The Great 'Get Paid To Generate Energy' Hunt

albyota

Cardew wrote: »

Of course your £2,500 would have yielded about £300 in interest in the 3 years and you will have saved about £150(if you are lucky) in 'free' hot water!

I know that now....don't I !!
anyone wanna buy some panels ?? :rotfl:

green_as_grass

Sorry to deviate from the original topic again, but for those interested, just one more post regarding thermal stores and stratification. Here is a link to a store design that takes advantage of, and channels convective currents to limit disturbance to stratification:

https://www.consolar.co.uk/index.php?option=com_content&task=view&id=32&Itemid=16

There are so many ways of doing things with solar water heating!

Please feel free to resume topic back to the top of Feed in Tariffs, Renewable Heat Incentive, etc.

albyota

green_as_grass wrote: »

There are so many ways of doing things with solar water heating!

only if the sun shines...!!

Cardew

green_as_grass wrote: »

Sorry to deviate from the original topic again, but for those interested, just one more post regarding thermal stores and stratification. Here is a link to a store design that takes advantage of, and channels convective currents to limit disturbance to stratification:

www.consolar.co.uk/index.php?option=com_content&task=view&id=32&Itemid=16

There are so many ways of doing things with solar water heating!

Please feel free to resume topic back to the top of Feed in Tariffs, Renewable Heat Incentive, etc.

As said above - only when the sun shines.

The bottom line is how many kWh your panels will produce and how much hot water you can use.

A typical system costing around £4000 produces around 1000kWh with approx 80% of that output between April and October. As is quite clearly shown by all the figures, that will save between £30 and £80 with WHICH and EST saying £55 is average.

Let us take the case where you have a system of double the size i.e. 2,000kWh(which would cost a lot more than £4000) double the savings above and you have £110 average.

However you will produce approx 1,600kWh in the summer 6 months and will be hard pressed to use all that hot water in Jun/Jul/Aug. In the winter 6 months it will produce around 400kWh which will save around £12 to £40.

Even in the unlikely event that you have a huge solar thermal system producing 2,000kWh and you can use all of that energy - the average savings are still only £110. Even if such a system could be obtained for £4000 you are still losing £160 a year in interest at 4%.

green_as_grass

Cardew and Albyota: "only when the sun shines"

Of course, but not necessarily DIRECT sunlight. Solar panels can absorb and transfer heat from diffuse sunlight (ie. moderately cloudy but bright) in much the same way as such weather will warm up your car significantly compared to the ambient temperature.

I've found my May 2010 issue of Which? Here are quotes from their Solar Thermal report - Members views:

Chris: "Over-priced, underperforming and badly installed. The company has since gone bust... promised constant hot water even in dull conditions... nowhere near true... pressured us to sign on the spot... I rejected the system two days after it was fitted in December 2008... refused to pay the £5,800 owed"

Mike: "We installed solar thermal on a west-facing roof in 2004 and have been really pleased... in first two years we used 750 litres less oil... saving of £275 a year... rarely use the boiler between end of March and mid-October. The suppliers and installers were extremely ethical, reliable and genuine. Some companies were like the worst of the double-glazing industry..."

Cardew: "A typical system..."

is averaged out of a LOT of poor over-priced systems (which are typical of the current UK solar thermal industry) and just a FEW well designed, good-value systems, as illustrated by the members' views quoted above. Do your research first before buying. The Navitron forums are brilliant at helping to understand how a good system is designed. My post no. 182 gives a quick summary of some design and installation issues that sellers SHOULD know about. Look for companies with recommendations (try Which?-Local or yougen.co.uk). Quiz a number of sellers/installers to check that they know what they are talking about, that they don't make ridiculous claims or charge exorbitant prices.

Cardew: "will save between £30 and £80"

Correction: £50 to £85 per year. https://www.energysavingtrust.org.uk/Generate-your-own-energy/Solar-water-heating
But remember these are typical (ie. poor) figures. Do your research. Go for the best. A well designed, good-value system will cost less and give better output.

Cardew: "In the winter 6 months it will produce around 400kWh"

It is important to realise that you can't realistically rely on solar thermal all year round. In the dead of winter you would need 10 times the number of panels to get what you can achieve in summer - who has that much roof space?! You will need an alternative heat source in winter.

A solar thermal system will last 20 years (most components much longer). Savings based on current energy prices will bear no relation to those prices in years to come. The era of cheap energy is coming to an end. Consider that global oil production is now in decline while global demand is escalating. What will happen to oil prices? Doesn't take a genius to work it out. Other fuel sources prices will, as ever, follow suit.

As for interest at 4%, who knows what interest rates will be like in 20 years? We don't know whether we'll even have a functioning economy by then. Will there still be a working National Grid? Will your money in the bank be worth anything at all? Spend it now, wisely.

If you've got 45 mins to spare this video of a talk by Dr Hermann Scheer from Holland on 'The Solar Future' gives more information:
https://www.ukpvconference.com/videos/

Despite the Which? report being scathing of most of the companies they investigated they concluded:
"Despite our findings, now is still a good time to invest in solar thermal..." and go on to detail the Feed-in-Tariff RHI incentive planned to start next April. Cardew doesn't mention this incentive in his figures above.

Cardew

green_as_grass wrote: »

and go on to detail the Feed-in-Tariff RHI incentive planned to start next April. Cardew doesn't mention this incentive in his figures above.

I have mentioned RHI on a number of occasions - you should actually read my posts - including this reply to you in this thread:

Of course RHI, if the proposals are adopted, will alter the equation and could make the solar thermal a viable proposition. The problem is that it has to then be installed by a MCS installer and DIY installations like yours won't qualify.

You are the great advocate of solar thermal; yet you have carefully avoided any estimation of the output of your DIY system in kWh.

You are quite happy to forecast massive inflation in energy prices to justify your purchase. Ditto to forecast that interest rates will be poor to justify your purchase. Yet on the most crucial forecast which is the output of your panels in kWh there is silence - despite there being masses of figures available on the internet and elsewhere on which to base your forecast. I think we know why not.

I have gone into great detail with figures from a number of sources and £50 a year is a reasonable figure of savings.

Also £4,000 installation costs for a small system is quite a reasonable average; again borne out by quotes.

You are quite happy to ignore any repair and cleaning costs in a 25 year life of a system.

Do you feel systems will get cheaper when RHI is introduced?

Why quote this nonsense:

Mike: "We installed solar thermal on a west-facing roof in 2004 and have been really pleased... in first two years we used 750 litres less oil... saving of £275 a year.

750 litres of oil contains 7,650kWh. - and they saved that amount?

Someone posting this week in the gas and electric forum claims £600 a year. Another claims a magnet strapped to the oil pipe of his CH supply reduces consumption by 30% as it lines up the molycules(sic) it also does the same for car fuel consumption!

Let's get real for goodness sake.

green_as_grass

Cardew: "I have mentioned RHI on a number of occasions"

So you have, but you did not include them in your calculations in post no. 255 (and many others). Not everyone will have read this thread from end to end, my comment was for their benefit, so they were not misled.

Cardew: "on the most crucial forecast which is the output of your panels in kWh there is silence"

I have described my system in previous posts and that I sized it based on our hot water consumption, roof orientation and recommendations related to that. I don't know its output in kwh and as I have admitted before I would need lessons in how to make calculations for forecasted output in those units. But I'm willing to learn.

Cardew: "despite there being masses of figures available on the internet and elsewhere on which to base your forecast"

Would you like to point me to some of the "masses of figures" available on forecasts for my type of system in kwh?

Personally I find figures such as percentage of hot water needs that can be met from solar (ranging from 40% to 70%) more meaningful to me.

Cardew: "You are quite happy to ignore any repair and cleaning costs in a 25 year life of a system."

Quote from May 2010 Which? report: "Maintenance costs are relatively low too - around £160 for a five-yearly service."
Compare that to a modern condensing combi boiler!
I've never heard of anyone cleaning their solar panels!

You compare my arguments to ridiculous claims about magnets lining up molecules. I'll leave others to judge what they believe about future fuel price inflation and whether my points are worthy of ridicule.

Cardew

green_as_grass wrote: »

I have described my system in previous posts and that I sized it based on our hot water consumption,


Personally I find figures such as percentage of hot water needs that can be met from solar (ranging from 40% to 70%) more meaningful to me.

Perfect, just what I have been asking for.

So would you care to share with us your hot water consumption and how you calculated(sized) your system to cope with 40% to 70% of that load.

The EST link you gave estimates annual savings with gas and oil as £50.

It also states a system to produce those savings will cost between £3,000 and £5,000.

Yet you felt it appropriate to reinforce your argument to post of someone claiming to save £275 a year at 2004/5 oil prices(750 litres and 7,650kWh). So, as that appears to be an exageration of about 600% why is the admiitedly stupid claim of magnets saving 30% any more reprehensible?

Why quote a 5 year service cost of £160 for solar and compare this with the servicing cost of a combi? You still need a combi or CH boiler which still needs servicing, so the £160(£32 a year!!) is an additional expence.

£50 savings less £32 maintenance - Mmmmm

This from your EST link.

Maintenance costs are very low. Most solar water heating systems come with a 5-10 year warranty and require little maintenance. You should take a look at your panels every year and have them checked more thoroughly by an accredited installer every 3-5 years, or as specified by your installer.

This, as I keep repeating, it is the crucial argument.

If you invest £4,000 in a solar system you will gain initially £50 a year and lose £160 a year in interest compounded at 4%.(you can invest in National Savings @ inflation +1% long term if you prefer)

Now play with those figures any way you wish and make an economic case on a money saving website.

green_as_grass

Do I detect a change of tack here? After asking for 'a pointer to some of the "masses of figures" available on forecasts for my type of system in kwh' Cardew now wants to know my water consumption and how I sized my system to "cope with 40 to 70% of that load"
I'm wondering if I called his bluff there!
Obviously, the 40 to 70% of hot water needs is the range that is considered achievable with solar thermal. It is not what people 'size their systems to cope with'.

Actually I've managed to comply with Cardew's original request and figure out from the Navitron website (without any help) the estimated output from my panels. 60 EV tubes at SSW orientation should give around 2300kwh/year delivered heat to my hot water. Also our estimated hot water needs are 100 litres per day. A very round figure, I admit - hard to estimate accurately. Hopefully this is satisfactory and will negate any future accusation of 'silence' on this issue.

Quote Cardew: Referring to the Which? member who was pleased with his solar system, "So, that appears to be an exageration of about 600%"

Really? Let's look at Cardew's figures:

He says "750 litres of oil contains 7,650kWh"
https://www.biomassenergycentre.org.uk give a figure of 10 kwh/litre for heating oil - only a minimal difference, so let's go with Cardew's figure here.
However, it must be understood that this figure represents the typical fuel energy of oil, but this is not the same as the delivered heat, which depends on the efficiency of the boiler.

So how efficient is an oil boiler? Well it depends on the boiler, but for an old heavyweight boiler it could be as low as 55% (https://www.sedbuk.com). In which case 750 litres of oil would give an actual delivered heat output of 4207kwh, not 7650kwh.

I'm not a heating engineer, just an ordinary consumer, yet I could figure out the difference between fuel energy and delivered heat by some internet searches very quickly. One wonders therefore, who is doing the 'exaggeration' here?

If this is the amount saved by a solar-heating system then it must be a very large system, presumably for a large household with large hot water consumption. Or possibly, like mine, an oversized system to cope with prolonged periods of little sunshine and to extend the heating season. Cardew seems to assume it must be an exaggeration presumably because he either thinks everyone has a 'typical' size system, a typically inefficient system or because he thinks all advocates of solar thermal systems are deluded or wish to delude others.

Quote Cardew: "You still need a combi or CH boiler which still needs servicing..."

Not necessarily. We plan to use a woodburner with back boiler for space heating and hot water heating through the winter. Maintenance costs for this are only £40 for chimney swept and system inspection per year.

Quote Cardew: "This, as I keep repeating..."

Yes, Cardew certainly does keep repeating those figures, completely ignoring my points that those figures are averages, not based on the most efficient and value for money systems, not taking any account of inevitable future fuel price escalation and ignoring any contribution from RHI.

Who is it that needs to 'get real' I wonder?

Cardew

Your post above is yet again obfuscation.

The facts are simple.

For a solar thermal system costing between £3,000 and £5,000 the annual savings are on average £30 and £80.

So the money saving calculation should be an average figure of £4,000 for installation for an average annual saving of £55.

Of course for a lot more money you can install huge systems if your roof is big enough; however given most small(£4,000) systems deliver sufficient hot water in the summer months for most domestic households, what is the point of paying many thousands of pounds extra for a solar thermal system that produces more hot water than a domestic household can use; it is just wasted.

So I say again, give some figures for solar thermal along these lines.

Cost of system £4,000. Annual interest lost at 4% = £160 compounded. Year 2 = £166.40. Year 3 = £173.05 etc

Annual savings £55. assume fuel inflation of 5% so year 2 = £57.5. Year 3 = £60.64 etc . investing those savings @4%

You can of course deduct the annual cost of servicing of £32(see your post) from those savings. Ignore if you wish the inevitable replacements costs for pump and electronic modules in a 20 year? life.

Use your figures for interest and inflation figures. If you feel a bigger system is required, give your estimation of the cost of such a system.

Why not give it a go?