bontwoody

Thats good to hear thanks 🙂

Yes I saw that as I was looking at some specs. My roof doesnt have any shading issues so Im not sure it would be worth the expense of going down the optimiser route. I also saw some negative reviews on trustpilot for solar edge https://uk.trustpilot.com/review/www.solaredge.com Have you had any call to use their support department?

Addendum. I was wrong about the installation having to be AC coupled if I want to keep my FIT payments. It can be DC coupled if a bi-directional meter is used.

So Ive had a couple of realisations on reading the documents. If I want to keep my FIT payments and use off peak charging for the batteries then I will have use an AC coupled system so I dont confuse the generation meter readings. In that case there isnt really any advantage to oversizing the panels since the clipped output would be wasted. I cant actually see either how the TIC would be calculated if the inverter size was smaller than the panel size. My guess is that they would use the panel size which would disadvantage me. I think my choices will be: 1. leave the panels and inverter untouched and just add an AC coupled battery system 2. upgrade the panels and current inverter up to 4kW and add an AC coupled battery system probably sensible to do 1. first and then complete 2. once the current inverter fails.

I hadnt really studied it in detail, but that is interesting, as is the battery info, so Ill take some time to do so thanks. It doesnt look like that is so Tony, but ill certainly make all the checks I can before changing anything

Yes, that is an issue, I will have a good look when im on the roof. Even if I could only get the total to 4kW, that would be something. No point in trying to ask one now though as they are all too busy. Im still on a cheap fixed energy tariff at the moment so there is no rush at the moment, but I would like to use something like Octopus Go or Agile once that ends, hence the battery system. Thanks

No, you are reading it correctly, you get no FIT payments on the extra installed capacity, but they prorate the reading so you dont lose out either, so if you doubled your capacity they would halve the meter reading and you would essentially get the same level of FIT payments. Im interested in the extra capacity purely for charging batteries (and running daytime appliances via the batteries) and am hoping that the installation fees will be lower because I already have the panel support system. I could even change the panels myself as its a bungalow and just get an MCS installer to change over the inverter.

Hi Dillsue Im fairly confident you can increase the capacity of your system, as Ive seen mention of it on various websites, also this https://www.ofgem.gov.uk/sites/default/files/2021-12/Feed in Tariffs_Consultation on the treatment of replacement generating equipment_Decision_13122021.pdf "From 15 January 2016, any extensions to an accredited installation’s TIC are not eligible to receive FIT payments. The generator must notify Ofgem and their FIT licensee if they do so and, if generation and export meters are shared, payments will be prorated accordingly" Im not actually trying to increase the FIT payments, just not to lose those I already have. The bonus for me is gaining the battery storage and power. I havent checked the physical size of the panels yet, but Im sure i could increase the output considerably by upgrading them to newer models. Im also fairly tight for roof space, so that would be the best way for me to go if possible.

I have recently bought a house with an existing solar installation of 14x190W panels and a 3kW Fronius inverter. Its rated output is 2.66kW and it has a FIT payment at the highest rate. I know I want to increase the solar output and I’ve been looking at ways in which I can do this in a cost effective manner. The idea I had last night, which I would like to get opinions on, is the following: Remove the existing solar panels and replace them with modern high output ones (say 400W) giving an output of 14x400=5.6kW, but using the existing roof mounted supports. Replace the existing 3kW inverter with either a 3kW or 4kW hybrid inverter. Add DC coupled batteries to the system at some point If I understand things correctly, then this should have the following advantages: No costs in providing addition roof or ground mounted supports The current inverter is about 11 years old and will probably need replacement soon anyway Minimised inverter costs for the smaller size, while still making use of the clipped output by charging the batteries A higher overall output from the array throughout the year No need to seek approval from the DNO The potential issue is, I think, with the FIT payments. As I understand it Ofgem are happy for people to increase a solar array size, so long as they notify them. The generation figures are then pro-rataed down to take account of the increased production. The change I am contemplating will produce an increased output when compared to a non-oversized system with the same inverter size but less than a system that has an inverter matched to its panel output. I’m not trying to pull the wool over Ofgem’s eyes but equally I wouldn’t want the FIT assigned output of the system to be below its current output. Does anyone know how Ofgem would view this? Would they take the Panel size as the rated size, or the inverter size? Or something in between? Thanks in advance

Update for the benefit of anyone else looking at the FIT database. I was using the wrong ID field to search. The correct field to search is FIT ID not Accreditation number. This brought back the correct installation, a 2.66 kWp one situation in the correct geographical area 🙂

I found this very good https://re.jrc.ec.europa.eu/pvg_tools/en/ you could calculate each direction indivdually

Hi Dave, yes, Ive already stressed to my solicitor about the FIT payment as when I sold mine there was no check at all. In the end I did it myself but if I hadnt who knows how long it would have taken to sort out. There arent any shading issues and the roof slope and orientation are included in the model used. Im eager to get in and have a look whats happening, it looks like the meter has been read and submitted. My last FIT provider insisted on a visit or photo of the meter every year so I dont think the total generated can be very far out.

Hi Joth. I got to 2400 kwh pa figure by taking the total production since it was installed and dividing it by years so its an average over its life, so the switched off inverter theory wont work. A faulty panel would though if it happened a long time ago! Yes, the like for like replacement is OK. Its interesting that if the array was over-producing then you would be inspected by the FIT authorities to see why, no such luck if its under producing 🙂

Thanks Redbeard. Just out of interest I used the same web model for my old house and it was spot on in terms of its annual production which just makes the under performance of the new array even stranger. The only things I can think of are that 1. The panels are of a very low wattage and the array size isnt as big as I think or 2. the inverter is undersized for the array, maybe its an IG 20 and not 30?. Its very odd that the FIT number on the statement does bring back a single entrty in the wrong place. Using my previous skills as an information manager I would be tempted to suspect that the file has become corrupted, which was a common error in the early spreadsheet days when a sort was done on one column without expanding the selection to the whole file. Given the recent cock ups regarding covid data, its easy to see that people in govt are still using early versions of excel. Any ideas on the re-siting of panels, its seems no worse than cleaning them to me. 🙂

Im buying a property that has solar panels fitted and receives a FIT payment of about £1500 per year. However Ive been trying to ascertain the actual installation size, but the owner has no knowledge of what it might be. Externally there are 14 panels facing SW at about 40 degrees inclination. The FIT payment is 60.23p/kWh so that puts the installation date before the 3/3/2012. Internally there is a Fronius inverter which I suspect is an IG 30 from a picture. On my old house I had polycrystalline panels installed in July 2011 and they were rated at 230W per panel. However if I guess the panels on the new house are the same that comes to 3.22 kWp for the array. Using this https://re.jrc.ec.europa.eu/pvg_tools/en/ model, if the array was this size then it should produce about 3200 kWh per year (image attached), however looking at the latest FIT statement it only produces about 2400 kWh per year. To make things even more confusing, I downloaded the FIT installation database. Searching for installations in the area at about the right time I found 24 potential matches. However then I noticed a field called “Accreditation Number” and a reference number on the FIT statement, which looked in the same format. Searching the database on this number brought back a single entry for a 2.7 kWp system, however the bad news was that it is situated in Bradford! If anyone can shed any light on what is going on I would be grateful. A related question I have is can a FIT paying installation be re-sited on the same property without affecting its tariff rate. Im thinking, maybe adjusting its slope or orientation to improve its output?

That sounds exactly the type of system Im looking for 🙂

That sounds highly likely given the lack of response from solar installers, Maybe things will calm down later in the year. I cant help thinking that for all the pain of fuel inflation, its given renewal generation and fuel efficiency a real shot in the arm.

That sounds sensible, im just eager to get my ducks in a row. Just hope the DNO is open to informal enquires 🙂

Great, thank you 🙂

OK, so I would need to have a seperate consumer unit and decide which circuits were battery driven and which grid driven. How exactly would you put them back on the grid if the batteries were dry?

Quite likely and it will be one of my first jobs 🙂

Im looking for some advice as I haven’t been able to get any answers from solar installers, probably due to them being run off their feet! Im buying a property that has about 3.2 kW of solar panels installed in around 2011. Im a bit vague because the homeowner has no details of the array, so Ive had to do some detective work to find this detail out (14 panels in SW direction on highest FIT tariff) The panels aren’t performing as well as I would have wished producing about 2368 kW per year, but it’s a useful FIT income of £1500 p.a. I would really want to increase the number of panels and could do so massively with a ground array as there is plenty of space around the property, Im conscious that this could be a problem and would require DNO permission if I go over 4kW. However it hardly seems worth doing unless I do go over 4kW. My question is, is there another way to go? Could for instance I have a separate array, not grid tied, that purely charges batteries, while the original array also charges the same batteries when it has excess production? Obviously I don’t want to lose the FIT payment, but I would like to up my production figures substantially. Any help would be greatly appreciated. Thanks

I was curious about a drain back system, thanks Ill have a look for it 🙂

Yes and yes, but doing the figures against a thermal store I still think its the better option. Another point I forgot to mention is the possibility of maxing out on the PV if you cant get DNO approval to go over 4kW. Id also like some battery storage but so far Ive had no luck in getting any installers to answer my queries about mixing up a 3kW FIT paying array with another new array and including some battery storage. I think Ill concentrate on the ST solar and improving insulation until the winter in the hope things calm down a bit. 🙂

Im actually thinking of doing the same. The house already has 3kW of PV panels which take up virtually all of the good roofspace. My plan is to use a smaller area of SW facing for for 30 evacuated tubes. Because of the higher efficiency of the ST, Im getting a lot of bang per square metre. This should produce most of my DHW for the year with the heatpump propping it up in the winter. Another issue in the UK is the escalating prices of PV and getting an installer to fit them at the moment. I plan to DIY install the ST and connect it to a twin coil cylinder.