Solar Panels

[RizZy]

Anyone got em? worth the effort?

[TeaLeaf]

For me yes, but I am on the original feed in tariff which pays a lot more than current scheme does/did.   Follow the below math but plug in your own numbers to give you an idea of what you might get back.

Whilst smart meters remain only a future hope for the electricity companies, the most efficient use of your capital comes with not maximising the kW size, but finding a system whose size best fits what you use during the day (ie sunlight hours) as you benefit most financially from actually using what you generate during the day.   So for me, working mostly from home, I sized a system to suit what I use and therefore benefit a lot from free electricity.

The theory goes:
You get paid 46p or so (it changes each year) for every penny you generate.
They have no clue how much of the generated amount you use, so they assume that you use 50% only (whereas I use close to 100%).
They then assume that the surplus 50% is exported back to the grid and they pay you a very small amount for it, about 4p per unit or so.

For ease of maths let's assume a 250W panel is £500, that you use 2kW/hr at home and that you pay 11p per unit for electricity and that you use 1,500kWhr during the day (generation time) each year. Therefore:

4kW system would cost £8k.(generating circa 3,200kWh pa*)
2kW system would cost £4k (generating circa 1670 kWh pa*)

*Pro-rata from my own system using 2012 and 2013

The 2kW system exports nothing, you get paid the 46p for 100% of the units, you get an extra 4p for 50% of the units and then you save 100% on your electricity bill during the hours you use the electricity from the panels.  
Generation cheques:
(0.46 x 1670) + (1670 x 50% x 0.04) = £801.60 per annum income
plus savings from electricity used during the day - I estimate I use 90% of everything generated by my panels as I work from home, computers on all the time etc, so:
Savings of (0.9 x 1670 x 0.12) = £180.36

Initial outlay: £4,000
Total benefit of a 2kW system = £981.96 per annum eg 24.5% pa return on initial investment

The 4kW system exports a lot more, you get paid the 46p for 100% of the units, you get an extra 4p for 50% of the units and then you save 100% on your electricity bill during the hours you use the  electricity from the panels.  
Generation cheques:
(0.46 x 3200) + (3200 x 50% x 0.04) = £1536.00 per annum income
plus the same electricity savings from the 2kW example (as your use remains constant and is not dependant on system size), so:
Savings of (0.9 x 1670 x 0.12) = £180.36

Initial outlay: £8,000
Total benefit of a 4kW system = £1716.36 per annumeg 21.4% pa return on initial investment
 
If you compare the % returns on initial investment the overall % return gets lower the more the size of your system exceeds your daytime use.   Peak efficiency is where you use 100% of the electricity generated.   They pay you for it, you don't pay the electricity for it and you use it all for free.

That having been said, a 21% return is still excellent, so still a great use for your money.    So you end up making a personal decision based on how much you want to spend, what your roof will hold (4kW max for the FIT scheme) and you get the return that results!

You can plug your own numbers into the above and it should give you a decent idea of the payback.   So yes, solar panels are great! :thumbsup:

[RizZy]

This is the pdf of the figures I got left with - link

[DuVeL]

Most important thing:
What kind of house do you live in currently?
How is the house placed? (Direction of the roof where the solar panels will be placed). N E S W

[RizZy]

End of terrace - last in a block of 4 houses, the back of my house points SSE I'd guess (looking at google maps) & the panels would go half on the back & half on the side that faces west-ish.

[JanuZ]

There is sun more than 10days a year? Only thing i thought of when I saw solar panels mentioned was this

[TeaLeaf]

This is the pdf of the figures I got left with - link

Looks like you got left with page 1 of a larger document, the formal quotes are much longer and follow a prescribed format .  What are the unit rates you have been quoted (generation/export)?   The bulk of the savings figure is from an assumed 10% pa electricity price increase.

[Gone_Away]

Guys,

Keep in mind that if you don't purchase the system outright yourself, you are leasing your roof space. If you plan on selling the buyer also inheirits the lease. Also, a lot of those "we'll install it free" cowboys have gone into liquidation recently.

If you do buy it outright, be careful of where you live. They aren't the most attractive things in the world and could affect your resale value.

[Blunt]

Guys,

If you do buy it outright, be careful of where you live. They aren't the most attractive things in the world and could affect your resale value.

That's why I haven't' got them.
They may look OK on a 70's 80's 90's house, but my place is 1670's so would look well out of place.
Can't argue with the maths though.

[BrotherTobious]

I saw a place that had a purpose built little structure to have them on to save the look of the house

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[TeaLeaf]

I saw a place that had a purpose built little structure to have them on to save the look of the house

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You can do that but then you need planning permission as it falls outside the permitted development rights afaiaa.

Re the value, it might affect the value, but solar is becoming more and more mainstream, almost all new developments have them for example, so the impact should be negligible or zero so long as you are not putting an array on your chocolate box thatched cottage in the middle of the conservation area (in which case you would have needed planning permission anyway).   Any value question is also offset by the fact that the revenue stream stays with the house, so if you sell it becomes the income of the new owner.

[suicidal_monkey]

How big/heavy are the panels? Might have about 2.5x2.5m space sometime soon, and it might ease the planning process...

[T-Bag]

The maths works out. My dad sells them and the savings you can get are pretty huge. But certain houses just can't sensibly have them. He's had to turn down houses that point the wrong way, or don't have a sensible roof design. There are other systems that can save you money in those cases, heatpump or air based heatpump, that don't need roof space in the same way.

[TeaLeaf]

How big/heavy are the panels? Might have about 2.5x2.5m space sometime soon, and it might ease the planning process...

Afaiaa you do not need planning permission for putting them on your roof unless you are in a conservation area or a listed building (it was an amendment to the permitted development rights a couple of years ago, max size applies).

[suicidal_monkey]

Afaiaa you do not need planning permission for putting them on your roof unless you are in a conservation area or a listed building (it was an amendment to the permitted development rights a couple of years ago, max size applies).

We need planning permission for the rest of the development on our roof, and increasing green credentials usually helps. We're in a conservation area but have permitted development rights - planning officer sounded unhappy when he told me that!

I was asking after size/weight more to get an idea of whether it was feasible structurally - how much space I would need to have and whether it would need further reinforcing.