Solar Panel installation

Energycheck

Good Afternoon all,

I would really appreciate some opinions please.

I've just been quoted a price for a 4kw 16 panel system from CJ Solar and wanted to gauge opinion regarding the installation price.

My house is East Facing with a pitched roof, it'll require scaffolding to install the panels.
I'm Based in Leicester

16 x 8.33 Eternity Panels (8 on the front of the house - East and 8 on the back - West)
iBoost hot water generator
Enphase micro inverters (Advised that string inverter is unsuitable due to chimney shading)

Total installed price including VAT £7250

I've asked if this is their best price and they have assured me it is.

Any opinions would be appreciated, thank you.

1animal1

I'm currently trying to get my price down for a duel aspect roof, 15x 265w JA panels with Solar Edge for £5350 inc vat.

There's a few firms hovering around the 5k mark now with edge or micro's (you need to look at both to see which you prefer if you haven't already)

Energycheck

Interesting - would you mind sharing who that's with? £5350 is a big jump from what I've been quoted!

1animal1

Not whilst I'm in negotiations as it may hamper me until the paperwork is signed. The supplier has asked that i don't repeat the price as they claim it is by far the cheapest install they've done:)

I can point you in the direction of my inspirational post which i used to get the price down

https://forums.moneysavingexpert.com/discussion/5320482

Energycheck

Understandable - Thank you very much for the link

pinnks

Welcome. Leaving aside the price which suggests they are taking the ... I wanted to comment on the kit.

While shading is undoubtedly an important issue and micro inverters (MI) of the sort you mention or something like the SolarEdge with its power optimisers (PO) will help with that, I think with an E/W house the impact of the shading depends a lot on where the chimney is. If it is at ridge level and the south end of your roof its impact may well be minimal and not worth the expense of MI/POs - the power management of inverters like SMA Sunnyboy may suffice. If it is at the north end it will have virtually no impact as the shadow will nearly always be heading off to the north of the roof and if it is on the ridge part way along its impact will be a little larger than at the south end, I think, but not significantly. On the other hand, if the chimney is below the ridge, such that it casts a shadow of fully lit panels its impact is massive.

My big roof is WSW-facing with chimney at the south end. I spent hours agonising about shading before I bought only to find that production from the west-facing roof is miniscule until the sun pokes its head round past due south. So, if a south-facing roof produces a bell curve of production, peaking at about midday, my roof produces a half a bell curve peaking later when the sun is (in simple terms) at 90 degrees to the panels. So, from sunrise to, say 11am I produce only a couple of hundred Watts at any point in time. Between 11 and 12 noon production shoots up to max 3kw or so depending on the time of year. I know this is not caused by the shading because I have two strings and they each produce similar levels even though one is shaded and the other not.

The chimney shadow is gone by 12 noon (ish), so its impact is on a system producing diddlysquat. I have turned on the SMA shade management software, which works well but am not convinced that POs or MIs would add anything material.

I think you'll find the same on your east-facing roof, so that you get 2 half bell curves of production with high production in the morning from the east roof when the shadow will be over the west roof (if your chimney is in the south) and high production in the afternoon form the west roof when the shadow is over the east side. If your chimney is at the north end then I doubt it will have any real impact as the shadow will always be heading off to the north other than very early in the day of later in the afternoon when production on the affect roof will be very low anyway.

By contrast, my chimney has a significant impact on production on my south-facing roof from about 3pm because the roof is in full afternoon powerful sunlight and one panel gets brushed by the shadow from the chimney. This knocks about 90% off production and by the time the sun moves past each panel that roof is shaded more generally by the ridge itself. POs or MIs would help this roof to the extent of, perhaps 3kWh per day on good sunny days. That could be perhaps £50 per year.

Energycheck

Thank you for the welcome!

I'm glad I found the MSE forums, as I was close to signing the contract for £7k

Pinnks your response was really useful for me and after you've explained it, it seems as though the Micro's may be a marginal saving if shading is minimal.

My Chimney happens to be right in the middle of the roof. Even more confusingly one salesman said string inverters are the way to go because I'll have minimal shading, the latest guy said I should go for Micros because of shading issues from the chimney.

I'm starting to consider not going ahead with any installation because it feels a bit like stepping into a vipers nest. My first quotation was from Euro Energy at £9500, second from CJ solar at £7250. I have two more quotes to go - here's hoping for a "honest" quote.

Thanks again, the responses have been great.

pinnks

Don't be put off by the viper's nest, we all go through that and you have a lot a time to meet the 31 December FiT change date.

We all make mistakes and look back with the benefit of hindsight but this forum is a fantastic resource. I wish I had found it when at your stage as I may have stumbled less around the edges of that nest.

This is quite a good time of year to look at your shading issues. In the summer when the sun is higher the impact will be less and in the middle of winter we never see the sun anyway - well if we do the shadows are very long and the time the sun is in the sky is very short.

Go out in the morning and take a few photos of each side of the roof and repeat at say hourly intervals throughout the day and see the extent to which the shadow will impact the east roof in the morning and the west in the afternoon, i.e. around the 12 noon point when the sun is due south. Then look at the west roof and shadow into the morning and the east roof and shadow in the afternoon. As I say, the generation on those roofs will be minimal when not in direct sunlight, so the impact of the chimney will be similarly low.

In summary, if you have shading when the panels are in full sun, then MI/POs will be worthwhile but if the shading only affects panels when they have borrowed/reflected sunlight then they are probably not worth the expense.

If I was to start from scratch again today I would do the west roof exactly the same but would consider MI/POs for shade management on the south roof.

If you search this forum for shade/shading you should get a feel for what happens. If you look at my posts you will find a couple focusing on my shading issues.

With or without shading and nests full of snakes, the effort is worthwhile. I have cut my import of electricity by about 45% (2,500 units) and most of what I now pay for is at night (3 fridge-freezers on the go now costs me a lot when the sun goes down). I also save 15%-20% gas with the diverter as the boiler goes off in April and has just gone back on this weekend. Saves me about £70-80 over the summer and a few quid for the rest of the year by marginally reducing the gas cost of water heating.

I have the immerSUN, which I replaced with the mkII for the monitoring and then bought a second immerSUN to power some radiators at this time of year. So far (system 1 June 2013; system 2 March 2014) my return is about 23% of total outlay. This includes the reduced import of electricity of course.

The other benefit is a generally raised awareness of energy in the household. We were already quite energy-aware and had invested in LED light bulbs etc but in my second full year of both systems being in operation we are seeing further reductions in imported electricity, which, on balance are probably down to better utilisations of self-generated power but also just being even more careful with waste.

I would go through the pain again.

pinnks

Take a look at my generation.

02/09/2013 (you'll need to navigate to it by clicking on the date box to bring up a calendar) was an almost perfect day when I had only the west-facing system. You can see how low the morning generation is.

Then have a look at 18/04/2015, which was a super day with the south roof now in there mix.

https://www.sunnyportal.com/Templates/PublicPage.aspx?page=0cf5b74e-2228-4210-b253-aa88366e4686

Energycheck

Thank you once again Pinnks the information you've provided has been ace.

Heedtheadvice

Pinnks, I have been considering the Immersun, so I would value you experience. I understood that the Immersun could power three separate heating systems and each system could be several heaters, within max power limits. What is your thinking installing a second one?
Also you would seem to be a fan of them. Can you comment further, please?