Solar Panels UK - is it worth it?

[yessuz]

so had similar quote from Octopus to what I have from Otovo for 14.4k. Octopus quote was 18k...

 

[Pete UK]

Not got any optimisers. Only Tigo's which don't work like those - don't seem to help my shading issue!
You can have panels just facing straight up and you'll get 50-60% of the ideal orientation. Yesterday with white clouds and no sun beaming through I was still doing 3kW off my 7.7kW - and bare in mind I've never seen more than 6.5kW. You can generate 25% of the rated power even off the panels facing the wrong way - especially if the sky is white clouds as the light is bouncing all around.
Google for "solar graph for orientation" and you'll see that facing North and you'll still get about 30% of due south. But 30% isn't much. You'll get about 70% for East or West. If the roof is at a low pitch like 20 degrees it'll do better if it's North facing.
Sounds like you should fill to the South as much as possible. Then the East, avoid the North. Check the measurements of the different panels - some vary. Old size was 1.6x1m. But most now are 1.9x1.1 or 2.1x1.1 - remember they're not supposed to fit them closer than 30cm to an edge - but most will go closer. Matters more if you're in a wind exposed area. The greatest issue is not the weight but the uplift if they stick above the roofline. You want to work out the best way to get as many as possible on the south roof. And make sure you get black framed panels. The silver framed look rubbish in comparison. Get black back-sheet as well if you're worried about what they look like. Black-on-black is going to look better than black-on-white if they're in an odd layout.
I was lucky - I've got 22 panels on a SW facing roof. 4 panels on a NE facing roof for some morning sun.

You could look at micro-inverters if you've got some that are going to be shaded when others aren't. Micro-inverters are guaranteed for 20 years I think.

Ok, thanks for that. 25% for full white cloud cover, that’s interesting and way more than I expected ! - but kind of ties in with the 45% effectivity figures I’m expecting (/been given) for the north facing panels.

Aren’t Tigo Optimisers…. Well, optimisers like other optimisers?

I think I’ve done all the research I can possibly do and need to for now. I posted the link to the “Solar graph for orientation” earlier

Can’t fit any more on the south, unfortunately, as mentioned previously. Only option I have is to max out all available roof space and hope for the best! (Tongue in cheek - I’ve researched a hell of a lot ) - To re-cap; I’m going to go for 5 on the south, 14 on the east and 8 on the north. All black 420w. 2x GivEnergy 5kW H2 inverters and 4x 9.5kW GivEnergy batteries for off-peak/ solar storage. That’s an 11.34kW system but kind of more like a real world 7.7kW system if facing only south. I calculate to generate about 7,000kW +/- a year with that. Which matches most of the estimates from quotes I’ve had. 7,500kW off peak from grid to batteries and 4,500kW off peak to the Model Y. All on Intelligent Octopus and seasonally adjusted of course !
That’s my 19,000kW a year I need. Think I’ve come up with the best solution I can get (for me).

Deposit going down tomorrow. Will be interesting to see the generation results after a year from the whole system and the, shall we say “panels facing the wrong way” . If I get 40-45% overall generation of what I get from the south panels, I’ll be pretty happy and it will have been worth adding them at the same time.

Install should be done within the next 3 months, just in time for generation to start dwindling off and electricity prices to come back down again

 

[Chimpy McChimp]

Install should be done within the next 3 months, just in time for generation to start dwindling off and electricity prices to come back down again

Hah. Same for me. I put my deposit down last week and was told up to 60 days to get DNO approval then a 15-20 week lead time after that. Which takes us quite nicely into less optimal solar season.
Hopefully electricity prices do come down but I have a fixed deal to next September so the crazy prices aren't affecting me yet. Investing in the solar panels was my way of protecting myself in the future. Plus we are a high energy usage house so anything to cut our bills is a plus.

 

[yessuz]

interesting. Otovo, when I placed the order, said that DNO approval takes 30 to 40 working days. however, why it should be additional 20 week (4 months) lead time?

after approvals are received - you need scaffold and installation. I would presume installer car get order for panels/inverters/batteries more or less at the same time as submission of the approval application as in general - this is a standard equipment. They should have a very high degree of confidence if you will get approved or not almost instantly (due to location, DNO, past experience).

 

[phil4]

interesting. Otovo, when I placed the order, said that DNO approval takes 30 to 40 working days. however, why it should be additional 20 week (4 months) lead time?

after approvals are received - you need scaffold and installation. I would presume installer car get order for panels/inverters/batteries more or less at the same time as submission of the approval application as in general - this is a standard equipment. They should have a very high degree of confidence if you will get approved or not almost instantly (due to location, DNO, past experience).

Installers are -really- busy, and stock isn't being shipped over anywhere near fast enough.

So the 20 week lead will be either they're waiting for the panels/inverter to ship, or that's the earliest free install slot. Back last year I signed and paid a deposit in June. The panels didn't arrive until Dec, and fitting was another 5 weeks as that was the earliest they could fit it in. And batteries, end of this year if I'm lucky.

It's defo not a "buy it off the shelf" experience at the moment.

 

[Chimpy McChimp]

Installers are -really- busy, and stock isn't being shipped over anywhere near fast enough.

So the 20 week lead will be either they're waiting for the panels/inverter to ship, or that's the earliest free install slot. Back last year I signed and paid a deposit in June. The panels didn't arrive until Dec, and fitting was another 5 weeks as that was the earliest they could fit it in. And batteries, end of this year if I'm lucky.

It's defo not a "buy it off the shelf" experience at the moment.

Yes. This. My installer said it's their timeframe to book installers. Not sure how long ordering the equipment takes but I think they are just swamped. Frustrating, but I'm at least happy I am doing something toward cutting my requirement from the grid.

 

[The_Cable_Guy]

As above, invertors coming from china is taking much longer than the 1-2 weeks it should take, and now its 3-4-5 weeks

 

[Mrklaw]

if installers are big enough and doing multiple installs you'd think they'd have stock being delivered continously and not wait to order install by install?

I'm apparantly being installed May 2 which means scaffolding next week but lets see..

 

[yessuz]

if installers are big enough and doing multiple installs you'd think they'd have stock being delivered continously and not wait to order install by install?

I'm apparantly being installed May 2 which means scaffolding next week but lets see..

Otovo?!

 

[yessuz]

if installer is large, they will have stock.

at the same time, they can book/order stuff on parallel to the DNO approvals

it takes 1 month for the container to arrive from China, DHL takes much less. You can book scaffolders/installers/whatever on Expected DNO approval (30-40 working days, as this is the term I got quoted by few installers) + 2 weeks (for safety margin)

 

[Pete UK]

Hah. Same for me. I put my deposit down last week and was told up to 60 days to get DNO approval then a 15-20 week lead time after that. Which takes us quite nicely into less optimal solar season.
Hopefully electricity prices do come down but I have a fixed deal to next September so the crazy prices aren't affecting me yet. Investing in the solar panels was my way of protecting myself in the future. Plus we are a high energy usage house so anything to cut our bills is a plus.

I was told DNO can take up to 45 days but usually coming back in 4 weeks.

Their lead time is 3-5 weeks after that and expect install in 8-10 weeks from now.

I don’t know why they can’t order stuff before the DNO comes back, after all that’s only for export. You’re gonna get 3.6kW export anyway, so it’s just a matter or limiting the inverters export to 3.6 if it comes back with less than they applied for.

High user here too. What kit have you gone for?

 

[WannabeOwner]

if installers are big enough and doing multiple installs you'd think they'd have stock being delivered continously and not wait to order install by install?

I would interpret that as the installer has a queue of installations booked and customers have to wait. Perhaps worry about any installer that doesn't have a backlog

 

[Mrklaw]

Otovo?!

no they were insisting on a hybrid inverter and that the hybrid inverter woudln't work with my other array (Which it should). I wanted AC coupled for better visibility to HA of both arrays. Have gone with a local company in Guildford. Lets see how reliable though. And they have givenergy batteries which works for me rather than growatt which are more an unknown quantity for what I want to be able to monitor

 

[Chimpy McChimp]

I was told DNO can take up to 45 days but usually coming back in 4 weeks.

Their lead time is 3-5 weeks after that and expect install in 8-10 weeks from now.

I don’t know why they can’t order stuff before the DNO comes back, after all that’s only for export. You’re gonna get 3.6kW export anyway, so it’s just a matter or limiting the inverters export to 3.6 if it comes back with less than they applied for.

High user here too. What kit have you gone for?

5.2kW Solar Array (13x Trina Vertex S 400W
Panels),
GivEnergy 5.0kW Hybrid Inverter,
Consumer Board, Circuit Protection,Bird
Protection
1 GivEnergy 9.5kWh LiFePO4 Battery storage
system

Another company quoted a larger panel array which was tempting but we got into a discussion about how far the panels would be from the edge of the roof. Second company were going beyond the recommendation. I read the guidelines and said this was technically ok as long as steps were taken to secure more and address any potential wind noise issues. When I asked about what additional steps they planned to take, they never responded so I took that as a bad sign.

I found this whole process slightly confusing and I'm not sure I fully understand all the ins and outs of having our own solar set up (this thread mostly confuses me!) But financial calculations from different companies all came out positive and savings were to be had from reducing reliance on the grid so I'm hoping to learn as I go.
Currently I am on fixed tarrif so don't need to be too clever about when and how the battery gets charged. But my fixed deal ends next year so I will need to get a bit smarter on managing being on potentially different rates during day and night.

 

[Chimpy McChimp]

I would interpret that as the installer has a queue of installations booked and customers have to wait. Perhaps worry about any installer that doesn't have a backlog

That's my understanding of the long lead time. In some ways frustrating we won't get install till much later this year. On the other hand I would have been suspicious if they had said they could do it next week.
I selected a local company as they were much more supportive through the quoting and answering my questions than the other companies.
There's always a risk they go bust or disappear with my deposit but they have mechanisms in place for this and I was allowed to make deposit on my credit card. So feeling a bit more protected.

 

[David T]

5.2kW Solar Array (13x Trina Vertex S 400W
Panels),
GivEnergy 5.0kW Hybrid Inverter,
Consumer Board, Circuit Protection,Bird
Protection
1 GivEnergy 9.5kWh LiFePO4 Battery storage
system

Another company quoted a larger panel array which was tempting but we got into a discussion about how far the panels would be from the edge of the roof. Second company were going beyond the recommendation. I read the guidelines and said this was technically ok as long as steps were taken to secure more and address any potential wind noise issues. When I asked about what additional steps they planned to take, they never responded so I took that as a bad sign.

I found this whole process slightly confusing and I'm not sure I fully understand all the ins and outs of having our own solar set up (this thread mostly confuses me!) But financial calculations from different companies all came out positive and savings were to be had from reducing reliance on the grid so I'm hoping to learn as I go.
Currently I am on fixed tarrif so don't need to be too clever about when and how the battery gets charged. But my fixed deal ends next year so I will need to get a bit smarter on managing being on potentially different rates during day and night.

Very similar to my setup. I also have an Eddi solar divert for excess energy into immersion heater and this kicks in every day now so I use no gas water heating. Most days I draw nothing from the grid apart from charging the car on Go overnight.

 

[Chimpy McChimp]

Very similar to my setup. I also have an Eddi solar divert for excess energy into immersion heater and this kicks in every day now so I use no gas water heating. Most days I draw nothing from the grid apart from charging the car on Go overnight.

I intend to look into the solar to heat water. I did discuss with my plumber (getting new boiler fitted soon) and I think he said it wouldn't work with the boiler I have selected but I'll need check.

Edit: the boiler we intend to install isn't compatible with solar set up. Oh well.

 

[KennethS]

I intend to look into the solar to heat water. I did discuss with my plumber (getting new boiler fitted soon) and I think he said it wouldn't work with the boiler I have selected but I'll need check.

Edit: the boiler we intend to install isn't compatible with solar set up. Oh well.

You need electric immersion heaters to heat water using electric. I don't think this is a function that a boiler performs, but I am probably wrong.

 

[Chimpy McChimp]

You need electric immersion heaters to heat water using electric. I don't think this is a function that a boiler performs, but I am probably wrong.

One of the options we looked at said it was possible. Not the one we did settle on. Nevermind. The boiler that is getting replaced is nearly 30 years old so we will see much better efficiency anyway.

 

[WannabeOwner]

the boiler we intend to install isn't compatible with solar set up

Not sure what the boiler has to do with it, but I may have misunderstood your setup.

We have evacuated tube solar thermal. The DHW tank has (separate) coils for solar and boiler (and also, separately top and bottom electric immersions). If Solar Thermal is hotter than DHW tank temperature it heats the DHW tank. So in summer, with boiler and immersion off, Solar will heat the DHW tank. Solar thermal contributes pretty much nothing in Winter, but from Spring to Autumn it provides DHW "majority of the time" - needs a run of cloudy days for that not to be the case - the DHW tank is "hot" by 11AM on a sunny day, so even an overcast day has plenty of hours to get the tank up to temperature.

Ideally you need somewhere else for the heat to go once DHW is up to temperature. Solar Thermal does have expansion vessel, so can "boil", but I don't think that cycling is good for it. We have pool. so excess Solar Thermal can go into the pool (notwithstanding, in our case, that the pool itself has solar thermal flat panels). If the waste heat is modest one route is to run the rads - they only get slightly warmer, and dump the heat that way, but of course that does contribute to slightly warmer house in Summer.

What we actually have is a hands-off system. We have an accumulator tank which is heated by either the boiler or the solar thermal (i.e. in Summer the Solar Thermal heats DHW tank first, and then "dumps" heat to accumulator tank). Separately anything that wants heat draws it off the accumulator tank - that includes the radiators, UFH (running at a much lower temperature) [or the pool and, in our case, "pre heat" of cold mains water before it refills the DHW tank] . This allows the boiler to operate in condensing mode for nice long runs, because it is heating the accumulator tank rather than the boiler coming on for just one Radiator that is asking for heat