The Great 'Get Paid To Generate Energy' Hunt

Sylvan

Cardew wrote: »

A figure of around 800kWh a year per kWp is typical for UK.

Thank you Cardew.
That seems extremely generous to me. 800x3.5=2800, which is almost 54kWh per week. Unless the power it produces in midwinter is considerably less than the average it doesn't look as though any extra would be needed.
That being the case has anyone costed a standalone DIY system? You wouldn't get the feed-in tariff but presumably the capital outlay would be much less so you would need less "income" to cover it.

Someone mentioned that the systems have an automatic kill switch that turns them off when the mains power is absent. Having had several 3 day power cuts (including one over Christmas, a few years ago) I'd think it would be more sensible to have a system that took a few extra years to break even, but wasn't at the mercy of the power companies.

Cardew

Sylvan wrote: »

Thank you Cardew.
That seems extremely generous to me. 800x3.5=2800, which is almost 54kWh per week. Unless the power it produces in midwinter is considerably less than the average it doesn't look as though any extra would be needed.
That being the case has anyone costed a standalone DIY system? You wouldn't get the feed-in tariff but presumably the capital outlay would be much less so you would need less "income" to cover it.

Someone mentioned that the systems have an automatic kill switch that turns them off when the mains power is absent. Having had several 3 day power cuts (including one over Christmas, a few years ago) I'd think it would be more sensible to have a system that took a few extra years to break even, but wasn't at the mercy of the power companies.

Unfortunately not that simple!

Firstly as you surmised, the output is vastly higher in summer than winter.

Secondly the output gets higher as the sun rises in the sky.

Thirdly there is nothing from the panels at night.

There is no practical way to store electricity. Don't even think about batteries!!!!

Lots of other reasons why it wouldn't work - but those above will suffice!

Sylvan

Cardew wrote: »

Unfortunately not that simple!

Don't even think about batteries!!!!

What's wrong with batteries?

aboard_epsilon

Batteries will only have a lifespan of 2-3 years and cost about £50 each for a normal deep cycle battery

for solar uses it is recomended that you use long life batteries 15 years .. .. they are made by Rolls Surrette orange/red in colour.they cost something like £800 each !!!!! and you need a few of them.

aqll the best.markj

Cardew

Batteries cannot cope with the power required in a household.

Sylvan

aboard_epsilon wrote: »

they cost something like £800 each !!!!! and you need a few of them.

:eek: Thanks Mark. That puts paid to that idea.

Cardew wrote: »

Batteries cannot cope with the power required in a household.

What sort of power are you expecting households to need Cardew? My son's friend's gran has a bank of either 4 or 6 (I can't remember exactly) batteries. The girls are normal 17/18 year olds (i.e. they listen to music, use computers, style their hair, take lots of showers, wash and iron their clothes regularly, use the fridge, freezer and microwave, charge their mobiles etc) and they've never had problems.
Admittedly they're using wind, so there's probably always at least a trickle coming through, but surely solar can't be all that much less reliable, otherwise why would anyone bother with it?

Cardew

Wind works at night and in winter!!

"

That being the case has anyone costed a standalone DIY system? You wouldn't get the feed-in tariff but presumably the capital outlay would be much less so you would need less "income" to cover it.

The great advantage these days of PV is that you get a feed in tariff(41.3p for each kWh generated - regardless of where it is used) and that is the major source of income.

So what possible reason would there be to 'stand alone'(and not get FITs) if you had mains electricity? The capital outlay would be greater for standing alone.

Sylvan

Either earlier on this thread or on the other one someone said they set it up so that if there's a power cut the power from the solar panels gets switched off as well.
We often have power cuts, of up to 3 days duration. To me the major advantage of solar, or wind, power would be to avoid those.

I just assumed the capital outlay would be less for a self-contained system, since you wouldn't be paying labour charges. I hadn't realised the batteries would be so expensive.

Dave_Fowler

clc5 wrote: »

Hi Dave, what figures did you base your calculations on? I calculate that it will be about 20 years before the PV system gives you a better return than investing the 18K. This assumes the 18K provides an after-tax annual return of 3%, compounded; versus £1236 PV money invested each year at the same annual rate of return and that the figure of £1236 increases each year by 3% (estimated inflation rate).

In my post, I was comparing the pension income I have been quoted with and without the inclusion of an 18k tax-free lump sum which I could take. I was remarking on the ludicrous situation where the PV system appears to give me a 150% increase in tax-free income over the pre-tax income from the pension.

However, let us assume I take the tax-free lump sum and invest it as you suggest.

I'm not sure how you've come to your figures. My calculations show that if I were to invest the £18k at 3% compounded it would be worth £31,563 after 20 years. The £1,236 indexed linked (3% inflation) also invested at 3% each year would amount to £43,887 by year 20. The break-even year is year 15. I agree that it would be 20 years before I would break even if I just took the annual savings and did not invest them. Incidentally, the invested income would be over £18,000 by year 11 - not that it is likely that anyone would be foolish enough to keep £18,000 in a current account earning virtually 0% interest.

To explain the basis of my calculations:- With the PV system, at the end of the first year the income will be £1,236. By the end of the second year the FITs income will be £1,277 (1.03 times £1,236). The first year's income has also been invested and is also worth £1,277. (Total £2554). FITS income year 3 is £1,315 which with the invested years 1+2 equals £3,946. etc.

But the predicted fuel price increase is several percentage points above inflation. This means that the savings each year on the electricity I use does not just increase by 3% but by 3% plus whatever the fuel price increase is likely to be. I'm not even going to start to predict the increase, but if the increase were as high as 7% above inflation, this would result in the savings each year on the electricity I use increasing from about £138 in the first year to £435 per year by year 20 and almost £700 by year 25. This is not a vast amount, but has to be added into the equations.

But the total unknown is the income tax increase. Should income tax increase to 26%, the first year's interest on the 18k reduces from £540 (20% tax) to just under £500 after 26% tax.

But who knows? ...

Cardew

Dave,

Don't disagree with the thrust your argument and there have been several posts along those lines.

However a few points.

You can currently get better than 3% on long term savings after tax.(standard rate)

If you assume 3% inflation (for FITs) then you can get inflation + 1% tax free from National Savings(so 4%)

If you have a mortgage you could use the £18,000 to pay off your mortgage.

The Governments target and Bank of England forecast is below 3% inflation.

You appear not to have allowed anything for repairs/replacement??

You, with your assumptions, make it 15 years to break even and that may well be fair.

So to sum up the financial proposition 'you' are putting to people is:

Invest £18,000 and provided my predictions are correct you will break even in 15 years and then start to make a profit?

I wonder how many people would think that an attractive proposition? A Bird in the Hand?