Solar: how much you paid (£) how much you have generated (kWh) and date of install.

zeupater

cepheus wrote: »

... I really hoped this thread to be a catalogue of real life experiences over time so we could have some evidence of the above claim. Unfortunately, you are determined to make it into an slanging match. I have no interest in demeaning solar, but you are in promoting it.

My concern about this board was that potential Eco-enthisiasts would think that 'Green living' is about solar panels. In reality it is probably the least effective methods in the UK, since the subsidy could be used to save so much more elsewhere. This includes not just generating power but avoiding the need for it.

I notice some people are posting good results which suggest they are producing around an unsubsidised 15 p/kWh verses about half that for commercial solar and onshore wind in the UK and a third of that for commercial onshore wind in Germany and Denmark. I have never claimed that solar is bad in the correct situation (large scale and low latitude) or that wind is good in all situations (far inland and small scale). I'm just trying to promote a database from which a rational non-partisan discussion could emerge.

Unfortunately, this will be impossible if people just post successes, we have to know about the failures as well such as this. The truth is somewhere in the middle, but it seems we won't know for some time. ...

Hi

I really don't follow the above ....

My understanding, from your previous posts, is that you are looking for 'real-word' data in order to assess a reasonable performance for pv systems and to, in some way, assess performance degradation over time in order to ensure that data from newly installed systems doesn't sway the results .... is that fair ???

Okay then, if that's the case, how many sample systems would you expect to have posted and why would it be considered reasonable to expect that collected data from this thread would counter the worry that your analysis "will be impossible if people just post successes" .... surely you're looking for a sample size which is both large enough to dilute anomalies and provide what could be accepted as being a reasonable average combined with having a data collection timescale to reasonably analyse performance over time ?? .....

So, here's the crunch ... would it not be better to simply analyse existing and readily available data from thousands of UK sites, hundreds of which provide data every 10 minutes ? .... panel performance figures could be analysed over a much greater data sample, after all, why would average degradation be different in any country of similar latitude?. Looking at data for northern European countries - http://pvoutput.org/country.jsp - there's a sample dataset of ~8500 installations over which the spread of average efficiencies (kWh/kWp) by country are similar ....

In a previous post you were going to 'have a look' at the data source with tens-of-thousands of records containing the data you were searching for ....

cepheus wrote: »

Thanks, I'll take a look.

I'm trying to cut through all the manufactures hype to see what their performance is in practice, and how competitive and cost effective they are as a serious means of supplying electricity for our economy ....

... but seem to have forgotten to do so, just three days later posting ....

cepheus wrote: »

I've only had one figure which can be worked on so far, where is all the data I asked for from MSE users, and why is everyone so shy about providing them? ...

... Actually, as of about 10 seconds ago, you've now got 20283 plus the one you referred to above, plus waywardmike's figures (which you missed at the time) and a few others since, so shall we just say 20285+ ?? ... The PvOutput database already provides analysis over somewhere around 9.7million daily generation records, now how much more data do you want and how long a thread are you willing to read through ??

The analysis is already there and if it's in a format which doesn't suit, the data to perform your own analysis is also already there .... the question that remains revolves around why it hasn't already been used ....

HTH
Z

zeupater

Martyn1981 wrote: »

... Care to explain that 15p figure this time? ...

Hi

I'd be interested in that too .... taking the average generation over 1870 UK systems on PvOutput as being 2.416kWh/kWp/day (http://pvoutput.org/country.jsp) (3527kWh/year for a 4kWp system) and 15p/kWh proposed by Cepheus as being the unsubsidised production cost we get the following original purchase & life maintenance table for a 4kWp system against a range of years (call it lifespan or whatever) ....

10 - £5290 (3527*10*0.15)
15 - £7935 (3527*15*0.15)
20 - £10581 (3527*20*0.15)
25 - £13226 (3527*25*0.15)
30 - £15871 (3527*30*0.15)
35 - £18516 (3527*35*0.15)
40 - £21162 (3527*40*0.15)

... so, the 15p/kWh figure roughly equates to a system at a typical current buy price being written off over 10years, that's ripped out and completely binned as opposed to additional expenditure on maintenance or a new inverter .... I just wonder how many will actually be planning/prepared to do that.

To me, it looks like the 15p originates from a calculation based on the price of a second half 2011 install over the 25year lifespan of FiTs at the time ... I find it odd that anyone would be open to such a basic error once, and extremely interested as to why the error would be repeated ...

HTH
Z

Martyn1981

zeupater wrote: »

I'd be interested in that too

Yep!

It's not a point I'm labouring for fun, nor petty pedancy.

I simply find it annoying (as you know) when false or misleading info is posted. I tried hard to steer cepheus towards current prices as he's quoting current on-shore wind costs.

I'm divided over the generation figures you give though. I think they are totally true and representative, so possibly are fairer than mine. But, the differing subsidies mean that supply side wind (and PV) has to be built in the most suitable areas, whereas with demand side FiT, the grant is more generous, to allow less suitable properties to take part ..... since you can't move your house.

That's why I concentrated on the better (but not best) prices, and the better (but not best) generation. Using £5k and 4,000kWh keeping the 10% + 10% better (£4.5k and 4,400kWh) extremes in reserve. My reasoning was to get a better comparison of cost of generation between the technologies.

Whatever method is used, I simply can't get anywhere near that 15p figure, for a current install.

I'm reasonably content that like many, cepheus wrote off PV as being unviable back at the start as the cost was so, so high. And failed to re-evaluate it. I'm pretty sure, somewhere on here many years ago, I stated that PV would never catch on-shore wind. I was shocked when it was suggested it might do it by the end of this decade, and further shocked when it was placed in the same CfD bidding pot as on-shore wind in 2015. Shock three was that it actually managed to win some contracts.

What is most fascinating about these exchanges, is that cepheus tries hard on MSE to stress the importance of action by all, in all areas (admirable behaviour). But is utterly dismissive of a demand side technology that could end up involving ~5m households (~10 to 15m Britains).

Mart.

nobby1963

My figures ;

£11000 paid for system- installed November 2011.
To date ; 14683 kWh produced
£7075 revenue.
We did add an Immersun to our system in 2012 / 2013 - can't remember exactly at a cost of £400 ish .
This has led to fair savings in our heating oil costs for hot water ( rural location no mains gas available).

Very pleased with our returns.
Nobby.

theboylard

nobby1963 wrote: »

Nobby.

I like your roof angle, well done!

cepheus

zeupater wrote: »

Hi

I really don't follow the above ....

My understanding, from your previous posts, is that you are looking for 'real-word' data in order to assess a reasonable performance for pv systems and to, in some way, assess performance degradation over time in order to ensure that data from newly installed systems doesn't sway the results .... is that fair ???

Okay then, if that's the case, how many sample systems would you expect to have posted and why would it be considered reasonable to expect that collected data from this thread would counter the worry that your analysis "will be impossible if people just post successes" .... surely you're looking for a sample size which is both large enough to dilute anomalies and provide what could be accepted as being a reasonable average combined with having a data collection timescale to reasonably analyse performance over time ?? .....

So, here's the crunch ... would it not be better to simply analyse existing and readily available data from thousands of UK sites, hundreds of which provide data every 10 minutes ? .... panel performance figures could be analysed over a much greater data sample, after all, why would average degradation be different in any country of similar latitude?. Looking at data for northern European countries - http://pvoutput.org/country.jsp - there's a sample dataset of ~8500 installations over which the spread of average efficiencies (kWh/kWp) by country are similar ....

In a previous post you were going to 'have a look' at the data source with tens-of-thousands of records containing the data you were searching for ....

... but seem to have forgotten to do so, just three days later posting ....

... Actually, as of about 10 seconds ago, you've now got 20283 plus the one you referred to above, plus waywardmike's figures (which you missed at the time) and a few others since, so shall we just say 20285+ ?? ... The PvOutput database already provides analysis over somewhere around 9.7million daily generation records, now how much more data do you want and how long a thread are you willing to read through ??

The analysis is already there and if it's in a format which doesn't suit, the data to perform your own analysis is also already there .... the question that remains revolves around why it hasn't already been used ....

HTH
Z

The only way I could access it was to pretend I was a solar generator a put some dummy figures in, although they were obviously fake in my case to avoid confusion. All the same it didn't give me confidence your typical rooftop generator was included.

Here's a comparison of the cost of rooftop vs commercial solar compared with onshore and offshore in Germany where perhaps the economies of scale make it even more competitive. It tends to confirm rooftop solar like offshore wind is almost twice the price of onshore wind, despite possessing moderately good locations near the Alps and less strong wind as in the UK.



http://energytransition.de/2014/12/infographs/

zeupater

cepheus wrote: »

The only way I could access it was to pretend I was a solar generator a put some dummy figures in, although they were obviously fake in my case to avoid confusion. All the same it didn't give me confidence your typical rooftop generator was included ....

Hi

Forget wind and everything else, just concentrate on the matter at hand .... there's no need to pretend anything, why would you even need to enter any dummy generation, just click here ... http://pvoutput.org/country.jsp to get your totals, select the country you want to see the individual systems for, I'll make it simple - here's the UK ... http://pvoutput.org/map.jsp?country=243 , then drill down to areas or individual systems - everything you need for what you want to do is already there, all you need to know is that the efficiencies are kWh/kWp/day and you're done ....

HTH
Z

Martyn1981

cepheus wrote: »

It tends to confirm rooftop solar like offshore wind is almost twice the price of onshore wind,

Have a look back at the thread where you first started this nonsense. You'll see that the CfD bids for on-shore wind were £80 to £82.50/MWh and for off-shore wind £115 to £120/MWh. So not twice as much. Yet another false claim perhaps?

Also, you have failed to take account of the differing economics of supply side v's demand side leccy. Clue, we don't pay 5p/kWh for our leccy.

I've asked you to show your calcs for the 15p figure .... care to do that now.

Here's a very simplified model, £5k for a 4kWp install. Generating 4,000kWh pa. Add on £1k for a replacement inverter, and £1.25k for cost of capital (lost interest averaged out at 1%). Total £7,250.

Assume generation degrades by 20% over the 25 years, giving an average of 90%. Total 4,000 * 90% * 25yrs = 90,000kWh.

£7,250 / 90,000 = 8.06p/kWh.

If you don't agree, then please explain. Please also prove that £5k for a 4kWp install isn't possible, and also prove that 4,000kWh isn't also possible.

Mart.

PS I note on the house values thread that you've snuck in another pro-wind anti-PV attack based on your unsubstantiated claims. M.

cepheus

You can't prove that a £5,000 for 4kW is possible either, since you don't know how reliable such as cheap system would be over the 25 years. There's all sorts of cheap appliances which are designed to sell not last, possibly like these companies themselves. What we can be sure of is that the same system will be far more cost effective in a sunnier country and with economies of scale. You can never win on a microscale in the Uk, because we are talking about the same technology.

Perhaps you can run through these figures from the consumer programme I posted, I don't think they will be on that site. These include a finance deal, but you can strip that interest out if you like.

Location 1 Yorkshire.
Cost £11,000 plus £6000 interest over 10y
It looks like much of their roof is covered both sides have a look at the link
They have generated £628 over 20 months
Payback time including finance 48 years. However because they took out finance they could claim of them when their installer went bust!

Location 2 Devon
£12,000+£6000 finance
They generate only £2 per day
This will take 40 years to pay off

zeupater

cepheus wrote: »

... since you don't know how reliable such as cheap system would be over the 25 years. There's all sorts of cheap appliances which are designed to sell not last, possibly like these companies themselves ....

Hi

It seems that you've overlooked the answer provided to help regarding product quality the last time you raised this point ....

zeupater wrote: »

Hi

Then you're exactly where I was regarding grid-connected pv systems about 6 years ago ! ... in the intervening time I've seen little to be too worried about. On panels the only 'iffy' manufacturer claims seem to be when comparing relative efficiencies outside the standard controlled flash-test (1000W/sqm @ 25C ) and relative degradation profiles (straight line vs step change). Overall the UK market seems to have decent protection against poor product through the MCS certification requirements in order to qualify for FiT ... if there is a potential for future issues it's probably more likely that it will manifest in cheaper mounting systems and/or inverters.

In emerging technologies there are manufacturers intent to maximise returns at all costs and there are ones with brand names and reputations to protect, so for peace of mind it might be better to stick with those with track-records and a broad technology base, but then again, at the moment, who knows ? ...

As Mart mentions in the above post, there are systems which have been around for years, after-all the technology isn't new, just the scale of production & installation .... some time ago there was a discussion on these boards which referenced a paper on longevity and degradation which included a remote system in a pretty harsh environment (Africa?) which had been running continually since the mid '70s ....

Regarding pv performance claims being seen as similar other 'iffy' products, well, unlike the 'official' MPG figures for cars the estimates for annual system generation stand up well and in most cases are reported to be accurate or bettered by a significant degree, there's also the ability with most systems to monitor & record performance down to a tremendous level of detail .... With the double glazing and insulation you mention there's very little you can actually do to monitor to an accurate level, therefore theoretical and long-term trend is all that's generally available .... it's currently 10:50(BST) and my system is generating 2.02kW with the house consuming 190W, whereas both the level of solar gain through the windows and heat-loss through the heavily insulated structure is unknown, apart from a modelled theoretical calculation ...

Regarding 'Neither do we know how well these systems would work in ten years time, and how much maintenance is necessary.' ... well, actually we probably know more than you would give credit. As already mentioned, the technology isn't new, it's just manufactured on a much larger scale, bringing in volume related manufacturing economies. Ten years ?, well our system is half of that already and 4 of the best 20 generating days have already been recorded this year, so unless the panels are removed from our roof and subjected to the same condition controlled flash-test as they were when manufactured any degradation-to-date must be considered in our case to be negligible, despite a film of dirt/dust which has accumulated ...

HTH
Z

So, have a look at MCS product test regime and accreditation standard for pv panels (MCS005) ... http://www.microgenerationcertification.org/mcs-standards/product-standards ... you'll note the references to independent testing in approved labs (UKAS, TUV etc) and conformance to further BS EN & ISO quality standards ... this is all there to ensure that all MCS approved panels meet a minimum standard, both on quality and performance ...

HTH
Z