Dillsue

Try this https://www.ofgem.gov.uk/publications/guidance-generators-co-location-electricity-storage-and-hydrogen-production-under-ro-fit-rego-and-seg

All he needs to do is add panels to the FIT system and change the inverter if it can't handle the new DC input. Declare the additional generation capacity and get paid pro rata for the existing generation meter. Simples!

Your correct, the FIT Generation Meter measures generation only. It's used for generation and deemed export payments. If you're on metered FIT export, then that's done by the premises smart meter. If you've got FIT and non FIT generation going through the export meter then it's not possible to measure the FIT element so you go onto deemed payments. No mention of how you've been previously paid in the Ofgem guidance.

Had a quick look at FIT guidance for eleccy suppliers which contains the following- "6.72. Where it is not possible or practical to measure export by export meter readings, export should be deemed for accredited FIT installations with a total installed capacity of up to 30kW. For the accredited FIT installations where export is permitted to be deemed, the Secretary of State determines the percentage of electricity deemed to be exported. Such a determination is published at least 1 month before the beginning of each FIT Year." I read that as its obligatory to make deemed payments if an export meter can't accurately measure FIT export. So if you've been on deemed then moved to metered export, all you need to do to move back to deemed is add some none FIT Generation which renders your FIT export meter reading inaccurate. At that point your leccy supplier is obliged to move you back to deemed???

Not sure that's necessarily correct! If you add PV in addition to your FIT system it's not possible to use metered export as there's more going through the meter than just FIT export. What you are saying is that export payments would then end??

I have long been under the belief that you can choose metered or deemed and could revert to deemed if you wanted to. Dont know where I've got that from but may be worth looking into. Deemed is certainly the way to go if you'll be daytime charging a car or battery

Sorry, replying to JamesPa!!

Assuming your existing is a FIT system?, look up the OFGEM guidance for FIT generators and either the guidance for generators(you or me) or FIT payers(electric Co.) includes schematics on allowable configurations for battery hook up. Basically it mustn't be possible to charge the battery from the grid and then discharge through the FIT Generation meter. Only site generated eleccy from your acredditted system can pass through the generation meter. DNO requirements are separate so an AC coupled battery downstream of your generation meter will likely meet with FIT rules but need G99 approval from your DNO

When I looked at the Octopus non MCS scheme you needed BC sign off that your roof is structurally able to take the extra weight and you need a part spark sign off. Potentially £500+ for those on top of the Octopus fee. Member if youre buying secondhand inverters to make sure they comply with current grid standards, if you want your connection to be legit

Yep. A PV diverter will do that for you. Ideally you want 2 immersions in your tank and a diverter that will heat the top of the tank first and switch to the bottom immersion when the stat in the top one switches off.

For export limitation, G100 requires the limitation to be password protected by a factory or installer password that the user shouldn't have! If you go for an inverter over your DNOs 5kw limit you'll need one with a G100 cert and professionally installed to comply. No idea if your DNO is bothered with such things?? Our DNO said if we went for export limitation they'd want to witness it and charge several hundred £ for the privilege If you go with a 5kw inverter with a G99 cert that should limit to 5kw but check the cert. I don't know about other manufacturers but Solaredge allow up to 200% DC input of the inverters rated AC output so an SE5000H can have 10kw of panels connected

Yep, with the right setup. If your battery is DC connected and your inverter carries a G98 cert then good to go.

I may be wrong but for your export I think Octopus accept manual readings where smart meters won't connect. They're obliged to pay SEG rates so if a smart meter isn't sending data, manual readings is the only way they can meet that obligation. Doesn't help with variable tariffs though!

Your azimuth figure should be -30 for a SES facing roof but that's not going to make a huge difference. Remember that to use PV, without batteries, you need to use it when the sun is out and generating. If you or your guests are out during the day and back in the evening to cook/wash etc then you'll be exporting lots of surplus PV during the day and importing in the evening. The only way to more accurately compare your usage with forecast generation is to use hourly figures.

Top of the quote says 10.9kw so probably just cut and pasted from previous quote

No apology needed. From lots of posts it seems that DNOs across the country do things slightly differently and I just wanted to see if that was another DNO quirk

Not sure if your talking about the limits set by 2 differing organisations. The 16amp limit is set by the DNOs and as you say is governed by the inverter. OFGEMs FIT scheme looks at generation capacity which is the capacity of the panels

AFAIK you can only change like for like so if you've got 13.4 kwp now you'd need to replace with the same capacity. If you want to do something different then read the guidance to understand what total and net capacity means and how it would affect payments.

Absolutely

I know of 2 people that put self installed and had it accepted without a part P sparks test cert- did you submit the electrical test cert to your DNO??

OP is doing a G98 notification so G100 is irrelevant as G98 already requires a set limitation

If you've got 13.4kwp of panels, run your figures through PVGIS to see what you should be generating. If you're around the forecast there's no point in changing your panels. Our 9 year old 250 watt panels are generating like new.

If you increase the size of the array it'll generate more over the year. May may not be clipped in the summer but total annual generation will go up. Whether your FiT payer notices or cares is anyone's guess.

Same for us

Put your sparks details in the installer section and include the inverters reference off the ENA type approved database in the inverter section. Include a single line diagram of your house electrics with the G98 form. Job done Do your sums for getting export payments from Octopus remembering that the 15p/unit isn't guaranteed.