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Afternoon all

I am based in Tarves, met with Joeboy not too long ago when he picked up a couple of panels. He put me onto this forum.

I am looking to move further away from the grid if possible. I currently have an old grid tied 3kw system with a decent FIT from circa 2012 with around 8 years left to run.

My aim is to boost my current system with a further 5+kw at first whilst maintaining my 3kw grid tie.

I would like it so that the grid tie feeds into an all in one inverter around 8KV+ and that the extra panels go to run the house and battery, only drawing from the grid when the solar PV supply and batteries are depleted.

I have land avaialable for ground mount and a South end facing gable space on the house with space for maybe 5 or 7 large vertical panels around 2-3KW.

So to summarise:
- 3kw grid tie with 3kw steca(want to keep the cheques flowing untainted).
- 8kw+ all in one, fed directly by a 5+KW array.
- 15-20 KW batteries.
- Aiming to dump the oil boiler and go air to air conditioning. 5KW downstairs and 6KW upstairs. Eventually have the hot water powered by excess solar as a dump load?

Can i feed in the grid tied solar to the AC input of an all in one 8KW inverter without it affecting the amount I pass back to the grid?

Kieran

Yes, in that you add a Hybrid Inverter (takes Solar and Batteries) and ensure the Hybrid Inverter does not go through the FIT Generation meter.

G99 or G99 Fast Track pre install application to DNO, no need to inform FIT provider in most cases.

Many on here have done it.

Two important things to consider.

First, how big an inverter will your DNO allow you to connect to the grid. The DNO will want to limit the maximum amount that could be exported to the grid, possibly, with a limit as low as 16 amps or 3.68kW. It is possible, with DNO approval, to have a CT control the export from the new inverter and/or batteries to keep under the limit (G99 application).

Second, your FIT payment is based on your generation meter reading. Your systems need to be wired such that only electrons flowing through your existing system flow through your generation meter. In particular, neither the new panels or battery are allowed to supply the generation meter.

You’re best off leaving the FiT system alone, you can fit a hybrid inverter to handle your additional solar and the battery storage from both systems.

A 5kW hybrid inverter should be plenty, even if you want to fit 8kWp or more of additional solar.

You do need DNO permission for the additional inverter.

Welcome to the forum Keiran, I'm not that far from Joeboy only about 6 miles.

I assume Fintray is Hatton of Fintray.

My main reasoning for an 8KW is that I am moving my heating over to Electric and the assumption is that the most the 5KW inverter or 8KW inverter could output when attached to the batteries would be 5 or 8KW.
I am aware that some inverters can limit export.

I want to be greedy

I assume by keeping the FIT payment I just get the benefit of FIT payment from the previous system and any extra hybrid inverter would bleed any unused or stored energy back to the grid without payment?

Any schematics to show how this would look would be appreciated.

Fueltheburn wrote: ↑Mon Sep 11, 2023 12:34 am I assume Fintray is Hatton of Fintray.

My main reasoning for an 8KW is that I am moving my heating over to Electric and the assumption is that the most the 5KW inverter or 8KW inverter could output when attached to the batteries would be 5 or 8KW.
I am aware that some inverters can limit export.

I want to be greedy

I assume by keeping the FIT payment I just get the benefit of FIT payment from the previous system and any extra hybrid inverter would bleed any unused or stored energy back to the grid without payment?

Any schematics to show how this would look would be appreciated.

Hi Kieran, both panels operating, cheers! Welcome onboard. The hybrid inverter doesn't send much energy to the grid if you set up to use it all. Batteries, EV, hot water tank and home Hive controlled storage heaters have been my solution.

Octopus now have non mscs export tariff, you could contact them. Sorry no schematic, in Italy.

Fueltheburn wrote: ↑Mon Sep 11, 2023 12:34 am I assume Fintray is Hatton of Fintray.

I assume by keeping the FIT payment I just get the benefit of FIT payment from the previous system and any extra hybrid inverter would bleed any unused or stored energy back to the grid without payment?

Hi Keiran, I'm not in Hatton of Fintray but just in the Fintray area towards Kinmuck.

When I added my second PV system I knew I'd have excess generation, as I'd already moved to Octopus for supply I then contacted them to move my export over to them. They contacted SSE (my FIT's payer) and cancelled the deemed export part (main FIT's payments stayed with SSE, but you can move this across as well). Octopus now pay me for all my export to them, you do need a smart meter for this.
They have recently increased the export payment on Octopus Outgoing to 15p/kWh which is higher than any other supplier that I'm aware of.