Funny I have often been accused of being gullible or naive , usually be students who attempted to blind me with excuses ... Maybe I am, sure if I was would not I be the last to know?
But back to the case in point. Wind power at a hub height of 100m is considerably different than at even 25 m, where the ground effects of forestry and housing estates dominate. Even at 10 m, the effects of a field of wheat can be noticeable.
The power from a turbine scales as the cube of the wind speed so average wind speed measurements will grossly underestimate the power available. The response times of these turbines is surprising, as they can react in fractions of a second by altering their blade pitch, and or stator currents.
The figure I quoted is from their website, and is presumably from the returns they sent to ofgen. Now these are not a single misplaced digit or number but are consistent over a full year. Unless you are going to allege fraud, ....
The same argument can be made for the siting of that windfarm. The vendors Vestas will probably be happy to site their product anywhere(within reason, they have a worldwide reputation to protect), the farmers or the crown or who ever owns the land will be happy to get a return . The contractors pumping the concrete, and the electrician's installing the interconnects, likewise happy for the work. But the investors putting up the money , who are the clients must have done their due diligence, hired consultants and made their judgements.
If they failed to do so, they were idiots, and fools from their money are soon parted . If they did so and were lied to by their consulting engineers , then they have the courts to turn to for fraud. However if the 27% figure is correct, they are getting a return on investment , and everybody except you is moderately happy.
Look on the Danish Wind Industry website.
The diameter of the blades at Frais are 112 m. The tip max height is 125 m. Hub height near enough 75 m.
Put in a figure of 6.1 at 25 m...( on their reactive spread sheet) and it gives the following
6.85 m/s at 130 m.
And 6.4 at hub height.
Wind sheer is problematic in that it loads hub unevenly..The important speed is obviously at hub height, but you are over estimating its effect any way...and forgetting fact it is quite possible ( and often case) at coastal sites to have reverse sheer. ( In easterly winds ground air is compressed by land, increasing its speed significantly at ground and up to probably 20 m .
This always creates problems for us as anemometers are always land based. In easterly winds ( at east coast) knock 20% or so off reading for wind at sea...or at height unaffected.( hub heights) The point being these exaggerated easterly readings are all part of that 6.1 m/s reading.
No matter what you explain you cant make it windier than it is at Fraisthorpe.. Average wind at 25m is at absolute most 6.1 m/s. At 120m its still only 6.85...Both figures barely into cut in speed.
Wind farm needs 11.25 mph to just rotate.( their figure) For days and days on end that's more than they get at Frais.
The engineers are selling turbines. The farmer gets grants to build on his land and an income even if turbine only operated at 5%. The government must be seen to be pushing green concepts. All rife for a bit of leeway on silly little thing like wind speed.
Please explain to me how Fraisthorpe can generate 27% of it max out put with average wind 1m/s over (assuming windfinder/ windguru/ XCweather are all wrong) cut in speed.?? ( if we assume those 3 are correct the average is under cut in speed)
Even NEAB argued sites were only viable with over 8m/s ( at 25m). A site with an average of 8m/s can create 75% more power than one with 6...If Fraisthorpe is genuine we could solve all energy issues with a few farms at the over 8 m/s sites. At this reckoning an 8 m/s site could be 102% efficient ?
Plainly it couldn't...and like wise Fraisthorpe is not 27% ....no matter what figures Variable Pitch make up.
And like I said earlier how can 27% be ok ? Only because we have other ways capable of producing 100% of what we need. Its a big con to tick green credentials.
A,lot of years ago a good friend of mine who knows about engines told me ( and everyone else who would listen) that manufacturers were fiddling emmisions on diesel engines...Nobody listened. He has since been proved correct. Now I,m not pretending to know about turbines ( even tho I have engineering and physics qualifications) but I do know about wind. Its actually surprised me how high cut in speed is at Frais...( 11 mph).. I honestly think that is higher than average wind we get here.( I live about 10 miles away) Even allowing for wind shear..
Think we should damn up the river Don in Sheffield and build a hydro electric plant. Its no dafter than a wind farm at Fraisthorpe.
Even if ( which I,m convinced is wrong) the farm achieved 27% its still very poor.
Take care.
Not answering anymore on this subject. Argument has run its course. Call in at Fraisthorpe for a sail..we get about 40 days a year over 13 mph.???!;; Choose one of these and you can watch turbines spinning.
PS ..I wonder if Woosh's point about Fraisthorpe being cheap electricity is a way of fiddling the MWH figure. They got a certain £amount, if electricity is cheap they can up the MWH..
Coincidence my pricing gives a 17% figure and that it seems cheapest price in country per MWH ??? Only saying ???
Perhaps they paid Hinckley price...figure would be around 12% then ??
Why should price per mwh be so cheap...because its up north ?
Something is wrong.
