Preface: Surface Power is constantly highlighting that solar hot water manufacturers, suppliers and installers need to take more responsibility for the performance of their solar collectors and installations. There is too much under performance in the industry and it is the end user who ends up paying for these bad investments.
It is on that basis that we kindly reprint the following article for your information.
Reprinted with kind permission of the author. 13th Jan, 2013.
It is with much interest that I see another shot across the bow of the UK solar thermal industry. Last week on Jan 8th, 2013, solar thermal world published the report prepared by Sheffield Hallam University and presented at the 2012 Retrofit Conference in Salford.
This report is the summary of a study of 23 new homes which are owned by South Yorkshire Housing Association and were analysed over a 2 year period. The results are consistent with what I have seen time and time again, solar hot water performance is promised and results show they do not materialise.
Each house had a solar system installed with aperture size of 4.12 sqm. The systems were all closed loop/glycol, typical of most standard solar systems.
The summary of the results is very revealing. The expected output of each system was supposed to be “up to 1064 kWhr/yr”. As with normal Solar Hot Water sales processes and because it is a requirement of MCS/RHI, I expect that this was calculated using a piece of software of which there are a few versions around the market. This produces a print out of a theoretical solar hot water output for the project. Anyone who knows me or reads my articles on this very subject will know this drives me to distraction. The day of theory is over, I personally don’t believe this hocus pocus any more. How about on-line connectivity and metering all solar hot water systems from all the manufacturers. Every time a study is completed about solar hot water, we see poor results over what was “predicted”.
In this study, not one system achieved the theoretical output even though the prediction was not that high to start with. The best performing system produced 241 kWhrs/m2/year (No 2 was 141 kWhrs/m2/year). The worst performing system produced a meagre 24 kWhrs/m2/yr, an astonishing £11 pounds worth of hot water for the whole year. On average, the 23 systems produced 95 kWhrs/m2/yr which in anyone’s book has to be a major thumbs down for performance.
What always amazes me is that people will accept this theory. I meet installers, distributors and other industry experts all the time and it never ceases to amaze me how much confidence they have in these software reports. I should be fair however, as several installers have stated that as MCS requires this type of prediction, they use it just to “cover themselves”. Another installer told me that they seem to work for Solar PV, but Solar Thermal reports seem to be a problem. That statement alone gives you an idea of the state of the industry.
The simple and only determination you can come to after reading this report above is that on-line metering revealed the extent of the under performance in these installations and hence should be part of the solution. Can you imagine if it was mandatory for all solar thermal systems to have on-line metering systems supplied by the manufacturers of the systems. Can you imagine the changes in the market place if the manufacturers had to stand over the performance “actually” being achieved by their end users.
In fairness, I must give credit to one solar manufacturer who is doing just that and I am beginning to really appreciate the bravery of their stance. A company called Surface Power is someone I am starting to watch with interest. I have been following them ever since I was tipped off about them, thanks to one of my installers friends in Norfolk who is already installing their central heating systems. You could only be impressed. Here you have a manufacturer telling you what their systems will do and then proving it on-line. What’s even more impressive is that the results are excellent. If other manufacturers were inclined to do this, it would help the industry and help people like me spend my money wisely.
I should also point out that Surface Power specialise in direct Solar Central Heating. They are the only solar thermal manufacturer producing this type of system in Europe so far so we know its a new technology. It’s really interesting that one company goes to extremes to give you connectivity to their solar systems and other seem to be avoiding the whole issue. If you go to their website www.surfacepower.com, you can spend hours looking at actual performance.
And if you think all that was interesting, what do you think payback looks like. Just think about the results in the study above. If I sold you the best performing system as detailed in the report above at 241 kWhrs/m2/yr for £9,500, lets say to use an example, then to get the exact same return on investment, you would need to pay just £954 for the worst performing system at 24 kWhrs/m2/yr. Personally, I think you would be bonkers to pay anything for any of these results, but even at £954, more shockingly payback would still be over 75 years with results that bad. I even think a well positioned black garden hose may even collect more energy than that in one year.
If you take the Surface Power Solar Hot Water PRO system @ 4.75 sqm during its major metering study from 2011, they produced 651 kWhrs/m2/yr in the first 12 months and 641 kWhrs/m2/yr in the second 12 months, that’s pretty consistent. If you use the same cost per kWhr/m2 as I used above, then you would achieve the same payback as the report above if you paid £25,600 for it. (remember, the system in the 23 houses above was 4.12 sqm in each case and the Surface Power PRO is 4.75 sqm by comparison) Its only when you see some real comparisons, you can see how big an issue this is for the industry and the poor sod who is supposed to buy a solar system.
Lets re adjust the Surface Power SP501 PRO system to its actual installed price of approx £6,500, then for the same payback you would need to get the best performing system in the report above for £2,406 installed and you would need to get the worst performing system in the report for £239 installed. All 3 systems above would have the same payback, that is a really bizarre situation and these are all REAL customer installations where REAL money has been spent and it’s too late to say NO.
This is my biggest issue with this industry, Lada’s and Bentley’s side by side but how do you know which manufacturer has the Lada or the Bentley. Solar hot water panels and systems are clearly not the same and the more we move to metering and on-line performance we can figure out if we are spending Bentley money on a Lada solar system. (I think its fairly unlikely you’ll be offered a Bentley system for Lada pricing, let’s be clear)
So how do you get the best value for your money. Simply I don’t know until we have more manufacturers who put their money where there mouth is. I used Surface Power in this example because they produce the on-line data and claim the highest performance per sqm of collector in the world but they give you the ability to see if its true. I’d love to compare other manufacturers but when they are all hiding in the long grass, I can’t.
So, what’s the moral of the story. I’d love to list the manufacturers who produce an end to end solution with on-line metering and management but there is only 1, how bizarre is that. Surface Power, support them and your money will be well spent as they are willing to prove what they can give you as an end user, as soon as there is another manufacturer, I’ll let you know who they are.
Otherwise, watch this space. It’s clear to me, if you don’t do your homework, buying a solar hot water system could be the biggest waste of money you do.
J.T. , mad scientist, advocate for business change in environmental opportunities, CSP rocks, support my media production…
Reprinted with kind permission of the author. 13th Jan, 2013.
Solar Thermal World