Solar PV - economics?

[Nimby]

Zoon said:

soofsayer said:

2Btoo said:

soofsayer said:

I have been dissuaded from having pv panels at ground level by 2 installers. I have a perfect spot for a large array but have been told that installation costs (hardware and time) is much higher than roof mounted (which is fairly simple),

Sounds pretty rum. Installing panels at ground level is harder than putting them on a roof a couple of storeys up? Points about shading and vegetation may be relevant but this first one sounds like someone is pulling a fast one.

Maybe, I am no expert on it but that was the advice, and I think I’d need planning permission for a ground installation due to the location and size.

Sounds like rubbish to me. How big an array are you talking?

Roof installation is pretty simple - just brackets under the tiles and bolted to the rafters, then run regular cable to the inverter in the loft.
On the ground you'll have to build supporting structures and presumably have many more electrical safety issues to deal with.

[Evanivitch]

Nimby said:

Roof installation is pretty simple - just brackets under the tiles and bolted to the rafters, then run regular cable to the inverter in the loft.
On the ground you'll have to build supporting structures and presumably have many more electrical safety issues to deal with.

The frame work is pretty standard and widely available. Giant mechano. No working at height, no roof damage, easy to clean, no pigeon issues.

Trench and armoured cable run will be biggest expense.

[DonkeyApple]

Canute said:

Hi,

I'm just about to start diving into this subject and have had a quote but not sure how to make sense of the maths. (numbers was not my strong point).

We are looking at a 50-panel system with a forecasted production of 14,194KW per year
We use around 20-23,000 KWH per year just depending on what kind of winter we have.
The total cost for this system is £16K

Also to note, I'm in Sweden so electricity prices are eyewatering. I pay around £2.5K a year for electricity.

If anyone could kindly help me make sense of the economics of it that would be great.

We would probably finance the project with an additional mortgage to our house with an interest rate of about 1.7%

This numbers suggest you'd be saving just over a grand a year? A similar sort of sum if you were to invest the £16k.

There isn't a tremendous eco angle either as Sweden already has the greenest electricity in Europe.

However, you're gearing up 100% which puts a different angle on it to consider which is that your gearing cost is £300/yr for a gross gain of £1,000/yr. which is pretty good if the risk on the variables is low enough.

The other area to research well is that being in Sweden a lot of your energy usage is going to be more heavily front loaded to the winter months and due to the extended darkness that'll coincide with a considerable drop in generation.

That could mean that in the longer summer months when you're not running any heating or lighting you have very little electricity demand but that's when your panels are producing everything.

Ie the proposed system might generate some good numbers that make you think you'll be halving your bills but in reality it may not reduce your bills at all as you get no solar in winter when you need it and loads in summer when you don't.

You've got to do all the maths yourself as solar salesmen are double glazing salesmen who weren't good enough to compete in that market. They are liars and the domestic industry is built upon a foundation of misdirection and misselling.

[Dedshott]

It's a solar based thread bump!

I have recently moved into a new house, and it's been difficult trying to work out exactly how much these bills are going to cost - a bigger house than I am used to, and I would love to try and reduce bills a bit - even with a huge outlay.

So - I signed up for a council run auction scheme to find the best bid for solar panel installation.

The results are in, and we have been quoted £5320 to supply and install 10 Solar PV panels.

They estimate 3274 kWh generated in a year.

For an additional £2137 I can install a 3.2 kWh battery.

What I am trying to work out is, with the huge rise in energy bills, is now a good time to get them fitted, or will they never break even. Anyone got any experiences they would like to share...

[2Btoo]

Not a clue, but am interested in the council-run auction scheme.

Care to tell us more?

[Pixelpeep 135]

DaveCWK said:

running AC on the sunniest days

In all my thoughts and research about the cost effectiveness of solar and i never considered that very thing.

Currently we don't have AC but we have been considering it for the back two bedrooms as they get like the devils furnace during the summer

The hotter the day the more you need AC, and the hotter/sunnier the day is, the more power you generate it's like they were made for each other.

1. latetotheparty

[Condi]

Dedshott said:

The results are in, and we have been quoted £5320 to supply and install 10 Solar PV panels.

They estimate 3274 kWh generated in a year.

For an additional £2137 I can install a 3.2 kWh battery.

What I am trying to work out is, with the huge rise in energy bills, is now a good time to get them fitted, or will they never break even. Anyone got any experiences they would like to share...

At the current price cap 3274kwh is worth about £925. This will go up in October again. It will probably also come down in 2-3 years.

The big question is how much can you use? If you can use all 3274kwh then it will pay for itself in about 5-6 years. If however you only use 25% of that energy because you are at work Monday-Friday 9-5 and out at weekends (ie when the solar panels are producing power) then it payback will be much longer. I would say the battery is quite expensive for the capacity, but if you can spec a bigger battery then it should be cheaper per Kwh. (One inverter, set of wiring etc irrespective of the size of battery). The average house uses 12Kwh or so a day, and if you can get a 10Kwh battery then you can probably pay nothing for electricity at all across the summer. If you have a water tank and immersion then use the solar to heat the water instead of getting a battery? Export tariffs for new solar are pretty crap, 7p/kwh at best, vs buying power at 28p/kwh, so you need to use as much as possible.

The other thing to think about is what else are you doing with the money? If your money is sat in the bank as cash then investing it in solar will at least bring a return.


Quite simply, there is no right or wrong answer. Solar provides a hedge against power prices going up, but you need to be using as much of the energy as possible to make it worthwhile.

[DonkeyApple]

It's really difficult. Personally, I just see that as additional evidence that it doesn't really add up.

£5k in the bin on day one. Realistically that capex has gone. So on day one you're suddenly in the hole for -£5k.

The best case scenario is that it will deliver £1000/year at today's prices. Deep down, we know it won't produce that much power and we also know that current prices will come back down in 18-24months. You might be lucky to get £3-£500/year in 'yield'. Let's say £500. But you've not invested £5k but spent £5k for that yield. That would suggest up to 10 years just to get your £5k back.

You're basically chucking £5k in the bin today and then sitting there for ten years to earn it back. Once you've earned it back you then actually start getting a return. But then your infrastructure that's no really worth anything is now getting into the realms of needing maintenance. The gross revenue is so tiny that even minor maintenance spend decimates the net yield.

Add in batteries to try and use more of the energy generated and in many ways the problem gets worse. It might save you a couple of hundred quid a year but you've just binned £2k. That's another ten years to get your money back but the industry estimates that the battery will be kaput by then. Ergo, £2k spent, wait ten years just to get your own money back and then pay someone to remove it and recycle it.

All in £7.5k spent, 10 years just to get your own money back and then you start having to pay to have the infrastructure binned or maintained, almost certainly eating up any revenue.

And that's assuming no one would be insane enough to borrow money to do that!!

Conversely, one can invest £7.5k into professional energy generation businesses, get a yield of 4-5%, still have all their money and even receive a capital uplift on it over the next decade.

Personally, I find being my own power generator appealing from a bloke perspective but utterly insane from a financial or even environmental one. Investing that money into professional generators means I create zero carbon footprint, don't spend any of my money, don't have any ongoing costs, am not reliant on weather and lifestyle to get a yield and my money will almost certainly grow in value. I spend nothing, get a comparable yield, do no damage, have no hassle. It's a no brainer, I just can't see any logic beyond edge cases for trying to home brew electrons.

[2Btoo]

DonkeyApple said:

Yes, but good sense like that doesn't cut it with the greens and those who are bent on 'virtue signalling'.

[Pixelpeep 135]

2Btoo said:

DonkeyApple said:

Yes, but good sense like that doesn't cut it with the greens and those who are bent on 'virtue signalling'.

Think of it like organic chicken - it costs more, but it's better for everyone eventually.

[Gareth79]

Dedshott said:

So - I signed up for a council run auction scheme to find the best bid for solar panel installation.

The results are in, and we have been quoted £5320 to supply and install 10 Solar PV panels.

Having seen a few quotes recently that seems on the steep side. A decent 400W panel is about £170 each, a good quality inverter is say £1k. Scaffolding say £500. Leaves quite a lot left over!

As above, if you have a high idle consumption and/or use a lot during peak daylight hours it will pay back faster than if you export most of it. The numbers add up a lot better with current rates, but if £5k is not much of a risk to spend then go for it on the assumption it will probably pay for itself in raw money terms in about 10 years.

Edited by Gareth79 on Monday 11th April 13:36

[bmwmike]

I was gifted 12 120W solar panels and the feedback that I got on here was that they were not worth fitting, and instead to purchase 250w ones. That told me all i needed to know about the economics.

[Dedshott]

2Btoo said:

Not a clue, but am interested in the council-run auction scheme.

Care to tell us more?

Applied via the council website (in this case Tunbridge Wells) - but run by Solar Together.

https://solartogether.co.uk/landing

[DonkeyApple]

Pixelpeep 135 said:

2Btoo said:

DonkeyApple said:

Yes, but good sense like that doesn't cut it with the greens and those who are bent on 'virtue signalling'.

Think of it like organic chicken - it costs more, but it's better for everyone eventually.

I'm not entirely convinced that it is better for everyone. What's the carbon footprint per kw for manufacturing the kit, shipping it, the local labour and transport to install and maintain etc compared to the carbon footprint of SSE.L producing 1kW of increasingly renewable energy?

It's surely impossible for me to run a cleaner renewable power station at my home than it is for a professional, centralised producer?

And long term there's the big problem that all our domestic energy will be renewable, possibly around the time that our home systems finally recoup their cost. At the point that we can buy carbon free energy surely all the stuff we've stuffed on our roof and into our homes gets revealed to be wanton environmental vandalism?

I think we'd be smarter to invest in efficient, centralised, mass production than spending to creat a million crappy and inefficient domestic power stations? I struggle to see the financial or environmental logic of the path we're currently heading down.

[Dedshott]

Dedshott said:

Applied via the council website (in this case Tunbridge Wells) - but run by Solar Together.

https://solartogether.co.uk/landing

Which I've just looked up on Trustpilot - and they have a terrible rating!

[Dedshott]

Condi said:

Dedshott said:

The results are in, and we have been quoted £5320 to supply and install 10 Solar PV panels.

They estimate 3274 kWh generated in a year.

For an additional £2137 I can install a 3.2 kWh battery.

What I am trying to work out is, with the huge rise in energy bills, is now a good time to get them fitted, or will they never break even. Anyone got any experiences they would like to share...

At the current price cap 3274kwh is worth about £925. This will go up in October again. It will probably also come down in 2-3 years.

The big question is how much can you use? If you can use all 3274kwh then it will pay for itself in about 5-6 years. If however you only use 25% of that energy because you are at work Monday-Friday 9-5 and out at weekends (ie when the solar panels are producing power) then it payback will be much longer. I would say the battery is quite expensive for the capacity, but if you can spec a bigger battery then it should be cheaper per Kwh. (One inverter, set of wiring etc irrespective of the size of battery). The average house uses 12Kwh or so a day, and if you can get a 10Kwh battery then you can probably pay nothing for electricity at all across the summer. If you have a water tank and immersion then use the solar to heat the water instead of getting a battery? Export tariffs for new solar are pretty crap, 7p/kwh at best, vs buying power at 28p/kwh, so you need to use as much as possible.

The other thing to think about is what else are you doing with the money? If your money is sat in the bank as cash then investing it in solar will at least bring a return.


Quite simply, there is no right or wrong answer. Solar provides a hedge against power prices going up, but you need to be using as much of the energy as possible to make it worthwhile.

On their calculations it says that if I don't have a battery I will only use 688 kwh. With a battery I can use 1735 kWh. Not looking good is it.

[Traffic]

Had solar fitted in November, my electricity bill for March would have been around £350 and instead it was £25. It's definitely washing its face whilst we have high electricity prices!

[2Btoo]

Traffic said:

Had solar fitted in November, my electricity bill for March would have been around £350 and instead it was £25. It's definitely washing its face whilst we have high electricity prices!

Sounding good, but how much did that £325 saving cost you?

[Traffic]

2Btoo said:

Sounding good, but how much did that £325 saving cost you?

Total investment was about £18K so not a bad amount to have shaved off of my electricity bill for just the month of March!

[gfreeman]

Traffic said:

Had solar fitted in November, my electricity bill for March would have been around £350 and instead it was £25. It's definitely washing its face whilst we have high electricity prices!

Details?
size of array?
Installed by?
Battery? Size?
Spec of kit? Manufacturers and models?
Genuinely interested in your experience....

On another note the buggers at SSE have advised me of my new tarrif.
Rate per kWh increase is from 20.68p to 28.46p - a rise of 7.78p
Standing charge of 24.11p is subject to a whopping increase of 19.28p per day!!!

Edited by gfreeman on Monday 11th April 19:29