Solar Power for the Workshop

Well not just for the workshop!

I'm contemplating installing a solar power system at home and this would, of course, provide "cheap" power for the workshop as a bonus. I've read the blurb, had the quotes and heard all the advantages from the providers but does anyone here have any experience of such a system?

My specific concern is:- Do the panels need cleaning from time to time?

I have a large, south facing roof which is wholly un-shaded and ideal for panels but this is a tall house and there is no possibility of my reaching the roof from a ladder. A web search returns information varying from " the panels are self-cleaning" to " they should be cleaned from time to time with a squeegee".

I would value any experience or comments you may have.

I had a squirrel about on the subject for a few weeks

Basic solar panels aren't that efficient or cheap.

If they were, solar panel manufacturers would stop making solar panels out of fossil fuel energy

They are getting better though

The biggest issue was STORING the energy and this means either putting it back into the main grid or living with a pile of batteries in the home

The most efficient solar panels seemed to be what they call evacuated tube collectors

http://en.wikipedia.org/wiki/Solar_thermal_collector#Evacuated_tube_collectors

Conversion is efficient, even in winter, energy is easy to store as hot water too

The biggest losses tend to happen when you "convert" one energy into another energy

heat-->electricity or electricity--->heat etc

Don't bother with wind unless you are putting up a giant windmill sized turbine, size really does matter with wind power

It's a fascinating subject

2cents

edit: As far as cleaning is concerned I would assume that they will always need done from time to time, no matter what the slick salesman tells you

Edited By Ady1 on 28/06/2012 10:34:45

The real question is, would you do this if the feed in tariff was not subsidised by all of us through our power bills? Personally I think these technologies should stand or fall on their own.

I would think that the manufacturers would used coated glass and this becomes self cleaning,

This works through sunlight and rain, I have my house double glazing with the Pilkington glass and and have not touched them in 3 years.

Al that happens is that they get dusty and then the rain comes and washes it off and bingo clean windows.

In any case the finances side of the Solar panels is a bit iffy, i understand to make any thing from it you need twice the rated output which in practical terms means twice the area of panels to work efficiently. There fore twice the price on installation.

Amortization is in 10's of years and you may never re-coup the outlay.

Clive

As Clive says, it takes a long time to recoup the capital outlay, which leads to the following questions:

How long does the guarantee on the panels last? If they cease working after it runs out, you would have to buy replacements.

To what extent, and for how long, are the utility companies obliged to hold the prices at which they buy any surplus electricity from you? The trouble with any long-term government-backed scheme is that the goalposts might be moved before things have run their course.

If you decide to move house, would the presence of the panels help or hinder a sale, and would they add anything to the value of your home?

I understand that some schemes involve you (in effect) in renting your roof to a solar energy company, so you have little (if any) initial outlay. Personally. I wouldn't do that, in case it affected a future sale. In any case, if you have a mortgage,leasing out your roof would need the lender's consent.

Andy

Edited By Andyf on 28/06/2012 14:22:07

Andy,

The magic words are "government backed", that is the real problem, it is not government backed, merely promoted at other peoples expense!

The other one to watch for is "ground sourced heat pump", only nearly viable where there is not a gas supply, most of the so called "free heat" has already been expended at the remote power station and in the transmission losses as far as the actual costs are concerned.

Edited By KWIL on 28/06/2012 15:35:06

Hi NGH,

not really a subject for discussion on this site surely! However I have had PV panels for over a year, including periods of 'Saharan Sand' falling on my roof and they appear to be as clean as new. i was advised to give them a once over with a hose to simulate heavy rain if the efficiency deteriiorated but there is no sign of that yet.

The feed in tariff is payable for 25 years and is secured with a written contract and mediated centrally by OFGEN. The FIT is index linked to the RPI.

In terms of panel warranty I quote:

"The following warranties will apply

Solar PV Panel performance 25 years (90% at year 10 and 85% at year 25).............."

After that I'm on my own.

I have saved about half of my electricity bill (we have no gas in our village) but it is difficult to calculate as we have also recently had an Air Source Heat pump installed to drive our central heating system and this uses electricity rather than the oil we used previously.  I will need another year or so to do a full calculation and of course oil is bound to rise in price substantially in future so I can't account for that.

I calculate on my first years results that the PV installation will pay for itself in around 7 years and the Heat Pump in around 9 years.

If I decide to move I can have the system taken down and re installed at a new property but would lose the FIT, however the FIT is transferable so the new owner would benefit from the tariff, so it would be an incentive for sale and actually increae the price you can negotiate for the property as the saving in electricity costs and the FIT payments can be substantial over a period. I wouldn't touch a 'Free' system with a very long bargepole.

Just a point, most electricity is obviously generated during the day and it is better if you can arrange for power hungry activities to carry on during the day. for example I have a cold fill washing machine and use this in the daytime so that it does not use my hot water (from Heat Pump) but it's own heater using my own generated electricity. It means that I use less than 40% of my total electricity during the day so I do not have the rip off of 'Economy 7'.  BTW most people do not actually benefit from that tariff.

I am thinking of installing a deep cycle leisure battery and and charger combined with an inverter of about 1kW, 250 V output to run my house lights at night, but I have to calculate the possible payback.

Just My 2 cents (with experience)

Terry

Edited By Terryd on 28/06/2012 15:52:35

Hi Terry

" not really a subject for discussion on this site surely!" - Well I did wonder but I thought it might scrape in under additional heating that would mean I might spend more time in the workshop......?!

The problem I have ( had?) is that there is conflicting advice on the need to clean panels and, knowing the wealth of experience and willingness to share knowledge amongst this community, I hope that I might be forgiven for raising the issue.

My difficulty is in the height of the roof which is 2 1/2 floors high and inaccessible (by me anyway) by ladder. I am somewhat reassured by your response and I think it might be possible to direct some water via a pressure washer to a sufficient height such that it falls on the panels . I live in the depths of the country so there is a good deal of dust generated by work in the fields around about.. The other concern, not so easily solved, is the large number of birds that seem to use our cars for target practice - especially when they have just been cleaned. I wonder if the shiney panels would also attract them?

Still mulling it over!

Norman

Obviously this is not the forum for this subject so try this one **LINK** which despite being set up by a business is less commercial than this forum ( which barely is at all) and is generally agreed to be the best renewable venue on the net. Renewable energy always looks attractive and 'free' but never is half as good as it looks. There is just one thing everyone should do though and that is insulate their workshop and not with a miserable 40mm but at least 4 inches of Kingspan or Celotex which is equivalent to 8 inches of fibre.

For electricity (called PV) look for the cost per kwp (the p is just 'produced'. A few years ago it was >£3k but now should be <£1.5k however mostly it isn't because the industry is dominated by ex double glazing salesmen. DIY is not elligable for subsidy so they have you over a barrel. Battery storage is not ecenomical at all unless the batteries are free.

Solar hot water (using 30 off 47mm 'tubes' is viable for a typical family of 4 if and ONLY if you are already having to replace the cylinder AND do it DIY. Any variation from the above may look like free energy but it really isn't . I have checked the sums repeatedly but it is all very close to the edge of being ecenomical.

edit - sorry about the smilies, they insert themsielves instead of closing brackets.

Edited By Bazyle on 28/06/2012 17:35:10

Hi Norman,

I also live in the middle of the countryside surrounded by arable farms (one in the middle of the village) with all of the dust generated by haymaking, combining and the ubiquitous oil seed rape etc. Not to mention that we are in the flight path of a flock of Canada Geese who commute between two lakes at local country houses. However have had little or or no problems with such menaces.

Regards

T

Hi Bazyle,

We have discussed this before, just add a space before the final bracket (like 'this' ).  As far as isulation is concerned my detached garage/workshop has cavity walls (with insulation) and I have a boarded ceiling with 8" of Rockwool between the joists, very comfy even in winter.

Regards

T

Edited By Terryd on 28/06/2012 19:08:23

Bazyle

Thank you for that link - I have run through about a dozen pages there so far and there is some information on cleaning - I will continue further. I think on balance though, having some feel for posters attitudes and competencies that I have gathered here over time, I find opinions from this thread more useful.

Kwil

I sympathise with your annoyance with the way government supports this technology but interferance is what governments do isn't it? Is it a good policy - who knows? It seems to me though that a move away from dwindling and polluting fossil fuels to sustainable energy forms is vital and new methods are expensive and need development when first introduced. I don't know who but governments are in a position to move these changes forward. I have to make up my mind based only on the economic benefit to me and the feasability of implementation in my personal situation.

Now I agree guys probably none of that is proper to this forum but thanks to you all for your input which has moved me forward somewhat towards a decision.

Regards

Norman

The last time I was in Spain I saw a Solar water heating panel, ground based and made in Israel.

It was a about 2mtrs. tall and about 1.5 wide.

it was too hot to touch and suppied the hot water for a small house quite easily. How it would cope with continuous use I am not sure.

A point to note is that if the cold water input is raised about 10C then your fuel consumption is about halved taking it up to 50C.

I have considered a roof top water solar panel/s with a storage tank to contain the heated water which would then be taken to the normal heating system for further heating and use. (Nothing to do with central heating, just domestic) This is all feasable now with some sophisticated controls and small pumps. One thing is using an anti freeze as a fluid as in this country we do get freezing but not insurmountable.

If I lived in such a country as Spain I would immediately create a solar water heating system.

Clive

Why not start small (like 100-200w worth of solar panels) and see few years how it works? Suppliers can help on dimenssioning, which is the most important step, but location of the panels is critical.

I live very much up north (southern Finland) and solar power works well in the summer cotages that have s low consumption and to hook them to grid would cost something like 10000 - 30000 EUR due to long distance....then anything is an option.

However, for a residental use it really does not fly here. We need heat/electricity most of the winter and then we ofcource get least of sun. It only works as an secondary system to cut dow anual grid power. power comppanies hate it ofcource, because they have surplus of enenrgy on the summer and deficit on the middle of winter....you do the math.

However, when grid is dow hours on the countryside, some stored energy to keep fridge running and lights on is a good idea and then it does not matter if a small amount of power is very expensive. This brings to very important question how much and on what rate you need energy normaly and on emergencies?

Over dimensioning system cost a lot and if it is under dimensioned then you run out of energy in emergencies. Right now it is not really economical to make your own energy unless you live really far away fron the grid or need energy when "system" is down.

I'm considering very small PV system to evaluate how it would work on my house and then some square meters of evacuated tube collector to produce hot water 1/2 of the year. Electricity would be used only for emergency light/news.

Pekka

I've had a 4KW PV installation since last Oct, it caused me to re think the heating of my workshop (and house/water). On a sunny winter's day I am normally generating over 2KW and that is being used by my fan heater in the workshop. The best bit is that I am still being paid 47p per unit I generate.

Cleaning? My panels are silicon coated so they are self cleaning, but even so the crud only comes off when it rains, I think I have only given them one hose down this year in March. A couple of other houses locally also have panels but they cannot get up to wash theirs, there was a slight difference < 10% between what they generated and what I generate back in March, then the rain came and has continued ever since.

It was a good purchase, changed my perspective on using power. It is now a case of use it whilst it is free. The workshop was warmer this winter than it has ever been.

Jo

Edited By Jo Thoms on 29/06/2012 08:33:49

The best bit is that I am still being paid 47p per unit I generate.

Jo's good fortune points to the reason why the Value For Money calculation is so difficult.

47p per unit is more than the consumer price ...

That's because the Feed In Tarrif is politically motivated ... it allows Government [on paper at least] to meet its obligations.

The sums look great whilst FITs are at the present high levels.

MichaelG.

Michael

Before anyone gets too excited I should point out that the FIT is not now 47p but 21p and shortly to fall to 16p. ! However I understand that the cost of panels has reduced considerably of late and, even at 21p, this represents a return on investment of something over 6%p.a. and index linked. I'm persuaded by that but it's other aspects, like cleaning and maintaining the integrity of the roof, that I am pondering.

Norman

For us engineers a DIY wind turbine would seem to be the most interesting option.

see **LINK**

A home made turbine to Hugh Piggott's design is ecenomically viable without subsidy (which DIY won't get) until you have to pay for a planning application which wipes out 3 years generation saving.

I was watching the news on TV while having my tea tonight, and there was a section on , a couple here in NZ (can't remember where), who have roofed the entire north facing side of their new house with PV panels in the form of tiles. They are going to, but have not yet fitted solar hot water panels. The cost is about 10,000 UK pounds for the PV system, a bit less for the water.

Quite a number of homes here in the south have solar hot water, even in areas with high frost and snow, without problems. I think the water is heated indirectly via an anti-freeze filled heat transfer unit. Ian S C

Norman,

I wasn't knocking it ... Sorry if it came over that way.

Just pointing out that the calculations are difficult.

MichaelG.