Source: BBC Radio 4: Today Programme
URL: http://news.bbc.co.uk/today/hi/today/newsid_9659000/9659126.stm
Date: 10/12/2011
Event: "Too much wind" for turbines
Attribution: BBC Radio 4
People:
John Humphrys: The image that is stuck - has stuck in the mind, from Scotland storms this week, was that wind turbine exploding into flames - very dramatic pictures indeed. Why? Why did it happen? Is it true that wind turbines really can't cope with wind? Paul Marks of the New Scientist, is with me. It looked a bit like that, Paul.
Paul Marks: Yeah, we've been puzzling about what caused it, back in the office, and there are a number of things that could have gone wrong. The whole idea of a wind turbine, of course, is to harvest energy from the wind, but you don't want to harvest too much.
John Humphrys: Why not?
Paul Marks: They're designed to put a certain amount of energy into the grid. If they - if you put too much in, you'll burn out the dynamo that sends that -
John Humphrys: Isn't that a failing, then?
Paul Marks: Well, kind of - yeah. I mean, it shouldn't have happened, and it doesn't happen very often, it seems to be slightly freakish, but -
John Humphrys: But isn't it -
Paul Marks: - why it happened, is the big question.
John Humphrys: But isn't it daft, to take in the bigger picture, isn't it daft that we have wind turbines that we've invested - and are investing - a massive amount of money in them - huge amount, and indeed many people believe sacrificing our landscape to them - some of the most beautiful bits of our landscape - and here they are - when the wind blows properly, we have to turn them off!? Because they produce too much power!
Paul Marks: It was much more than "properly". I mean, they're designed to kick off at about 55 miles per hour for safety reasons -
John Humphrys: Right.
Paul Marks: - but something went very wrong with this one, and it's - what it's meant to do, it's supposed to be like stalling an aeroplane on purpose. They're meant to turn their propellers, um, sideways so that they don't generate a turning force -
John Humphrys: Too much of a turning force -
Paul Marks: Too much of a turning force -
John Humphrys: Right.
Paul Marks: -so they're not whizzing round too fast, sending too much current through the wires and burning them out. But this one appears - it does another thing, and that is to swing on its, um, axis to face the wind. And something seems to have gone wrong with that, it seems to have been turning all the time in the wind. It seems to have broken, basically, so stalling the blades to stop the turning force didn't matter. It was facing every direction -
John Humphrys: Right. So this, you think, probably was just a one-off. This isn't a design fault, or, as we now have to say, a systemic fault, with the turbines?
Paul Marks: It appears to be a one-off. This has happened before - if you look on YouTube, you'll find wind turbine fires around the world.
John Humphrys: Ah?
Paul Marks: Not huge amounts but there have been some. But, but the question here is what caused this, and do we need to - do these companies need to re-engineer wind turbines for the greater extremes of weather we might get, as the climate changes?
John Humphrys: Mm, interesting thought. Thank you very much indeed, Paul Marks of New Scientist.