Adding to a Solar PV system

djmattc

Hello

I've got a 3.6kWp system which was installed last June. Since then I had trouble with the chimney (leaking etc.) so we had the chimney removed.
So now there appears to be space so I can install another 3 panels in addition to the 12 I already have.
I wasn't really happy with the company that installed my panels for various reasons. However, my questions are :-

• Would a company bother coming out to install only 3 panels?
• Is it possible to add to existing structure without disturbing the existing panels?
• Has anyone had this done before?
• Would I need to re-register the new power levels or would this invalidate the FIT I have already signed up for?
• Is it worth it?

I understand that adding to the system means that I would have to upgrade my inverter but I've got my eye on a hybrid inverter anyway as I'm interested in battery storage.
Your thoughts?

Exiled_Tyke

I'm thinking of doing the same. What I understand is:

1. No more FIT payments available. You'd be best running through a separate inverter and not bothering with a meter. The best solution may be micro-inverters - which I think you can run 2 panels through each one.
2. Leave it until after March when installers will have finished the rush of final FIT qualifying systems. They probably will take on any business they can get.
3. You need to make sure you don't exceed the DNO export limit. I would expect this can be achieved as you don't need to export any electricity - as there are no payments available to you.
4. the new export deals will come through at some point and may change this advice. But I'm guessing the rules will state that your entire property has to be on FIT or the new scheme so it may not affect an extension.
5. I'm told you could have two inverters feeding the same battery. personally I'm very pessimistic as to whether batteries will ever now become financially viable for domestic use.

djmattc

Thanks for your message.

It's interesting stuff. Personally, as long as batteries don't make me bankrupt then I'm still interested in an investment. As the technology stands it looks like it will be quite a way off becoming financially viable. However, I'm willing to take on some of the cost to do my "bit", mostly because it's annoying that the excess I generate is being sold at more than twice what I get paid for

So, generally, the advice is investigate this again in April?

mmmmikey

Hi - my system comprises a 3kW array on an east facing roof and 1kW array on a south facing roof and I have two separate inverters. I have just ordered a Powervault battery and can confirm that 2 arrays are no problem for one battery system but there are considerations about how it is connected.


I echo comments above re: financial viability. Like you, I'm happy to spend a bit of money to save my little bit of the planet. Having done the sums, my conculsion was that at best I'd have a fighting chance of recovering my investment in the lifetime of the system. In my case the only thing that gives me this fighting chance is storing very cheap off-peak electricity at night.



As a very rough order of magnitude estimate (caveat, caveat, caveat, you get the picture) with a solar only charging you may well only recover half the cost of the battery system in it's lifetime, which may or may not be acceptable to you depending how much you're prepared to spend.


With regards to the solar panel additions "plug in" systems become an option if you treat this as a completely separate installation and may be your most cost effective route (Google "plug in solar uk").

sevenhills

Exiled_Tyke wrote: »

4. the new export deals will come through at some point and may change this advice. But I'm guessing the rules will state that your entire property has to be on FIT or the new scheme so it may not affect an extension.

Will there be FIT payments in the future, I don't see why there is a holdup if they are coming back, solar panel companies will be going bust in waiting.

Exiled_Tyke

sevenhills wrote: »

Will there be FIT payments in the future, I don't see why there is a holdup if they are coming back, solar panel companies will be going bust in waiting.

My understanding is (although I'm sure others on these boards know more than I do). FIT payments are gone (probably for good), but the government is looking at export payments. The expectation is it will be more generous than the current export payments. I'm guessing that this will work on metered export rather than assumed percentage of generation AND importantly allow for a variety of situations e.g. homes using batteries to buy cheap off peak electricity and the sell it back to the grid at peak times. Those I have spoken to are of the view that a house will have to be on current FIT payments or the new scheme. ie. current PVers who add batteries and want to sell to the grid at half decent rates will have to forgo FIT altogether.