I have seen discussions in the past looking at problems of locally overloading part of the distribution network. The load on a cable is usually monitored and controlled at the traditional source point, 800A fuses in the substation for example. A significant V2G source on that cable segment could allow an overload. A depot for EVs could be capable of sourcing a couple of hundred amps.

The principle you are suggesting, using V2G in a local part of the network to reduce the need for expansion of the wider grid seems to increase that chance of this without significant local monitoring.

I have seen discussions in the past looking at problems of locally overloading part of the distribution network.

There's certainly a risk local imbalance - e.g. while the grid overall and the part of town with little terraced streets may be short of power, just chucking out 32A per car from the other side of town where there are detached houses with two EVs on each drive certainly wouldn't be workable solution at the moment. There may be solutions though. In the short term, EV charge points could be rigged not to export from the overall installation (some domestic charge points currently are connected to a CT on the meter tails and restrict the charge rate to avoid overloading the supply - so same hardware just acting in reverse). The effect on the overall grid might not be quite as beneficial as being able to export all the available power, but simply removing the load of an installation will make a contribution. Or it could be limited to a small export current - maybe 5 or 10A - which the existing networks should be able to cope with.

Longer term, we already have communication of grid data into the home via smart meters and internet - which is in effect used to encourage or discourage import and export at different times. It shouldn't be beyond the wit of man to feed the amount of spare substation capacity into the formula and pipe the data to the appropriate meters. The DNOs should already know which meters/customers are on which feeder after all.

Back to my original post, if there were significant storage on the grid (e.g based on millions of  EV batteries), these peaks in demand could be satisfied from stored renewable energy, hence reducing the grid carbon intensity.

Indeed, but don't forget the primary purpose of an EV - which is to move. A lot of demand is concentrated into the morning and especially late afternoon/early evening peak (e.g. 1600-1900) - just when a many commuter's cars will want to be on the road. Then of those that are actually plugged in when needed (which probably cuts off all those in terraced housing etc who charge at public/supermarket charge points) many will want a decent charge left in the car,so they can use it later on - so me be willing to share only a smaller proportion of the overall capacity for the greater good. So what starts of as looking like tens of millions might shrink quite considerably by the time it's put into practice. Don't get me wrong, I still think it could be a very useful contribution and well worth developing the technology, but I see it as one more brick in the overall much larger solution rather than a game changer all by itself.

   - Andy.

AJJewsbury said:

So what starts of as looking like tens of millions might shrink quite considerably by the time it's put into practice. Don't get me wrong, I still think it could be a very useful contribution and well worth developing the technology, but I see it as one more brick in the overall much larger solution rather than a game changer all by itself.

Hi Andy - many thanks for your insightful responses. 

I guess where I'm coming from is that if each car manufacturer were to build bi-directional charging capability into their car as standard (and I realise there are at least 2 standards out there - based on DC vs. AC interfaces) then that would maximise the opportunity for EVs to become an "asset" to the network (and help with load spreading / demand side management / carbon intensity reduction) rather than the opposite case where EVs without bidirectional charging are a "burden" to the network - with a high proportion needing to be charged at the same time (when travellers arrive at their place of work / residence / shopping). 
If drivers were sufficiently informed & incentivised, it may even be possible to influence their driving habits (e.g. so that those not needing to drive during peak grid demand periods were "remunerated" for leaving their cars grid-connected.)

Stuart

Roger B said:

The principle you are suggesting, using V2G in a local part of the network to reduce the need for expansion of the wider grid seems to increase that chance of this without significant local monitoring.

Hi Roger
I agree there would need to be some monitoring, and I think AJJewsbury has provided a good answer.  Where I'm coming from is that without bidirectional charging there could be an even larger demand on the network of many EVs needing to charge at the same time.
With bidirectional charging, a proportion of the EVs may be able to reduce the peak demand by releasing some of their stored energy.
As Andy mentioned, the export current could be limited as an early mitigation, and as more intelligence comes into the network, export could be adjusted to minimise peaks / avoid overload.   

And what would the local monitoring achieve.

Does it switch off the loads before things get out of hand?

EV owners waking up to uncharged vehicles is already a problem. Some part due to the very old cabling. This overstretch of the aging infrastructure will cause issues. 

V2G is yet another pie in the sky ideological non starter.

Personally I sit the idea along with heat pump, solar panels and wind turbines, basically very expensive and useless.

Jon Steward said:

V2G is yet another pie in the sky ideological non starter.

Personally I sit the idea along with heat pump, solar panels and wind turbines, basically very expensive and useless.

Hi Jon - sorry to disagree with you on all 4 points.
I think this is an engineering forum, so let's leave ideology to one side. 
I see solar PV and wind turbines as excellent engineering solutions for renewable energy generation witnessed by the global adoption of these technologies (with costs significantly below fossil fuelled alternatives - https://www.irena.org/Publications/2024/Sep/Renewable-Power-Generation-Costs-in-2023).
Similarly, heat pumps are a great engineering solution for efficient heating & cooling.
Electric Vehicles will ultimately replace ICE vehicles and I believe bi-directional charging / V2G could be an enabler to  this happening in a way that can ease the demands on an aging network, rather then be held back by inadequate infrastructure.
Stuart

Thank you for your reply Stuart.

We disagree, that fine.

Unfortunately netzero is ideological and is important to associate that with the mandated transition to renewable.

In the uk we have the highest cost energy in the world due to the net zero transition to renewable. This will only increase as turbines and panels increase.. 

Bare in mind that we need to spend trillions of pounds on infrastructure to accommodate the grid expansion. 

The countries economy is a complete mess so where's all the cash coming from?

Another reality check for you is that Only 13 % of the uks cars are ev so not much chance of backing up the grid when the sun doesn't shine and wind won't blow.

As I said. It's pie in the sky.

Thank you for your reply Stuart.

We disagree, that fine.

Unfortunately netzero is ideological and is important to associate that with the mandated transition to renewable.

In the uk we have the highest cost energy in the world due to the net zero transition to renewable. This will only increase as turbines and panels increase.. 

Bare in mind that we need to spend trillions of pounds on infrastructure to accommodate the grid expansion. 

The countries economy is a complete mess so where's all the cash coming from?

Another reality check for you is that Only 13 % of the uks cars are ev so not much chance of backing up the grid when the sun doesn't shine and wind won't blow.

As I said. It's pie in the sky.

Jon Steward said:

In the uk we have the highest cost energy in the world due to the net zero transition to renewable. This will only increase as turbines and panels increase.. 

Bare in mind that we need to spend trillions of pounds on infrastructure to accommodate the grid expansion. 

The countries economy is a complete mess so where's all the cash coming from?

Hi Jon

if cost is your main concern, please don't ignore the cost of the effects of climate change - particularly significant for the UK.

I agree the proportion of EVs in the UK is currently low (and probably only a small proportion of these are V2G capable). 
This is the reason for my original post - to increase the future proportion of EVs that are V2G enabled, so that EV's can help reduce the future cost of the grid infrastructure by providing storage distributed throughout the network. 

Stuart

Your barking up the wrong tree with Climate Alarmism.

I've read enough science facts to educate myself off the nipple of doom.

You should try it it's quite enlightening 

Another point is that the CO 2 footprint of an EV is massive. Maybe 50K miles before it goes positive.

Plus the CO2 footprints claimed  never includes the upstream costs like transportation, manufacturing with Chinese coal fired power stations and mining of minerals by Conganese children and pregnant women. 

Built by slaves, maybe a 20% CO2 saving over 100K miles. Might need a new battery after 10 years, worthless second hand value. Why on earth would I want to own an EV. Definitely not to prop up a failing energy system.

Anything that say 'could' rings my BS bell.

And this from your link says all I need to know!

There is a slight risk that V2G could be used as an excuse not to invest in updating the grid 'properly', in terms of replacement transformers, thicker cables and so on. We have about a century of grid design experience design around centralized generation, and voltage drops that slope downwards towards the load, we have a similar length of time that has led to reliable design rules, like 1.5 -2 kW per house when sizing substations, and an arteries and branches approach to cables that means that the street main has an apparently oversized cross-section, when looking at those average loads, so that any one house can draw 100A for as long as it needs to. But no more than perhaps half a dozen houses in the street can do that at once, or the substation fuses pop ! And historically that never happens, and the design rules work OK,

A transition to electric heat pumps for heating and electric cars that need charging, at least if you expect cars to be charged at home, and not at dedicated charging hubs with their own substations, renders all those DNO design rules and assumptions obsolete, and replaces it with 'here be dragons'.

The ability to borrow a few tens of amps from the neighbour and save roasting the substation may initially look attractive, and allows some demand leveling, but then so does the far simpler measure of staggering the charging times that share a phase on a substation. At the moment, conventional  EVs are still a fairly niche thing - there are none in my street  for example but there are a few in total on the whole housing estate, so maybe less than ten per substation at the moment.

Equally I don't live in a street of detached houses where folk buy cars new from a main dealer - those that do will have a different perspective on 'normal' ;-)

I see that there is a lot of network reinforcement to be done before say every third house that currently has a car, can have an EV - V2G may be a way to shirk that.

Mike

https://youtu.be/K8Nz-4eEBTw

Mark P Mills gave this speech on the Economics and Future of Electric Vehicles on November 12.

Well.worth an hour of anyone's time to listen to him.

Hi Mike - some good thoughts.

I understand your view about V2G leading to risk of non investment in network upgrade.

I also like your thought about staggering charging - "smart" chargers could manage this recognising the capacity in the local network versus demand. People could be rewarded (with low cost) for scheduling their charging in advance (hence easing the management of the demand on the network). 

I'm thinking V2G may be a way of extending the lifetime of existing infrastructure such that the future investment could be optimised (e.g. prioritised based on the weakest points in the network.)

As solar and wind will play an increasing role in the future, and these are more distributed in nature than the centralised power station concept, I suggest that new investment would be optimised by recognising this de-centralisation rather then re-creating the centralised architecture of the past?

Stuart

I'm thinking V2G may be a way of extending the lifetime of existing infrastructure such that the future investment could be optimised (e.g. prioritised based on the weakest points in the network.)

quite, but if we only do that at the pace of the current system has developed, then it will take 70-120 years to complete, by which time the goalposts will have moved again.

Generally the  UK system either dates from when the house was built if post war, or from whenever the pre-war supply (if any) became inadequate for increasing load.

By way of anecdotal support for my 70-120 year figure.

I'm not sure how old the transformer that feeds your house is for example. but the one that feeds mine was installed at some point in 1969, and there is an adjacent unused pad for another to take extra load that has never materialized, and the street cabling is the same age except in a couple of places where the consac has gone bang and 6 foot lengths of plastic clad CNE between pairs of 'torpedo joints' bypass the blown out bits of SNE.

The transformer feeding my dad's place however went in during  the mid 1950s, and there is no room to upgrade it if that were ever needed without compulsory purchase of adjacent property or some seriously messy  building work- indeed by current standards of accessibility, it is already too small for the transformer it currently supports. The good news though is that the cable is PILC, not consac, and lead seems to be far more long lived than aluminium.

Here in town the pre-war houses have TT supplies coming in overhead on singles, and where they have failed, are replaced with concentric cable to the houses and ABC for the street mains. Transformers are an odd mix of H mounted pole pigs and things in brick sheds or ground mount fenced enclosures between buildings... Those transformers are mostly  50-70 years old and in terms of wear, in many cases barring an oil change and a rust inspection, in good shape for the the same duration again into the future.

(BSEN60076 Part 7, requires transformer insulation to be designed for 180000 hours of service (20.5 years) working at full load current and 98°C hot spot temperature - now the model predicts insulation lifetime doubles (or halves) with a ten degree change - so changes in load and seasonal load, are really critical to lifespan. In reality this is probably not as clear cut.)

But this situation is far from unique - almost every town in the land has miles of installations like this, and if the load profile is unchanged, it can carry on for many decades yet - and the number of DNO staff and rate of manufacturing of spares and many other things, reflect that pace.

Mike

Jon Steward said:

https://youtu.be/K8Nz-4eEBTw

Mark P Mills gave this speech on the Economics and Future of Electric Vehicles on November 12.

Well.worth an hour of anyone's time to listen to him.

Thanks for the link, I did listen to Mark P Mills speech…

I'll start with the positive points:

He highlighted 2 key challenge areas: the production of the EV battery and the need to upgrade the network to support the additional load.

Relating these challenges back to the message of my original post - both can be eased with a "bi-directional charging" (V2G) approach as this could:
(i) reduce the demand for house batteries
(ii) maximally leverage the investment in the EV's battery (for energy storage as well as transport)
(iii) ease the peak load on the network as a consequence of the energy storage (and hence reduce / defer the network investment need).

However, his views on EV battery end of life are simply wrong: "when the battery is exhausted it's garbage because its electrochemistry is just exhausted".
I know from personal experience (15 years ago as General Manager of a metals recycling venture) that Lithium Ion batteries can be recycled with high (>95%) recovery rates to produce high quality materials ready to manufacture new batteries.
Just taking a "common sense" view of this, why would anyone "throw away" a concentrated source of strategic materials when these have a high value?

I was also very concerned about his view of CO2 emissions: "if you burn oil you make carbon dioxide that's the point of burning it … it's not a pollutant it's an objective of the activity".
Despite claiming to understand climate science, he doesn’t seem to understand that there is a need to reduce CO2 emissions.

In summary, nothing he said detracts from the potential role V2G could play in support of EV rollout - but I won’t be wasting any more of my time following his thoughts.

Stuart

Hello Jon:

I watched the speech by Mark Mills yesterday and while it had some excellent points it does failed to mention the current economic situation in the US - high personal debt loads, overpriced new car prices, high insurance (both property and auto) costs, and high interest loan rates..

Peter Brooks