicles. A Model S has a very good cd rating and super efficient up to 60-70-80MPH compared to others, but clearly at lower speeds (around town being a good example) that advantage does drop. So 200 miles at 60MPH in an EV will be very efficient in comparison to an ICE.
Most aren't all that slippery TBH. Tesla do well but a lot of the others (including ground up designs) aren't anything special. The EV6 and Ioniq5 are both around 0.29 compared to the Model 3 at 0.23 and Model Y at 0.24. For reference the current BMW 4 series is 0.25 and Mercedes C-Class 0.24.

Efficiency also doesn't work that way with EV's from both what I've read and experience. Once you get over 15-20mph efficiency continues to drop and they're a lot more efficient at 30mph than they are at 56mph unlike ICE?


anonymous-user

55 months

Tuesday 30th November 2021
quotequote all
politeperson said:
I gave up after 20 minutes, someone here might actually have dome some proper work on this.
https://lmgtfy.app/?q=uk+average+grid+carbon+intensity+2019




dmsims

6,555 posts

268 months

Tuesday 30th November 2021
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Hmm if you Google National grid energy mix this is the first result:

https://grid.iamkate.com/

Jonny_

4,135 posts

208 months

Tuesday 30th November 2021
quotequote all
SWoll said:
off_again said:
And dont forget that almost all EV's are super slippery and optimized for higher speeds compared to many other ICE vehicles. A Model S has a very good cd rating and super efficient up to 60-70-80MPH compared to others, but clearly at lower speeds (around town being a good example) that advantage does drop. So 200 miles at 60MPH in an EV will be very efficient in comparison to an ICE.
Most aren't all that slippery TBH. Tesla do well but a lot of the others (including ground up designs) aren't anything special. The EV6 and Ioniq5 are both around 0.29 compared to the Model 3 at 0.23 and Model Y at 0.24. For reference the current BMW 4 series is 0.25 and Mercedes C-Class 0.24.

Efficiency also doesn't work that way with EV's from both what I've read and experience. Once you get over 15-20mph efficiency continues to drop and they're a lot more efficient at 30mph than they are at 56mph unlike ICE?

Can I ask where you found that graph, and if it pertains to a specific model of EV?

I was recently trying to explain (poorly) to a colleague how an EV is most efficient at fairly low speeds due to aero losses, but that there's a point where travelling more slowly actually decreases efficiency due to the power consumption of the car's electronic/heating/lighting systems becoming significant in relation to the power actually used to propel the car. Your graph illustrates that quite nicely! smile

SWoll

18,502 posts

259 months

Tuesday 30th November 2021
quotequote all
Jonny_ said:
Can I ask where you found that graph, and if it pertains to a specific model of EV?

I was recently trying to explain (poorly) to a colleague how an EV is most efficient at fairly low speeds due to aero losses, but that there's a point where travelling more slowly actually decreases efficiency due to the power consumption of the car's electronic/heating/lighting systems becoming significant in relation to the power actually used to propel the car. Your graph illustrates that quite nicely! smile
Wil have to have a look but the below explains it quite well. Will be for a specific model but the curve will apply to almost all EV's with the exception of the Porsche Taycan/Audi eTron GT that have a 2 speed gearbox and do quite well at motorway speeds.

Department of Transport said:
High speeds increase energy consumption in EVs
more than they increase fuel consumption in
conventional vehicles. Typically in a conventional
vehicle, the most efficient speed (and therefore
maximum MPG) is achieved at approximately
40 – 50 mph, but the most efficient speed for
EVs is lower than this. The reason for the higher
energy consumption at speed is that air resistance
(drag) increases by the square of the vehicle speed.
With conventional vehicles this effect is somewhat
countered by the fact that vehicles are more
efficient in higher gears, but with EVs the countering
effect of gears does not come in to play. This is
why electric cars are well suited to city driving
where speeds are often lower.
https://www.energysavingtrust.org.uk/sites/default...

anonymous-user

55 months

Wednesday 1st December 2021
quotequote all
SWoll said:
Department of Transport said:
High speeds increase energy consumption in EVs
more than they increase fuel consumption in
conventional vehicles. .
That's a fairly poor choice of words. In actual fact, the consumption (note not efficiency, two very different things!) of an EV increases LESS as it's speed rises because it has none of the sliding mechanical friction and parastic losses of an ICE, and because it does not need to use extra energy to manage it's exhaust emissions (NoX mitigation and exhaust line component protection)

What they meant to say was:

"An ICE is least consumptive at medium speeds, where below and above that speed its consumption increases, whereas for an EV consumption is broadly proportional to its speed at all speeds"

Unfortunately the truth is too complex for the average person, so it gets simplified and then mis-understood and mis-quoted........





InitialDave

11,971 posts

120 months

Wednesday 1st December 2021
quotequote all
kambites said:
But then to make that a fair comparison, you can't only look at the tailpipe emissions of the ICE you're comparing to
Even if you did, and even if they were very similar, the thing that always stands out for me is the location of the emissions.

Most people drive where they live and where they work. The emissions from internal combustion are wherever the car is, so you have the emissions around those same places, right where the people are.

However you generate the power for an EV, you can choose where the power plant, and so its emissions, are located.

Hopefully nuclear can become more accepted as the necessary solution to meet out power needs, though.

politeperson

Original Poster:

544 posts

182 months

Wednesday 1st December 2021
quotequote all
Well I knew there would be some geniuses on the forum and I wasn't disappointed.

Thankyou very much for some well researched input.

It is certainly quite a complicated picture.

rscott

14,789 posts

192 months

Wednesday 1st December 2021
quotequote all
politeperson said:
Well I knew there would be some geniuses on the forum and I wasn't disappointed.

Thankyou very much for some well researched input.

It is certainly quite a complicated picture.
Polestar published a life cycle assessment for the Polestar 2 against the very similar Volvo XC40 ICE.

https://www.polestar.com/uk/news/polestar-2-lca-re...

They determined the mileage at which the total CO2 emissions of the ICE vehicle production and usage surpasses that of the EV.
If fuelled solely by wind power, the EV becomes less polluting at 31,000 miles. With the EU energy mix (which has a higher co2 level than the UK), it's 48,000 miles.

I don't believe it includes the emissions from petrol production and transport though, so the breakeven point would actually be far lower.



Muddle238

3,912 posts

114 months

Wednesday 1st December 2021
quotequote all
Max_Torque said:
SWoll said:
Department of Transport said:
High speeds increase energy consumption in EVs
more than they increase fuel consumption in
conventional vehicles. .
That's a fairly poor choice of words. In actual fact, the consumption (note not efficiency, two very different things!) of an EV increases LESS as it's speed rises because it has none of the sliding mechanical friction and parastic losses of an ICE, and because it does not need to use extra energy to manage it's exhaust emissions (NoX mitigation and exhaust line component protection)

What they meant to say was:

"An ICE is least consumptive at medium speeds, where below and above that speed its consumption increases, whereas for an EV consumption is broadly proportional to its speed at all speeds"

Unfortunately the truth is too complex for the average person, so it gets simplified and then mis-understood and mis-quoted........
Seems a bit odd to me. Are you saying that the energy required to propel an EV is broadly proportional to its speed at any speed?

kambites

67,634 posts

222 months

Wednesday 1st December 2021
quotequote all
Muddle238 said:
Seems a bit odd to me. Are you saying that the energy required to propel an EV is broadly proportional to its speed at any speed?
To the square of its speed, surely? Plus a small linear chunk for mechanical drag if you want to be picky.

Muddle238

3,912 posts

114 months

Wednesday 1st December 2021
quotequote all
kambites said:
Muddle238 said:
Seems a bit odd to me. Are you saying that the energy required to propel an EV is broadly proportional to its speed at any speed?
To the square of its speed, surely? Plus a small linear chunk for mechanical drag if you want to be picky.
That's where I was going with it.

Drag increases as a square of the velocity, so naturally higher speeds = much higher drag = much more energy required to maintain those higher speeds, regardless of whether that energy comes from fossil fuels or electricity.

I wasn't quite sure what he meant by energy required was proportional to its speed at all speeds, when drag increases as a square.

JonnyVTEC

3,008 posts

176 months

Wednesday 1st December 2021
quotequote all
Don't forget when you square the power in terms of roadload you can't do the same for the consumption as the car is covering more distance in the same time period.