V2H and V2G

Martyn1981

JKenH wrote: »

Joe/Mart, that was a very interesting and informative exchange which has made me aware of issues I hadn’t previously considered. I had, for instance, not realised that approval from the DNO could be an issue when installing batteries.

My back dated application to the DNO for my PV, which my installers are handling, is reaching what I hope is a satisfactory conclusion but it has been a battle as the DNO were holding out for a 5.9kw limit.

I would imagine, in the light of Mart’s experience and Joe’s comments, if I told them I was going to install V2G or batteries they would say no.

I imagine there are a few other people like me who might have thought that one could just go ahead and install a battery but will now need to think again.

Yep. That was kinda why I posted the issue, and will update if anything changes.

I'm going to assume that we are all pretty much aware of issues such as Joe raised about PV in rural NI, and had my situation been similar it would not have been worth posting.

But, as my situation appears to be one where PV, batts etc would be 'easy', especially as I had no problems getting the 5.9kW export approval (they commented that it would have gotten a 'no' under the old cabling and looped set ups), I think it's an opportunity to learn

I think the problem will come under one of three issues, firstly, there is something more going on, that is not initially obvious, about the local grid. Secondly, they are summing the theoretical exports from my property*. Thirdly, it's just an administrative error, misunderstanding etc as the technology is still in its infancy (perhaps gestation). Finding out any of these will, I hope, be useful.

*Whilst I hope it's not down to summing, as that should never happen, I appreciate why they might have to take worst case into account, and of course that could apply to all PV'ers with domestic batteries connected to the grid (mains) with no intention of grid export, just because it could happen.

We shall live and learn, but from a not personal position (well personal too I suppose), I dearly hope that supply side battery support, of all types, does not get restricted as it has the potential to remove the peak part of peak demand from the grid. Or to be pedantic, it doesn't remove the peak demand, but the NG and DNO's will no longer see it in their power loads or demand needs, and neither will the equipment built out to cope with the extremes.


Edit/addendum - For anyone interested, I should probably add some info from the OVO end. On chatting about why this might have happened, the guy handling my application said he'd never heard of this before (though I've now found a similar instance from many months ago, probably handled by another), and also confirmed that he thought my situation was one of the easiest ones. He also confirmed (when we pondered a summing of PV & batt export) that they would never be exporting at the same time as that defeated the whole object [again I appreciate that the issue could be one of accidental dual export].

JKenH

It is surely on the local distribution grids that are already stressed that installing batteries makes most sense. The intention with batteries, smart metering and flexible tariffs is that the battery owner will reduce import when demand is high. So is V2H not a better solution than V2G in these areas?

Edit: it is also those in rural areas that are most likely to lack network coverage for the installation of smart meters and hence least likely to shift demand. We may well see EVs still being charged at 8 am just before setting off for work and again at 5.30pm on returning home as there is no incentive to charge at less convenient times. When I applied to EDF for their electric car tariff they said “no” because of lack of network coverage and offered me a cheaper flat rate as an alternative to the E7 tariff I am already on.

Martyn1981

JKenH wrote: »

It is surely on the local distribution grids that are already stressed that installing batteries makes most sense. The intention with batteries, smart metering and flexible tariffs is that the battery owner will reduce import when demand is high. So is V2H not a better solution than V2H in these areas?

Edit: it is also those in rural areas that are most likely to lack network coverage for the installation of smart meters and hence least likely to shift demand. We may well see EVs still being charged at 8 am just before setting off for work and again at 5.30pm on returning home as there is no incentive to charge at less convenient times. When I applied to EDF for their electric car tariff they said no because of lack of network coverage and offered me a cheaper flat rate as an alternative to the E7 tariff I am already on.

That's what I would conclude too. So adding batts would be a benefit, and tbh my greatest concern here, is that the issue is one of 'summing' (batts and PV) as that would then undermine a great solution, and also be more difficult to solve.

Eventually with enough national RE, or localised PV, we will need storage to help. So if I'm right (might not be) that stationary batts and BEV's will have a PV bias, then the last thing we want is for one to complicate the other. [Edit - I mean that batts will be more prevalent in PV homes (but also non PV homes where the local DNO trials multiple rollouts for peaking solutions), and I think PEV's are more popular with PV'ers, but I don't know if that is due to economic reasons having PV export, or environmental bias. M.]

That said, many of the V2G'ers Wifey has been chatting with, seem to have PV, so hopefully my concerns about summing are mistaken.

So is V2H not a better solution than V2H in these areas?

I'm assuming one of those was meant to be V2G. Not sure which way round, but personally, also not sure which is better/worse etc.

V2H would help with that homes peak demand, V2G could hope with additional peak demands, V2H could help reduce peak export, V2G could help reduce peak export from multiple local PV'ers ..... and so on. No idea which is best, probably a mix of everything, including stationary batts and 'virtual powerstations' comprised of multiple battery stores.

JKenH

Yes, typo, I meant to say V2H is better deployed in that situation than V2G. I have corrected the original post.

joefizz

Martyn1981 wrote: »

That's what I would conclude too. So adding batts would be a benefit, and tbh my greatest concern here, is that the issue is one of 'summing' (batts and PV) as that would then undermine a great solution, and also be more difficult to solve.

Im going to have to intervene here a bit with some generic technical stuff.
First of all, can we agree to stop conflating batteries with storage. There are many ways to store energy locally at home, substations, network entry points etc etc. Some of them may be what most readers here consider batteries but in generic technical terms its all energy storage. Different storage mechanisms will depend on locality, cost, availablity etc, theres no one size fits all solution.



As Ive mentioned in the past in different threads there are trials ongoing on various different levels of network storage. From batteries in the home to batteries/storage at local substations (more in a minute) to batteries/storage at PV/Wind/Generation entry points and other places in between.

Other than the home batteries these are mainly to balance, not to generate so like renewables (Ireland was forecast to hit its highest wind generation ever last night but that would have possibly exceeded demand) this all has to be managed at a certain percentage.
Its why Ive commented in the past about localised storage etc and legacy networks.

One of the issues ironically is that in recent years the push towards using less energy has had a detrimental effect on rollouts (again something I mentioned on a previous battery thread discussion but nobody asked why I was experimenting with increasing summer usage with battery and time shifting annual tasks - now I know!)


The issue that Martyn mentions is only an issue because he is attempting to connect to his locality,possible generation that may exceed locality demand. Its that simple. Its the possibility of the generation that is the problem, not the actual implementation.
If the DNO was controlling this with regularly serviced and monitored equipment then it really wouldnt be an issue. The DNO has to consider what happens when things go wrong.



Home batteries have been mentioned but most home batteries dont have the capability even in meltdown to export massive amounts of energy into the local network compared to a vehicle to grid situation. Thats not to say there isnt a problem but it would depend on the size of the battery connection. I know the pylontech/sofar is limited to 19.2kw but limited to 3kw output. That could possibly cause some damage but consider the possibility and probability of damage if a car battery started dumping at full charge rate, either through fault or a fault in the management companies software/monitoring.

Most of my work is working out all the possibilities, then assigning probabilities. I dont really get involved in outcomes and my work is only based on 6 months to 3 years out. I make money on possibilities and probabilities of outcome. Yes, I get residual income from the research 6-15 years after the fact but thats really of little consequence. DNOs will work the same, hence my previous points about wind power and 10-15 year planning. We have plans for what will happen in 15 years time so thats why we are having 2 year trials now so that the results can be measured against estimates/models and then a further trial can be arranged based on results not models then rollout (or not).
That follows that part of the reason why fit/rocs were time limited, time enough to get enough to get enough valuable data. Now that that has reached a safe 'saturation' point (for the chemists, saturation not super saturation) its time to work with the likes of home battery trials, V2G, V2H etc etc as all of these are at low enough levels to not cause major issues but at least track real world usage compared to models. (read my previous comments about plug in hybrids usage being way off modelled data).


I think Z mentioned in another thread about expensive home battery systems vs substation/distribution storage. Its not an either or. I was out for christmas lunch with some engineering colleagues yesterday and I mentioned some of the discussions on here and our opinion was a lot of the problems people have with this stuff is not having an engineering mindset. 1st year engineering at uni is bloody tough and its to sort out the linear thinkers (the vast majority of people) from the non-linear thinking required to be successful at engineering. (part of the reason I keep banging on about people not extrapolating out as that never works in real life). Thats a roundabout way of saying there isnt a one size fits all solution and why Ive repeatedly mentioned substation storage (pylontech batteries being standard equipment rack size) as this will allow more localised pv rollout as the excess can be stored on that one branch (or charged from the grid).

This is all complicated by various dnos and various suppliers, we are lucky here in NI (why we are a test bed for a lot of this) in that its one DNO and pretty much every supplier is owned by the same company. Even then its not exactly joined up thinking but at least you dont get someone attempting to do a v2g trial over someone elses network, interfacing with someone elses network, with someone elses supply.

This is key to understanding Martyns problem. The control. Whilst whoever is doing the V2G bit might have stats and usage at an overview level etc, they may not have enough customers on Martyns end connection to use that energy and may not even have the control aspect of it. The DNO have to ensure that the maximum (for want of a better word) output will fit in with the usage profile of the local connection. In time with current trials that will change but if it doesnt fit now then DNO computer says no. Add battery/network storage at your substation and then go for it as it will be able to absorb the extra load.


Martyn, one of your fundamental difficulties with understanding this is in your line about if there was enough pv then we would need the storage. From an electricity perspective its the other way round, hence the V2G trials. Those trials are independent from PV, you are conflating the two. The V2G/V2H trials are designed around nights like last night where there was so much wind energy generated but yet we still had to keep the coal fired station going because of run down/ramp up times for tomorrow. Stop conflating these with PV, as this is your issue. You dont see these as two separate issues, one of generation and one of storage both managed independently (currently).
It doesnt really matter that other PV people have V2G as they arent connected to your branch of your substation. Thats all that matters for your case. You will effectively be connecting 2 independent electricity generators to the DNOs local branch that the DNO has no control over.


Another long rambling post but also consider this. These are all trials, some people installing V2G may never have it actually utilised because either the trial people have no customers on their branch (or people switch supplier during the trial).


As Ive said many times, its complicated. That reason is why we are an ideal test bed over here or why as mentioned in a recent thread trials are geography limited.

joefizz

Martyn1981 wrote: »

Just a thought, but I was wondering if any of the people on here with grid connected batteries

Sorry to pick on you again Martyn (Im not really, honestly!) but I dont know anyone with grid connected batteries. Only DNOs will have grid connected batteries. You have to have certification to connect batteries directly to the grid.


Most home battery systems are connected via inverters which may or may not be grid tied. Those that are grid tied will be certified via PV certification. V2G and V2H will need certification/approval.



Its an important clarification, anything which can feed back into the grid needs certification/approval. (hence your issues).

Martyn1981

joefizz wrote: »

Sorry to pick on you again Martyn (Im not really, honestly!) but I dont know anyone with grid connected batteries. Only DNOs will have grid connected batteries. You have to have certification to connect batteries directly to the grid.


Most home battery systems are connected via inverters which may or may not be grid tied. Those that are grid tied will be certified via PV certification. V2G and V2H will need certification/approval.



Its an important clarification, anything which can feed back into the grid needs certification/approval. (hence your issues).

OK, there has to be a language/translation problem, as you are doing exactly the same thing yet again!

So, I mention grid connected batts, you talk about grid connected batts, such as gried tied, V2H and V2G, but also claim that you don't know anyone with grid connected batts ..... when several folk on here chat about them.

Additional questions, why do you think grid tied batts will be certified through PV, when they could be in a non PV house, or AC side?

Also, as asked before - could you clarify your statement:

Ive mentioned telling the DNO even when you dont have to

as I'm really not aware of any situation when grid-tied PV (or any SSEG) doesn't have to reported to the DNO.

joefizz

Martyn1981 wrote: »

when several folk on here chat about them.

;-) I dont know anyone on here ;-)
I dont think Im the one with a language problem. I base everything I say on real life interactions and measured data, not stuff on the internet.

Martyn1981 wrote: »

Additional questions, why do you think grid tied batts will be certified through PV, when they could be in a non PV house, or AC side?

Conflating again Martyn. Some will be certified through PV (connected to PV inverter at time of install). Non grid tied will have a certificate of conformance.
As I said non PV house grid tied will have to have certification particularly retro fit - which is your issue.


Heres some homework... examine your own data and find out why they possibly turned you down. Its very easy to do...

Martyn1981

joefizz wrote: »

Im going to have to intervene here a bit with some generic technical stuff.
First of all, can we agree to stop conflating batteries with storage. There are many ways to store energy locally at home, substations, network entry points etc etc. Some of them may be what most readers here consider batteries but in generic technical terms its all energy storage. Different storage mechanisms will depend on locality, cost, availablity etc, theres no one size fits all solution.

TBH I hadn't spotted any confusion, the issue of storage and particularly batt storage is discussed all the time.

joefizz wrote: »

The issue that Martyn mentions is only an issue because he is attempting to connect to his locality,possible generation that may exceed locality demand. Its that simple. Its the possibility of the generation that is the problem, not the actual implementation.
If the DNO was controlling this with regularly serviced and monitored equipment then it really wouldnt be an issue. The DNO has to consider what happens when things go wrong.

That may be the case, as I mentioned, and then Z mentioned, and then finally yourself. However, we don't know if that's the issue, and it doesn't seem to be a problem with many of the V2G trialists so far, and according to OVO, should not be an issue.

But yes, as I've stated over and over, it could be, and that's my real fear (not for myself) as batts be they stationary or BEV related, would appear to have a PV household bias, and I'd hate for 'summing' to be a holdback.

joefizz wrote: »

Home batteries have been mentioned but most home batteries dont have the capability even in meltdown to export massive amounts of energy into the local network compared to a vehicle to grid situation. Thats not to say there isnt a problem but it would depend on the size of the battery connection. I know the pylontech/sofar is limited to 19.2kw but limited to 3kw output. That could possibly cause some damage but consider the possibility and probability of damage if a car battery started dumping at full charge rate, either through fault or a fault in the management companies software/monitoring.

You seem to be conflating power and energy. The OVO trial is for upto 6kW, which would compare well with the Tesla PWII at 5-7kW. I think it's fair to say that too much power will be a problem, though I appreciate energy would make it worse. Using your Pylontech example, two such installs would also be a comparable problem, hence my interest in hearing from those with grid connected battery storage (connected to their home mains), if they've heard any issues.

Once again, and we need to be really clear here, batt storage be it home, virtual powerplant, V2H and V2G do not intend to export when demand is low. I'm confident in suggesting that those with home batts, don't aim to discharge them when their generation exceeds demand.

joefizz wrote: »

I think Z mentioned in another thread about expensive home battery systems vs substation/distribution storage. Its not an either or. I was out for christmas lunch with some engineering colleagues yesterday and I mentioned some of the discussions on here and our opinion was a lot of the problems people have with this stuff is not having an engineering mindset. 1st year engineering at uni is bloody tough and its to sort out the linear thinkers (the vast majority of people) from the non-linear thinking required to be successful at engineering. (part of the reason I keep banging on about people not extrapolating out as that never works in real life). Thats a roundabout way of saying there isnt a one size fits all solution and why Ive repeatedly mentioned substation storage (pylontech batteries being standard equipment rack size) as this will allow more localised pv rollout as the excess can be stored on that one branch (or charged from the grid).

It's rude of me to speak for Z, but I don't recall him ever suggesting it's an either or situation, just interesting to consider all the pro's and con's.

I also feel the same, so once again I think you are commenting on what I haven't said, or what you've decided I've said, rather than the reality.

If I was pushed on the point, I'd probably suggest the benefits of DNO storage, however, as well as the engineering issues, you should also consider the economic issues, and it might be that the household generating PV leccy at a very low value (export rates) can make the numbers work where the DNO can't. But I'm hypothesizing there, and something I've suggested many, many times would be for domestic batts but with financial support from all beneficiaries, and that would be HMG (helping to meet targets), leccy supply companies (not generators) who don't want daytime PV excess, but would like to minimse peak demand purchases, DNO's through savings on having to meet peak demands, and of course the homeowner through reduced leccy import costs.

joefizz wrote: »

This is key to understanding Martyns problem. The control. Whilst whoever is doing the V2G bit might have stats and usage at an overview level etc, they may not have enough customers on Martyns end connection to use that energy and may not even have the control aspect of it. The DNO have to ensure that the maximum (for want of a better word) output will fit in with the usage profile of the local connection. In time with current trials that will change but if it doesnt fit now then DNO computer says no. Add battery/network storage at your substation and then go for it as it will be able to absorb the extra load.

I think we are all aware of this, but once again, as my situation would appear to be ideal, I thought it worth raising so that we can become better informed. As explained multiple times to you already, if potential accidental export is a concern, then so would 'deliberate' export from a couple of additional PV systems. Since (my situation) appears to have far, far less PV than neighbouring areas, and has been upgraded to better cope, we need to be careful jumping to conclusions on what the problem is, it could simply be one of misunderstanding.

joefizz wrote: »

Martyn, one of your fundamental difficulties with understanding this is in your line about if there was enough pv then we would need the storage. From an electricity perspective its the other way round, hence the V2G trials. Those trials are independent from PV, you are conflating the two. The V2G/V2H trials are designed around nights like last night where there was so much wind energy generated but yet we still had to keep the coal fired station going because of run down/ramp up times for tomorrow. Stop conflating these with PV, as this is your issue. You dont see these as two separate issues, one of generation and one of storage both managed independently (currently).
It doesnt really matter that other PV people have V2G as they arent connected to your branch of your substation. Thats all that matters for your case. You will effectively be connecting 2 independent electricity generators to the DNOs local branch that the DNO has no control over.

I didn't realise I had a problem understanding this. I think you are simply reading too much into what I've posted.

Also I'm confused as to how you've concluded the problem is one of PV and V2G, whilst at the same time are telling me that I'm conflating the two issues, by, from the start, suggesting that this might be the issue, and Z also raising it.

Once again ...... I've posted this issue as I thought it would be interesting, my reasoning being that I'd hate for V2G (or V2H or domestic grid tied batts) to be held back based on the potential for them exporting when they shouldn't. I don't know if that's the problem yet (even if you do), though it may be, and hence why I thought folk would be interested.

To conclude, yet again, I really don't understand what you are trying to say. You seem convinced I've said or believe things I don't, or haven't said things that I have.

I appreciate that my posts are boring, but please, please, please read them before you reply to them, or we'll keep going in these circles like your claims that BEV's cause young low mileage cars to be scrapped, batteries will degrade massively more than actual results are already showing, and the TM3 in the UK has gone up from £25k to £45k, when in reality it's gone from £35k for the standard range, to £39l for the SR+.

I'm pretty sure we are talking the same 'waffle', even if you are convinced I'm saying something different.

Martyn1981

joefizz wrote: »

;-) I dont know anyone on here ;-)
I dont think Im the one with a language problem. I base everything I say on real life interactions and measured data, not stuff on the internet.




Conflating again Martyn. Some will be certified through PV (connected to PV inverter at time of install). Non grid tied will have a certificate of conformance.
As I said non PV house grid tied will have to have certification particularly retro fit - which is your issue.


Heres some homework... examine your own data and find out why they possibly turned you down. Its very easy to do...

Sorry I'm still baffled, you challenge my question:

Martyn1981 wrote: »

Just a thought, but I was wondering if any of the people on here with grid connected batteries have had any issues with their DNO's when notifying them? Also, do you need to give sustained or peak power figures, for instance the Tesla PWII has an output of 7kW (if I remember correctly) but 'only' a sustained power output of 5kW.

with the statement:

joefizz wrote: »

Sorry to pick on you again Martyn (Im not really, honestly!) but I dont know anyone with grid connected batteries. Only DNOs will have grid connected batteries. You have to have certification to connect batteries directly to the grid.

then go on to talk about grid tied batts:

joefizz wrote: »

As I said non PV house grid tied will have to have certification particularly retro fit - which is your issue.

Is this a joke ..... I'm starting to think you are just pulling my leg, and I suppose it is a bit funny?

Edit - BTW you seem to have missed out the biggest group (at the moment) which is PV households, but AC side grid-tied batts, so not PV tied. there are a number on here, and I asked them a question, even if you don't believe they exist.