Dillsue

So are they all on their own DNO meter and have their own MPAN? How many flats are there?

Page 65 is within the section on eligibility criteria for FlT installations/payments and I read that as applying only to the FIT accredited part of your installation?? The section on extensions talks about accredited and non accredited installations and the tariff rates you are entitled to on p23 section 3.18. It gives 3 scenarios which I read as follows- Original accredited installation-MCS, entitlement to FIT tariff(80% in their example) Extension accredited installation-MCS, no FIT entitlement but entitled to SEG tariff(20% in their example) Extension non accredited installation- non MCS, no FIT or SEG entitlement. (20% in their example) You may get PPA from Octopus and Co., but no entitlement to anything. These 3 senarios suggest to me that self installed/non MCS extensions to a FIT system are allowable An inverter swap may impact DNC but not TIC which is driven by the panel capacity, as I read it! You'd be increasing the TIC if you added panels so wholly notifiable as an extension. From what's on our original MCS cert the G98 limit is what defines the DNC. Our FIT install has 4kw of panels and a declared TIC of 4 kw. The inverter is limited to 16amp so the DNC is declared as 3.68kw. Yep!!

I dont believe that MCS is required for any alteration or repairs/replacement to a FIT system. As an example, if you extend a 4 kw system by 4kw to give an 8kw system you get paid FIT rates on the original 4kw. If the 4kw extension element is MCS installed you can claim SEG on the extension. If the 4kw extension isn't MCS certified then you can't claim SEG but you could get paid under a PPA by the likes of Octopus. It's all in here https://www.ofgem.gov.uk/sites/default/files/2024-09/Guidance_for_FIT_Generators_V18.pdf

If your inverter supports it or you can change it for one that does, I believe you can DC couple within the FIT rules. If you can charge from the grid and potentially export it again through the generation meter then you need to replace your generation meter with a bi directional meter that gives a net reading so the net reading only represents the PV generation.

Have a look here https://www.ofgem.gov.uk/sites/default/files/2024-09/Guidance_for_FIT_Generators_V18.pdf section 5.6

Ouch. Through all that sunny weather too!

It is the lower value but definitely worth checking your own figures before jumping from deemed to metered as you can't go back for 12 months. One of our systems is 4kw on 2015 FIT rates and it's only because we have a second self installed system that it was worth giving up the deemed element from the 4kw system and going for metered export from both systems.

That setup needs prior approval via a G99 plus G100 to cover the setup of the export limitation. I think there's an awful lot of inverters that support export limitation but unless the limit is factory set to 3.68kw and G98 documented as such, then you need consent before connecting.

Yes...I missed the presence of 3 phase! If the 3 phase inverter distributes the PV equally over all 3 phases but the house loads aren't evenly balanced across the 3 phases then it may be more beneficial to have a single phase inverter hooked up to the phase with the bulk of the load on it??

Hopefully you're aware that if you want to connect an inverter greater than 3.68kw output you need prior permission from your DNO so a 5kw inverter is a no no without approval

SEG is a government backed scheme that typically pays 4-6p/unit. The 15p/unit rate is a Power Purchase Agreement ie a contract between you and an eleccy company. There's no government involvement/backing and in theory could end at anytime. Lots of people including me sell under a PPA but best that you understand it's different to SEG

Your FIT generation payments won't get affected by switching to a smart tariff. If it's an export tariff then you'll loose your deemed export but still keep the lucrative generation element.

Putin added a bit of fuel to the fire that was already raging with post covid recovery....we were on our 4th eleccy supplier when Russia invaded!!

The SEG is the governments replacement for the FIT scheme but... only pays for actual export and pays a pittance per unit, typically 4-6p/unit. Being on early FIT rates you might be best sticking with your generation and deemed export payments but if you know what you'll likely export in a year you can run the figures. Octopus Outgoing will pay you 15p/unit based on actual export from your smart meter. I don't know what deemed rate you get but you'll probably be better off sticking with what you've got??

Don't you want to export everything you can and charge the battery and hot water overnight on the 7.5p rate....assuming your battery and DHW tank are large enough for a days use??