V2H and V2G

1961Nick

I struggle to understand why V2G can ever be a problem for a DNO. Surely the only time a vehicle is going to export is when the DNO asks for some support to assist the grid? Coping with excessive PV export sounds like a much more complicated problem.

Martyn1981

1961Nick wrote: »

I struggle to understand why V2G can ever be a problem for a DNO. Surely the only time a vehicle is going to export is when the DNO asks for some support to assist the grid? Coping with excessive PV export sounds like a much more complicated problem.

It's the potential for unwanted export, be it a fault with the V2G/V2H kit, or for a domestic batt to decide to discharge when PV gen is high and you are already exporting PV.

I see their point, they are working to worst case, but it is a bit sad. Ho hum.

GreatApe

1961Nick wrote: »

I struggle to understand why V2G can ever be a problem for a DNO. Surely the only time a vehicle is going to export is when the DNO asks for some support to assist the grid? Coping with excessive PV export sounds like a much more complicated problem.

The future grid can be more effectively managed with smart resistance heaters and smart immersion hesters

£20 smart plug £20 resistance heater
When too much wind they turn on
When not enough they turn off

If the DNO needs more capacity they tell the smart heaters to back off

The exact same thing can happen with cars there is no need to get cars to push power into the grid you can just tell them to draw not so much at that point in time which is virtual power to grid

Martyn1981

JKenH wrote: »

Would one option be to install an export limiting device?

Forgot to mention this, but big big caveat, this is just me (not the industry), referring to a couple of phonecalls, and future possibilities, so lots of room for errors, but here goes.

So, the DNO did say that they'd be open to these battery storage options (AC side of the PV) if house export was capped appropriately. I asked the obvious, for clarification, and yes the 'device' would have to have DNO approval - be G100 certified.

Now, onto the chat with OVO, they are currently working on their V2G chargers, and developing capping, but they probably won't be seeking/getting G100 certification (my recollection is a bit vague on that bit) till early 2020.

OVO are aiming for G100 compliance, so their V2G would deduct any household export from their 3.68kW discharge (if the two ever happened at the same time), so at 3.68kW* PV export, the V2G would not export anything.

*I'm a slightly odd case (and so is my PV), so the V2G could see PV export greater than 3.68kW, but would work to that limit for DNO compliance in my case.

Total speculation now, and others may already know far more about this, but if this is possible for OVO and V2G, then presumably the same tech/kit could be utilised by V2H and AC side stationary batts.

Hope this helps, but take it all with a large pinch of salt, as we are at the early end of this tech since it's a young but growing area.

Nice to be able to post some good news on this .... for a change.


Edit - Perhaps export compliance already exists in some of the battery tech people have deployed? Anyone that has installed AC side batts, such as Pylontech, Tesla etc, does it have this / what did the DNO's say when notified/registered?

1961Nick

Martyn1981 wrote: »

It's the potential for unwanted export, be it a fault with the V2G/V2H kit, or for a domestic batt to decide to discharge when PV gen is high and you are already exporting PV.

I see their point, they are working to worst case, but it is a bit sad. Ho hum.

It's hard to imagine that the odd Leaf dumping it's charge into the grid because of a faulty controller would have any impact on the grid whatsoever. Compared to normal PV fluctuations 30 kWh is totally irrelevant.

What's more, the fault would more than likely be quickly rectified as the Leaf owner would soon get brassed off if the grid had depleted the battery.

JKenH

Martyn1981 wrote: »

Edit - Perhaps export compliance already exists in some of the battery tech people have deployed? Anyone that has installed AC side batts, such as Pylontech, Tesla etc, does it have this / what did the DNO's say when notified/registered?

Maybe if not when. I wasn’t aware, prior to the recent posts, of the need to notify the DNO and I wonder just how many others have notified their DNO when they have installed or added extra batteries?

JKenH

1961Nick wrote: »

It's hard to imagine that the odd Leaf dumping it's charge into the grid because of a faulty controller would have any impact on the grid whatsoever. Compared to normal PV fluctuations 30 kWh is totally irrelevant.

What's more, the fault would more than likely be quickly rectified as the Leaf owner would soon get brassed off if the grid had depleted the battery.

Whereas a long range Tesla dumping its load might be a different story.

Martyn1981

1961Nick wrote: »

It's hard to imagine that the odd Leaf dumping it's charge into the grid because of a faulty controller would have any impact on the grid whatsoever. Compared to normal PV fluctuations 30 kWh is totally irrelevant.

What's more, the fault would more than likely be quickly rectified as the Leaf owner would soon get brassed off if the grid had depleted the battery.

But it's not 'the grid' that's the issue, it's the supply line the house/BEV is on. I can absolutely believe that this would/could be a problem, and that's why I appreciate their 'problem' of having to work to worst case scenario for each individual property. My confusion at the start was that my house seemed to be 'OK' and I didn't know that they summed potential exports, but I did say that that might be an issue, and again I have to accept that this is a fair concern.

Have you notified your DNO of your additional export potential by registering your grid connected batteries?

Just to be clear, we are all in agreement, us, OVO, V2G, PV, domestic batts etc etc, there is no intention to discharge these batts into the house or export to the local grid when PV gen is high, and demand is low - the problem is a theoretical one based on kit going 'rogue' and I can't hold that against the DNO's. I just have to take it on the chin for now ..... but .....

Martyn1981

....... but .......

learning more from others in similar boats, and there is a lot of good news. For instance OVO already have 'dumb' capping, so in one example where PV inverter is capped at 5kW, and DNO export permission is up to 10kW, the OVO V2G can be capped at 5kW.

In another example, there is 3kW of headroom, but that's not a 'dumb' capping option, so the person has mentioned they are waiting for the new year (bit like me) for intelligent capping, where the V2G caps output in relation to total house export. 3.68kW is an option, and the DNO (in chatting with me) have said that they'd have no issue with that (for me).

And for further clarification, the reason the DNO are looking at a capped export of 3.68kW when I have 5.9kW approval for the PV is 'interesting' ..... they may have gotten their sums wrong in 2012, and now note that whilst I'm in the middle of a street, I'm actually on the end of a line, so if I applied today I wouldn't get the 5.9kW, but they won't revoke it ..... phew!

All of this seems like good news to me, both for V2G and V2H.

Martyn1981

JKenH wrote: »

Maybe if not when. I wasn’t aware, prior to the recent posts, of the need to notify the DNO and I wonder just how many others have notified their DNO when they have installed or added extra batteries?

Fair point, I hadn't realised that it's been a whole 3yrs since I started the battery thread, and I don't think DNO compliance has come up for a long time.

It's certainly a strong argument for DC side batts with PV (v's AC side).