Wind Turbines - are they all they're cracked up to be?

[sophiecentaur]

Whenever I see a wind farm, a huge proportion of the turbines just aren't going round. I don't mean in a flat calm, either. Why aren't the stationary ones doing their stuff? What were they put there for?
I have a theory that politicians feel that they understand the wind (they are full of it anyway) and that's why they love Wind Energy so much and spend all our money on them.

 

[berkeman]

If the wind velocity is not high enough to produce useful electricity, then the windmills won't be connected to the grid, and will either spin on their own, or will have their blades turned so that they do not have a net torque or spin. It probably helps to minimize their maintenance needs if they do not spin unless they are producing power.

There is a very large wind farm not too far away from where I live (it is east of Livermore, California), with many windmills of different construction types. On days where the wind is not that strong, the windmills (that do not need repair) generally are free-wheeling. But most days the wind is strong enough, and each type of windmill is phase-locked to the others by their connection to the grid.

 

[sophiecentaur]

OK but my point is that, whenever I see a group, so many of them seem stationary. If my sample is at all representative then, bearing in mind what you say, and that even the ones that are spinning may not be outputting much power when others are not turning, for what proportion of their lives are they paying for themselves?
Are they a seriously good investment or just monuments to politicians' egos and a way for the contractors to make money?

 

[berkeman]

Good questions. The wind farm near me is at the Altamont Pass, which is windy has heck much of the year. It's a natural place for a wind farm, and has had windmills there for as long as I've been driving through that area:

But I could imagine that wind farms have been put in lots of places with marginal return on investment. Maybe some of those places need to file some sort of planning/ROI documentation with local government agencies? Maybe as part of the Environmental Impact Report requirements. Do you have EIR requirements for projects like that in the UK?

 

[sophiecentaur]

Your farm seems to be much more worthwhile than several I have seen in the UK.
Yes - there are plenty of environmental interests which oppose wind farms even when there is a factory which could be making parts in their own, under-privileged and high unemployement area!

But I have also seen wind farms in France and Germany which don't seem to be doing much 'turning', either, so it's not just the UK. Perhaps it's an EU thing.

 

[ronniescott]

I think the original post is a slight exaggeration and that has led to a misunderstanding. I too have noticed that when there is a large group of turbines, say 30 to 100 in one farm, then generally 10 to 20% of them are not rotating. I have assumed that this indicates the reliability of the technology, where a given turbine will spend 10 to 20% of its life awaiting repair. Clearly this would be unacceptable in a consumer product such as a washing machine or a car.

Is the question "are windmills really so unreliable?"

 

[sophiecentaur]

I think the original post is a slight exaggeration and that has led to a misunderstanding. I too have noticed that when there is a large group of turbines, say 30 to 100 in one farm, then generally 10 to 20% of them are not rotating. I have assumed that this indicates the reliability of the technology, where a given turbine will spend 10 to 20% of its life awaiting repair. Clearly this would be unacceptable in a consumer product such as a washing machine or a car.

Is the question "are windmills really so unreliable?"

Yes, ha ha, my OP was a bit of that, too. I imagine that early designs would have had weak links but there is no new technology involved so what could go wrong as long as things were made robust enough? It's all based around ship, aeroplane and generator design, surely. I suppose it's all down to money and an engineer is someone who can design, for £5 what any other guy can make for £20.

But I also stick to my original observation about general inactivity in many of the sites I have passed. I am sure that there is /was a lot of optimism in some of the choices of site. Listening to British politicians gives me the impression of all their eggs in one basket -plus a Nuclear option.