The Great 'Get Paid To Generate Energy' Hunt

Cardew

green_as_grass wrote: »

Current decent interest on savings is around 2.5% without having to lock your money away for years, and this compares to 4% current inflation so I stand by my assertion that the value of savings are currently diminishing.

!

If you buy solar, you have indeed locked your money away!

You cannot compare short term savings rates to suit an argument. Whilst there currently is a 'blip' in inflation rate, it was negative last year. All the forecasts are that it will drop dramatically in the next few months.


Surely the facts are quite simple. The Government have tested solar thermal systems, responsible manufacturers give realistic figures for output, and these all indicate that 1,000kWh a year is a ballpark figure for savings.

1,000kWh will give a saving between £30 and £100 a year(the latter if you have no gas and heat with daytime electricity)

Given £4000 is a ballpark figure for an installation you lose £150 a year in interest - compounded don't forget!

Now whatever scenario you envisage for fuel prices - double in ?? years, I just cannot see any economic case for solar thermal.

How on earth anyone(except a solar salesman!!) could put forward the notion that payback is in 10 years! it is beyond comprehension.

green_as_grass

Cardew

I must admit I need a lesson in how to make these calculations for myself, but can I point you to an example from a Navitron website Solar energy thread where people are discussing their own calculations from their own systems. It is in the Solar Thermal Systems section of the Forum, the thread is titled 'Payback, etc'

Quote:
"Just done a comparison between 90 days from Sept to Dec 2005 without solar, and 2006 with solar...

These are some actual figures - note: efficient warm air gas central heating (been on for ages already!) and one heavy bather in household of three, previous total gas use 17,000 to 18,000 kWh pa.

period days units KWh KWh day
Sep – Dec 05 90 165 5186 57.6
Sep – Dec 06 90 106 3362 37.3

difference - - 1824 20.25

...So - 1824 x 3.277p / kWh (what I am paying) = £59.80p.

If that has been a typical quarter re: heating and DHW use, which I think it has, even allowing for weather this year, I reckon I am currently saving more than £200 pa.

My self-install payback is therefore less than 5 years at this gas price, which is very pleasing.

For a commercial Navitron installation as simple as mine lets say it would be about £2500, so that equals a payback of 12.5 years. And if gas prices rise a little more then that is almost down to the magic 10 year level...

Mick."

There are similar posts from other solar thermal panel users, and they are not 'solar salesmen'.

I suspect the discrepancy between the figures you quote and those quoted on the Navitron forum may be largely to do with the expensive installation costs of a typical installer (£4000) and the poor design efficiency of the typical systems on offer. My advice to people considering solar thermal would be:
1. do thorough research into efficient system designs
2. shop around extensively for value for money.

I don't think the Government and Which? have done this thoroughly enough with the systems they have tested.

You say, "all the forecasts are that [inflation] will drop dramatically in the next few months." Yes, I could possibly accept that, but I am more interested in the next 20 years (probable lifetime of solar thermal panels) than the next few months.

The current 'blip' in inflation is, I think, a precursor of unstable economic times ahead (we are all aware of how many western countries including Greece, USA and UK have dangerous levels of debt).

I maintain that the 'peak oil' issue (diminishing supplies of fossil fuels, while demand increases, increasing demand for raw materials because of emerging economies etc.) will mean that fuel and raw materials prices will escalate. It is not possible to predict accurately when this escalation will start because it is widely believed that OPEC countries' statements regarding their oil reserves are simply 'made up' because their allowed production levels have been linked to their stated reserves. Some commentators believe that oil production is already starting to diminish and that gas supplies will follow suit (gas and oil come generally come from the same fields). This is why I mention 'energy security'. I want to prepare for this scenario now, for the sake of my own family, rather than wait for the inevitable panic and 'mad rush' when prices start to soar.

Again, I'm afraid I'm starting to sound like a doom-monger, but the sooner people wake up to these issues and start to prepare the better, in my humble opinion.

If I'm wrong on this no-one will be happier than me. And I'll have some free solar -heated water as a bonus!

Cardew

Green as grass,

I don't think the Government and Which? have done this thoroughly enough with the systems they have tested.

Have you read the report? - see post #150. It couldn't be more thorough.

on all the systems the average annual output was 1,000kWh. Why would WHICH lie.

The very worst people to ask about solar thermal are those who have installed systems and feel the need to justify their purchase.

Someone who claims to have saved 1,824kWh in a Sep to Dec quarter would make even the most lying solar salesman blush. Complete and object nonsense.


I had actually looked at Navitron and spoken to them. They are very reluctant to commit to the actual annual output of their panels however they claimed verbally that their 30 tube panel will produce 35kWh in December in Southern UK.

Just how many kWh of energy do you envisage your solar thermal system will produce annually? 1,000kWh? 2,000kWh?

That is the bottom line!!

albyota

Solar Thermal

if the sun don't come out......you have useless roof orniments.......I have had 4 square metres of Genersys flat plate solar thermal panels (hot water) for over two years now, and has probably yielded a total of £130 worth of hot water, 'yippee'.....

they will be being removed soon to allow the space to be used for solar PV, if any one wants to buy them off me, contact me

green_as_grass

Cardew

Yes, I had read the Cranfield study a year or two ago when first looking into Solar Thermal, found it interesting then, and even more so having just re-read it, knowing more about current developments in design than I did on the first reading.

When I said that this study, and the Which? report hadn't done 'thorough research into system designs' and 'shopped around extensively for value for money' what I meant was that I suspect that the systems they were testing were probably not the best of the bunch in terms of their design, their quality of installation and their value for money. The quality of the research is not in doubt. Sorry for the ambiguity.

Clearly the Cranfield study is an excellent and rigorous piece of research and Which? investigations are always above reproach (I am a Which? subscriber and I hang on their every word!)

However the Cranfield study is now 9 years old and the technology has developed considerably since then. Amazingly, considering that the systems were installed by their manufacturers/retailers who knew they were part of a research project, the quality of installations were poor in some respects judging by the basic things that went wrong with two of the systems including debris blocking a valve - had the system not been pressure washed prior to commissioning!!? Also pipe runs were not minimised because of the necessity of the side-by-side layout and the pipes were exposed to the external elements (admitted lagged) rather than hidden away beneath the roof. The fact that there was initially no circulation through one system - and this was not immediately discovered - suggest that the sophisticated electronic controllers (which are in standard use in good modern systems) were not available then. All these factors would reduce the efficiency of the systems. My conclusion is that this study is now too out of date to be relied upon for judging output of the best systems available today.

The Which? study - although its integrity is unquestionable - is I suspect a small selection of the most widely marketed systems available. There is a catch22 here - you can't know which are the best systems to test until you have tested them. My impression is that the companies that focus most heavily on marketing are also those that focus least on real quality of design and careful installation.

In any case, the figures you quote 'ballpark 1000kwh per year' are the output per panel, yes? Many systems, particularly I think with Navitron forum users, have more than one panel, so the output I quoted by one forum poster is not outrageous as you imply. I attribute their favourable output measures to better designs and careful installations (minimised pipe runs, optimum bore pipes, high standard of lagging, clever controllers that can help diagnose faults/inefficiencies, knowledge of best settings to optimise output, adapting patterns of hot water usage to make best use of sunshine, designs to ease maintenance eg. bleeding of air without climbing on the roof, pressurised systems including use of expansion tanks that automatically refill the system after stagnation... ) The list could go on.

Also, claims of reduced payback times are more believable since most of the forum users would not pay £4000 even for a very large system (including full installation) since most have done their research and found a better value-for-money installer.

There may be some enthusiastic posters whose claims are exaggerated, I can't say. Others would say that a decent payback period would only be achieved with a DIY (ie. cheaper) install (or RHI). I'm sure most would say however, that your figures are very pessimistic compared to their own results. Not all posters are so enthusiastic and those who are disappointed are not shy of saying so (as is albyota above, for example). However the forum often helps people discover their problems and come up with solutions.

Agreed, December output is negligible in UK however efficient your system is.

My system output? I've no way of knowing the annual output in kwh of my system until it is up and running. I've designed it based on our hot water useage, recommended size of thermal store based on this (+ a bit more storage to tide over cloudy days), then recommended number of evacuated tubes to heat this amount of water - 5 litres per tube - (+ a bit more for good measure!).

I suppose the real factor regarding payback is what you believe will happen to energy prices in the future. A common attitude I read in the forums is that we don't worry about payback periods for a kitchen refit / an expensive holiday / a new car, all of which give negative financial benefit, so why worry about the payback period for a solar thermal system?

Cardew

Green as Grass,

How has "technology has developed considerably" in the 9 years. Sun heats water flowing through panels.

Because an detailed report detailed some procedural problems you feel qualified to dismiss it?? Really? and the WHICH conclusions?

As explained repeatedly above, you lose around £150pa(compounded) in interest on a £4000 'investment'. You save £55pa in fuel costs according to WHICH - less if you have gas.

Now you give me any scenario of future increased fuel prices where solar thermal is going to become viable!

Give examples of bigger system( and costs) and attempt to justify them. Sure if you have a system double the size you will get more water in summer(more than most people can use) but still very little in winter. 2 x 30 tube navitron panels will give 70kWh in December in Southern UK - so £2 saving if you have gas.

We won't even talk about repairs to the system in the many years it will be on the roof. Pumps and electronics never go wrong - do they?

A common attitude I read in the forums is that we don't worry about payback periods for a kitchen refit / an expensive holiday / a new car, all of which give negative financial benefit, so why worry about the payback period for a solar thermal system?

You strap something costing £4,000 to your roof, and it doesn't matter that it loses you money! Why, pray, would you put solar panels on your roof - for aesthetic reasons?

You cannot be serious! On any forum - let alone a money saving forum.

ziggyman99

Why does there need to be a payback? It always puzzles me. You never here anybody working out the payback on their new BMW or the 50" LCD TV they've just bought.

Cardew

ziggyman99 wrote: »

Why does there need to be a payback? It always puzzles me. You never here anybody working out the payback on their new BMW or the 50" LCD TV they've just bought.

I really can't understand the logic of this line of thought.

If you buy a BMW or 50" TV you get use from it, pleasure, pride of ownership etc.

What possible use is a bunch of panels on your roof if they are costing you money to keep them on your roof? Do you feel they enhance the appearance of your house?

People buy solar thermal because they have been persuaded that it saves them money; and then feel that they have to justify their purchase simply to save face.

The facts are overwhelming - solar thermal in money saving terms is a joke.

threekittymother

Hi, I haven't posted before, but have been reading all your posts on solar PV, ASHP, GSHP etc for a while now. Very interesting stuff.

We have recently bought a house that needs an entire new heating system. It is a large detached property, and needs a bit of updating, all cosmetic except the heating system. There is not currently gas installed although it could be installed for around £600 ish (transco say). House came with aluminium double glazing but very poor loft/no cavity wall insulation, which we have already rectified.

As we are starting from scratch we thought we'd look into different ways to heat the house, especially as we plan to stay in this house for 10-20 years. We intend to use radiators for now but intend to upgrade to underfloor heating in a few years (after we've knocked down some walls internally).

We got a few quotations in for different heating methods as follows (all quotations are for whole system inc. radiators controls etc):

Gas central heating with condensing boiler £7986.23

Daikin Altherma ASHP (16kw Low Temperature) £11934.66

Mitsubishi Ecodan ASHP (Ecodan HW 140) £14815

Micro CHP (Baxi Ecogen) as fitted by British Gas £11684

With the two gas installations we would also need to get gas installed. With the 2 ASHPs we should be able to get £900 grant.

We are quite keen to have some insulation against rising energy costs, and are also keen to get some of the FIT money if we can. We would welcome your opinions and advice on the subject. Thanks

albyota

Hi tkm, You are absolutely spot on with your forward thinking of energy security and rising costs and your best move would be the ASHP route, although I think the quotes you have had so far could be improved upon as there is a lot of competition out there. A 14kW Ecodan with 250L cylinder could be fitted by an MCS installer for circa £9k, a houseful of rads and pipework therefore should not cost £5.8K as you describe above, get some more quotes for the ASHP & Cylinder and rads/pipework, and get quotes for plumbers to install pipework and rads seperately just to get an idea of costs, the whole package is subject to 5% Vat, while if done seperately would be charged at 17.5% for rads & pipework. The RHI if it happens makes this the most sensible decision, and if the RHI does not, you can be certain of lower running costs with the proposed UFH against oil or gas.