12 Small Windmills Put To the Test In Holland

"A real-world test by the Dutch province of Zeeland (a very windy place)
demonstrates that small windmills are a fundamentally flawed technology.
Twelve much-hyped micro wind turbines were placed in a row on an open
plain. Their energy yield was measured over a period of one year (April 1,
2008 ? March 31, 2009), the average wind velocity during these 12 months
was 3.8 meters per second, slightly higher than average. Three windmills
broke. The others recorded ridiculously low yields, in spite of the
optimal conditions. It would take up to 141 small windmills to power an
average American household entirely using wind energy, for a total cost of
780,000 dollars. The test results show clearly that energy return is
closely tied to rotor diameter, and that the design of the windmill hardly
matters."
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Reply to
John Stumbles
so does that mean it'd take one windmill to power 141 small european households who don't any of the power hogging crap the yanks stuff into their homes?
Reply to
gazz
y during these 12 months
Well any aerodynamicist could have told him that.
Its roughly diameter cubed times windspeed IIRC.
Our results from model aircraft propellors suggest there is only about=20 2:1 change in efficiency (sort of 35%-70% eff.) from the very best blade =
design to the very worst.
And at low airspeeds, what you want is diameter, diameter, diameter..
'1001 ways to pretend to be saving the planet whilst wasting your money=20 into snake oil salesmen's pockets.'
Firmly in there with Uk domestic solar heating, CFL bulbs, and=20 unplugging all your chargers..and your TV..or using LCD TV..
Reply to
The Natural Philosopher
Well any aerodynamicist could have told him that.
Its roughly diameter cubed times windspeed IIRC.
Our results from model aircraft propellors suggest there is only about 2:1 change in efficiency (sort of 35%-70% eff.) from the very best blade design to the very worst.
And at low airspeeds, what you want is diameter, diameter, diameter..
'1001 ways to pretend to be saving the planet whilst wasting your money into snake oil salesmen's pockets.'
Firmly in there with Uk domestic solar heating, CFL bulbs, and unplugging all your chargers..and your TV..or using LCD TV..
Hi We will have to do all of that and more when people/tree huggers start buying electric vehicles
Robbie
Reply to
Roberts
Hmm. Consider air moving at a speed S m/s through an area A m^2. The volume of air passing through in one second is AS, which has a mass of rAS, say, where r = density. The kinetic energy in this slug of air is (1/2)mV^2 = (1/2)rAS.S^2 = (1/2)rAS^3. The power captured by a turbine with cross section area A and efficiency e is therefore (1/2)erAS^3 where A is proportional to the square of diameter (in the case of a disc).
Reply to
Gib Bogle
The obvious variable to change here is r. Holland, being nice and low, has denser air than us. So the inefficiency of windmills in the UK would be even worse. Or have I missed something?
Reply to
Rod
No? And it only took 12 months to work that one out?
Nope, if any of this is going to work it will probably be water not air.
T i m
Reply to
T i m
I don't think that will help, not even people on flood plains will get enough water through their turbines. ;-)
Reply to
dennis
In article , Gib Bogle writes:
You can only extract a tiny amount of that energy. If you could extract it all, the air would all stop dead at the windmill, and after a short time, the build up of stationary air concentrated there would build up quite a high pressure ;-)
Reply to
Andrew Gabriel
Anyone know what the efficiency of these sea slug type wave machines is like? How does the ROI look on these devices?
Phil
Reply to
TheScullster
On 19 Apr 2009 22:49:29 GMT
What we really need is a small nuclear reactor. Isn't it a pity that cold fusion didn't work out....
R.
Reply to
TheOldFellow
nightjar "Roberts" wrote in message=20
Me too. One passed me on the A11 heading back to base.. Not hanging=20 around for sure..
But it would further wreck the govts coffers..no road fuel duty on=20 electricity..
Reply to
The Natural Philosopher
, the average wind velocity during these=20
Good math, but some wrong assumptions. However I haven't the corrections =
to hand right now.
Reply to
The Natural Philosopher
Yet. As the treasury gets something in the order of 25% of it's total income from fuel duty if something starts to reduce that they'll find a means of getting it back.
Reply to
Dave Liquorice
About as good as investing in a northern rock.
All of these low energy solutions require massive installations to=20 produce any power at all. The physics is all about how much energy you=20 can extract from essentially diffuse and low specific energy streams of=20 power. Its like trying to run a steam engine off warm water: the energy=20 is there, but its very hard to get it out in a useful way.
Thats why 'renewables' are almost universally flawed. The best use=20 direct sunlight where ultimately you can reckon that the sun is in fact=20 a very hot thing indeed..a solar furnace using mirrors is really quite=20 efficient..
At its very best, a desert location will yield about 250w/sq meter=20 averaged over a day.
So a 3GW (a fairly large power station) requires that at even 50%=20 efficiency, which is probably optimistic, you need 6 sq meters per Kw,=20 or 6 sq kilometers per Gw, or around 18 square kilometers of mirrors to=20 achieve what a a few hundred sq meters of e,g. nuclear power can do..and =
that does it day and night, and doesn't pack up at sunset.
Biofuels are even worse.. about 1000 litres per hectare for rape seed=20 oil, or about 10,000 kwh per hectare per year. Divide that by the number =
of hours in a year (about 8760 or so) and its a bit over a watt per=20 square meter..
Oh I found a lovely one here.
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"the sun shines approximately 1,000 kilowatts of energy per square metre =
of the land surface"
followed later by
Insolation (yearly average in KWh/m2) =09 Edinburgh 825 London 953 Plymouth 1172
Now 1172 Kwh/yr/m2 is in fact 0.113 watts per quare meter. In fact both=20 figures are wrong. Its actually 1172 Kwh per DAY, which is around 50W/sq =
meter.
Which makes biofuel about 2% efficient at its core., But of course to=20 get those yields requires fertiliser, pesticides and mechanical tilling=20 sowing and harvesting: The ultimate efficiency is about 1% according to=20 Dr Mackay..
Even at 50 watts per square meter the UK domestic energy consumption is=20 around 200 GW.So at 40% efficiency we still need an area of 10^10 sqare =
meters..or 10^4 square kilometers..or roughly 60 miles by 60 miles=20 covered in these putative 40% efficient solar panels..under which it=20 will of course be pitch black, and nothing at all will grow except maybe =
mushrooms fed on the bullshit produced by eco warriors..
Just as a nice round figure, the total energy used in the UK divided by=20 the population means that on average, we all use about 5Kw every minute=20 of the day..That does NOT include energy spent overseas on imported=20 goods either.
Put that into the perspective of - e.g. saving perhaps 3 watts by=20 turning the TV off at the wall overnight.
What it means is that every person would need about 100 sure meters of=20 100% efficient land space to collect solar energy on, or in terms of=20 farming, around 5000 square meters (5 hectares) growing rape, and about=20 another 1-2 to grow the food on. Take away modern farming and go=20 organic, and you quickly see why the UK population pere the industrial=20 age was less than 6M.
Looking back at windmills, here's a proposed site..35 square kilometers=20 of offshore windmills that headline at either 350MW, or 88 x 3.5MW,=20 depending which line you read.Presumably the 350Mw is the true figure.=20 allowing for load averages and so on.. and remember these are 260ft=20 high. 4 stacked on end would be 'mountain' sized..and so taking the=20 350Mw and 35 square kilometers, thats 10Mw per square kilometer, or a=20 staggering and appalling energy density of just 10w per square meter of=20 surface.
never mind all the concrete that will go into them, the diesel needed to =
run the boats that will plant them and maintain them, or the incredible=20 expense of actually getting the power onshore, and storing it when its=20 not needed for when it is.. and the whole mostrosity supplies less than=20 2% of the UK's consumption of energy. When the wind is blowing.
The lovely brochure features sunny landscapes, traditional windmills,=20 and boats sailing in sunny seas. None of which you will be able to do or =
enjoy when 88 turbines the size of jumbo jets stood on their sides=20 turning a seascape into an industrial landscape are littering the skyline= =2E
The cost is not even mentioned.
Compare and contrast with E.g. Sizewell B, that occupies about 300x600=20 meters.. 18 hectares hectares only and produces 1.2GW 17 months out of=20 18, and cost =C2=A32bn to build. =C2=A31600 per Kw only, and has been pro= ducing=20 that for the last 20 years. a base cost of 0.9p per Kwh neglecting=20 interest charges..fuel..and maintenance. And will continue to produce=20 for another 30-40 years.
A power density of around 6Kw per square meter land use, and nowhere=20 near 260ft high..
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to put it in perspective, the givernment has spent =C2=A31.5=20 trillion..enough to build 800 Sizewell B's - and more than enough to=20 power the whole country on zero carbon altogether, on bailing out crooked financial institutions.
To generate the requisite 250-350GW (mean/peak est.) to power the WHOLE=20 country, would use up at 6Kw/sq m, just 52 sq kilometers, worst case.
Our village is bigger than that.
Reply to
The Natural Philosopher
On Mon, 20 Apr 2009 14:09:52 +0100
ty during these 12 months
I don't really disagree, but small ones would make good power-plants for, say, locomotives and ships-smaller-that-aircraft-carriers.
Living in Cumbria, where we love Atomic Power. Please build more here and give us first divs for our trouble, when the power cuts come.
R.
Reply to
TheOldFellow

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