Large Solar PV wanted Glasgow

scubajoe

Hi all, I want a Solar PV system for my house in Glasgow.

I'm interested in the largest system I can get on my roof. My supply is single phase. I've spoken with my DNO and they're OK with my proposal, although nothing in writing yet.

I've had a look at my electricity bills and over the last calendar year I've used 6,348 kWh. I take my own readings every month. The supply company is called Extra Energy and the unit cost is 10.34 with a standing charge of 22.47 pence per day, both plus VAT.


For the purposes of the Solar PV, the roof pitch is 45 degrees and facing 190 degrees. I also accurately measured the roof using a laser and it's 10.2 metres wide by 5.2 metres high to the underside of the ridge tile so plenty of room for the panels.

I've been on the Swithenbanks website so have a rough idea of costs. I think I can get 27 panels on the roof and like the SolarEdge system, no shading issues, I just like the system and am happy to pay the extra.

I would like all black panels. If I get 27 panels at 330w the array would be 8910w and would need 2 inverters.

I've had a few quotes but mostly feel that it's been from salesmen!

Any advice please in general, on costs or installers?

I also want Solar Thermal on the adjacent garage roof. One of the salesmen has tried to advise me not to and said the Solic200 is better and would work out more economical over the years, is this true. What's the best return on investment, Solar PV with an immerser device or proper Solar Thermal?

Thanks in advance.

tunnel

First and foremost, get clarity from your DNO as to whether that would be acceptable through a single phase, my parents were asked to upgrade to 3 phase for a 10kWp system so remained on a single with a 4kWp system(until I get my hands on the house(eventually))


I like your thinking....BIG....but why go so large when 285Wp panels come out nearly £100 per panel cheaper than 330's, at the end of the day it comes down to ROI(return on investment) and as the FiT would be the 4-10kWp band(about 10% less than the upto 4kWp) then any savings has to be looked at. 285's are 40% cheaper than the 330's.


With solaredge there's an extra 27 possible problems on your roof, I have them but on a garage with easy access. If it's monitoring you're after then there's loads of kit you can get(prob chucked in as a freebie with a system that size) to keep an eye on your system


As for thermal....hmmm, how do you currently heat your water? Gas or leccy? So many questions but don't worry....there's plenty of folk on here who'll help you get the best and cheapest deal that suits you(hopefully).

scubajoe

Tunnel, thanks for your response.

I did check with SP Networks and they confimed that my proposals for my adddress were fine and they would only by concerned if I were planning something around 50kw!

I see your point about the savings on a lower output panel. This brings me to another point, I read somewhere that you can install 2 separate systems and get them both at the higher tariff, not that I was planning that but just curious.

The water is heated with gas just now and I'm in the process of trying to upgrade the boiler to a new condensing one and fancied the Worcester Bosch 30cdi with a TC300 solar cylinder coupled to Solar Thermal. I want pressurised hot water (currently a vented system) and so need a new cylinder and it's not much more for a twin coil cylinder.

tunnel

scubajoe wrote: »

This brings me to another point, I read somewhere that you can install 2 separate systems and get them both at the higher tariff, .

You read wrong I'm afraid(unless you have 2 postal addresses at the same property) There's only upto 4kWp, then 4-10kWp after that. Yours would come into the 4-10 bracket. I know because my ESE and SSW take me to the 4kWp and my WNW is on the 4-10 FiT rate.......sorry to burst that bubble but at least you know now rather than later when some lying salesman sells you a system(or 2)

scubajoe

tunnel wrote: »

There's only upto 4kWp, then 4-10kWp after that.

I sort of knew that anyway :-)
If anyone wants to jump in on this thread please do! I want a system up and running asap.

Martyn1981

Hiya scubajoe, welcome to the world of PV.

A few thoughts. Location sounds good, and a steep south facing roof will work well (compared to a shallow roof) as it will produce a little less in the summer, when you'd be exporting lots anyway, and slightly more in the winter, when you need all you can get.

I think there may be some confusion over the system size and export rules. For single phase you will normally be limited to 3.68kW, and for 3 phase 11kW.

I appreciate that you say you've spoken to the DNO, but something doesn't sound quite right, perhaps there may have been a misunderstanding. I don't think the 'around 50kW' figure makes any sense since most properties have an 80 or 100A supply, so any export close 20 kW could blow that.

I got permission for 5.9kW, but had to be assessed, and only got it due to recent upgrades in the road.

Subsidy rates, perhaps what you'd heard is the sort of loophole, that you could install 4kWp, get the 0-4kWp FiT rate, then install a second system, so that only the second system gets the 4-10kWp rate. TBH no point in doing this as the difference is peanuts, so probably best to install it all in one go. There is info on large systems, or extensions in section 10 of the PV FAQs.

Regarding solar thermal (ST), it's a great idea, and I think it can generate more energy (kWh's) per £1 than PV, and takes up less space. But hot water is a lower value product, and you can't export it, when you have too much. So as PV got cheaper, it sort of overtook ST as you could get a PV system and divert some of the leccy to heat your DHW. Not a criticism of ST, it's just that PV as a package may be better for you. However, if you have the space, the money and the desire, then installing both does give you a nice package, but expect lots of spare in the summer.

Roof space, 10.2m by 5.2m is great. Probably not tall enough for 3 panels portrait as that would be 4.8m, and not leave enough space top and bottom, but 4 rows of 6 landscape should fit fine. Approx 9.6m wide, by 4m tall. 24 panels will give you a considerably large PV potential. Using cheaper (not cheap quality) 250Wp panels, that's 6kW. Even worse case scenario and you are limited to 3.68kW export, you still wouldn't lose too much generation to capping. Certainly worth trying to get an analysis of the numbers.

Mart.

scubajoe

Thanks for a very helpful response. What's a TGM please?

Martyn1981

scubajoe wrote: »

Thanks for a very helpful response. What's a TGM please?

See section 7.

Mart.

scubajoe

Martyn1981 wrote: »

See section 7.

OK thanks.
I need a good installer now, preferably one that wasn't a double glazing salesman in a previous life. If there's anyone who can do an installation quickly for me please get in touch. I specifically want Solaredge.
Thanks

scubajoe

Still looking for a good installer for my area if anyone could recommend please?

scubajoe

So, system 1st array installed on Friday and now producing energy. I've decided to go with the recommendations from this site and use E.on for the FIT payments. I have everything necessary from check list on the form EXCEPT the MCS certificate which I understand comes from the installer, how long should this take please?