Solar panels in Scotland - worth it?

Herzlos

I'm looking at a 9-panel / 4.2KWp system with/out about 11kwh of battery, in central Scotland.
House is almost exactly South facing an clear of obstructions.

The quote details reckons we can produce about 3500kwh/year and our consumption is about 4500kwh.

Cost is about £6,250 for panels only, £10,000 with Fox11.5khw battery.

My figures seem to work out about 7 years to pay for itself if the numbers are right. Are those figures realistic and am I likely to see that kind of payoff or is that an unattainable best case?

Edit: Another interesting dilemma I've now got is that 1 company thinks I can fit 9 panels, whilst another thinks 14, which is quite the difference! My assumption is that the 14 panel company is either wrong and working really tight on margins?

Thanks!

badmemory

Personally I wouldn't have a system without batteries. In fact my installers said they wouldn't install without. In winter though I fill my battery during the night at the cheapest rate.

QrizB

That's not too bad for Scotland, either with or without a battery. (For England and Wales I'd have expected the "no battery" quote to be £4.5-5k, but Scotland is its own market.)

The folks over on Green & Ethical are usually happy to discuss options for solar power.

https://forums.moneysavingexpert.com/categories/green-ethical-moneysaving

sheenas

Sound decent. You definitely benefit with the slightly longer summer days in Scotland.

Herzlos

https://forums.moneysavingexpert.com/discussion/comment/82031636#Comment_82031636

I can't decide if batteries may much sense though. It's a neat idea being able to buy cheap overnight and use that instead of buying at peak, but the numbers don't seem so great.

Assuming I can fill and drain the battery completely every day (8.5kWh usable), and I buy at 8p/kWh instead of at 30kWh (I'm currently on a 24p tariff), I save £1.87/day. At about £3600 for the system it'd take 5.25 years to pay for itself.

If I'm drawing less than that from the grid on-peak every day, then the payoff gets longer, and it seems there's only a 10 year warranty so I'm wary that the savings will be marginal at best. Of course I can get it to dump what's in the battery to sell back to the grid for ~15p/kWh and make 7p/kWh.

I do like the idea of having a battery to deal with power cuts, but that'd mean keeping some percentage of the battery charge because sods law means that the power cut would happen when the battery was nearly empty.

debitcardmayhem

Is 9 the maximum panels based on roof space? If you can fit more the extra cost is minimal taking into account the cost of scaffolding. Also what size is the inverter, and does it include bird netting and G99 mcs certification..

I would ask to get this moved to the gem board and @Screwdriva will probably give you another opinion

Qyburn

We have an 8.1kWp system in NE Scotland. In 2025 we generated 7,205 kWh, of which we exported 5,531. Exceeding the installers estimates.

From a financial point of view we joined Intelligent Octopus Flux on 11st March this year, and so far that has worked well. March made a profit of just over £90, more than offsetting the net cost for Jan and Feb. April made £125 and May £132 even though those were not good months.

RAS

I'd start by checking the number of hours sunshine in your area of Scotland, as some western areas have high rainfall, cloud cover even though some islands are very sunny.

And I'd research the best angle for your latitude. How far out is your roof?

Herzlos

https://forums.moneysavingexpert.com/discussion/comment/82031827#Comment_82031827

The 9 panels was based on roof space, from Google Streetview and a visit. They suggested a possibility of getting 10 on but "it'd be tight".

The 14 panel quote was done from Streetview alone though it looks plausible from their diagram. I definitely think more panels is better.

Both were a 6kW inverter, which I've queried on the 14 panel setup as that's 6.5kWp. Both have bird netting. The 14 panel is about £200 more expensive but as you said most of the cost is in the scaffolding and labour.

QrizB

6kW of inverter is plenty for a 6.5kWp solar PV system. You'll hardly ever have the right combination of sun intensity, angle and temperature to exceed 6kW of potential output.

Herzlos

https://forums.moneysavingexpert.com/discussion/comment/82031868#Comment_82031868

What do you mean by far out? It's a fairly standard 1970's pitched tile roof, at a guess it's somewhere around 45o from horizontal. About half of the roof has a dormer in it but that wouldn't obscure the panels as there would be 1 row above and 2 rows to the side.

Cloud cover is a concern. We had a pretty sunny patch for about 2 weeks before the visit and then the 2 weeks after it have been pretty grey, so I've no idea if the estimated annual figures are attainable.