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Chat Area => General Discussion Area => Topic started by: Tony H on 04 October 2011, 15:07:08

Title: Domestic solar panels
Post by: Tony H on 04 October 2011, 15:07:08
Hi all, I'm considering the idea of having solar panels fitted opinions please on the pro's and cons both financially and technically


TIA
Regards
Tony
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 04 October 2011, 15:58:37
Technicaly useless, financialy, probably enough subsidies about to help but how long they will be about for is questionable.
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 04 October 2011, 16:09:39
Be careful.

The attractive feed in tariff is currently set @ 43.3 pence per unit GENERATED at the moment - for installs fitted until the end of march. Its guaranteed for 25 years and also RPI index linked. Installs completed after April will be at a lower rate as the Govt needs to save money.

You are limited to a 4kW system for the feed in tariff. The cost will be beween £10k and £13k - but will return many times more than that over the term before the cost of increasing electricity, inflation etc is taken into account. It still has a breakeven of many years so is a long term investment.

Beware the firms that offer "free" panels. They put them up for nothing agreed and let you use the electricity generated during the day - but they get the tariff back from the govt and are basically squatting on your roof for 25 years. Makes it difficult to sell the house also.

The panels performance will also reduce gradually with time - which is why I've ignored that in the calculations and also the inflation aspects as they cancel each other out.

HTH - Rob
Title: Re: Domestic solar panels
Post by: zirk on 04 October 2011, 16:25:38
Depends how much money you floating around and how long your prepared to invest in it.

Under the current deal which ends April next year, if your prepared to outlay your cash for MCS approved Panels and Installation, the Government will return your Feed Tie in for 25 years at something like 42p per Joule being sold back to the Grid, after what you have used of course, works out something like an average of 15% tax free investment.

If your not going to go down the MCS route but thinking about doing a home brew, then Panels and installation will be cheaper, so cheaper electric bills, but no long term feed in available.

If you have no money at all to invest, then get One of the big suppliers to install it for free, and just benefit from Cheaper bills while they collect the cash over the next 25 years.

Personally Im still pondering over the last 2 options, but Im know more steered to Hot Water Panels, as it the most effective way of getting free energy from the Sun rather than using Gas or Electricity to heat your water or heating.

You can go down the MCS route with Water Heating but the pay back is not as attractive as with Electric Solar or Wind.

Chris.
Title: Re: Domestic solar panels
Post by: Kevin Wood on 04 October 2011, 16:28:29
at something like 42p per Joule...

 :o Quick! where do I sign?  ;D
Title: Re: Domestic solar panels
Post by: zirk on 04 October 2011, 16:32:41
You know what I mean Kevin, not edit button  :y
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 04 October 2011, 16:39:43
It's 43.3p per kW hour.

On the basis that there are 3,600,000 Joules in a kWh that would be a wonderful tariff to be on.  :y
Title: Re: Domestic solar panels
Post by: Radar on 04 October 2011, 16:45:16
A friend is getting it done and mentioned the inverters have a life expectancy of approx. 10 years - current cost to replace is £1200. Thought it might be of use to you.
Title: Re: Domestic solar panels
Post by: Kevin Wood on 04 October 2011, 16:45:41
It's 43.3p per kW hour.

On the basis that there are 3,600,000 Joules in a kWh that would be a wonderful tariff to be on.  :y

Shucks! There goes my retirement plan. :(

 ;)
Title: Re: Domestic solar panels
Post by: zirk on 04 October 2011, 16:46:19
It's 43.3p per kW hour.

On the basis that there are 3,600,000 Joules in a kWh that would be a wonderful tariff to be on.  :y

Probably something like what we will be paying for electric in 25 years time the way its all going.
 :y
Title: Re: Domestic solar panels
Post by: Kevin Wood on 04 October 2011, 16:50:29
A friend is getting it done and mentioned the inverters have a life expectancy of approx. 10 years - current cost to replace is £1200. Thought it might be of use to you.

.. and the inverter is the one part of the system that I would expect to last the payback period - if it was remotely decent quality, of course.

I have also heard that they are electrically noisy. Not something I'd install as a radio amateur.

My parents have a hot water solar installation. Seems to work quite nicely and their 2 panels will give about 4kWh of hot water in a decent sunny day. (and absolutely noting on a cloudy day, contrary to the marketing claims) I very much doubt they'll break even on the installation costs, but they needed a new tank, in any case, when it was installed.
Title: Re: Domestic solar panels
Post by: Radar on 04 October 2011, 17:00:01
Another point that was brought up was that you only get the full efficiency if the panels are installed on a south facing roof.
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 04 October 2011, 17:20:20
A friend is getting it done and mentioned the inverters have a life expectancy of approx. 10 years - current cost to replace is £1200. Thought it might be of use to you.

The Fronius range of inverters warranty can be upgraded to 20 years for a £200 one off payment at the time of purchase.

HTH  :y
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 04 October 2011, 17:22:34
Another point that was brought up was that you only get the full efficiency if the panels are installed on a south facing roof.

Indeed yes. A 250 watt panel will only generate than in direct sunlight. In normal daylight it will only generate about 20% of that. So sunlight levels are important.
Title: Re: Domestic solar panels
Post by: scimmy_man on 04 October 2011, 22:08:19
I had 20 panels fitted five weeks ago, we are south facing, so far its turned in 300kw, at 43.3 plus 3p per unit not used,
total cost £11500
Title: Re: Domestic solar panels
Post by: feeutfo on 04 October 2011, 22:17:40
For those that re mortgage regularly, which is wise in the current financial climate with low interest rates and all....

 Do your homework with the rental roofs space ones, or whatever the correct term is. There is a theory that mortgage company's don't like other parties having a potential say over a property the mortgage company effectively own, or are about to own, if your applying for their mortgage.

This can make remortgaging difficult in theory. Making vital monthly savings somewhat out of reach. Or could scupper a sale if your after moving house etc.

Depends very much on the lender, some are more fussy than others. Beware.


There is no issue if they have been bought outright of course. Afaik anyway. But look into repair costs if the system falls on it's arse.
Title: Re: Domestic solar panels
Post by: Kevin Wood on 04 October 2011, 22:37:32
Yep. Good point. I'd think twice about buying a house where a third party presumably has a charge over part of my roof. I really don't like that sort of thing, as the former alarm maintenance company here discovered when they tried to charge me north of £100 plus an £85 per year maintenance contract to program in a new alarm code. ;D
Title: Re: Domestic solar panels
Post by: Lioned on 04 October 2011, 22:39:07
Its taken me 30 years to build my house and pay off my mortgage and tempting though it may be to save a bit of money i'm not going to allow some spotty oik on the end of the phone in Scotland squat on my roof for the next 25 years and bugger up any chance of selling it,if and when we choose to.
Thats the thing,to save £5 per week (my estimate was £230 per year) i'm going to have a sitting tenent on my roof dictating what i can and cant do.

There are better ways to save money and not be at the mercy of the automated attendent every time a tile slips just to please the global warming conspiritors.
Title: Re: Domestic solar panels
Post by: Lioned on 04 October 2011, 22:40:46
Also they file a notice on your proprerty at the Land Registry.
Title: Re: Domestic solar panels
Post by: feeutfo on 04 October 2011, 22:51:32
Yep. Good point. I'd think twice about buying a house where a third party presumably has a charge over part of my roof. I really don't like that sort of thing, as the former alarm maintenance company here discovered when they tried to charge me north of £100 plus an £85 per year maintenance contract to program in a new alarm code. ;D
It's a general issue covering many aspects. Flats above shops, or flats or buildings with advertising hawdings on the side/roof spring to mind. Situations that could affect the value of the property in the future all fall foul.

It's hard to get anyone called out and do, for instance, an hours labour for less than a oner these days ime. But a service contract as well? Yeah right. ;D

Title: Re: Domestic solar panels
Post by: feeutfo on 04 October 2011, 23:13:38
Might affect house insurance as well I guess?  :-\

Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 05 October 2011, 08:43:20
Yep. Good point. I'd think twice about buying a house where a third party presumably has a charge over part of my roof. I really don't like that sort of thing, as the former alarm maintenance company here discovered when they tried to charge me north of £100 plus an £85 per year maintenance contract to program in a new alarm code. ;D

Tear it out and fit a new panel, cheaper, probably more reliable and most likely better maintained!

Or just get the info on the current one and reset it  ;D
Title: Re: Domestic solar panels
Post by: Kevin Wood on 05 October 2011, 09:58:56
Or just get the info on the current one and reset it  ;D

Exactly what I did, after pointing out that they have no legal right to carry out their threat to come and remove it. :y
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 05 October 2011, 10:35:56
I can so see this elevated price per Kwh being bin'd way before the currently committed period, particularly when most people finaly realise that renewables are a joke at the moment
Title: Re: Domestic solar panels
Post by: bob.dent on 05 October 2011, 10:52:08
I've no idea how efficient modern day domestic solar panels are these days, but I wouldn't have thought we get sufficient sunlight in this country to warrant them. :-\
Title: Re: Domestic solar panels
Post by: albitz on 05 October 2011, 10:54:56
That may well depend on whether or not Chris Huhne gets banged up for perverting the course of justice. If he does its just possible we might get a sane energy secretary. :)
Title: Re: Domestic solar panels
Post by: Kevin Wood on 05 October 2011, 11:04:23
You should have heard the BS Huhne was spouting yesterday about our current energy policy not being at all responsible for an exodus of heavy industry. Specific example - smelting aluminium. Yep, that will be really cost effective here with that loony in control. ;D
Title: Re: Domestic solar panels
Post by: Sir Tigger KC on 05 October 2011, 18:13:07
I can so see this elevated price per Kwh being bin'd way before the currently committed period, particularly when most people finaly realise that renewables are a joke at the moment

I thought that the current feed in tariff is guarenteed for 25 years if you sign up at the moment, but it will change next year?  I take Mark's point however and wonder how watertight the contracts are? should the Govt intervene?  ::)

If I was to consider either type of solar system, I'd prefer to do business with a local company, rather than a 'national' company who employ direct salespeople working on commission, as these guys will tell you any old BS to get the deal!  ;)

Title: Re: Domestic solar panels
Post by: Sir Tigger KC on 05 October 2011, 18:33:39
If you go for one of the big company's and get a salesguy round, haggle hard for say 40% of his opening price and depending on what sort of week he's having, he may go for it as at least he'll get a minimal commission say £100 rather than the usual 10%!  ;)  If he dosn't go for it kick him out and get the next guy in....

Don't believe any crap about discounts for using your house in their marketing or nipping out to phone the manager to authorise your 'special deal' either.  I believe that such direct sales tactics are now illegal anyway  :y

The margins on any sort of home improvement products are huge, nevertheless these companies have a habit of disapeering..... So bear that in mind when the salesguy's selling maintenance contracts or warrenties....  and if you sign a deal in your home you have a statutory cooling off period of 14 days (Might be 7 days?) during which you can cancel and get your deposit back  :y
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 05 October 2011, 20:27:06
I had one salesguy walk away when I asked him "difficult" questions .............  :o
Title: Re: Domestic solar panels
Post by: Shackeng on 05 October 2011, 20:58:45
I had a 3.9KW 20 panel system fitted last November. The estimated generated KW was 3218 per annum. I passed that two months early. I was reluctant to have them fitted as the government was talking about changing the system of payments, so I wrote to Chris Huhne and had a reply confirming that there would be no retrospective changes to the payments described above, ie if you join on a tariff, it is guaranteed (as much as anything ever is) for 25 years, index linked. I estimate I am getting at least 12.5% return on capital at today's price of electricity, which of course will stay at this level, I don't think. My electricity meter is only reading about 10KW more than it was in March, and I have used the immersion heater to heat water since March, and have not used the gas boiler since April. My array points to 168 degrees at 27' to the horizontal. Personally, I think its a no-brainer, as it is highly unlikely you will ever get a better return on capital, and which can only increase as prices rise. PM me if you want to discuss it in more detail. I agree with those advising against the so-called 'free' offers.
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 05 October 2011, 21:06:21
I had a 3.9KW 20 panel system fitted last November. The estimated generated KW was 3218 per annum. I passed that two months early. I was reluctant to have them fitted as the government was talking about changing the system of payments, so I wrote to Chris Huhne and had a reply confirming that there would be no retrospective changes to the payments described above, ie if you join on a tariff, it is guaranteed (as much as anything ever is) for 25 years, index linked. I estimate I am getting at least 12.5% return on capital at today's price of electricity, which of course will stay at this level, I don't think. My electricity meter is only reading about 10KW more than it was in March, and I have used the immersion heater to heat water since March, and have not used the gas boiler since April. My array points to 168 degrees at 27' to the horizontal. Personally, I think its a no-brainer, as it is highly unlikely you will ever get a better return on capital, and which can only increase as prices rise. PM me if you want to discuss it in more detail. I agree with those advising against the so-called 'free' offers.

Thanks Shackeng  :y

I'm just about the bite the bullet in the next few weeks. What make inverter have you got, any issues with it?
Title: Re: Domestic solar panels
Post by: feeutfo on 05 October 2011, 21:37:38
Re sales guys, I have real problems with my behavior when talking to these people. So simply don't talk to them. For both our sakes.  :(
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 05 October 2011, 21:42:24
I personaly hope they come to thier senses and knock the ridiculous inflated fed in rates on the head VERY soon.
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 05 October 2011, 22:14:47
I personaly hope they come to thier senses and knock the ridiculous inflated fed in rates on the head VERY soon.

After I've got my install finished please  :'(
Title: Re: Domestic solar panels
Post by: Shackeng on 05 October 2011, 22:51:47
I had a 3.9KW 20 panel system fitted last November. The estimated generated KW was 3218 per annum. I passed that two months early. I was reluctant to have them fitted as the government was talking about changing the system of payments, so I wrote to Chris Huhne and had a reply confirming that there would be no retrospective changes to the payments described above, ie if you join on a tariff, it is guaranteed (as much as anything ever is) for 25 years, index linked. I estimate I am getting at least 12.5% return on capital at today's price of electricity, which of course will stay at this level, I don't think. My electricity meter is only reading about 10KW more than it was in March, and I have used the immersion heater to heat water since March, and have not used the gas boiler since April. My array points to 168 degrees at 27' to the horizontal. Personally, I think its a no-brainer, as it is highly unlikely you will ever get a better return on capital, and which can only increase as prices rise. PM me if you want to discuss it in more detail. I agree with those advising against the so-called 'free' offers.

Thanks Shackeng  :y

I'm just about the bite the bullet in the next few weeks. What make inverter have you got, any issues with it?

Ever Solar G83 3200, no problems so far. http://www.pvpro.co.uk/inverter/class/EverSolar-Inverter-tl3200-tl4600-tl5400.html. Good luck, and I don't think you will regret it. :y
Title: Re: Domestic solar panels
Post by: Shackeng on 05 October 2011, 22:55:33
I personaly hope they come to thier senses and knock the ridiculous inflated fed in rates on the head VERY soon.

Clearly a subjective opinion  ::) ::) ::)
Title: Re: Domestic solar panels
Post by: Martin_1962 on 05 October 2011, 23:05:39
My boss is trying to get this done but he is doing it completely differently.

He is buying the panels from a friend who makes them, and getting them installed - that way he gets all the money.
Title: Re: Domestic solar panels
Post by: Kevin Wood on 05 October 2011, 23:10:33
My boss is trying to get this done but he is doing it completely differently.

He is buying the panels from a friend who makes them, and getting them installed - that way he gets all the money.

Will he qualify to sell it for umpteen times its' market value, though? ;)
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 05 October 2011, 23:24:27
My boss is trying to get this done but he is doing it completely differently.

He is buying the panels from a friend who makes them, and getting them installed - that way he gets all the money.

The ONLY way he will get the feed in tariff (the bit that is worth having) is by having the installation accredited by an approved MCS installer. The installer then registers the install and you get the benefit. It isn't possible for a DIY install to do this..........

You might want to point that out to him. He will probably invalidate his buildings insurance on a DIY job also. High voltage DC is nasty (i.e. lethal stuff) - hence the requirement for an accredited installation.
Title: Re: Domestic solar panels
Post by: Kevin Wood on 05 October 2011, 23:27:36
My boss is trying to get this done but he is doing it completely differently.

He is buying the panels from a friend who makes them, and getting them installed - that way he gets all the money.

The ONLY way he will get the feed in tariff (the bit that is worth having) is by having the installation accredited by an approved MCS installer. The installer then registers the install and you get the benefit. It isn't possible for a DIY install to do this..........

You might want to point that out to him. He will probably invalidate his buildings insurance on a DIY job also. High voltage DC is nasty (i.e. lethal stuff) - hence the requirement for an accredited installation.

Thought there'd be a "jobs for the boys" clause in the deal somewhere. ;)
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 06 October 2011, 08:14:30
I personaly hope they come to thier senses and knock the ridiculous inflated fed in rates on the head VERY soon.

Clearly a subjective opinion  ::) ::) ::)

Quite the contary, the infeed rates that are being underwritten are stupidly high for what is a very environmentaly damaging (to make) technology and they are not the answer to energy production.

Whats more is the subsidy given towards the rates could be far better spent in getting wind power etc to actualy be a USEFUL energy source rather than a blot on the landscape which contributes jack all.
Title: Re: Domestic solar panels
Post by: Shackeng on 06 October 2011, 15:14:43
I personaly hope they come to thier senses and knock the ridiculous inflated fed in rates on the head VERY soon.

Clearly a subjective opinion  ::) ::) ::)

Quite the contary, the infeed rates that are being underwritten are stupidly high for what is a very environmentaly damaging (to make) technology and they are not the answer to energy production.

Whats more is the subsidy given towards the rates could be far better spent in getting wind power etc to actualy be a USEFUL energy source rather than a blot on the landscape which contributes jack all.

I would be interested to know what the carbon trade-off actually is, as these figures are not readily available. I assume that HMG encourages their fitment to help us meet our carbon reduction targets. I have heard similar arguments to yours before, but have never seen any figures to assist in coming to an objective conclusion. In the meantime, as they have been screwing taxes out of me forever, I'm quite happy to get something back. :y
Title: Re: Domestic solar panels
Post by: Shackeng on 06 October 2011, 21:01:00
I really would like to know the answer to this.  :-\
Title: Re: Domestic solar panels
Post by: zirk on 07 October 2011, 13:00:14
My boss is trying to get this done but he is doing it completely differently.

He is buying the panels from a friend who makes them, and getting them installed - that way he gets all the money.

The ONLY way he will get the feed in tariff (the bit that is worth having) is by having the installation accredited by an approved MCS installer. The installer then registers the install and you get the benefit. It isn't possible for a DIY install to do this..........

You might want to point that out to him. He will probably invalidate his buildings insurance on a DIY job also. High voltage DC is nasty (i.e. lethal stuff) - hence the requirement for an accredited installation.

Thought there'd be a "jobs for the boys" clause in the deal somewhere. ;)

Thats a messy one as well, looked into this as a possible for myself, apart from having to spend crap loads of money for the MSC course, bit less if your already NIC, and pass the exams, you still dont get MCS approval untill you have completed and installed at least 2 full feed in tarrif systems and had the work inspected by MCS but you cant even think about installing anything to do with feed in unless your MCS approved!

Chicken, egg, chicken, egg.
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 07 October 2011, 13:07:47
I really would like to know the answer to this.  :-\

Its very dependent on the install but , its well recognised that its takes 4-8 years to produce the same level of energy that was requried to make it.

The issue is that the efficency of the panel falls off with age with most panels only being truely good for about 10 years (they will operate for much longer but at nothing near the efficiency they were originaly built to).

Hence you might get a few years of energy gain and thats only thanks to the latest production developments, its not many years ago that they would enver produce the same energy required to make one.
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 07 October 2011, 13:25:11
Fair enough re the NIC bit - but surely the guys that are MSC had it get it somewhere. I'm not surprised that it tight as dealing with high voltage DC is something that needs to be done properly
Title: Re: Domestic solar panels
Post by: zirk on 07 October 2011, 13:50:49
Fair enough re the NIC bit - but surely the guys that are MSC had it get it somewhere. I'm not surprised that it tight as dealing with high voltage DC is something that needs to be done properly

My understanding or guess work are, two options, give up your day job and go and become an apprentice for an existing MCS Company to get the Certs, guessing their going to happy when you leave shortly afterwards. Or get two guinea pigs to pay for your first 2 Installs (do a trade deal with them Im guessing) and pay an MCS Guy to help you install them, still not convinced how this one works.

Another factor that pops up now and then, is MCS approval doesn't allow you to sign off any structural changes made, something depending upon local Councils or Insurance Co's may need. So  more money for the Structural Engineer and their not cheap. 

 
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 07 October 2011, 14:05:51
Fair enough re the NIC bit - but surely the guys that are MSC had it get it somewhere. I'm not surprised that it tight as dealing with high voltage DC is something that needs to be done properly

I would imagine that the real challenge is ensuring that there is grid quality mains which is suitably interfaced and protected would be a bigger challenge.

DC is much easier to do the calcs etc on
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 07 October 2011, 14:08:42
Fair enough re the NIC bit - but surely the guys that are MSC had it get it somewhere. I'm not surprised that it tight as dealing with high voltage DC is something that needs to be done properly

My understanding or guess work are, two options, give up your day job and go and become an apprentice for an existing MCS Company to get the Certs, guessing their going to happy when you leave shortly afterwards. Or get two guinea pigs to pay for your first 2 Installs (do a trade deal with them Im guessing) and pay an MCS Guy to help you install them, still not convinced how this one works.

Another factor that pops up now and then, is MCS approval doesn't allow you to sign off any structural changes made, something depending upon local Councils or Insurance Co's may need. So  more money for the Structural Engineer and their not cheap. 

 

I am very pleased to hear that as the structual clacs are not trivial and potentialy more dangerous than a poor electrical install.

To me, the panels should require building regs to ensure roof loading etc is considered
Title: Re: Domestic solar panels
Post by: tunnie on 07 October 2011, 14:24:08
What about if one fails? Surely any cost of replacement/fix would offset any gains?

What about yobs throwing stones at them, or natural issues like branches falling on them? Would that be covered by house insurance? Surely any claim there is going to hit you on return as well  :-\
Title: Re: Domestic solar panels
Post by: zirk on 07 October 2011, 14:54:42
Talking of Solar Panels, this seems like the bargain of the century.

http://www.ebay.co.uk/itm/Broken-Solar-Cells-6x6-Multi-Wafers-Solar-Cell-Untabbed-/320769951527?pt=LH_DefaultDomain_0&hash=item4aaf610727#ht_720wt_932

Is it me or Im I missing something here.  :D
Title: Re: Domestic solar panels
Post by: Shackeng on 07 October 2011, 17:44:15
I really would like to know the answer to this.  :-\

Its very dependent on the install but , its well recognised that its takes 4-8 years to produce the same level of energy that was requried to make it.

The issue is that the efficency of the panel falls off with age with most panels only being truely good for about 10 years (they will operate for much longer but at nothing near the efficiency they were originaly built to).

Hence you might get a few years of energy gain and thats only thanks to the latest production developments, its not many years ago that they would enver produce the same energy required to make one.

Having had a chat to my installer today, he pointed me to this link,  http://info.cat.org.uk/questions/pv/what-energy-and-carbon-payback-time-pv-panels-uk which suggests that your information is somewhat out of date. The study from 2008 claims a payback of only 2.5 years, and as the efficiency and production methods will have improved since then, it will be less than that now. :y
Title: Re: Domestic solar panels
Post by: Tony H on 07 October 2011, 18:13:15
'kin 'ell I've opened a right can of worms with this one  :o thanks for all the replys all keep them coming  :y
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 07 October 2011, 21:52:24
I really would like to know the answer to this.  :-\

Its very dependent on the install but , its well recognised that its takes 4-8 years to produce the same level of energy that was requried to make it.

The issue is that the efficency of the panel falls off with age with most panels only being truely good for about 10 years (they will operate for much longer but at nothing near the efficiency they were originaly built to).

Hence you might get a few years of energy gain and thats only thanks to the latest production developments, its not many years ago that they would enver produce the same energy required to make one.

Having had a chat to my installer today, he pointed me to this link,  http://info.cat.org.uk/questions/pv/what-energy-and-carbon-payback-time-pv-panels-uk which suggests that your information is somewhat out of date. The study from 2008 claims a payback of only 2.5 years, and as the efficiency and production methods will have improved since then, it will be less than that now. :y

I can assure you that it is the latest, I am currently working with a solar panel manufacturer where we are developing a flexible solar panel  :y
Title: Re: Domestic solar panels
Post by: Shackeng on 08 October 2011, 09:17:42
I really would like to know the answer to this.  :-\

Its very dependent on the install but , its well recognised that its takes 4-8 years to produce the same level of energy that was requried to make it.

The issue is that the efficency of the panel falls off with age with most panels only being truely good for about 10 years (they will operate for much longer but at nothing near the efficiency they were originaly built to).

Hence you might get a few years of energy gain and thats only thanks to the latest production developments, its not many years ago that they would enver produce the same energy required to make one.

Having had a chat to my installer today, he pointed me to this link,  http://info.cat.org.uk/questions/pv/what-energy-and-carbon-payback-time-pv-panels-uk which suggests that your information is somewhat out of date. The study from 2008 claims a payback of only 2.5 years, and as the efficiency and production methods will have improved since then, it will be less than that now. :y

I can assure you that it is the latest, I am currently working with a solar panel manufacturer where we are developing a flexible solar panel  :y

Can you post the reference to the 4-8 years payback time  please Mark, as my installer is very interested in the discrepancy. :y
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 08 October 2011, 10:19:09
As you will be aware, the real figures are closely guarded by the manufacturers and there is plenty of 'spin' out there with many figures quoted based on cooled arrays close to the equator (in fact, these are the figures your fitter will have seen and the ones used as promotional material in the sales lit) which are 'ideal'.

Now, this is due to there being no standard test setup although hopefuly the new draft (yes draft i.e. not even fully finalised!) standard which DERlab have proposed may well help to clarify things (which only appeared in July of this year!) in the US and Europe.

We are currently working with Sanyo and the figures I have quoted is what you would expect with the latest tech in the Uk (we have just completed a study which is not in the public domain to base line results using a number of different panels due to the above lack of standardisation in order to allow us to the get an idea of the effectiveness and efficency of our flexi panel).

So as said, the figures you see today are based on spin and no baseline test standard.....hence are not accurate and cant be trusted.
Title: Re: Domestic solar panels
Post by: Shackeng on 08 October 2011, 11:40:57
Thanks Mark, very interesting, but I have difficulty reconciling the the figures you quote of 4 - 8 years with the quoted 2008 figure of 2.5 years, which are an improvement on earlier figures from the same source. Also it seems very odd that with improvements in manufacture and panel output, that, according to your figures, the payback time is getting worse. Unless the figures in the link I quoted are completely bogus, in which case if you can give me a positive reference to qualify that, I will take it up with them, as clearly many people will use such information in deciding to fit PV.  :-\ :-\ :-\
I am not sure whether there are any figures for payback from Govmnt sources, but I feel it is worth pointing out that the annual generated figure estimated for my 3.9Kw array, as calculated in accordance with official guidance, is 3218KW.  This figure was exceeded after only ten months, so clearly they are very conservative estimates, and I would have expected payback times to have been calculated equally conservatively. :-\ :-\ :-\
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 08 October 2011, 11:46:16
Thanks Mark, very interesting, but I have difficulty reconciling the the figures you quote of 4 - 8 years with the quoted 2008 figure of 2.5 years, which are an improvement on earlier figures from the same source. Also it seems very odd that with improvements in manufacture and panel output, that, according to your figures, the payback time is getting worse. Unless the figures in the link I quoted are completely bogus, in which case if you can give me a positive reference to qualify that, I will take it up with them, as clearly many people will use such information in deciding to fit PV.  :-\ :-\ :-\
I am not sure whether there are any figures for payback from Govmnt sources, but I feel it is worth pointing out that the annual generated figure estimated for my 3.9Kw array, as calculated in accordance with official guidance, is 3218KW.  This figure was exceeded after only ten months, so clearly they are very conservative estimates, and I would have expected payback times to have been calculated equally conservatively. :-\ :-\ :-\

I can totally see mark's logic here - but Shackeng's real world experience seems to be in the opposite direction. The config that I'm looking at is a nominal 4.0Kw system with a design output of 3643. I haven't signed yet - but will be very soon.

There is a window here which I want to exploit - and for once want to get "something back" from the "system".
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 08 October 2011, 11:58:35
Be aware that I am not talking cash pay back figures (as they are not real due to the stupid inflated feed in charge) I am talking the time to produce the same quantity of energy required to make them!.

At no point have I talked financials as that is not a level playing field!

I am very keen to see the subsidised feed in rates got rid of and the money used to make renewables work properly as today, they are practicaly useless.
Title: Re: Domestic solar panels
Post by: Shackeng on 08 October 2011, 12:17:47
Be aware that I am not talking cash pay back figures (as they are not real due to the stupid inflated feed in charge) I am talking the time to produce the same quantity of energy required to make them!.

At no point have I talked financials as that is not a level playing field!

I am very keen to see the subsidised feed in rates got rid of and the money used to make renewables work properly as today, they are practicaly useless.

No, I appreciate that, we are both talking about carbon payback.  I only use the output figure to show that the authorities appear to be treading warily when quoting figures. So if you can point me to some definitive statement contradicting the link vis-a-vis carbon payback I posted, I would be very grateful. :y
Title: Re: Domestic solar panels
Post by: I_want_an_Omega on 08 October 2011, 12:34:55
I think we are all in "violent agreement" here  :-X
Title: Re: Domestic solar panels
Post by: Shackeng on 08 October 2011, 18:31:56
Another more up to date (2010) link here, http://zeroemissionproject.com/blog/article/40/do-photovoltaic-solar-panels-need-more-energy-to-be-manufactured-than-what-they-generate states carbon/energy payback in the UK is about two years. :y
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 09 October 2011, 21:08:29
Be aware that I am not talking cash pay back figures (as they are not real due to the stupid inflated feed in charge) I am talking the time to produce the same quantity of energy required to make them!.

At no point have I talked financials as that is not a level playing field!

I am very keen to see the subsidised feed in rates got rid of and the money used to make renewables work properly as today, they are practicaly useless.

No, I appreciate that, we are both talking about carbon payback.  I only use the output figure to show that the authorities appear to be treading warily when quoting figures. So if you can point me to some definitive statement contradicting the link vis-a-vis carbon payback I posted, I would be very grateful. :y

As already said, you wont find the info on the web and I certainly wont be revealing the results as its more than my jobs worth.

However, I am very aware that it is one of the only truely independent set of tests carried out in a controled way (and hence why the manufacturers were so interested!).

The energy figure is based on extraction through to completed instal (and not just the production costs the government figures are based on)
Title: Re: Domestic solar panels
Post by: Shackeng on 09 October 2011, 22:54:17
Thanks for that Mark, I have written to Chris Huhne asking for clarification, because from what you say, it sounds very like a conspiracy to mislead the public. :y
Title: Re: Domestic solar panels
Post by: Marks DTM Calib on 10 October 2011, 08:03:53
Thanks for that Mark, I have written to Chris Huhne asking for clarification, because from what you say, it sounds very like a conspiracy to mislead the public. :y

For a second there, you almost sounded surprised!

The governments have to meet targets and being the kings of spin, will give out what ever info drives thier 'chosen' techs to meet them.....despite them having not an ounce of real knowledge in the subjects!
Title: Re: Domestic solar panels
Post by: Shackeng on 10 October 2011, 15:21:39
Yes, I don't know why, as a confirmed cynic, I should expect anything other. :y