Adding PV and Battery System to existing fits PV install - DNO involvement.

[Stinsy]

I think the original plan is the best one:

- AC coupled battery inverter (DNO permission required).
- Additional solar panels feeding batteries via charge controller (none of DNO’s business).

While battery/inverter setups aren’t silent (there can be hums/clicks) the days of “active cooling” with noisy fans are gone.

[martinW]

Thanks for all the replies.

I will go down route of Sofar ac Coupled inverter and notify DNO of the inverter and batteries only. This will complement my existing 3kw solar PV.

Then once approved/ sorted I can add a DC PV charging system for the batteries.



Anyone done this with Western Power? I've looked at their DNO notifications for installing a Battery system, and so far it doesn't seem to make any sense to me. There is a G99 fast track, but none of the links work on their website. It looks like a simple system is treated like a 1MW system from the paperwork I can see... Also it looks like they are treating it like 3kw PV AND 3kw Battery system from what I read so 6kW in total, this surely can't be right.

I might go to Future Build in March and see if there is anyone there I can talk to sensibly (mind you not looking forward to being crammed in the tube). Basically my mate will do the BS7671 certification as I am no longer registered to do electrical works (too busy with other works), I can do the installs and test it no problem.

[marshman]

Pretty sure this is the form you need. (Link below)

https://www.westernpower.co.uk/download ... iteme/2786

The system is not keeping up with technology in my opinion. They seem obsessed with "generation" i.e. wind or solar so the 3.68kW from your battery storage doesn't seem to matter as long as there is an export limiting device . It seems to me they will allow 3.68kW solar "generation" AND 3.68kW from battery storage (export control limited to 16A), but not an "additional" 3.68kW from an hybrid inverter with batteries and PV - export limited in the same way! The Hybrid Solis inverter I want to use is G100 certified and export controls to 0 so I can't see the issue. I am in a similar situation and am awaiting a response from UK Powernetworks as to whether I can use the fast track route or need to do a G99 "Type A" ( < 50kW) application.


Roger

[Mart]

Hiya, I had the same issue with WPD when I applied to be part of a V2G scheme, they added the PV potential (sum of inverters) to the V2G, as it didn't have G100 compliance at the time.

I also have the same problem with adding more PV, I can't do it as a new AC system because I'm at DNO limit. I could add it through my existing Solaredge system and get FiT's apportioned, but there might be a lot of curtailment, and also a long DC run from existing panels to new panels.

My imiginary solution, sounds similar to your original post, if I can get a battery system installed that's G100 (or is it G99) approved, then put the new PV directly into it, then the battery's compliance covers the PV, by restricting too much export, and if there's too much 'new' PV gen, it'll simply curtail that PV?

Chatting with WPD, they basically explained, and I see their point, that without the correct certification, then the equipment, in this case the V2G, could export in fault, and added to the PV export exceed limits, hence why they add it all together, even though you wouldn't want to empty your car battery whilst exporting PV, when equipment is working correctly.

[Stinsy]

Also it looks like they are treating it like 3kw PV AND 3kw Battery system from what I read so 6kW in total, this surely can't be right.

Yes it is right and yes it is dumb. They just see a solar "generator" exporting at full whack while the battery "generator" exports at full whack. They then assume everyone on your local transformer has their solar/batteries doing the same thing at the same time and see if the local grid can handle that.

The DNO completely ignores the fact that the purpose of the batteries is to store solar generated electricity for self-use later and to shift peak electricity usage to off-peak.

[marshman]

Also it looks like they are treating it like 3kw PV AND 3kw Battery system from what I read so 6kW in total, this surely can't be right.

Yes it is right and yes it is dumb. They just see a solar "generator" exporting at full whack while the battery "generator" exports at full whack. They then assume everyone on your local transformer has their solar/batteries doing the same thing at the same time and see if the local grid can handle that.

The DNO completely ignores the fact that the purpose of the batteries is to store solar generated electricity for self-use later and to shift peak electricity usage to off-peak.

Not quite true. The fast track application specifically limits TOTAL export to 16A per phase via a G100 compliant device.

"I confirm that design of the complete installation has been carried out to limit the export capacity to a
maximum of 16A per phase via an export limiting device in accordance with ER G100."

It is also annoying that every DNO seems to have their own variation. UKPower Networks are also concerned about the load the battery / storage present when charging - which is not unreasonable being as heatpumps and car chargers are also notifiable.

[nowty]

I'm with marshman, its a light touch G99 certification ONLY if the kit is G100 compliant and has a type tested certificate. But some kit might not be G100 compliant and the DNO would not want any of that installed and if it risks higher than 3.68kW export.

[martinW]

Pretty sure this is the form you need. (Link below)

https://www.westernpower.co.uk/download ... iteme/2786

The system is not keeping up with technology in my opinion. They seem obsessed with "generation" i.e. wind or solar so the 3.68kW from your battery storage doesn't seem to matter as long as there is an export limiting device . It seems to me they will allow 3.68kW solar "generation" AND 3.68kW from battery storage (export control limited to 16A), but not an "additional" 3.68kW from an hybrid inverter with batteries and PV - export limited in the same way! The Hybrid Solis inverter I want to use is G100 certified and export controls to 0 so I can't see the issue. I am in a similar situation and am awaiting a response from UK Powernetworks as to whether I can use the fast track route or need to do a G99 "Type A" ( < 50kW) application.


Roger

Thanks for that Roger,

for the life of me I could not find a fast track form on their website.

"Will both your generation and battery storage devices be prevented from operating in island
mode, i.e. when there is no mains supply?"

This bit has got me confused.. I want to use my batteries in the event of a power outage for my house. I thought that was the point of a sofar inverter with emergency /critical loads (or whatever it is called). Or does island mode means prevented for exporting to grid when there is grid failure...

[Stinsy]

Pretty sure this is the form you need. (Link below)

https://www.westernpower.co.uk/download ... iteme/2786

The system is not keeping up with technology in my opinion. They seem obsessed with "generation" i.e. wind or solar so the 3.68kW from your battery storage doesn't seem to matter as long as there is an export limiting device . It seems to me they will allow 3.68kW solar "generation" AND 3.68kW from battery storage (export control limited to 16A), but not an "additional" 3.68kW from an hybrid inverter with batteries and PV - export limited in the same way! The Hybrid Solis inverter I want to use is G100 certified and export controls to 0 so I can't see the issue. I am in a similar situation and am awaiting a response from UK Powernetworks as to whether I can use the fast track route or need to do a G99 "Type A" ( < 50kW) application.


Roger

Thanks for that Roger,

for the life of me I could not find a fast track form on their website.

"Will both your generation and battery storage devices be prevented from operating in island
mode, i.e. when there is no mains supply?"

This bit has got me confused.. I want to use my batteries in the event of a power outage for my house. I thought that was the point of a sofar inverter with emergency /critical loads (or whatever it is called). Or does island mode means prevented for exporting to grid when there is grid failure...

You have to read and understand everything solely from perspective of the DNO. They want to know that your system will stop providing power to the grid in the event of an outage. And that the device(s) will do so in the proscribed manner. They don’t want their engineers to be electrocuted when working on the lines.

The DNO has no concern about circuits in your house. Those circuits can operate in the event of a power cut because they are isolated from the grid.

Imagine you live in a little hamlet of 3-4 houses in the middle of nowhere. Then in a storm a branch takes out the 11kV power line supplying your hamlet. A temporary solution could be to provide a generator to your group of houses. This is called “islanding”. The DNO does not want your system to try to provide such. So all grid connected “generators” must have “anti-islanding” features built in, and they all do, you have to confirm that yours does!

[nowty]

"Will both your generation and battery storage devices be prevented from operating in island
mode, i.e. when there is no mains supply?"

This bit has got me confused.. I want to use my batteries in the event of a power outage for my house. I thought that was the point of a sofar inverter with emergency /critical loads (or whatever it is called). Or does island mode means prevented for exporting to grid when there is grid failure...

The emergency output from the Sofar ME3000SP is a separate (Off Grid) circuit and is not connected to the grid so you can correctly tick that box. Your Solar PV generation will also disconnect and not operate.

My SMA system is a bit more sophisticated as I have a G99 failsafe relay which disconnects me from the grid, then makes my whole house an Off Grid system. The beauty is its all automatic and the Solar PV generators re-connect and throttle back if necessary to maintain voltage stability. It even resynchronises with the grid frequency and voltage before it reconnects.
https://camelot-forum.co.uk/phpBB3/view ... f=14&t=128

I've had to make a few changes recently to avoid high power circuits like storage heaters, EV chargers, etc, coming back on and overloading the battery inverter.