OT - at what wind speed to turbines start to get into difficulties?

[David]

Just wondering what will happen at extreme wind speeds.

Smoking bearings or feather the blades?

Cheers

Dave R

[Andy Burns]

They shut them down in high winds, rather that let them run over speed, of course if they fail to shut down properly, then they get into difficulties

The type that fell over is rated up to 25 m/s (55 mph)

[Chris Green]

Rated as in will produce electricity or won't fall to pieces? If the latter then surely that's nowhere near enough as winds over 55mph are not that uncommon are they?

[Andy Burns]

yes, generation stops above 55 mph

Survival speeds seem to range from 90 mph to 180 mph

[The Natural Philosopher]

one or the other certainly. normally feather and brake

[Brian]

There is an obvious wind farm off the coast near Whitstable - a place we visited regularly pre Covid for a walk, a bimble around the shops, perhaps lunch etc.

I got into the habit of checking whether the windmills were turning. I think we?ve won the lottery more often than they were. (We walk on windy days BTW.)

True, I?ve noticed some windmills elsewhere which have been turning but the wind farms seem to prefer standing still. As I understand the plan, the wind farms are key to the net zero nonsense- not least due to objections re having windmills in beauty spots where the wind is favourable.

The fact is, the windmills are designed to produce electricity over a limited windspeed. Too little wind, they stand idle. To much, they stand idle. The owners still get a subsidy which, of course, we pay.

The blades have a limited life. I understand they have near zero recyclable content. Certainly the infamous carbon footprint of some of the designs (especially the tower part) exceeds the CO2 ?saved? over the design life.

I?m not saying we shouldn?t use wind etc, simply that it is being misrepresented. Plus, of course, we need a stable main supply - such as Nuclear, coal, gas etc to supply the bulk of our power.

[Martin Brown]

They should normally feather the blades and put the brakes on if the windspeed is too high. If either fail or a single blade refuses to move then the unit is in danger of catastrophic failure.

It gets really interesting (and dangerous) if the thing spins up without a load in a big storm. I recall one early experimental linear blade on a test rig at my university which got to the point where the blade tips were at the sound barrier and it sounded like a machine gun as the blade tips shockwave interacted with the single rod support.

Remarkably it survived. Picture of it Fig 4 in the Nature paper linked to from this review of Martin Ryle's work on the 70's energy crisis.

Follow the first link to get free access to the Nature paper on alternative energy written from the perspective of mid 1970's.

Indeed. They are quite spectacular when they go wrong in bad weather. We just missed seeing this one that went crazy.

Today the storm is coming in waves up in N Yorks. Half an hour of blue sky and sun followed by apocalyptically dark clouds and driving rain. Wind speed for the moment is high but not a full storm.

We are toast the moment it really gets rough since I have identified an electricity pole in my survey after Arwen that is listing at 30 degrees and someone else found one 10" worn down to 4" at cow shoulder height.

Northern (incompetent) Powergrid seem to have a new policy of replace only on failure and so save money on summer preventative maintenance.

[Brian Gaff (Sofa]

It usually can cope with strong winds, its the gusty winds from variable directions that tends to kill them. There is a lot of mass in them there blades, you know. I always thought the vertical kind of reverse centrifugal design was a lot more robust, but maybe it was just not as efficient. Brian

[Brian Gaff (Sofa]

When you say rated at, is that for actual generation? I think the more crucial thing is wind loading on the structure or the blades when stationary. Brian

[Brian Gaff (Sofa]

Certainly not over the highlands and at see, they are not.

Brian

[Harry Bloomfield Esq]

Brian pretended :

+1

[The Natural Philosopher]

I am.

If we had spent all the money we have spent on wind on nuclear, electricity prices would be half what they are now. And emissions less. Not that I give a flying f*ck about emissions.

[misterroy]

There were 6 possibly 1mw turbines installed here about 8 years ago. The brakes were put on in a storm with the turbines, I think, facing the storm. There was a powercut, and a wind direction change meaning that the turbines could not turn to the new rest position. The bearings needed replaced before they started again. They were about 6 months old. I have also seen a maybe 50kw one here where the head of it had been all bent over. Probably a gust spilling over the hillside it is situated on.

[Steve Walker]

Wouldn't you think that they'd plan for that. How about fitting the things with a small, vertical type turbine, wrapped around the tower and that is deliberately inefficient, so that it will not overspeed in high winds, but at wind speeds likely to endanger the main turbine, it will generate enough to automatically brake, feather and rotate the main turbine into the wind in the absence of external power?

[Harry Bloomfield Esq]

+1 A magnificent waste of public money.

[Harry Bloomfield Esq]

Steve Walker submitted this idea :

Don't bring common sense into the discussion.

[David]

Thanks for the explanations.

Explains why the wind generation at the moment doesn't reflect the amount of wind that we have.

Cheers

Dave R

[Another John]

But they're shit-hot at sending out mass e-mails telling us what we already know.

But Martin: what is this: "preventative maintenance"? What is "maintenance" even?!? It's SOOOO "yesterday" my dear chap! Besides: you'd have to employ people to do it! Nobody wants that, do they?

Yours, cynically,

John

[Martin Brown]

The best one was a text that arrived 0800 the following morning to suggest we make alternative arrangements for where to spend the night! Their website crashed and was utterly wrong for my village anyway.

Latest MFU was issuing compensation cheques to some people for account number values of trillions of pounds. You really couldn't make it up!

The previous incarnation NEDL used to spend a couple of days trimming back trees and checking for poles that were on the verge of failing in mid-summer every year or it might have been every other year.

Advanced warning and a few hours without electricity on a nice warm sunny day. They have bastardised Bayesian methods to come up with a replace only on failure model that screws customers to make profits.

Northern Powergrid have their key priorities sorted:

1. CEOs bonus
2. Share Price
3. Dividend to Shareholders

[keep scrolling down]

1. Customers

Their customers come a very distant 4th. And we have no choice about who provides our final link to the grid - these shysters have a monopoly.

[Another John]

....

You said it (so have I - many times: WHY isn't the Labour Party (or any other Party for that matter) making this now-criminally negligent state of affairs a big issue? And it's not the only public scandal that needs seeing to, BIG-time!

sigh

By the way: have you seen the area covered by "Northern Powergrid"? We used to have something called NEEB: North-Eastern Electricity Board. It looked after both distribution and selling ... in the vast expanses of North East England. Now they've conglomerated from the Borders down to Licolnshire. They tell us (like they do vis-a-vis the NHS) that it's for efficiency, and thus "to the advantage of the customer". It's a bare-faced lie: it's the precise opposite.

In my humble opinion.

John