Shouldn't you be asking which turbine gives the best output compared to rated power ?
I would have thought you'd get a pretty good idea of small wind turbine (actual) output at different wind speeds from the MCS figures. Bigger ones, who knows?
Actual performance of an individual turbine depends on it's location as you could have a perfectly good turbine in a dreadful location thus producing very little. No good just having, say, 6m/s annual average wind speed. You need clean air flow, turbulence is your enemy.

All of them. Wind turbines are aerodynamic devices, they generate torque by producing lift much like an aircraft wing does. Turbulent air is no good.

There are two methods of looking at load factor, rolling and annual
The worst turbine on the annual is Catchgate Primary School, on the rolling it is Upper Nibberdale College. These are both small turbines.
On the >500 kW it is Chelker Windfarm with an annual load factor of 0.9%
Rolling Load Factor is Mynydd Glandulas with a rolling load factor of 1.3%

The best are Burgar Hill with an annual load factor of 54% and Burradale Windfarm with a rolling load factor of 52.3%

The mean figures for the >500kW is Rolling Load Factor of 26.1% with a SD of 6.7 and Annual Load Factor is 28.8% with a SD of 7.9

The data is from the REF website who claim it if from Ofgem, but searching around the Ofgem site I could not find it.

When the data is plotted as Frequency Distribution you can see that the claim that most turbines are about 30% efficient has some grounds, but it is a simplistic and poor interpretation of the data.

Tony, There's plenty of stuff out there about wind turbine siting and turbulence. What you need, for any turbine (but small ones are more susceptible) is a steady, laminar, air flow. The worse performing ones are invariably sitting next to buildings, trees or abrupt changes in landform. It's why off shore wind is seen as attractive.
Plenty of research papers out there show that turbulent wake effects from big turbines reach well over 16 times the blade diameter down wind, so many wind turbines are adversely affected by their neighbour - particularly marked in the USA where they stick hundreds up.
As Seret said, they are aerodynamic devices - think of it like flying a Tiger Moth behind a Jumpo 747 - not going to get the best trip in the Tiger but you wouldn't notice any difference in the 747.

Rolling Load Factor is Mynydd Glandulas with a rolling load factor of 1.3%

that'd be the turbine at CAT, which supplies the main CAT site first, and only exports any excess, which presumably would be the figures used to give this load factor figure.

I thought those figures were suspiciously low.

I think those figures are very misleading. They describe the electricity as "worth" £100,000 compared to the "subsidy" of £130,000
when that seems to calculate down to what I presume is an export price of 3.7p/kWh which I am not sure is right?
then if you consider the retail price of say 17p/kWh the "worth" of the electricity is £457,640 which is 3-and-a-half times more than the subsidy.

I may be wrong with my figures and elec prices, but there would seem to be enough profit in there somewhere to cover the "subsidy".

Anyhow, I do not see the problem as the "subsidy" is directly linked to generation. No generation, no subsidy.

Perhaps we should work out the VAT on the electricity and see how much George Osborne gets per MWh?
[I think at 5% it might be £73,222 of the total - that brings the "subsidy" down by about half]

Are they suggesting that the nuclear industry has developed without subsidy? Or is that okay if you don't have to see it in the landscape (well, some of us anyway...)

tony - well that all depends. Which hill, which turbine? That's the problem with the question you first asked - unless you have 10 different turbine models on exactly the same site at exactly the same time, it is difficult to get a direct comparison between 10 different turbines. The manufacturers give their theoretical production figures which are (sometimes) backed up by field test data but each test site is slightly different and even the same site will experience different wind each day.
I have a Gaia 11kW turbine and I can see 3 others (Gaias) from the base of the tower, all within 5 miles. All are at similar altitude, on hill tops but all will have different daily production figures. Some days only 1 of 4 is turning, sometimes 2 of 4, 3 of 4 etc. Each location will be slightly different.

<blockquote><cite>Posted By: gustyturbine</cite>Chelker has 4 x 300kW turbines. They are a 2 bladed turbine that we also had here on LLangwyryfon and Cemmaes sites before repowering. Coldnorthcot in Cornwall still has them running at above 99% availability. Any good site should be running at around 98% availability. Turbine manufacturers are now going away from availability as a performance indicator and going towards lost production factor. It makes much more sense. Chelker are finding it hard to get a company that can keep those turbines running, partly due to spares.
In their day they were a very advanced turbine. The wind speed limit has absolutely nothing to do with it. </blockquote>

I drive past them fairly regularly, and they've only had 2 with blades on them for several years. It's a shame really because it's a really high profile site, and I'm sure the lack of blades on 2 of those turbines sets people wondering about the lifespan of all turbines being installed.

I'm obviously guessing about the cause of this, but the lie of the land there really does look as if it would funnel the wind in, and cause some seriously turbulent air for the front 2 of the 4 turbines in particular, which are the 2 that have no blades on them. I'd be surprised if that wasn't a factor.

They also has a low speed shaft problem but I will spare you the details. I know those MS300 turbines well. Their shut down speed is 25m/s. The same as a normal modern turbine (not enercon).

nope

I noticed a new turbine at LLanarth today....

Gavin_A,
When you say lost are you meaning removed or broken? Big difference.
It could be down to lots of issues. I know some time ago the maintenance lads used to pinch parts from one to service another. The supply of parts and costs of new blades would make the site a no brainer. I think they are looking at a repower soon. It was mentioned some time ago but you need a certain amount of turbines running or generation to qualify I believe,
Gusty.

I am all in favour of wind in the correct place and I can see problems when it is sited incorrectly but some articles do not help the anti wind case either. The lower link is absolutely pathetic and does not mention the improvement in capacity factor of modern machines or the fact that wind can help with energy independence. It just states that nuclear and fossil fuels are great!!!! They do not have any problems then obviously. Just rubbish.
That is my opinion though. Others may vary......

My local lot are claiming that the inland based wind turbines in our area are efficient and that we should have more of them, I dont agree as the one we have would be much better sited on on a hillside somewhere nearer the coast same capital cost, hugely better output.

What subsidies do these wind farms get other than FITs payments? Any?