Batteries for solar, FIT - is it worth it?

rarees1

My husband and I are both pensioners with a small amount of savings.  We invested in solar panels for our energy about 14 years ago.  The cost then was very much higher around £12k for a 4kw system but the FIT payments rate much more generous than for new installations now.  To be honest I don't know how we would have managed to pay our bills without them, especially when made redundant or long term sick.  The FIT payments are paid for a total of 25 years so we're more than half way through.   

Now we're pensioners the money is even more important because there's no opportunity to increase our savings but we're wondering whether it might be worth investing in battery/batteries.   We don't understand how things work.  Would our FIT rate drop?   We've always claimed it from the energy provider we were with at the time of solar panel installation even when we changed companies for our energy.  We are with Octopus now.

Can someone please explain the advantages/disadvantages of the battery system and how we would stand financially going forward?

gefnew

You could post in this forum.
https://forums.moneysavingexpert.com/categories/green-ethical-moneysaving

Qyburn

Your FIT payments will be made up of two parts, "Generation" where you get paid for every kWh you generate whether you use it or not. And "Export" which pays you for the surplus. This will be at a much lower rate, only a few pence per kWh. Given the age of your system this is probably what they call "deemed" where they simply guess (deem) that 50% of your generation is exported.

If you fit a battery your FIT provider will need assurance that it doesn't invalid the generation meter readings, for example by allowing you to charge from the grid then claim generation payment when you use the power later. I expect they'll require a schematic to assure them.

They may raise issues about export, since the battery by definition means you use more energy yourself and export less. They might want to to change to metered export where you get paid for your actual export. The counter advantage is that metered export can pay something like three time the rate you're getting for deemed export. It requires a smart meter.

Petriix

If you do get batteries, keep them independent of the existing system and go for what they call an AC coupled battery system; don't, whatever you do, install anything on the solar side of your generation meter.

The calculation for adding a battery is complicated but, unless you're high users, intuition says it's not likely to be cost effective for you.

The thing that's more likely to be of benefit is to switch to a more lucrative export scheme. You can keep the generous FIT generation payments but opt out of the deemed export payments, switching to something like Outgoing Octopus at 15p per kWh.