BEV emmissions

GreatApe

EricMears wrote: »

Not sure of the full context of the quoted question, but I can supply some possibly helpful figures:-

In the 20 months I've had my Nissan Leaf, whenever the battery has been charged to 100%, I've made a note of the reported 'energy efficiency' figures and the 'real' ones based on metered power (or an accurate guess when actual readings not available from unmetered free chargers) since previous 100% event. After each full charge, I've reset the car's figure.

The average of the car's individual figures has been 3.63 whereas averaging my 'real' ones has been 3.21. That would suggest the conversion efficiency of the charging system is around 87%.

HTH

3.21 miles per KWh all in = 79g /km in a gas heavy grid like the UK

Your twin in a coal heavy nation like Germany or China the emmissions would be about double so 158g/km

Vs about 106g/km for a efficient hybrids ICE

So in the UK a BEV is about 25% lower carbon emissions
(That's mostly because methane has less carbon than petrol not because BEVs are more efficient from chemical to kinetic)

And in Germany/China etc they are 50% worse in co2 emmissions

And more of the world is coal marginal grid rather than gas marginal grid so on most the world at.least for now (and probably for the next 10-20 years) BEVs are significantly more emmissions heavy than an efficient ICE

GreatApe

EVandPV wrote: »

Here's my figures with the Zoe, my daily commute involving about 10 miles urban and 15 miles motorway averaging 65-70mph on motorway.
In the summer, I was averaging 3.8m/kwh and currently 3.5m/kwh.
The lowest I've seen it during several days of -5°C was 3.3m/kwh so cold weather not having a huge effect.

If you take the mid point of you 3.8m/kwh and 3.5m/kWh and use the other posters 13% loss in charging and 407g/kWh from your home socket you get... 70g/km

If your car was in Germany or China it would be 140g/km
An efficient ICE is 106g/km for comparison

GreatApe

almillar wrote: »

I don't think I get much better on a motorway TBH. People don't live on motorways, and once again you're choosing the best of ICE (as good as 106g/km), versus the worst of EV (a supposedly inefficient one at motorway speed). Even the playing field!

I didn't use the best Vs the worse I stated both the Tesla and the e golf not just the e golf

Gobsmacking. That 75g figure came from YOU, with corrections from ME. I can stand over my figures much better than any you've provided.

So far assuming all the info on a biased form is absolutely correct we have

Yourself at 75g
EV&PV at 70g
Eric at at 79g

So sure I am willing to go with you 75g/km for BEVs although would be nice to have more points of data

Just for reference I estimated the e golf at 106g and the model 3 at 95g/km
We've yet to get anyone post their figures for those two models am willing to amend if anyone wants to pop up with true figures

I thought you were referring to the heating system in the car. But I already stated 50%, and you corrected it to 49% - it's an overall figure, so the entire conversion of gas - heat - kinetic has already taken place.

? I'm not sure what you are talking about here
If the aim is to convert chemical energy into kinetic energy a BEV is a little more efficient overall Vs an ICE if charged by CCGTs and a good deal less efficient if charged by Coal

Sure. It's there, but you are double counting. My car moves 3 miles, and uses 1kWh. That 2-5% loss is included in that figure! Double counting

That isn't a measure of efficiency because where did you get that 1KWh from and how did you get it?

Just for reference an ICE goes 1.4 miles per KWh if petrol

Ridiculous! You've already said yourself that hybrids are up to 40% efficient. The rest is heat and noise and friction, from all the bits banging off each other. An electric motor is far, far more efficient in this regard. Again, from your own figures, it's 95-98% vs up to 40%.

Sure but why would this be worthwhile considering?
You don't have a magic fairy that gives you magic 100% efficient derived electricity into your batteries

The chemicals to kinetic energy steps is what matters
For an ICE it's pretty easy it's how efficient the ICE is minus a tiny bit lot to mechanical forces
For BEV first it's the CCGT or Coal then all the grid losses then the charger losses then the dance from DC back to AC then the electric motor then also the mechanical forces.

Such that when you compare one to the other the whole chain of losses the BEav is less efficient if driven on coal and only a little more on gas

You're the one making the controversial claims. I am ONE real world user. Actually 2, if you count 2 years, 15,000 miles in the Zoe, at 3.7 overall average. You do some research. I'm trying to help with some real world numbers, and you're telling me to go get more. No. Just beleive me

I do believe you but one data point is just one data point. We now have 3 data points and your 75g stands still it's only 3 data points but I accept it as valid for this discussion

.

Bottom line? That 75 is the best you've got until you improve it. I've taken so, so many of your figures as read, do me the same courtesy for ones I've actually experienced.

Fair and agree I'll use 75g although it would be nice to have a few more points of data

You're only comparing against the most efficient ICE.

Any hybrid and many diesel get this 106g figure
All you need to hit that is a real world 62mpg
I even used to have an old diesel that was nearly 20 years old which used to return a true 60-65mpg

Negligable transmission in your world is 60%+ of the energy, that is waste heat and noise and friction. I know you think that the 2-5% loss in an EV is significant, so why are you ignoring the 60% in the most efficient ICEs?

You and are are talking about different things
I was talking about the losses post the piston
The losses in the transmission things like the differential the conversion from taking the power from a. Front engine to rest wheels etc. The steel on steel transfer of power if you like. That's negligible and also exists in BEVs







Anyway what are you arguing about?

This is how you calculate it if you are so inclined
Let's say you start with 1 litres of petrol
You can put that into a corrolla hybrid and it will get you 21.8km

How much would the very same 1 litre of petrol get you in a BEV?

Well you feed that 1 litre of petrol (9.7KWh) into a CCGT (yes they can use petrol)
Which gives you 48.9% back as electricity
You put that through the grid which gives you 93% back in your home socket
You out that through your charger which gives you 85% in your battery

So you have 3.75 KWh in your battery
You say you get 3.7 miles per KWh = 22.2km

So there you go an apples to apples comparison
You start with 1 litre of petrol in both cases
The hybrid corrolla gets 21.8km out of it and your smaller Zoe gets 22.2km

So whatever you think the efficiency of your Zoe is, the hybrid ICE is 98.2% of that figure

GreatApe

Efficiency of ICE Vs BEV

1 litre of petrol in a hybrid = 21.8km
1 litre petrol into a CCGT power station into a Zoe @ 3.7m/kWh = 22.2km
1 litre of petrol into a coal station into a Zoe @ 3.7m/kWh = 17.3km

Yes you can put petrol into a CCGT or a coal plant we don't because it's more expensive than coal or gas.

An apples to apples comparison

As I said before the BEV is only marginally more energy efficient than an efficient ICE by about 2% if powered via a CCGT. If powered by coal technology it's 20% less efficient than an efficient ICE

michaels

Another data point.

Electric car 3.7 miles per kwh
Prior 1.9 tdiesel 7.5 miles per litre
Prior 1.6 petrol 5 miles per litre.

Our usage case is extreme, large numbers of short journeys from cold but not that atypical for a second car used for parent taxi duty.

We also avoid squirting out particulates and brake dust on local streets.

EVandPV

ABrass wrote: »

even on ignore I still get his FUD leaking through.

That has another meaning here, but I feel it's still appropriate. :whistle:

Martyn1981

EVandPV wrote: »

That has another meaning here, but I feel it's still appropriate. :whistle:

Shall I criticise GA's 'purpose' just to see how many of the diet-deniers jump on me again ....... no .... sure ..... OK then.

[Sorry, couldn't resist a quick joke.]

JKenH

Apologies first. This is in essence similar of to a post I submitted on the Electric vehicle news thread. To avoid taking that thread further off topic I am also posting the content here as well.

had perceived our electricity grid mix would be quite clean so I was somewhat surprised to see as I write this that the CO2 emitted is currently 250g/kWh and the average CO2 for yesterday was 158g/kWh.

So if I plug my car into the grid now am I using 240g/kWh CO2electrity. For those charging their cars overnight on Octopus Go 5p tariff grid CO2 emissions were 89g/kWh at 00.30 and between 0100 and 0230 stayed around 100g/kWh falling to 86g/kWh by 4am.

Average grid emissions in November were 215g/kWh.

Surprisingly in May they were 190g/kWh which is identical to the average for last 12 months.

I attach a link below and hope I have understood the figures correctly. These figures seem really high so I am off to look for another source.

Please don’t shoot the messenger. This is not having a downer on BEVs, it is just telling it as it is.

https://electricinsights.co.uk/#/dashboard?start=2019-12-19&&_k=97fhr7

Edit: Sorry folks. Having one of those days. Finally realised I need to divide the CO2 by by the miles/kWh performance of the car which is I probably about 3.6 this time of year and 4.2 or so in summer. Doh!

So charging my car now at 250g/kWh translates to around 69g/ mile before conversion losses but if I had charged it overnight on Octopus Go it would have been around 28g/kWh. If I had charged on Go on 24May this year (just chosen as I remember it as my best solar day of the year it would also have been around 28g/mile (117g/4.2). Charging it at 1pm on 24 May would have produced a figure of 38g/mile.

GreatApe

JKenH wrote: »

Apologies first. This is in essence similar of to a post I submitted on the Electric vehicle news thread. To avoid taking that thread further off topic I am also posting the content here as well.

had perceived our electricity grid mix would be quite clean so I was somewhat surprised to see as I write this that the CO2 emitted is currently 250g/kWh and the average CO2 for yesterday was 158g/kWh.

So if I plug my car into the grid now am I using 240g/kWh CO2electrity. For those charging their cars overnight on Octopus Go 5p tariff grid CO2 emissions were 89g/kWh at 00.30 and between 0100 and 0230 stayed around 100g/kWh falling to 86g/kWh by 4am.

Average grid emissions in November were 215g/kWh.

Surprisingly in May they were 190g/kWh which is identical to the average for last 12 months.

I attach a link below and hope I have understood the figures correctly. These figures seem really high so I am off to look for another source.

Please don’t shoot the messenger. This is not having a downer on BEVs, it is just telling it as it is.

https://electricinsights.co.uk/#/dashboard?start=2019-12-19&&_k=97fhr7

Edit: Sorry folks. Having one of those days. Finally realised I need to divide the CO2 by by the miles/kWh performance of the car which is I probably about 3.6 this time of year and 4.2 or so in summer. Doh!

So charging my car now at 250g/kWh translates to around 69g/ mile before conversion losses but if I had charged it overnight on Octopus Go it would have been around 28g/kWh. If I had charged on Go on 24May this year (just chosen as I remember it as my best solar day of the year it would also have been around 28g/mile (117g/4.2). Charging it at 1pm on 24 May would have produced a figure of 38g/mile.

The act of charging your car changes the grid co2
The grid is big and your car is small so it's not a huge amount
However this tiny amount a fraction of a fraction of a gram them impacts literally a billion electrical devises on the grid

This is hard for people to imagine so just look at the grid between 4pm to 6pm as people get home and start plugging in. What happens to co2 of the grid during that time? It goes up.

So plugging in doesn't just use whatever the grid emmissions are at that point
It also pushes the grid to be higher emmissions

What this all means is, that your BEVs emmissions are the same irrespective of when you plug in. The only exception is the 2% or so of hours we curtail wind if you plug in then your emmissions are zero

almillar

So far assuming all the info on a biased form is absolutely correct we have

Yourself at 75g
EV&PV at 70g
Eric at at 79g

So sure I am willing to go with you 75g/km for BEVs although would be nice to have more points of data

Excellent.

That isn't a measure of efficiency because where did you get that 1KWh from and how did you get it?

It IS a measure of efficiency. We're talking about a lot of things over a couple of threads, but in this context, we're talking about you claiming 2-5% of losses in the electric motor. I don't allow that, because you're trying to take it off the m/kWh figures quoted. They're already inlcuded in that.

Sure but why would this be worthwhile considering?

You're trying your very best to make BEVs seem less efficient. You've done your thing on the grid side, and now you've moved inside the car. But once you're inside the car, the losses are already accounted for within the real m/kWh figures that are being quoted.

then also the mechanical forces.

These only apply to EVs?!!

I do believe you but one data point is just one data point. We now have 3 data points and your 75g stands still it's only 3 data points but I accept it as valid for this discussion

Good. And while we're counting, you've provided Zero.

Any hybrid and many diesel get this 106g figure

Like I said, the most efficient ICE. Not representative of the broad spectrum of cars on the UK's, or the world's roads. Whilst you're running the planet's EVs on coal, you must realise the planet isn't also driving round in efficient ICE.

I was talking about the losses post the piston
The losses in the transmission things like the differential the conversion from taking the power from a. Front engine to rest wheels etc. The steel on steel transfer of power if you like. That's negligible and also exists in BEVs

Of course you are, because you want to ignore the inefficient bit in the ICE. Well since virtually all (?) ICE have gearboxes, as in gears, there are bigger losses between 'motor' and wheels than in a BEV, with no 'gears'. 'Gears' being R, N, 1, 2, 3, 4, 5 - automatic or manual.

So whatever you think the efficiency of your Zoe is, the hybrid ICE is 98.2% of that figure

And improving all the time...

Just read we ran without coal for 2 weeks this year. What will it be next year?