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Thursday, 26 August 2010

On the bag of a fag packet.

solar panel


No. This post is not about smoking, although I’m puffing away while I write this.

I’ve just been delving around on the internet, to see if I could see the benefits of fitting a photovoltaic solar panel to my roof. You know saving the planet etc, etc, Bollocks, etc.

And here’s what I’ve come up with:

Initial fitting would be £12,000 for the fitting of the panel, wiring, and installing an inverter. Ok, fine.

Expected overall saving per year is calculated at £839. Calculated for the South of the country. If you live in Scotland, then the figure drops to £716.

Looks jolly good I hear myself think. (All figures calculated for me by The Energy saving trust).

Now for the twist.

The panels are expected to last for 20 years, but at the end of their life will only be capable of delivering 80% performance. (The calculations are based on 100% through life output).

The panel will require cleaning on a regular basis. in my case I’ve based it as every two years due to the Oak trees across the road, and the numerous pigeons we have here for some strange reason.

Now seeing that I have a three story house, H & S decree that work on the roof requires scaffolding in my area.

Lets throw in £200 for that (Most likely double). Therefore after 20 years the cost in total will be £2,000.

Inverters burn out in time. Well the good chaps at MugsRyou, installed a top of the range model that lasts 10 years. So I’ll only need two of those. £1000 a throw.

The upshot of this long rambling story is that it will take me 19.07 years to break even. That’s if the panels deliver that 100% for the whole period and we actually get some sun.

Mind you I expect I’ll have long died from a smoking related disease by then.

Did I mention smoking? Oh dear.

Wind turbines anyone?


  1. Well done FE. The more the cost of these things are made public, the more folks will realise they're being taken for mugs. Nae wunner MugsRU is such a success.

    I'll be long gone in 20 years because I don't want to turn into a replica of my mother at that age. Bitter and twisted - then she always was.

  2. I'll have a look at roof mounted wind turbines next. I'm sure I won't be at all shocked with them. I mean if Call me Dave thinks they are such a good thing, surely they must be a GOOD.

  3. Nice piece. Funnily enough, I wrote one myself a couple of days back when Homebase of all people were trying to sell me one. I have it scheduled to post while I'm on holiday.

    I savaged their numbers and claims but you have mentioned a few things I never even considered!

    At least if you put up a wind turbine it'll slice up a few of your damned pigeons! And you can use the remains for pigeon pie so don't forget to factor the food savings in...

  4. Oh - and my missus says "Is the roof strong enough to take it? And are we insured if they damage it during the installation?"
    Canny lass!
    I figure they are best left to roof terraces in Greece meself where they make perfect sense as they are easily accessible. But even the Greeks only use solar heating for water.

  5. I'm sure I read somewhere that if you have a 'personal wind turbine' you get screwed for cash as you must pay the national grid for the privelage of owning it?

    Or am I talking shite?

  6. I'm not sure you have looked at all the costs.
    Savings = 839/12 = 70/mth
    Loan repayments @ 5% & 20yrs = 80/mth
    (12000 loan)
    depreciation = 12000/20/12 = 50/mth

    plus annual maintenance costs.
    I think it looks very sad.

    Here, in Australia, we can get a government subsidy and a feed-in tariff (at the moment double the rate charged, most are net but one state has a gross feed-in tariff)

    Still not an attractive proposition.

    Excellent blogs which I enjoy reading. Thank you

  7. Anon

    My fag packet wasn't big enough for any more calculations.

  8. Ah, now whatyou're doing is going about this one in entirely the wrong way. Thanks be to that nice fella Gordon Brown, there are different feed-in tariff rates for different origins of power, this being an example of a Socialist government trying to pick winners. Solar has the highest feed-in rate.

    So, what you do is this:

    Firstly, obtain some solar panels. Any old tat will do, as long as they look the business.

    Secondly, obtain some decent capacity batteries; China will be your friend here.

    Thirdly, make sure you have an electricity meter which does Economy 7 metering, whereby electricity at night is cheaper than normal.

    What you then do is this: charge up the batteries at night on the old Economy 7 power, then feed this stored power back into the grid during the hours of daylight, purportedly as product from your solar panels (you might even feed a bit of real power from the panels in too, though this is a bonus.

    This will net a decent profit for not such a great deal of outlay, and is ethically sound. After all, all you're doing is exploiting political stupidity and reclaiming some of the money the bloody stupid green energy malarkey is taxing you at present....

  9. Mmmm. Why didn't I think of that? Could work.

  10. I looked into this aswell. The reliability of the inverters is a big worry. I read a US DOE report which said the inverters had a 5-10 year MTBF. And the inverter cost was £2000- so that's £6000 worth of replacement inverters over 25 years.

    Also, when the inverter dies - you won't notice it immediately - so you need to budget for some lost months with zero income while you get the thing fixed.

    Now throw in the risk of roof damage during installation or cleaning - and the potential fire hazard of high-current PV cabling.

    At this point I lost interest. I don't want the daily hassle of maintaining my own power station for the promise of a small pay-out in 20yrs time.

  11. Eliminate the inverter by feeding DC output from photovoltaic panels to base board heaters in a separate circuit in the house. Mount your panels on a sun tracking device in your (large) garden to double output.
    Have panels about 20 ft from the ground on the tracking device for easy cleaning.
    Forget feeding the grid and keep the power for yourself and save money that way.
    Mount panels on the tracking device latitude +15 deg for summer and latitude -15 deg for winter

  12. Anyone who thinks of wind power for your home. Forget it.
    Wind is like war. 99% boredom, 1% sheer terror.

    Attach it to your brickwork and never sleep on any wind blown night ever again due to vibration and noise.

    Solar panels for electricity are good. Providing you order it all yourself from China. Its the end user cost where the money is made and you'll never get your money back.

    Inverters are 100% reliable of you buy 2x size that is required.

    Heating water? I've got that. Brilliant! £500 all in. Vacuum tube system, fitted by myself. Live Nr. Manchester and reckon on payback after the second year.

    Green? Pah! I'm just a stingy git :)


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