Dillsue

Have a look at your contract with your electricity supplier and I think youll find it includes a reference to a "national supply agreement" or something similar that governs your connection to the grid. Youll likely find something in there. Edit-It National Terms Of Connection that you want

First sunny summer day after some of Wil's neighbours have installed G98 systems or bigger systems without permission?? Our TX is 5Kva just for our house and is getting replaced at the DNOs expense. When our G99 went in they could easily have told us we needed to pay for the upgrade but they said it was under specced by modern standards so they would upgrade it and lower the supply voltage at no cost to us. Couldnt have been more accomodating. The problem with circumventing the rules is if problems start to happen on a section of the grid where theres unauthorised systems, the DNO will investigate and the unauthorised systems will get disconnection notices. It maybe that the problems have started because neighbours have legitimately added G98 systems but it will be the unauthorised systems that get the disconnection notices and may have to pay for network upgrades before they can reconnect!!

Thats more like it. Hopefully theyll informally give you some idea of the local constraints and what youll likely be able to connect.

Im not questioning whether things can be physically done, but trying to understand the process that you are using to do things, above board. I took your previous posts as saying that you could put in an export limited system(zero export) without using the G99+G100 application process. If its not through the G99+G100 route then intrigued to know what other routes there are to legitimately connect to the grid??

Yep, an empty garage is probably a better bet but that would be the place for any battery pack, in my world anyway. I had another look at PV connectivity when using Storedge to charge from another inverters output and I dont think you can do it so definitely check with SE before making any decisions, if you can get your head round the cost!!

Maybe theyve seen the thread on parasitic load and are off loading Ecodans before word gets out and they become unsellable

Our DNO was happy to discuss technical detail and I think/hope we agreed the scheme that our G99 application has formalised. Cant speak for UKPN but SPEN were great, so far. Ive no idea what other manufacturers offer but have a look at the SE Storedge system to see what is possible... charge from PV, charge from the grid, charge from another inverters output all on DC coupled batteries so they dont add to potential export figures.

As the OP already has a FIT system thats likely to have been declared as being at the 16A allowable export limit, surely the DNO is going to be asking questions if you send in another "statement of compliance" without a G99 application or manufacturer declaration of zero export? Have you actually done this and had it accepted?

Still needs a a bit of G99 begging for the inverter unless the new system is off grid

Just looking at your figures, youre listing a 5kw SE inverter, a Victron 5.5kw charger and the 4kw existing system which totals up 14.5kw of potential export. Thats a fair bit of export to get approved so might be worth having an informal chat with your DNO to see what they think before you submit the G99??

Thats for 3 phase systems to declare there wont be more than 16A per phase difference in export on each phase

Other manufacturers may have different settings but the UK spec SE inverters we have are set to shutdown at 262v Yep spreading the array round will help but I guess a battery bank is going to put a fair load on the PV which should keep things in check. On an SE inverter there is supposed to be a power control feature that you can use to throttle production as voltage rises and so keep household voltage sensible. Im waiting to hear from SE as to where in the menu it is as Ive not been able to find it despite installing the latest software!!

Should be on the inverter spec sheet but 1 is likely to be accepted.

I think shutdown voltage is a fair bit higher than the UK max of 253v....262v? Our supply is at 250v and our existing PV pushes us over 253v on a sunny day, but inverter keeps churning out the kw.

With an SE Storedge system theres a CT on the grid connection so the charge controller knows if theres generation going to export and then diverts excess to battery charging. As far as I know any decent PV charge controller would need a CT to govern whether to charge or not?? The G99 need for installer details is a stupid requirement! Until you get your G99 approved you dont know what youll be installing... if approval needs an export limitation system with a commissioning demonstration thats likely a specialist system outside the abilities of your local part P spark whose details youve put on the application. I put TBA on our applicatiion and the DNO wouldnt process it. I then told them I was installing myself with a test and inspection carried out by our local Building Control department...that was accepted.

If youre happy with the SE system you have, Id be looking to install a Storedge system. They can charge from the grid or the AC output of another inverter like your existing FIT system. I think you can connect additional PV to the inverter doing the battery charging but thats worth double checking with SE. If you really want to add PV and storage but your DNO says no or upgrades are prohibitive, you could add export limitation to stay within the 16A limit you already have. With batteries and maybe a PV diverter youll not want to be exporting much anyway. The NW facing roof would help with late afternoon/ teatime production but if youve got batteries youre probably best getting max daytime production on the garage to charge the batteries and draw on the batteries later in the day

With a very large quantity of potentially toxic chemicals stored near me Id be wanting to know all the measures taken to deal with fire, chemical leaks etc. I know very little about battery chemistry but I doubt the contents are something you want drifting in the air or leaching into local ground water.

Outside of peak sunshine months, youll likely to be able to use everything a 12kw array will produce. Year round production is where bigger arrays come into their own. Youll always have an export limit. If you cap export at the 3.68kw G98 limit then you just notify the DNO. If you want to export more than 3.68kw then you need to apply for chargeable permission and that permission would come with an export limit determined by what the local grid can handle or what grid upgrades you want to pay for. How you limit the export is up to you but youll need to convince the DNO that you have an effective limitation system in place. Weve applied for 2 x G98 certified inverters in our G99 application so 2 x 3.68kw. You could have an inverter(s) without a certified limit and add an export limitation system. The export limitation system would need a G100 application in addition to the G99 application. Speak to your local DNO and they may be able to give you an informal indication of what you can connect, ours did and was very helpful.

With panels over a decade old it might be worth checking annual production hasnt dropped to much. With lucrative FIT payments it could be worth renewing the panels if output has dropped.

Is that because the neighbours septic tank runs into it🙈

Adding panels to a FIT accreditted install almost certainly increases the Total Installed Capacity so would need FIT payer approval and MCS install. If its a separate system within the house, then fill your boots, with DNO approval if needed.

As I understand things any alterations on the inverter side of the generation meter are alterations to the FIT accreditted system and risk loosing FIT payments. Any alterations to the consumer unit side of the generation meter and thats part of the house electrics which is nowt to do with the FIT accreditted system.

Having posted on an internet forum the suspicion that the meter may run backwards, Id hazard a guess that knowingly exporting anything through a backward running meter from now on would be fraud????

Or dont install a DC isolator on a SE system with safe shutdown?? Im not saying its the correct thing to do on every system, but on a SE system you remove the chance of a non techy person(householder) doing something detrimental. On a SE system switching off the AC isolator, flicking the on/off switch to off, switching off the inverter MCB, power cut will all shutdown the optimisers and kill the hazardous DC voltage.

Not sure how much space youve got on the east side but you can get 450+ watt panels so not far short of 1kw if you can get two x 2100 x 1050 panels in. Only you know if you can get them in and if its worth the effort. Maybe worth running the 2 panel set up through PVGIS to see how much theyll produce If I was in your place, Id speak to the local planning office and sound them out about panels on the flat roof. If they sound positive I design what you do now assuming that youll be adding to the system in the near(ish) future