EV Discussion thread

silverwhistle

subjecttocontract said:

I just don't think the country is ready for BEV's for everyone. Whilst they might suit my wife who never travels more than 30 miles from home, they don't suit me. I just made a 250 mile journey to Yorkshire then onto the Lake district & 300 miles home. It would have been a nightmare making sure I had enough charge or could find a charger. I pulled into a couple of service areas and both times there were people waiting for chargers. Any long journey requires planning but no guarantee a charger is working or available. definitely not for me.

Funnily enough I did a very similar trip two weeks ago. Hampshire, Sheffield, Dales then back to Hampshire in one hit. Same distances and no charging problems, although I did take a couple of wrong turnings and roads were busy or blocked and as a result I changed my charging plans on the fly.  Car was an MG4 SE, the lowest range model, the bladder was a much older model and nowhere near the same range!

michaels

I think people are overcomplicating this.  If there is no RE curtailment and any demand adjustment just means ramping up or down equally efficient gas generation then it makes no odds when you charge your EV (or use any other power) and the co2 should be considered to be the average grid CO2 over the 24 hour period.

Where there is curtailment or additonal generation is from dirtier sources then shifting consumption (like for example EV charging) into periods that minimise the this will obviously reduce average grid CO2.  Where this happens it may make sense to attribute the CO2 saving to the shifted load but exactly how much CO2 should then be attributed to the electricity used for the time-shifted activity is unclear.

EG If I charge at night rather than in the day but there is no curtailment/dirty mix at any time then it makes no odds and the CO2 should be taken as the average CO2 over the day.  If there is going to be curtailment and I charge at that time that means I use RE that would otherwise be curtailed then I would say the CO2 of the charge power could be considered to be zero.

silvercar

subjecttocontract said:

I just don't think the country is ready for BEV's for everyone. Whilst they might suit my wife who never travels more than 30 miles from home, they don't suit me. I just made a 250 mile journey to Yorkshire then onto the Lake district & 300 miles home. It would have been a nightmare making sure I had enough charge or could find a charger. I pulled into a couple of service areas and both times there were people waiting for chargers. Any long journey requires planning but no guarantee a charger is working or available. definitely not for me.

For this reason we made sure that one of our cars (the TM3 LR) was (a) long range and (b) had access to a good charging network. 

JKenH

michaels said:

I think people are overcomplicating this.  If there is no RE curtailment and any demand adjustment just means ramping up or down equally efficient gas generation then it makes no odds when you charge your EV (or use any other power) and the co2 should be considered to be the average grid CO2 over the 24 hour period.

Where there is curtailment or additonal generation is from dirtier sources then shifting consumption (like for example EV charging) into periods that minimise the this will obviously reduce average grid CO2.  Where this happens it may make sense to attribute the CO2 saving to the shifted load but exactly how much CO2 should then be attributed to the electricity used for the time-shifted activity is unclear.

EG If I charge at night rather than in the day but there is no curtailment/dirty mix at any time then it makes no odds and the CO2 should be taken as the average CO2 over the day.  If there is going to be curtailment and I charge at that time that means I use RE that would otherwise be curtailed then I would say the CO2 of the charge power could be considered to be zero.

You make some interesting points there. On an individual basis it makes no difference when we charge our EVs. No one will be throwing an extra shovel full of coal into the furnace at Radcliffe on Soar power station or opening a gas tap just because our individual EV goes on charge, but our collective behaviour does make a difference and EV tariffs aggravate this. If 100,000 EVs start charging at 1am to take advantage of cheap overnight rates then there has to be some form of response from the grid to meet that 0.7GW increase in demand. In winter during curtailment more wind can easily be brought on line and that will not affect CO2 emissions so you have a valid point that charging during curtailment is zero carbon. (We do though also see negative Agile prices during the day associated with curtailment so it is not a uniquely overnight phenomenon). 

However, for most of the year the additional generation will come from gas (or imports) although there may be a short term frequency response from batteries or pumped hydro. That however will only be giving the gas generators time to get up to speed and after a few minutes (or however long it takes) all that extra 0.7GW will be provided by gas (I am ignoring biomass  and coal for simplicity and to avoid argument). Smart charging like Intelligent Octopus might dampen down the sudden load by spreading the start of charging over 10 minutes but there are still those 100,000 EVs that need charging in the TOU window. The situation is compounded by EV owners taking advantage of special electricity TOU tariffs to also charge their domestic batteries, switch on immersion heaters, do the washing etc.  

I believe it is perfectly reasonable, therefore, to attribute a CO2 cost based on gas generation to that sudden surge of charging and associated activity that occurs every night. 

I think that on the whole EV owners with the best of intentions assume charging overnight on a cheap TOU tariff automatically makes their EV cleaner than charging at other times of day (just as many believe charging their car using grid tied solar has no CO2 cost). I just wanted to challenge that assumption. I am happy to acknowledge that much of the time, particularly in winter it might be the case that overnight charging might be the cleanest but hopefully by having the debate people will at least have thought about it.

As I repeatedly have to say, this is not an ICE vs EV argument. It is not about whether EVs emit more or less CO2 than ICEVs, although I see one post has been made comparing the two. It is, like the big battery post I made, simply about looking realistically at EV emissions and how we minimise them. 

thevilla

Why single out EVs? ( ok it's an EV thread) When should we turn on the oven, put the lights on etc.  There's a general rule of thumb low demand mostly equates to low emission.  Agreed not always but EVs have to charge, meals have to be cooked etc.

Dismissing ICE from the argument is a false narrative leading us all marching to the top of the hill and down again.  I could charge my EV deliberately at tea time and it would still be 'greener'.

JKenH

thevilla said:

Why single out EVs? ( ok it's an EV thread) When should we turn on the oven, put the lights on etc.  There's a general rule of thumb low demand mostly equates to low emission.  Agreed not always but EVs have to charge, meals have to be cooked etc.

Dismissing ICE from the argument is a false narrative leading us all marching to the top of the hill and down again.  I could charge my EV deliberately at tea time and it would still be 'greener'.

That should have been apparent from my last post.

“On an individual basis it makes no difference when we charge our EVs. No one will be throwing an extra shovel full of coal into the furnace at Radcliffe on Soar power station or opening a gas tap just because our individual EV goes on charge, but our collective behaviour does make a difference and EV tariffs aggravate this. If 100,000 EVs start charging at 1am to take advantage of cheap overnight rates then there has to be some form of response from the grid to meet that 0.7GW increase in demand.”

The grid is ticking over during the night at about 20GW, using what renewables are available and the rest by and large from gas. Then boom, we all plug in our EVs and all that generation comes from gas. If we all have a night off charging then the gas doesn’t get used. 

You pointed out, yourself that if instead we all started charging at 15.30 the emissions would shoot up. The reality is that the amount of additional gas generation required for our current population of EVs doesn’t make a big difference to the average emissions compared to the tea time surge in demand. Turning on the oven, putting your lights on also triggers a response in terms of gas generation. That’s why we pay more between 4pm and 7pm.

JKenH

thevilla said:

Dismissing ICE from the argument is a false narrative leading us all marching to the top of the hill and down again.  I could charge my EV deliberately at tea time and it would still be 'greener'.

I’m not comparing EVs with ICEs. You can if you want to but we’ve done that one to death. EV emissions in use are far superior to ICE on a like for like car basis so I really don’t see the point of resurrecting that argument unless someone thinks differently. 

This is an EV discussion thread. Would you join an ICE thread on fuel economy and then start talking about EVs? 

ABrass

In reality the nighttime cheap rates are cheap because we have too much nuclear and renewable power overnight most of the time so if we don't boost use then power gets wasted.

JKenH

ABrass said:

In reality the nighttime cheap rates are cheap because we have too much nuclear and renewable power overnight most of the time so if we don't boost use then power gets wasted.

That may be true some days but in the early hours of this morning we had 10 GW of wind, 4.3GW of nuclear,7.5GW gas and 0.5GW coal.

Edit: I was interested to know how frequently we were wasting power and the only way I could think of accessing this information easily was to use negative Agile prices as a proxy. 

I looked at this year to date and chose the London region, simply because I presumed this to be the most populous. My source was agileprices.co.uk.

Each day is divided into 48 half hour blocks.

The results are as follows (number of half hour blocks and % of time.
January 24 and 0%
Feb 0 and 0% 
March 1 and 0% (at 0500)
April 6 and 0% (5 between 0000 and 0330 on one day and 1 at 2330
May 0 and 0%
June 0 and 0%
July 59 and 4% (of which 9 blocks were between 0000 and 0700 over 2 days and 50 outside these hours)
August 0 and 0%

From this it appears that only on 4 days this year have Agile prices been negative at any time between 0000 and 0700 and for a total of 7.5 hours or approximately one hour each month on average.

https://agileprices.co.uk/?region=C&fromdate=20230731

michaels

JKenH said:

ABrass said:

In reality the nighttime cheap rates are cheap because we have too much nuclear and renewable power overnight most of the time so if we don't boost use then power gets wasted.

That may be true some days but in the early hours of this morning we had 10 GW of wind, 4.3GW of nuclear,7.5GW gas and 0.5GW coal.

Which probably still gives a cheaper average unit cost of generation than in the daytime when we might have same wind, nuclear etc but 17.5 of gas, hence lower prices in the market in the night period that are passed on to the consumer to some extent via the TOU tariffs.