Battery Electric Vehicle News / Enjoying the Transportation Revolution

Martyn1981

JKenH wrote: »

I made no ‘arguments’ against against BEVs. I actually love them.

Don't worry, I was talking about GA. I think this is just another of the many, many occasions that you've gotten the accounts confused.

Regarding the mix of green leccy to the grid, as discussed recently, the FF capacity has been falling, the RE capacity has been growing, and general/traditional demand has been falling, so we could, if we wanted, argue that the 'new' demand from BEV's (which is of course still tiny) is completely covered by the new RE generation, with the remaining (bulk) of new clean generation going towards old demand.

In truth, it's all pointless, we are going greener, BEV's are greener, and we clearly agree that they are GGGGGGrrreat.

JKenH

JKenH wrote: »

I made no ‘arguments’ against against BEVs. I actually love them.

The argument was whether BEVs use marginal generation or core generation. Either way, with the current make up our grid some of the electricity used to power them comes from FF sources. The exception would be if you added stand alone solar panels to your house solely to charge the car and they alone were used to charge it. If you have existing panels and then later add a BEV, the charging of the BEV will increase the amount of electricity the grid must produce.

It is like my ASHPs. They can run a lot of the time on solar I have generated and I might perceive this to be cost free and CO2 free electricity. The reality is the solar pv used to run them would be powering something else and relieving the grid if I switch them off. So if I run my ASHPs the grid has to generate more to make up for the lost solar. While running the ASHPs is cost tree to me when there is plenty of solar PV spare just like charging my car from solar, neither is CO2 free because the grid has to generate more at its marginal CO2 rate to compensate for what I am not sending to it.

I agree on the whole BEVs should use less CO2 than ICEs although the saving will vary depending on the CO2 of the grid when used to charge them. I had perceived our 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.

I attach a link below and hope I have understood the figures correctly.

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

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.

EVandPV

JKenH wrote: »

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.

Finally, some realistic figures ! :T
The vast majority of ev drivers will of course be on an ev tariff like Octopus Go.

EricMears

JKenH wrote: »

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.

Why does charging at a different time of day alter the gms of CO2 per mile ? Agree that if most (or all) of the charging was using your own solar power, CO2 gms/mile would drop considerably (or even vanish) but if it's all imported power, the CO2 gms/kWh should be the same - unless of course you have access to the % renewables at different times of day.

JKenH

Martyn1981 wrote: »

Don't worry, I was talking about GA. I think this is just another of the many, many occasions that you've gotten the accounts confused.

Regarding the mix of green leccy to the grid, as discussed recently, the FF capacity has been falling, the RE capacity has been growing, and general/traditional demand has been falling, so we could, if we wanted, argue that the 'new' demand from BEV's (which is of course still tiny) is completely covered by the new RE generation, with the remaining (bulk) of new clean generation going towards old demand.

In truth, it's all pointless, we are going greener, BEV's are greener, and we clearly agree that they are GGGGGGrrreat.

From the same website.

Average emissions from generation in
2010 were 467g/kWh
2011 452g/kWh
2012 507g/kWh
2013 474g/kWh
2014 415g/kWh
2015 352g/kWh
2016 269g/kWh
2017 235g/kWh
2018 216g/kWh
2019 190g/kWh

JKenH

EricMears wrote: »

Why does charging at a different time of day alter the gms of CO2 per mile ? Agree that if most (or all) of the charging was using your own solar power, CO2 gms/mile would drop considerably (or even vanish) but if it's all imported power, the CO2 gms/kWh should be the same - unless of course you have access to the % renewables at different times of day.

I have. Just select the day and click on any point on the graph and the emissions at that moment in time are shown. The time appears at the bottom. The % contribution from various sources is also shown.

https://electricinsights.co.uk/#/dashboard?start=2019-01-01&category=renewable&&_k=10czng

GreatApe

JKenH wrote: »

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.

This is incorrect

What you and everyone is missing and don't understand is that things plugged into the grid change the grid itself. People assume that the grid is huge and whatever they plug in is small so this can be discounted but it's not the case

Let's for a moment pretend I have a brand new special secret Tesla which charges up in 10 seconds and has a 1000KWh battery. It does this with a 360MW charger. It's the same as a model 3 the same efficiency it just has a bigger battery pack that can charge really fast

Okay so I plug in a 360MW load onto the grid during the day when demand is 36,000MW
To simplify let's say 1 unit and 100 units as 36,000 is 100x 360

So this charger takes the grid demand from 100 units to 101 units
Let's say at the beginning it is 50 units supplied by wind 50 units supplied by gas
Well we can't just throw more wind on the grid but we can throw more gas in a turbine.
The supply is now 50 units wind 51 units gas

My argument is plugging in one unit of demand just resulted in one unit more gas so this whole unit should own this additional demand

The 'lets use averages' group think no.
The grid is 50 units wind 51 units gas so my BEV emmissions are 49.5% wind 50.5% gas but they ignore the fact that the grid was just changed so if they want to use averages the externalities of their BEV being plugged in has resulted in a dirtier grid for everyone

You don't need no special Tesla for this to be true I just used that example so the numbers are raised. It's the same argument if you plug in any BEV into any 7KW charger.nits even true for your 1 watt battery toothbrush so the size of the demand doesn't matter only it's hard to see with smaller numbers as you have to do the math to more and more decemal places to see it as

GreatApe

JKenH wrote: »

I have. Just select the day and click on any point on the graph and the emissions at that moment in time are shown. The time appears at the bottom. The % contribution from various sources is also shown.

https://electricinsights.co.uk/#/dashboard?start=2019-01-01&category=renewable&&_k=10czng

Let's say you have a lightbulb

Pretend the light bulb is 100MW rather than 100W it might help you overcome the small load Vs the big grid bias/confusion

If you turn off this load the grid can fire down 100MW of CCGT generation
Turning off the light bulb just allowed 100MW CCGT capacity to be removed from the grid so why is allocating this marginal demand to marginal supply not the right thing to do?

If an hour later you turn the light bulb back on again the grid will fire up 100MW of CCGT to power this load.

Your light bulb switch in this example is more or less a switch to fire up/down a 100MW CCGT

The rest of the grid doesn't matter
How much is nuclear or wind is irrelevant
Your light bulb switch is directly working a CCGT

Now let's say instead you move to France with your light bulb
Now the light bulb is effectively turning on/off 100MW of nuclear capacity so for all intents your switch is directly working a nuke. At least for 9 months of the year when they are marginal nuclear

Let's say you tire of France and move to Norway with your light bulb
Well now it's working hydro. Turn your bulb on and 100MW more water runs down a dam. Turn it off and 100MW less water runs down a dam



Now you come back to the UK
Your switch is still a direct switch to a CCGT
No matter if at 3pm the grid is X CO2 and at 7pm it's Y CO2
Your light bulb controls a CCGT it's the same emmissions irrespective of when you turn it on

The only acception is the 2% or so hours in the UK when we are marginal wind
During those times your light bulb turns on/off 100MW of wind turbines



Now you don't have a 100MW light bulb but the same is true for a 100 watt bulb only the scale is different. The same is true for your BEV. Switching the charger on or off turns a gas fired plant on or off.

GreatApe

JKenH wrote: »

From the same website.

Average emissions from generation in
2010 were 467g/kWh
2011 452g/kWh
2012 507g/kWh
2013 474g/kWh
2014 415g/kWh
2015 352g/kWh
2016 269g/kWh
2017 235g/kWh
2018 216g/kWh
2019 190g/kWh

Marginal supply is 380g/KWh

Ask yourself this

If we close a 1,000,000KW (1GW) nuke today are the additional emmissions 1,000,000 X 190grams of the 2019 figure or 1,000,000 X 380g? Per hour

It is clearly x 380grams as 380grams is what the replacement CCGT will emmit

If a loss in supply is resulting in marginal (380grms) emmissions
Then why isn't an additional load resulting in marginal emmissions?

JKenH

GreatApe wrote: »

This is incorrect

No, the figures as a comparison of charging at different times of day are correct based on the wide held assumption that BEVs are charged from core generation. You don’t agree with that and neither do I but, in so far as they go and what they demonstrate, they are correct.

GreatApe wrote: »

What you and everyone is missing and don't understand is that things plugged into the grid change the grid itself. People assume that the grid is huge and whatever they plug in is small so this can be discounted but it's not the case.

You should read my posts more carefully. I have been arguing that the appropriate basis for the calculation should be marginal generation emissions not average but I don’t have the figures for marginal only average. You could, though, if you wanted to spend the time, make a reasonable estimate from the data in the link I provided as the split between the various generation sources is given.