Battery Electric Vehicle News / Enjoying the Transportation Revolution

michaels

JKenH said:

Nothing to worry about then. All EV use is spread out evenly over the week and no one wants to charge their car between 4 and 7pm. Except me of course. I use my Octopus Go Faster tariff to fill up my car before a long run but the last two long runs necessitated rapid (actually not all that rapid in a Leaf) charges in the late afternoon because I wanted to get home. I’m not aware of time of use charging on rapids but perhaps it will come - not sure I will want to hang around after a long day though for a cheap rate to get me home.

Once we have full penetration of EVs then the 30% of users without off street parking will be using public chargers and when better to plug in than on the way home from work, maybe if you’re lucky at a free charger at the supermarket or at a rapid if you can’t be bothered to wait. Maybe that will only be a full charge once a week for most people but they will have to charge sometime and between 8pm and 8am might not be the most convenient time. 

“As for price rises, that seems highly unlikely given the rapidly falling costs of renewable energy, ” - well that’s not quite working out as planned. 

My leaf is already supporting the grid between 4-8pm helping all those without off street parking get a charge on their way home from work.

I was one of the later joiners to the earlier ovo v2g trial when they had already sorted out most of the issues and mine has worked fine for the 12 months I have had it.

Main problem seems to me to be the economics and the fact that there is such a huge gap between the retail price per unit and the wholesale price.  So if on a time of use tariff I import when prices are lower at 12p unit and try and sell back when they are at 22p per unit it turns out that although the price to me is 12p/22p the wholesale value of my export is only 2p/12p as 10p of the retail cost is not the electricity at all but 'add ons' so there is no profit to me for using the car battery to balance demand and supply.

JKenH

Something to bear in mind when calculating the demand on the grid is that electric cars typically have a charging efficiency of 80-90%
https://www.autoevolution.com/news/evs-dont-rely-solely-on-their-own-efficiency-onboard-chargers-also-count-167661.html

Secondly you need to start with the right figures in terms of energy consumption.

https://ev-database.uk/cheatsheet/energy-consumption-electric-car


EV Database shows an average consumption of 307wh/mile which is 3.26 miles/kWh consumed from the battery. After consideration of charging losses a realistic average is 2.77miles/kWh drawn from the plug. 

These figures do not take into account drain from the battery when the car is parked (vampire drain). On some cars it is significant and on others less so. Tesla’s are particularly prone to this when left with Sentry mode turned on.

It is hard to put an average figure on this as a car that spends a lot of its time standing idle is likely to suffer a greater % loss than one being used regularly. If the average car lost 1kwh per day while standing that would add in the region of 14% to the annual consumption of a 8000 mile a year car. 

It is not inconceivable therefore that for every mile driven the grid will need to supply around 400 watts. Now If when we all have EVs there are say 30m on the road averaging 8000 miles per annum the total demand would be 96TWh (current demand over the last 12 months was 275TWh so around 35% increase assuming the EV fleet imposes negligible demand at the moment). If car usage was spread out evenly each day of the year that would be 263GWh/day and if charging were uniformly spread over the day that would add 11 GW to demand. Of course usage is not spread out evenly everyday of the year and we don’t all ask who else is charging before we plug our cars in. 

But if half of us were being good bunnies and charging overnight on a cheap tariff, say Octopus Go then that demand would be 131.5 GWH/4 hours or 33GW on top of normal baseload demand  (around 20GW in summer and 30GW in winter) so we would be looking for 53 to 63 GW of reliable generation overnight. If that cheap charging periodwere extended to 12 hours and two thirds of us charged in that period then additional demand would be around 15GW over that period. Remember this is the best case scenario where we all put just enough in our cars to cover average daily usage.

Now there might be some days such as before we set off on our summer holidays when we might put considerably more than 8.76 kWh of charge into our cars. We might fill up on Sunday nights ready for the working week. We don’t know enough about charging patterns to speculate, hence I have adopted the best case scenario of even usage and charging. 

Peaks can happen as Tesla owners will recall when queuing to fill up one Christmas or as Bjorn Nyland recently reported at the end of the Norwegian holidays. How much more this would add I don’t know but I don’t think it is beyond the realms of possibility that on a bad day in winter demand for EV charging could be 25% higher.

Will we have a grid that will be able to respond to this?

(This is purely the overnight charging situation and daytime charging peaks might be higher or lower.)

Edit: there is an error in there which I will be correcting. Sorry

Edit 2: corrected with new figures.

Edit 3: second overnight charging scenario added. 

JKenH

michaels said:

JKenH said:

Nothing to worry about then. All EV use is spread out evenly over the week and no one wants to charge their car between 4 and 7pm. Except me of course. I use my Octopus Go Faster tariff to fill up my car before a long run but the last two long runs necessitated rapid (actually not all that rapid in a Leaf) charges in the late afternoon because I wanted to get home. I’m not aware of time of use charging on rapids but perhaps it will come - not sure I will want to hang around after a long day though for a cheap rate to get me home.

Once we have full penetration of EVs then the 30% of users without off street parking will be using public chargers and when better to plug in than on the way home from work, maybe if you’re lucky at a free charger at the supermarket or at a rapid if you can’t be bothered to wait. Maybe that will only be a full charge once a week for most people but they will have to charge sometime and between 8pm and 8am might not be the most convenient time. 

“As for price rises, that seems highly unlikely given the rapidly falling costs of renewable energy, ” - well that’s not quite working out as planned. 

My leaf is already supporting the grid between 4-8pm helping all those without off street parking get a charge on their way home from work.

I was one of the later joiners to the earlier ovo v2g trial when they had already sorted out most of the issues and mine has worked fine for the 12 months I have had it.

Main problem seems to me to be the economics and the fact that there is such a huge gap between the retail price per unit and the wholesale price.  So if on a time of use tariff I import when prices are lower at 12p unit and try and sell back when they are at 22p per unit it turns out that although the price to me is 12p/22p the wholesale value of my export is only 2p/12p as 10p of the retail cost is not the electricity at all but 'add ons' so there is no profit to me for using the car battery to balance demand and supply.

I was wondering if there are any “round trip“ losses or are these catered for in the billing?

Martyn1981

Martyn1981 said:

The fears and dodgy claims about the grid have been around since BEV's were touted as a serious option.

[Since writing this, I believe that the NG have also suggested a net increase of ~10% in leccy demand, if all UK cars became BEV's.]

Probably should have provided a link to that, but I was being lazy this morning:

6 myths about electric vehicles busted

1. Can the UK energy grid really cope with a huge increase in the number of electric vehicles being plugged in for charging?

There are two aspects to whether we have the capacity to manage lots of EVs being plugged in at once – whether we have enough energy and then whether we have sufficient capacity on the wires that carry that energy to where it’s needed.

Enough capacity exists   

With the first of these, the energy element, the most demand for electricity we’ve had in recent years in the UK was for 62GW in 2002. Since then, due to improved energy efficiency such as the installation of solar panels, the nation’s peak demand has fallen by roughly 16 per cent. Even if the impossible happened and we all switched to EVs overnight, we think demand would only increase by around 10 per cent. So we’d still be using less power as a nation than we did in 2002 and this is well within the range of manageable load fluctuation.

Overall the NG estimate that an additional 100TWh pa will be consumed when transportation is electrified. I did previously suggest a higher figure, based on 60TWh (gross) for cars, plus more for other vehicles, but now I've checked, cars consume far more fuel (energy) than commercial vehicles, about twice as much.

Can the grid cope with the extra demand from electric cars?

"There is definitely enough energy and the grid can cope easily,” he explains. “The growth in renewable energy means this is not static and smart metering will make this more efficient. For example, the growth in wind power from the extra offshore wind farms being developed will adequately meet the future demand for electrifying transport – an extra 100 terrawatt hours from our current 300 terrawatt hours consumed.

Heedtheadvice

@Martyn1981 to try and clarify for your question "Can I ask, in your example of those that don't have home facilities, so would most likely rely on street charging and shared communal chargers, why won't they use overnight charging? I'm not saying they all will charge overnight, and I suspect workplace charging, and street charging (near work) will take place during the day for many, I'm just not clear why they won't charge overnight."

Wel I do not have any hard facts and figures to support what I expect will be the situation. However I find it difficult to visualise there will not be a shortage of street charging (much less than one suitable charge connector per parked car) or shared communal chargers available when one needs to charge. Much of this I envisage will be typically in the more densely built up areas such as where I once lived in a city area. Finding a parking space was a robkem often let alone one that in the future might be at a charger. When we all drive BEV's I do not believe each space will have a charger, working, not damaged, not expensive etc.

Communal charging is fine providing one can wait to charge if they were all busy, but for many the prospect, if you cannot initially plug in when you arrive home in the evening, of having to go out at 3 in the morning in your pyjamas to find a free one is not a practical proposition.

So far from people not wanting to charge overnight it could be more one of availability when desired and of convenience. I do not think convenience (and independance, social status etc.) as a desire should be underestimated. If people did not rate it highly there would be fewer cars on the road and more using public transport.

Far from viewing those type of issues as negative they are potential problems that we need to recognise and thus have an opportunity to find a solution.

I have for a long time thought that a system of interchangeable batteries at say a "refilling station" that takes just a few minutes (were it technically possible) could be a solution but I doubt that will come!

Solarchaser

I'd suggest that instead of approaching the car in your jammies at 3am, you would just wait till later in the week to charge.

You see very very few EV's will need charged every day, even those of us using them for business don't charge every day, id suggest that's the stumbling block in thinking every charging space needs a charger, or that there would be a fight over them.

Much like a petrol of diesel car, if the pumps are busy you either go to another station or visit another day.

The only time you would que would be the same as for petrol or diesel, when you are so low you can't go anywhere else

Martyn1981

Heedtheadvice said:

@Martyn1981 to try and clarify for your question "Can I ask, in your example of those that don't have home facilities, so would most likely rely on street charging and shared communal chargers, why won't they use overnight charging? I'm not saying they all will charge overnight, and I suspect workplace charging, and street charging (near work) will take place during the day for many, I'm just not clear why they won't charge overnight."

Wel I do not have any hard facts and figures to support what I expect will be the situation. However I find it difficult to visualise there will not be a shortage of street charging (much less than one suitable charge connector per parked car) or shared communal chargers available when one needs to charge. Much of this I envisage will be typically in the more densely built up areas such as where I once lived in a city area. Finding a parking space was a robkem often let alone one that in the future might be at a charger. When we all drive BEV's I do not believe each space will have a charger, working, not damaged, not expensive etc.

Communal charging is fine providing one can wait to charge if they were all busy, but for many the prospect, if you cannot initially plug in when you arrive home in the evening, of having to go out at 3 in the morning in your pyjamas to find a free one is not a practical proposition.

So far from people not wanting to charge overnight it could be more one of availability when desired and of convenience. I do not think convenience (and independance, social status etc.) as a desire should be underestimated. If people did not rate it highly there would be fewer cars on the road and more using public transport.

Far from viewing those type of issues as negative they are potential problems that we need to recognise and thus have an opportunity to find a solution.

I have for a long time thought that a system of interchangeable batteries at say a "refilling station" that takes just a few minutes (were it technically possible) could be a solution but I doubt that will come!

Thanks, that makes sense, I just couldn't understand why they'd all charge during the day. Perhaps I confused the matter by seeming to suggest none would, but that was just to create a worst case situation for nighttime power demand.

Reading what you've now posted, seems to set out a future where a lot (perhaps most?) charging for those using street charging, will be done at night, but not all of it, as an available charger may not always be available. That seems fair. A point I tried to make earlier based on an average weeks driving, is that most BEV's now will have packs capable of managing that, so theoretically, and in an ideal world, chargers at ~1/7th of spaces would be enough. Now obviously that's not enough, but as @Solarchaser pointed out, you don't need to charge every day, so not every space will need to have a charger. Yet we could still see the majority of charging for those without a dedicated parking space, being done overnight.

The crucial issue here is power - energy isn't an issue, since the amount needed for BEV's isn't as much as it might at first appear, as confirmed by the NG, and of course, if demand rises, so will supply (these folk want to sell leccy) - the issue is power, but even then, the only real concern is avoiding the evening peak (5-7pm), and the wider higher demand period of ~4-8pm. So long as we don't place too much additional demand on that time period, then BEV's aren't a big concern. In fact, compared to a massive rollout of heat pumps, BEV's are almost a side issue.



Regarding swappable batts, that's what Nio does in China, and has done for several years. It seems to work well, and takes less than 5mins. This idea has a lot of merits, especially the ability to charge the batts slowly and if possible, when leccy is cheaper and lower carbon intensity.

However, there are a lot of negatives too, such as the need for additional (spare) batteries. Also a car company will need to settle on a standardized battery pack size, which doesn't sound difficult at first, until the issue is flipped, and you have to settle on a standardized 'hole' for your car models. The problem then becomes one of packs being too physically large for small cars, or too capacity small for large cars, or then having to have multiple size packs / spares at charging stations. Can companies today, settle on a pack type/size for future vehicles, when those, and their chassis, have not yet been designed.

Also I remember an engineer pointing out that electrical equipment is incredibly reliable because there are so few moving parts, but items that tend to fail are switches and connectors, so swapping a battery will necessitate many connections/disconnections. But, my simple brain, would assume that very meaty connections would be used to prevent this issue.

Also a need to consider the size of these stations, which would probably have the footprint of 2-4 'normal' spaces, and cost many, many times more. If a swap takes about 5mins, then how much could a BEV be charged in 20mins (4 BEV's @ 5mins each), in the case of a Tesla, that's probably about 2hrs worth of driving, which would take you to your next break, leg stretch, coffee and a pee.

So, lots of pluses and minuses, and it'll be interesting to see if swapping stations gain any ground outside of China.


Slight digression, but there is a tractor manufacturer producing BEV's, with swappable packs, which sounds like an excellent idea, since farms are great locations for PV, so a pack charging, whilst you work away.

Also, there's a company in Australia that wants to convert diesel long haul trucks to BEV's (when their major overhaul is needed, or engines fail). They plan to have swapping stations along the main highways at regular intervals, with a swap taking place whilst drivers take a break.

shinytop

Martyn1981 said:

Heedtheadvice said:

@Martyn1981 to try and clarify for your question "Can I ask, in your example of those that don't have home facilities, so would most likely rely on street charging and shared communal chargers, why won't they use overnight charging? I'm not saying they all will charge overnight, and I suspect workplace charging, and street charging (near work) will take place during the day for many, I'm just not clear why they won't charge overnight."

Wel I do not have any hard facts and figures to support what I expect will be the situation. However I find it difficult to visualise there will not be a shortage of street charging (much less than one suitable charge connector per parked car) or shared communal chargers available when one needs to charge. Much of this I envisage will be typically in the more densely built up areas such as where I once lived in a city area. Finding a parking space was a robkem often let alone one that in the future might be at a charger. When we all drive BEV's I do not believe each space will have a charger, working, not damaged, not expensive etc.

Communal charging is fine providing one can wait to charge if they were all busy, but for many the prospect, if you cannot initially plug in when you arrive home in the evening, of having to go out at 3 in the morning in your pyjamas to find a free one is not a practical proposition.

So far from people not wanting to charge overnight it could be more one of availability when desired and of convenience. I do not think convenience (and independance, social status etc.) as a desire should be underestimated. If people did not rate it highly there would be fewer cars on the road and more using public transport.

Far from viewing those type of issues as negative they are potential problems that we need to recognise and thus have an opportunity to find a solution.

I have for a long time thought that a system of interchangeable batteries at say a "refilling station" that takes just a few minutes (were it technically possible) could be a solution but I doubt that will come!

Thanks, that makes sense, I just couldn't understand why they'd all charge during the day. Perhaps I confused the matter by seeming to suggest none would, but that was just to create a worst case situation for nighttime power demand.

Reading what you've now posted, seems to set out a future where a lot (perhaps most?) charging for those using street charging, will be done at night, but not all of it, as an available charger may not always be available. That seems fair. A point I tried to make earlier based on an average weeks driving, is that most BEV's now will have packs capable of managing that, so theoretically, and in an ideal world, chargers at ~1/7th of spaces would be enough. Now obviously that's not enough, but as @Solarchaser pointed out, you don't need to charge every day, so not every space will need to have a charger. Yet we could still see the majority of charging for those without a dedicated parking space, being done overnight.

The crucial issue here is power - energy isn't an issue, since the amount needed for BEV's isn't as much as it might at first appear, as confirmed by the NG, and of course, if demand rises, so will supply (these folk want to sell leccy) - the issue is power, but even then, the only real concern is avoiding the evening peak (5-7pm), and the wider higher demand period of ~4-8pm. So long as we don't place too much additional demand on that time period, then BEV's aren't a big concern. In fact, compared to a massive rollout of heat pumps, BEV's are almost a side issue.



Regarding swappable batts, that's what Nio does in China, and has done for several years. It seems to work well, and takes less than 5mins. This idea has a lot of merits, especially the ability to charge the batts slowly and if possible, when leccy is cheaper and lower carbon intensity.

However, there are a lot of negatives too, such as the need for additional (spare) batteries. Also a car company will need to settle on a standardized battery pack size, which doesn't sound difficult at first, until the issue is flipped, and you have to settle on a standardized 'hole' for your car models. The problem then becomes one of packs being too physically large for small cars, or too capacity small for large cars, or then having to have multiple size packs / spares at charging stations. Can companies today, settle on a pack type/size for future vehicles, when those, and their chassis, have not yet been designed.

Also I remember an engineer pointing out that electrical equipment is incredibly reliable because there are so few moving parts, but items that tend to fail are switches and connectors, so swapping a battery will necessitate many connections/disconnections. But, my simple brain, would assume that very meaty connections would be used to prevent this issue.

Also a need to consider the size of these stations, which would probably have the footprint of 2-4 'normal' spaces, and cost many, many times more. If a swap takes about 5mins, then how much could a BEV be charged in 20mins (4 BEV's @ 5mins each), in the case of a Tesla, that's probably about 2hrs worth of driving, which would take you to your next break, leg stretch, coffee and a pee.

So, lots of pluses and minuses, and it'll be interesting to see if swapping stations gain any ground outside of China.


Slight digression, but there is a tractor manufacturer producing BEV's, with swappable packs, which sounds like an excellent idea, since farms are great locations for PV, so a pack charging, whilst you work away.

Also, there's a company in Australia that wants to convert diesel long haul trucks to BEV's (when their major overhaul is needed, or engines fail). They plan to have swapping stations along the main highways at regular intervals, with a swap taking place whilst drivers take a break.

IMO, for what it's worth, removeable battery packs is/was the biggest trick missed by the EV industry.  This could have been something really revolutionary. Instead we have EVs that look exactly like their ICE predecessors and try to mimic their range and manner of refuelling.  The result is larger, heavier and more expensive vehicles that do neither.  

Heedtheadvice

All good points regarding charging.

I had not considered the frequency of charge to be as low as you suggest. If that is the case then perhaps the issue is not as great as I envisage. Yet again considering how difficult it is to find parking spaces in some locations it would be galling. When you did need to charge, to find any available spaces were not alongside a charging point and those points that are not in use taken up by non charging vehicles as the only places  they could park when they arrived. A bit like being ICEd.

So I am led to a conclusion that it might not be a huge problem but could be very significant on a reduced scale at important times. This summer our rural location (having a lower number of chargers owing to low population as previously discussed) has been swamped with our two town chargers in the car park hardly coping well due to visitor influx. I wonder if some cars needingcharged had problems. Certainly findind any space has been an issue.

That over the year will be abnormal but that only highlights the point. We might be able to cope with the average demand but we need to have enough capacity to ride out the peaks too. It is many a year since I had to wait more than a few minutes to fill a car with petrol. Plenty of stations available on demand - including not waiting till I ran on just fumes! We should aim for the same whaterver the fuel system.

The NG link was interesting but did not seem to address the similar short term peaks of demand but more about typical capacity. Neither was there much mention of risk mitigation such as when renewable beneration is at minimum times and we perhaps do not have other sources (fossil/nuclear/international imports) available to give a boost for that duration. Not really a BEV problem but more a general continuity of supply issue should risks materialise. There would be a knock on effect to BEVs though. Consider worst case scenarios such as terrorist attack, failure of interconnectors etc.

It was not long ago that the Scottish gov were claiming that Scotland is 'self sufficient' in power generation from renewables. Over a long period of months thay may well be true and export takes place at times of high generation in oarticular to England. No mention was made of the times when capacity is very low and import was required. When all works well no problem. The UK is in a similar position having an undersea interconnect to France (if I remember correctly) which helps us out from their nuclear generation. Bit of a sticky wicket if that was not available for whatever reason when demand required it. Peaks and troughs occur and balancing them is no mean feat especially when we do not have full control over generation capacity. Do we oversize which is innefficient or accept unavailability. Obviously we need to and do work towards smoothing both demand and availability.

It is a bit like hospital services. Spare capacity is planned in for normal service and demand. Elective admissions are more controllable, emergencies are not and thus are pkanned with more spare capacity. As we have seen lately sometimes the plan does not work for one and has a knock of effect!

Martyn1981

Yep, it is a fun subject, and I could (and regularly do) waffle on about storage.

On the subject of interconnectors, the old UK / France one has had issues with storm damage (from an anchor I think) but is now fully up and running again. A new one, in the channel tunnel came on line this year, and in total I think 4 are currently operational, connecting us to various European countries, with a couple more coming on line in the next few years. Ideally these will allow for the transmission of excess RE in the future, and excess nuclear from France when demand is low. Ironically, a few years ago during winter we were exporting about 2GW of coal generation to France, when they discovered faults with about a quarter of their ageing nuclear fleet. I've no idea how things will work in the next decade as France closes more and more of their nuclear, and expands RE, perhaps we'll see as much export of off-shore wind, as we see import of European low carbon generation ...... so exciting!

Edit - Should have mentioned that the Norway link is currently under testing, so should be operational soon. And another 7 totalling 8.5GW are due to be commissioned between 2022 and 2025.