Free solar panel discussion

hethmar

Im trying to wade through all this thread but it has occurred to me that there is a large number of new posters on it?

Ive contacted Homesun who say Im not in an area covered by them (south east england) and ditto the northern based freebie supplier.

Its a tempting idea but I have this awful nagging at the back of my mind that it could be a massive failure

Jon_Tiffany

hethmar wrote: »

Im trying to wade through all this thread but it has occurred to me that there is a large number of new posters on it?

Ive contacted Homesun who say Im not in an area covered by them (south east england) and ditto the northern based freebie supplier.

Its a tempting idea but I have this awful nagging at the back of my mind that it could be a massive failure

What aspect of it do you think could be a massive failure and why?

What do people think about agreeing to a 25 year lease? Is it a concern or not bothered?

digitaltoast

Jon_Tiffany wrote: »

You can get everything you are asking for here:

http://www.pvwatts.org/

An estimation site based on weather data from 20 years ago is rather different from a "here's what I've generated" site.

Jon_Tiffany wrote: »

Here some sample hourly figures for a 4kWp system in London:

Jan figures:

Date/Time/Watts
1991, 1, 1, 10:00, 14
1991, 1, 1, 11:00, 187
1991, 1, 1, 12:00, 400
1991, 1, 1, 13:00, 402
1991, 1, 1, 14:00, 204
1991, 1, 1, 15:00, 17

July figures:
Date/Time/Watts
1991, 1, 7, 09:00, 0
1991, 1, 7, 10:00, 845
1991, 1, 7, 11:00, 1970
1991, 1, 7, 12:00, 2281
1991, 1, 7, 13:00, 2325
1991, 1, 7, 14:00, 2049
1991, 1, 7, 15:00, 745
1991, 1, 7, 16:00, 0

Interesting - so what it shows is that at the very peak of a sunny day in winter, the system is producing one tenth of its capacity, and in the middle of summer, it you're lucky, it'll produce about half its capacity between 11am and 2pm. Before you go to work at 9 and before you come back after 4pm, it is producing zippo, zilch, nadda. (of course, it feeds into the grid then, right when it's not needed).

Here's a posting on an Australian forum from the middle of their summer:
"Perfect day in Perth today....sunny....got to 26.6 degrees....no cloud.....my 1kw system generated about 6.5kwh.

I've found the max my system does is 6.5kwh, I haven't seen it any higher than this over the past 3 months".

Australia - hot, dry, and 20 degrees nearer the equator. And it gets 10 hours of daily sunshine in November.

As the weather centre point out:
"In Britain daily sunshine hours range from between one and two in midwinter to between five and seven in midsummer".

I've been doing some sums, do feel free to correct me if you think I've done them wrong:


Looking at http://www.nef.org.uk/greencompany/active-pv-basics.htm

2 years = 365*2
installed size: 6.47kW
10202kWh / 720 = 14.17kWh per day
14.17/6.47 = 2.19010819
2.19010819*3 (kW system from Isis) = 6.57032457
6.57032457 * 41.3p paid per kWh = 6.57*.043 = £2.8251 per day.

2.8251*(365*25)= 2.8251*(365*25) = £25779, less the £14,000 for the system = £11,776 is what people with "the wrong roofs" are paying owners of big houses in the right location.

Now if we take that as "normal" prices of about 12p/kW domestic:

6.57 * £0.12p saved per kWh = 6.57*.043 = £0.78 per day = £7,194.15, a loss of £6806. No wonder it needs you and I to pay for rich people with large roofs to have it!


Let's divide that by 25 years, that's £287.76 per annum.

According to Isis, the Govt are paying them £800 per year per installation, so from everyone's taxes, Isis are being given £512.24, and from all other electricity payers the difference between a more efficient technology like wind (9p/unit) and the massively subsidised hugely inefficient PV at 41.3p.

Remember, the ISIS system pays you nothing per kilowatt generated, you only get to keep the surplus for free.
(meaning, as pointed out, you'd have to always make sure you were off work and at home in the middle of sunny days, or predict that it wasn't going to get cloudy after setting the timer - anyone up for that?).

Is it just me who think this is all a grotesque sqaundering of other people's money? Thanks, New Labour, for landing the majority with larger bills and more tax.

Jon_Tiffany

digitaltoast wrote: »

An estimation site based on weather data from 20 years ago is rather different from a "here's what I've generated" site.



Interesting - so what it shows is that at the very peak of a sunny day in winter, the system is producing one tenth of its capacity, and in the middle of summer, it you're lucky, it'll produce about half its capacity between 11am and 2pm. Before you go to work at 9 and before you come back after 4pm, it is producing zippo, zilch, nadda. (of course, it feeds into the grid then, right when it's not needed).

Here's a posting on an Australian forum from the middle of their summer:
"Perfect day in Perth today....sunny....got to 26.6 degrees....no cloud.....my 1kw system generated about 6.5kwh.

I've found the max my system does is 6.5kwh, I haven't seen it any higher than this over the past 3 months".

Australia - hot, dry, and 20 degrees nearer the equator. And it gets 10 hours of daily sunshine in November.

As the weather centre point out:
"In Britain daily sunshine hours range from between one and two in midwinter to between five and seven in midsummer".

I've been doing some sums, do feel free to correct me if you think I've done them wrong:


Looking at http://www.nef.org.uk/greencompany/active-pv-basics.htm

2 years = 365*2
installed size: 6.47kW
10202kWh / 720 = 14.17kWh per day
14.17/6.47 = 2.19010819
2.19010819*3 (kW system from Isis) = 6.57032457
6.57032457 * 41.3p paid per kWh = 6.57*.043 = £2.8251 per day.

2.8251*(365*25)= 2.8251*(365*25) = £25779, less the £14,000 for the system = £11,776 is what people with "the wrong roofs" are paying owners of big houses in the right location.

Now if we take that as "normal" prices of about 12p/kW domestic:

6.57 * £0.12p saved per kWh = 6.57*.043 = £0.78 per day = £7,194.15, a loss of £6806. No wonder it needs you and I to pay for rich people with large roofs to have it!


Let's divide that by 25 years, that's £287.76 per annum.

According to Isis, the Govt are paying them £800 per year per installation, so from everyone's taxes, Isis are being given £512.24, and from all other electricity payers the difference between a more efficient technology like wind (9p/unit) and the massively subsidised hugely inefficient PV at 41.3p.

Remember, the ISIS system pays you nothing per kilowatt generated, you only get to keep the surplus for free.
(meaning, as pointed out, you'd have to always make sure you were off work and at home in the middle of sunny days, or predict that it wasn't going to get cloudy after setting the timer - anyone up for that?).

Is it just me who think this is all a grotesque sqaundering of other people's money? Thanks, New Labour, for landing the majority with larger bills and more tax.

Most people have only had their systems installed this year, so not many are going to have a years worth of data. The estimates are good enough for what we are discussing.

Your maths are not very clear - you start off with a 6kWp system and then use a 3kWp system? If its a 6kWp system you have used the wrong FIT rate. Maybe if you explain what you are trying to show I can help with the math.

You are wrong to suggest that taxpayers money is used - it is not. You really should stop posting misleading information.

This is not limited to rich people with large roofs. I am certainly not rich and do not have a large roof, yet I am getting solar PV.

'Poor' people can make use of the free PV offers.

We agree on one thing, and this only applies to the free PV offer, and then only those where the meter does not spin backwards - you will not benefit much if you are out at work all day.

Pincher

I'm not having a lot of luck with these free initiatives.

Had a pre-sale loft insulations surveyor come a few month ago.
The rafters are too low for their workers! This is despite my builders have put in a loft ladder and fluorescent lighting, and we go up there to do work all the time.

Now my roof is East-West, so no joy again.

I do have three dormer windows with flat roofs, 2x1.6m, 2x1.6m, 2x2.5m, which I am re-enforcing with ply, in preparation for solar panels. These are suitable for south facing panels mounted on A frames, but not 24m2 worth.

I like East-West, because you get the sun into the rooms which is great. South facing panel is actually a compromise, as it's optimised for the noon position. If money was no object, two panels, one facing east, and one facing west will maximise use of the roof area, and generate more electricity. I estimate my roof will need replacement in about 25 years, so hopefully I can replace the whole roof with solar technology at replacement time. Two birds with one stone.

I hear the solar cells can be etched on a layer of film, so why can't they make a roof bra containing PV cells? Imagine a tarpaulin draped across the roof front to back. You tie the corners into the wall at the gutter level. It needs to be designed so failed cells do not short circuit the system. When too many cells fail, just untie it, and put a new one in.

Jon_Tiffany

Pincher wrote: »

I do have three dormer windows with flat roofs, 2x1.6m, 2x1.6m, 2x2.5m, which I am re-enforcing with ply, in preparation for solar panels. These are suitable for south facing panels mounted on A frames, but not 24m2 worth.

Be aware that if they protude above the ridge line you may need planning permission.

grahamc2003

hethmar wrote: »

Im trying to wade through all this thread but it has occurred to me that there is a large number of new posters on it?

Ive contacted Homesun who say Im not in an area covered by them (south east england) and ditto the northern based freebie supplier.

Its a tempting idea but I have this awful nagging at the back of my mind that it could be a massive failure

Not sure what the reference to new posters (including me) is supposed to imply - are they (we, me) a different breed or something?

I think the only way the system could massively fail is if those offering 'free' panels and paying a very small amount for roof rental have got their sums wrong. Their business model obviously relies on the installed panels generating according to the numbers thay have been supplied with by the manufacturers. Some of us are very sceptical of numbers put out by those with an obvious interest - obviously, they don't out and out lie, but they do arrange for ideal conditions in every respect as the basis of their numbers, which often are not replicated in the field. If they expect say 3000kwhpa/installation (meaning an approx £1385 payment for each installation to them from other customers) but they only manage 2500 (meaning approx £1065 mpayment) they may or may not survive. Trees grow, buildings get built, and shading has a very large effect on the generation. If the company has 500 installatioon for example, it rakes in £693k or £533k under those assumptions (again the payment plus operational and development costs being loaded onto other customers bills).

The other risk of failure is if the government belatedly realise it is a very expensive futile gesture as far as a practical contribution to our energy needs, and cancels the systems at some stage.

I suppose a further risk is if solicitors start advising purchasers not to take on the remining term of the contract for some reason, and houses become unsaleable. (This risk to me is unknown, and because of that, I wouldn't go for the 'free' panels offer - the 100 quid or so pa return being (far) too small in my view for an unknown risk).

I'm playing devils advocate a bit, but I think these risks (which apply to the 'free' panel type offers and whether purely in my imagination or not) should be given an airing. It certainly is not a free lunch as many seem to think.

grahamc2003

digitaltoast wrote: »

Is it just me who think this is all a grotesque sqaundering of other people's money? Thanks, New Labour, for landing the majority with larger bills and more tax.

No, there are two of us!

I think the lib dems are even worse for this sort of 'green' nonsense, and as for Dave C cycling to work with his paperwork in a following Jag - well that just about sums everything up!

Hugh_Coward

Have had 2 visits by the structural engineer of A Shade Greener and told everything ok. Follow up e mails requesting information and indicating going ahead. Further telephone call for appointment to have everything explaied and date given for the fitting. failed to keep appointment and firm said we had failed on the rafter depth not being correct. No e mail or phone call to explain.My neighbour across from me has an identical house and has had it installed. Beware.

quoia

digitaltoast wrote: »

2 years = 365*2
installed size: 6.47kW
10202kWh / 720 = 14.17kWh per day
14.17/6.47 = 2.19010819
2.19010819*3 (kW system from Isis) = 6.57032457
6.57032457 * 41.3p paid per kWh = 6.57*.043 = £2.8251 per day.

Jon_Tiffany wrote: »

Your maths are not very clear - you start off with a 6kWp system and then use a 3kWp system? If its a 6kWp system you have used the wrong FIT rate. Maybe if you explain what you are trying to show I can help with the math.

Despite the error, it's quite clear to me.

The data is from a 6.47kW system over a 2 year period

The maths get an average kWh generated per day for a 1kW system

this is then fed into the ISIS model