The leaflet has lots of impressive numbers. The one sentence in bold type says "It should also be noted that the Expected Safe Life period [viz 10 years] is NOT the stated warranty period of the product". IOW it should be good for 10 years but we don't guarantee this [there's a 2-year warranty not mentioned in the leaflet].
But assuming it does last 10 years, it has to save £150 per year to recover the cost which is more than 1/3 of my electric bill (OK I'm a single person household). If it's not back feeding for credit then on my occupancy pattern it would only doing anything significant when I'm at home - all day long and overnight the only consumption is the fridge, CH and TV etc on standby.
"Payback can be achieved in as little as 5 to 7 years depending on your local annual wind speed. This is also taking into account the grant assistance or any additional income from ROCs. Our calculations are based on an average UK domestic consumption at the average cost per kilowatt hour of the electricity, with the average UK windspeed."
This cleverly ignores the fact that the average wind speed in the parts of the UK where the vast majority of people live (like the clientele of B&Q Chiswick) are in areas of below average wind - if you look at the map on their website,
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most of England has a mean wind speed of 6m/s or less at *25m* above ground level. The rated output is with a wind speed of 12.5m/s.
Tempted - laughing too much to be! Someone once described the lottery as a tax on the gullible. Now it seems they have something else to spend their money on.
That is one of the great conundrums. If the tree huggers eat their beans they create excess methane which causes the end of the world. Do you give up beans or the world? It isn't easy being the soul mate of Swampy.
Does the long drop save more water than the proportional ROC of a bean fed Methane emission? How many eco-conferences does one have to not fly to to make up for the beans? It's a hard life as an eco warrior.
Excellent links thank you very much peter. Now the big question would anyone like to make an honest estimate to the average wind speed I need to make the B&Q wind generator a viable economic proposition with todays elec prices. No gas locally, two night storage radiators and I work form home so im using elec 24/7.
Wind generators are popular in the USA (and have been for some time) because of the number of remote homes with no grid electricity. The general feeling there is that for grid connected supplies you need an average wind speed of greater than 6m/s (14MPH), slightly less for battery applications.
If you play with the Danish calculator you should be able to plug in your own figures although it isn't easy.
To be honest, I don't think it is a good proposition at all, regardless of your circumstances or available wind speed. It is a toy. and a very expensive one. At full speed it produces 1kw, which is probably 2/5ths of the power needed to run one storage heater.
A better choice for you would be to get a 2kw diesel generator for £150 from Makro and get the local chippy using oil to let you take away their old oil. Converting to bio is very easy and there are no tax problems, as it is not used in an excise situation.
On Tue, 17 Oct 2006 23:41:07 GMT someone who may be EricP wrote this:-
And? I doubt if anyone installing one would be using storage heaters anyway.
1kW is 1/3 of the electricity to run a washing machine. One can look at this as "it hasn't saved 2/3 of the external supply" or "it has saved 1/3 of the external supply". It depends on one's outlook.
On Tue, 17 Oct 2006 16:33:41 +0100 someone who may be Roger wrote this:-
Readers can look back through the thread and see who has provided links to reports supporting their arguments and those who had to be prompted to provide such links.
The message from David Hansen contains these words:
Oh yes! I said the governments own figures but you wouldn't accept that. I pointed you to the Dti and even that wasn't good enough for you. You persist in rabbitting on about some shadowy 'nuclear lobby' that is supposedly responsible for everything that you are against.
OTOH you have promised me so real 'facts' if only I would ask. Well I asked but I am still waiting so where are they?
Don't think you will find a kit these days The easiest why of building one with _readily available_ components is with a cycle speedo/computer The better wired ones will display and record average and highest MPH. FWIW I built a wind generator using a motorcycle rotor and stator it works ok in keeping the starter motor batteries on my generator charged, but I was quite surprised just how much wind is nessserey to get any worthwhile voltage.
It gets much worse than that. Create a bit of turbulence with buildings / trees and the wind speed drops by around 2/3.
Someone at work had the leaflet for the Windsave turbine the other day, which got me thinking. Now I have an electronic weather station at home, with lots of data available.(see eig) The anemometer is mounted in a similar position to that suggested for these turbines, in my case about
8ft above the end of the roof ridge of my bungalow. Taking my 10 minute average wind speed data for the whole of 2005, the power curve of the turbine in question, the standby power (6W), I reckoned it would provide a net power generation of, wait for it, hold on there........52kWh per year.
Average wind speed ~1.9m/s.
Now don't get me wrong, put these in a suitable exposed site, on a decent (~8-10m+) tower, away from obstructions and I don't doubt you'll see the generation / savings suggested.
BUT in a semi urban environment (I'm relatively rural), mounted close to houses / buildings, the wind is below the cut-in speed for ~75% of the time.
What bothers me is blatant mis-selling, backed by government grants, to Mr 2.2Kids "must do something green for environment". Money which would be far better spent on other environmental improvement measures. Just look at the promotional picture...
No just a means of isolating the dc side but still having mains available for a dedicated circuit, a sort of cheap kludge in order to see what could be contributed by a non scheduled input and then the possibilities to maximise its benefit.
I've not seen that, AFAICS the requirement is to trade the electricity before you can gain ROCS. Either way I wanted to see the possibilities of making better use of the electricity on site without just dumping any excess into a resistive heater (which may only be required in the winter. It strikes me that to make any impact you need about 2kW installed capacity in an area with a wind resource capable of generating at a ( perceived wisdom claims)30% capacity factor.
This is a wind generator of over 3m rotor with average 7m/s wind and quite serious money unless d-i-y. It also needs to be on a high tower so unlikely to be suitable for 99% of british homes.
Anyway the natives have become restless so take it to the other place if you are interested in furthering the discussion.
On Wed, 18 Oct 2006 20:19:38 +0100 someone who may be Steven Briggs wrote this:-
One of the myths put out by the anti lobby is that people are being told that all they have to do to "save the planet" is to install a wind turbine on their roof. The anti lobby then attack this myth. It is a tactic that is presumably taken from party politics.
However, I have read many articles on energy by many organisations. These range from environmental organisations like Friends of the Earth, through independent advisors like the Sustainable Development Commission, to arms of government. Not once have I seen an article which does not advise doing things like fitting energy saving light bulbs, more efficient freezers and insulation before even thinking of generating electricity locally. Even the British Wind Energy Association says
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"Isn't it cheaper to save electricity?
"It is cheaper to save electricity than to generate it, by whatever method. The latest information on how much it costs to save electricity is available from the Energy Savings Trust. In their Energy Efficiency Standards of Performance Review, they cited the cost of energy efficiency measures as costing around 1.3 pence per kilowatt hour (per unit). The cost of wind energy is currently around 2.4 pence per unit. However, to combat climate change, the UK will need a mix of both renewable energy technologies and energy efficiency measures."
Anti lobby? Anti what? Anti the emotional politicisation of what should be a simple engineering discussion?
The tactic of inventing non existent bogeymen was largely devised by the likes of Greenscreech and FoE who learned very early on in their existence that lies work better than honesty. They are the ones who introduced "agendas" to replace evidence.
Not "all what they have to do", but it is part of the greenwash "changing attitudes" package and people _are_ being told that it is a really good thing and worthwhile - when for the vast majority of people it isn't and never will be.
"Generate your own clean energy by installing solar photovoltaic (solar PV), solar water heating and small-scale wind generating capacity for your home or business. " (Greenpeace)
"Small domestic wind turbines can provide 30 to 35 per cent of an average homes electricity needs, and pay for themselves in 8-10 years. This is a much quicker payback than most solar-power generated electricity systems." (Which?)
"The average UK wind speed is about 6 metres-per-second (m/s)" (Which?) (Both above quotations apparently supplied to Which? by FoE with whom they have some sort of partnership).
"In the UK we have 40% of Europe's total wind energy. But it's still largely untapped...small-scale building-integrated wind turbines suitable for urban locations are currently being developed and will be available to install in homes and other buildings within the next few years."
(EST)
Which myth? It isn't a myth that rooftop windmills are largely useless - it's a fact.
I really cannot understand how an intelligent person can consider the SDC to be even remotely "independent" of anything except experience and competence.
Which has nothing whatsoever to do with the point that people _are_ being encouraged to buy rooftop windmills which will, for the vast majority of them, not do anything worthwhile.
Look at what's needed to get a grant for these things :-
a. insulated the whole of the loft of the property to meet current building regulations e.g. 270mm of mineral wool loft insulation or suitable alternative. b. installed cavity wall insulation (if you have cavity walls) c. fitted low energy light bulbs in all appropriate light fittings d. installed basic controls for your heating system to include a room thermostat and a programmer or timer.
It isn't unreasonable for anyone to think that once they have done this the windmill becomes worthwhile. It won't.
You then have to chose an "accredited product". It isn't unreasonable for someone to assume this means the product has been tested and gone through some form of performance measurement. As you probably know - it means nothing of the sort. The "accredited" wind turbines have gone through no performance testing at all yet appear as "accredited" products.
Even the EST think this is rather silly :-
"There's a lack of independent, verifiable evidence to support the performance claims of turbines attached to buildings,' says Kirk Archibald of the Energy Saving Trust (EST). 'There's been a lot of hype and a lot of interest, but you could have a situation where they get rolled out and don't work.'
One consultant who sits on the government's renewables advisory board and has undertaken extensive testing of some of the turbines says: 'We found the performance of them is on average between 10 and 25 per cent of what the manufacturers are claiming.'
Unlike solar panels, which were thoroughly tested with government field trials before their introduction, rooftop wind turbines have seen very little such testing, says Archibald. They were assumed to perform like larger wind turbines on poles sited in exposed areas, but air turbulence caused by neighbouring buildings and obstructions such as trees can affect performance dramatically.
Windsave...says its 1.75 metre turbine produces 1,000-2,000 kilowatt hours of electricity a year. Renewable Devices says its Swift 2 metre turbine produces between 2,000 and 3,000 kwH of energy a year, and could save the householder up to £300 a year, including the value of green energy generation certificates.
But Archibald says that low wind speeds in urban areas mean that most installations will never come near that. ...
Nick Martin of the Hockerton Housing Project, a sustainable development in Nottinghamshire, is a construction expert who has monitored performance of much larger, pole-mounted turbines and investigated the claims of the rooftop turbine makers. He says that Swift and Windsave's performance claims 'defy the law of physics'."
(Observer, June 25, 2006)
It also says -
"The UK has the best wind resource in Europe, an asset that has the potential to provide a considerable proportion of the UK energy market in years to come. Together with several innovative manufacturers, the UK has a chance of becoming a world leader in small wind energy technologies...Small scale renewable energy technologies such as small wind turbines generate clean and renewable energy with no harmful emissions and can thus help reduce a significant proportion of the UK's CO2 emissions."
"The UK is an ideal location for wind energy. We get 40% of Europe?s total wind energy, but we don?t make the most of it - only 0.8% of our electricity needs are currently met by wind power.
Most of us are familiar with the huge wind-farm turbines that you sometimes see on hillsides ? but did you know that you can now save up to 30%* off your electricity bill, by getting a smaller turbine fitted to your house?
You can also take advantage of Government grants, covering up to 30% of the installed cost" (B&Q)
If all this isn't dishonestly encouraging people to bolt scrap iron to their roof what is?
I find this comment completely irrational. People forced to heavy electric use are exactly the ones that would be desperate enough to install them and probably more than one at that. i certainly would, if they were remotely worth the outlay, which they aren't.
Again I find this a completely irrational comment.
There appears to be little point in further discussion on the topic since there is no common ground for agreement.
To me it seems to be simply one of Common Sense vs Care in the Community.
On Thu, 19 Oct 2006 12:12:14 GMT someone who may be EricP wrote this:-
Were I asked to advise someone in this situation then I would look at a number of other things first. For example a wood burning stove to provide heating and hot water, coupled to a thermal store. That would reduce electricity consumption dramatically.
It is far better to treat the disease than the symptoms.
In the long run, having done may other things, generation of a limited amount of electricity by wind turbine would be on the list.
The message from Peter Parry contains these words:
This is a claim I find completely baffling. Even if we make some allowance for sea area the UK is still less than one fortieth the size of Europe as a whole.
We are principally a small island off the coast of a large continent sheltered to some extent from the prevailing breeze by part of a smaller island. If we have 40% then the British Isles as a whole must have well over 50%.
But Norway on its own has as long a coastline as Britain (and more exposed), bigger hills and and a more northerly position (worse weather) and should be better endowed with wind energy than the UK. Apart from that there are more than a dozen mountain ranges that individually dwarf the puny pimples that pass for mountains in the British Isles all of which should be windy places. And even the Bay of Biscay has a reputation for heavy weather.
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