AKA wind turbines.
The weather forecast this morning showed high pressure stationary over the UK and winds in excess of 10 mph only along the South coasts of England and Wales.
Certainly not enough wind to get a domestic turbine generating so what wind do the big buggers need and is the BBC forecast a reliable indication of the wind speed in the exposed locations the windmills are sited in?
Has anyone seen an inland wind farm working today?
And have the off shore farms fared any better?
Presumably wind speeds at 70m AGL are a bit higher?
There are a pair between Wressle (East Yorks) and the big, evil Drax. The other week the steam from Drax was rising straight up and the windmill were looking sorry for themselves. I thought of two things: how many of those (when turning, not 100% of the time) equal Drax. Answer: LOTS! The other was what minimum wind speed is needed to make them turn.
They don't need any wind. They have motors inside to turn the blades so they look like they're working.
Owain
Actually there's a grain of truth in this. According to RES who propose a wind power station near here they allow them to turn in light wind but don't load them, they will of course look to the observer as if they are working. Strangely in really high winds whey stop them turning at all for safety reasons.
Has anyone seen a wind farm 'working' ever ... ? :-)
Arfa
As far as I know they need (unless technology has changed in the last couple of years) Beaufort scale 4 minimum and the blades are 'feathered' at Scale
Jb
I guess the idea is that over time the technology will get better, much better. Out other main energy sources are already well developed, so are likely to see less gains in financial and energy efficiency.
NT
Not significantly: During the day high level steady winds become gusts more or less abut the mean falling to a lot less at absolute ground level..the boundary layer as such being about 100ft at most. From experience of flying model aircraft..at dusk and dawn vertical movement is at a minimum and you get a calm patch below that height.
So whilst a domestic windmill is certainly blanked out, there isn't much advantage of going over about 100ft or so tall and indeed you will see that is the sort of blade tip minimum used on a big windmill.
The wind for the next three days is low across the UK - about 10-15mph in the east, almost dead calm in the west.
It is unlikely windpower will contribute anything, on or off shore, of any value whatsoever in this period.But lots of standby gas stations will spin up to compensate, having been burning gas doing nothing just for this eventuality..
:
IIRC its about 10mph-15mph.
Which is, actually, pretty windy. For cyclists, that's a potential headwind as fast as most CAN cycle.
I have seen them turning. :-)
What I was hoping from this thread was eye witness accounts of what is actually happening over the country. We do after all have a widespread contributor base.
Whilst it may, the laws of physics aren't going to change any time soon.
Chris
And the higher the wind, the faster they make then turn, so it always looks right.
No technology can get better than physics allows. Windmills are already computer modelled to be as good as they can be within a few percent.
And about 50 times better than a traditional windmill probably ;-)
Extracting energy from a very slow moving air mass is inherently inefficient. You are in essence slowing it down to release the energy. You cant bring it to a halt, because where would it go?
If the energy you can extract falls below the frictional losses in the turbine, it stops. If its just enough to overcome them, the blades turn but no useful output is produced.
If the air at height is faster than the air at ground level, then the blades at ground level may actually INCREASE the local wind..
Windmills are the prefect eaxmple of a really highly engineered elegant solution to a machine problem that is theoretically doomed to be crap by dint of the physics. One that compared with e.g. a nuclear power plant, uses three times as much carbon to build, three times as much copper to vuild, requires about ten times as many power lines to be laid, many of them undersea and very exponsive, costs twice as much, and over its lifetime requires 50 times as much maintenance, and takes up about 2000 times the surface area, to produce and unreliable and fluctuating output.
Only the fact that the EU guarantees a buy price of about 10p/Kwh, versus the 2-5p paid for nuclear or conventional, makes them viable at all.
Like CFL's they are there because undeducated people have been conned into thinking they will save the planet, whereas in fact we all are paying through the nose for needless and unnecessary monstrosities that when examined on any sane rational basis, are no solution to anything.
The silly little one here is working. Well its going round anyway.
In message , Roger Chapman writes
Nothing moving in the off shore North Wales farms that I saw on Thursday.
FloDesign's er, design looks pretty good - much wider range of wind speeds, less noise, tends not to fail dogstrophically and birds can see an almost 'solid' obstacle with no external moving parts:
Yes, that speed is a drag :-) There was a suggestion some years ago that these windmills could be made viable by hiring cyclist to ride around the immediate area, on the grounds that there's always a bloody wind! Of course, Sod's Law doesn't work if you try to use it, unless you're trying to use it to stop it working, in which case...!
The two at Wressle were turning yesterday afternoon but are just out of sight from my home, however my small weather station shows the wind speed here to be 4 mph at 30 feet above ground level some 8 miles to the East of them. I should add to anyone unfamilar with large wind turbines with synchronous generators that the speed of rotation is fixed regardless of the wind speed (within the operational limits of the machine) so simply seeing them turn is by no means an indication of what they are producing. At low wind speeds they produce a small amount of power, at high limit they produce a significant amount of power but the speed of rotation stays the same. I emailed Yorkshire Water who own the site at Wressle to ask for performance details of the two mentioned but have had no reply. It would be interesting if they would put the continuous output data onto the iternet for interested people to look at
The technology has not advanced much since Grandpa's Nob wind turbine was built in 1941
You would think that coaal fired stations ought to have reached the limit of development long since. However, Drax is currently engaged on an upgrade that should increase its thermal efficiency by around 5%.
Colin Bignell
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