Solar panels in Scotland - worth it?

debitcardmayhem

HAVE a look here for where you are https://re.jrc.ec.europa.eu/pvg_tools/en/

QrizB

> What do you mean by far out?

There's an optimum angle which largely depends on your latitude. In Scotland, 45 degrees is pretty close.

> Cloud cover is a concern.

That, and the azimuth & inclination of your roof, should already be factored in to the installer's output calculations.

For example in the south of England your 4.2 kWp system might be expected to make 4000kWh a year or more.

As mentioned above, PVGIS is a useful tool for calculating likely outputs.

https://re.jrc.ec.europa.eu/pvg_tools/en/

Screwdriva

https://forums.moneysavingexpert.com/discussion/6672142/solar-panels-in-scotland-worth-it

Hi Herzlos,

Some great advice already shared. Hope you won't mind a few questions?

1) Any plans to get a heat pump (yes they work well in Scotland)?
2) What are the brands of panels/ inverter on offer to you?
3) Do you experience regular power cuts?

In my experience, different installers often quote for varying numbers of installed panels. I would ask for as many panels as will fit on the South/ West/ East aspects if any but skip the North aspect.

At 4500 kWh, you're at the threshold where a battery starts to make financial sense, more so if you plan on additional electrification. If you experience power cuts, the Fox solution will not provide relief but a Tesla Powerwall 3 will provide reliable whole house backup (with Storm Watch). Return on investment seems accurate at ~7 years, give or take.

I know of zero installers in Scotland but down here, 10 panels with a PW3 costs £11K fully installed (less £375 rebate). Hope this helps!

Herzlos

1) Any plans to get a heat pump (yes they work well in Scotland)?

Not currently. I'd be tempted by the idea of eventually getting rid of the gas connection since it's only used for hot water and a heat pump, but that is a long way off I think.

2) What are the brands of panels/ inverter on offer to you?

The 9-panel setup was Aiko AIKO-A475-MCE54Mb with Solis S6 string inverter. That was offered with Fox or Tesla batteries, I was leaning towards Fox due to the price difference and skepticism towards Tesla.

The 14-panel setup was Trina Vertex 465W Solar Panels with Fox ES 6kW. Battery was a Hanchu 9.4 which I haven't looked into.

3) Do you experience regular power cuts?

We've had 3 in the last year; one during the day due to a mishap with some roadworks that lasted a few minutes. The other 2 were maybe 20-30 mins in the evenings.

Power resiliency is definitely a nice to have, as I assumed it'd be a standard feature or selling point.

If you experience power cuts, the Fox solution will not provide relief but a Tesla Powerwall 3 will provide
reliable whole house backup (with Storm Watch). Return on investment seems accurate at ~7 years, give or take.

The Fox solution would involve a Fox EPS which supposedly provides whole house backup though it takes a couple of seconds to bring it back up.

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/82032623#Comment_82032623

Thanks for sharing. I would insist that the installer:

1) Swaps out the Aiko panels for Eurener 500 or 515W bifacial panels (should be available through their wholesaler). They are a ethical brand and will generate more power in real world conditions through the year.

2) Installs the Powerwall 3. Nothing Fox sells comes close. You will not need a Solis inverter as the PW3 has one built in. Also has 13.5KW of usable storage (vs. < 10?) which will come in handy when you do electrify heating. The PW3's cold weather performance/ software/ app/ warranty leaves Fox in the dust.

3) Maxes out panel coverage on your roof.

Hope this helps! Feel free to let us know if they try to suggest the above 3 points aren't a good idea.

QrizB

Despite my own misgivings about Tesla (both the company which seems to be going down the pan, and the CEO who we all know) I'd agree that the Tesla PW3 with the Home Gateway seems a much better fit for your requirements than the Fox battery with EPS box.

And I'd also agree that if your installer can get 500+ watt panels it'll probably make better use of your roof space.

Heedtheadvice

I am SW Scotland so maybe marginally better geographically. Balance that out in that my roof is very shallow angle 22.5 degrees so will be better in Sumner but worse in winter season than what you could achieve. 4kWp gives about 3800kWh per annum typically. Temper that if your area is particularly cloudy.

I agree with virtually everything written about panels, you could hardly get better advice. I do wonder if your dormers will give you some shading? That can have a significant effect on output but there are solutions to minimise that.

On the battery front I am in favour of doing an assessment of how much grid outages will affect power loss. In a rural area with maybe overhead lines ( especially if they are in the vicinity of trees ) and if the loss has a significant impact ( no heat, no hot water, large freezer warming, no cooking, medical needs etc.) then backup, especially for long periods( like storm Arwen) just about goes from great to have towards essential. 30 minute outages? Maybe not worth it or just nice to have.

Batteries indoors, they do not need heaters. Unheated outbuilding, heaters essential. Outdoors heaters and a very good IP rating essential. Fogstar have a good reputation great customer service) and some with built in heaters ( such as the 16kWh versions, slightly more usable energy than the Tesla ones favoured by Screwdriver) and seriously and easily expandable. A lot cheaper than Tesla PW3 ( but Inverter would be extra).16kWh last I saw about £2k. Tesla would win hands down for outside location and need for whole house backup.

On costs ( installed ) typically ( Screwdriver can give better Information on Tesla ) I would expect PW3 about £5.5k or £7.5k for the whole house Gateway backup vs £3k Fogstar ( including inverter ). The £2.5k difference would be several years electricity - especially at cheaper rate Tarrifs..

On batteries generally , I consume energy amount very similar to you. Winter buying 8kWh to fill my batteries ( daily average) at 6p/unit, Summer about 2 units. I cannot detail it better at present but that includes about 1000 units for the EV. That is charging the battery in the order of 70% winter, 40% summer of my 15kW batts ( older Pylons). I doubt my maths is accurate but should give you a good heads up.

I do not know the central belt installers but do know of one purchaser who was seriously let down ( installing a now typical trade deal), not particularly cheap but absolutely no support following an obvious and one not so obvious failure. Choose carefully with recommendations if you can!

Screwdriva

While I do agree that every household's requirements are different, there are a few things about Fogstar I have learnt recently:

- Not all inverter brands will honour their warranties with a Fogstar battery. e.g. Solis has a list of "approved" battery manufacturers that meet the terms of their warranty and Fogstar is not on that list.

- Fogstar is a "DIY" battery, which means that the electrician who installs it is responsible for the implementation of the warranty, not Fogstar itself.

- Fogstar is ineligible for the intelligent flux tariff (assuming it does return).

It has its place but is likely on the opposite end of the spectrum of offerings rather than a competitor, in my view.

Heedtheadvice

Good that you raise those points Screwdriver to give balanced comments on batteries. You often get responses to your posts being critical of the source/owner, and that I can use derstand too.

Can you expand on your point "Fogstar is a "DIY" battery, which means that the electrician who
installs it is responsible for the implementation of the warranty, not
Fogstar itself. "

Fogstar certainly provide products and support for DIY enthusiasts as well as retail sales of their 48v solar range, camper/caravan range of batteries and also larger commercial systems. They also have a number of installation company partners and Lux as a partner for their Fogstar inverters- which I suspect may be rebranded Lux designs.

Their warranty ( for the domestic ranges ) is explicitly, I understand, with the customer. Can you explain what you mean by warranty implementation being the responsibility of the installing electrician?

Spot on about a number of manufacturers ( such as Solis) possibly not honouring their warranty though they ( Solis) use wooly words like 'can' and 'may' invalidate in their warranty. For balance, as well as Lux, Fogstar do seem to have a good relationship with some others such as Victron.

I do wonder why that disparity exists and thinks it might be owing to Fogstar's documented aim to avoid choice restrictions, cost implications to join approved lists or other commercial considerations.

Nevertheless less there is good reason to buy from a UK company (with Chinese cells admittedly,)

Martyn1981

https://forums.moneysavingexpert.com/discussion/comment/82031993#Comment_82031993

Big thumbs up for PVGIS. If I remember correctly, an update maybe 10yrs ago, started to take local weather conditions into account, not just local solar levels. So it should give very reliable guestimates.