Dillsue

Rock solid then. If youre not used to swinging a sledge hammer, get someone who is to do it!!!

With no bracing shown on the sides Im guessing the vertical tubes get knocked well into the ground??

I genuinely don't understand why you think theres going to be a 50% loss in generation for the new 1.5kwp of panels. Inverter losses are a few % so having a second inverter is going to have negligible impact. Putting half of the new panels on a flat roof will have an impact but not much. Running 1.5kwp of panels through PVGIS gives annual generation of 1376kwh at 35 degrees and 1251kwh at 10 degrees inclination, so a loss of under 10%. OP only has 2 out of 4 panels on a flat roof so under 5% loss. How much shading there is on the OPs 2 flat roof panels we dont know, but we have 3 out of 16 of our panels shaded til lunchtime and our array still generates significantly more than the MCS forecast year on year so the shading cant be too detrimental.

If youve had the system stripped it can take a while to get the slugs of air out of the system. An auto air vent will catch any bubbles circulating and stop them accumulating. I'm not sure what you define as the solar station but you definitely want to be venting the collector on the roof

Interesting stuff. I'd have thought that there would be more than 25% difference between identical shaded and unshaded panels so not sure how Tigo deal with that?? Solaredge dont seem to have the same restriction as you can have 250w and 500w optimisers in the same string. Probably not relevant to the OP unless he's gonna migrate the lot to SE

Why would adding 40% more generation capacity, in the same location, only give a theoretical 40% increase in generation? OP is putting 2 panels on a pitched roof and 2 on a flat roof which may or may not be angled but I dont think that gonna cost him a loss of half his additional generation which youre suggesting at quoting 20%. In terms of 'getting excited" I like people to see the bigger picture, which includes the risks in doing certain things, like breaching the FIT rules, as you suggested. We had our FIT payments suspended a few years ago due wholly to an admin error by our FIT payer, Scottish Power. Despite extensive dialogue with them the payments only got reinstated after 6 months following a formal complaint to OFGEM. If youd breached the rules and had payments suspended I could see that taking a very long time to sort out, based on my experience.

I cant see electricity suppliers not wanting to buy excess renewable generation so I'd be surprised if SEG or a similar system wasnt in place for a good while. If youre making a decision to install kit based on receiving payments its probably prudent to also consider the same project without payments.

Adding 1.5kw to a 4 kw system is around a 40% hike in generation. Factor in the new panels will almost certainly be more efficient that the old 250w panels and that's a blatantly obvious hike in generation. I'm not sure if FIT payers monitor that sort of thing but it would be very easy to do. Youd almost certainly get your FIT payments suspended and possibly loose them entirely for not notifying the system extension. I'm not sure how the FIT scheme is funded but likely we all contribute through eleccy bills/tax, so taking payments youre not entitled to is money out of everyone else's pockets!!

But that's exactly what optimisers are designed to deal with. There's no difference in varying panel outputs from a mix of shaded and unshaded panels compared to a mix of panel sizes/outputs. We have 310 and 320w panels on one string and 335 and 405w panels on a second string. Being able to use differing size panels is an often overlooked feature of optimisers that allow a system to be very easily expanded over time without having to source panels to match originals that may have been obsolete for years. Like the OP our original FIT system uses 250w panels and I doubt Id be able to easily find 250w panels if I wanted to expand that system. Fortunately that system uses optimisers so I can add pretty much whatever panels I want up to the inverters DC input limit😁

Run a beefy SWA as suggested and a run of blue alkethene water pipe with a draw wire in it and you can pull in whatever data cable you/your installer wants.

The 4000tl spec Ive just looked at has max DC input as 4.2kw so quite limited. It also seems to have 2 MPPT inputs so if only one is currently wired you could hang your new panels on the free input. PVGIS will give you hourly data which you can crunch in Excel. Put in all the panels facing the same direction AND inclination as a single array and down load the data for the best FIT generation year youve had. Repeat for the remaining panels grouping them in separate arrays by common direction and inclination. Once you've downloaded all the data put the date, time and kw from each dataset into a new sheet. Add all the kw values to give you total kw for every time period. Then sort the entire sheet by kw total column to see what your likely peak kw DC input is. If its 4.2kw or less then youre good to go, otherwise a bit more thinking. Bear in mind that if your max PVGIS input is close to the inverter limit, then over time you might have problems with changing weather. Despite the fact that panel output is supposed to drop off over time, we've just had our best annual generation since 2015 on our FIT system.... climate change or a one off???

Have a look at the spec for your existing inverter as you may well be able to have way more DC input from panels than the inverter rating. Our older 4kw inverter can accept 5.4kw of panels and our newer 3.68kw inverter can accept 5.7kw of panels. Extending the system rather than adding a second system keeps you within the OFGEM guidance for pro rata payments and no worries about export limitation. If you put a second system in with DIY export limitation, you probably dont want to declare that to Octopus as Id be surprised if they'd accept a casual limitation set up that you could easily remove or alter yourself........unless anyone has done this????

Not sure of your figures but if youve got a PV diverter wouldnt you be better off on deemed export??

The DNO has said the extra panels will be ok so no need to limit export

You were talking about a micro inverter solution so I assume that's what youve already got?? Solaredge optimisers deal with a mix of panel sizes and I assume micro inverters do too but that would be a question for the manufacturers tech support. It's the micro inverters that interact with each other, not the panels, so you can probably use whatever panels you want up to the limits of the micro inverters they are connected to. Plugging in 4 additional micro inverters into an existing loop shouldnt be a problem and if you use factory assembled and tested inverters/cables/plugs then its straight forward to connect up.

The FIT rules have changed and you can alter a FIT system without losing your payments- https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.ofgem.gov.uk/sites/default/files/2021-12/Feed-in%20Tariffs_Guidance%20for%20renewable%20installations_V16.pdf&ved=2ahUKEwi91OP77aT8AhVHTUEAHebpBEoQFnoECBIQAQ&usg=AOvVaw3i84Pu-SO0Ibm-lhEjzfaT

No experience with Solis kit but an RS485 connection could well be a local network for connection to an energy meter, battery pack or another inverter. If your expecting to see a value for grid export then have you got or going to have an export meter? If thats yet to be installed/cabled, that could be why you got red lights/errors and your installer idnt too concerned??

If you are having for about to have the house wired, is that utilising the 3 phase? If not, I'd speak to your sparks and tell them you may be going for 3 phase and could they consider that in any work they are doing now. If you go for a 15kw system, WP could well ask you to spread it over the 3 phases so you would need the house wiring over 3 phases to use your PV. That said there was a post on here a while ago saying if you have a smart meter with net metering any unused exported PV on one or two phases will cancel out an equivalent amount of imported energy on the third phase. You look to be calculating the forecast monthly PV generation with a panel "efficiency" figure. You'll likely get more accurate figures if you Google PVGIS, input your data and use their forecast figures. If you are focussed on ROI, you might want to run your calculations using a variety of grid kwh unit figures. I cant see the current unit rates lasting too long!

Tradesparky/solarsparky always seem competively priced but Google the panels you want and see what comes up. Bear in mind that for panels, there can be significant delivery charges so somewhere near to you may work out competitive if you can collect.

Google PVGIS and put your details in to see what output youll get

No provocation intended, but if it did then guilty as charged

I think the UK intent would include CCS too. As for viability, we might know in the next 5 or so years- https://www.essar.com/essar-oil-uk-to-build-360-million-carbon-capture-facility-to-deliver-on-its-ambition-is-to-be-a-leading-low-carbon-refinery/

Then read the BEIS forecast doc I pointed you to if you want a finger in the air guesstimate. This is hard work!

I'm trying to help you find the info you want. You asked what percentage peak providers needed to cover. If the wind isnt blowing on a cold winter evening then alternatives need provide not far off 100%. If you look at gridwatch, CCGT alone was doing up to 65% around 12 Dec. If you want to know generation breakdown in 2050 you should have said that. Google BEIS energy predictions and youll find forecasts through to 2050 by generation type. Unfortunately for you, FF use is predicted to be 19% in 2040 and 14% in 2050, from memory!!

If you go to Gridwatch and scroll down the home page, theres a list of UK generators that includes fuel type and capacity so if you get your calculator out you can add up whatever figures you want to understand. If youre clever you may be able to paste it into Excel to play around with??