Page 94 - 6748

UNIT 10 PUSHING THE BOUNDARIES

I Discussing performance and suitability

1a In pairs, answer the following questions about wind turbines.
1 What function do wind turbines perform?
2 What are the main advantages and disadvantages of wind turbines?
3 What types of location are most suitable for wind farms?
b In pairs, discuss the functions and technical characteristics of the following wind
turbine components.
blades; tower; generator;

2a ► 10.1 Mike, Loreta and Hanif, engineers at a wind turbine constructor, are
discussing performance and suitability issues relating to offshore wind turbines. Read the
conversation and answer the following questions.
26 Which wind turbine component do the engineers discuss?
27 What is the big problem with offshore installations?
28 Which two types of construction material are being compared?
29 Why are coastal defences mentioned?
30 What point does Hanif make about regular maintenance?
31 What comparison needs to be made with regard to lifespan?

Mike: Obviously, a tubular steel tower only gives you sufficient structural strength if you give it
adequate protection from corrosion - the big problem with offshore installations. So, technically,
you could say steel is inappropriate in that environment.
Loreta: They make ships out of it.
Mike: I know, Loreta, but only because there’s no cost-effective alternative. But we’re not
talking about ships, we're talking about fixed structures. The point is, I think we should look
more seriously at alternatives to all-steel supports. And the obvious alternative is reinforced
concrete. Loreta: We’ve already looked into it, though, and it wasn’t cost-effective.
Mike: Not in the short term. But we didn’t really look into it properly over the long term.
Loreta: But you made the point yourself, Mike, that steel’s completely ineffective if it’s corroded.
And one of the main constituents of reinforced concrete is steel.
Mike: It’s protected, though, isn’t it? It’s embedded inside concrete. That’s a much more
effective protection than paint.
Loreta: Not necessarily. If we’re talking about the long term, as you say, what happens to
concrete when it’s exposed to the sea for a few years? It erodes. Which means the steel
eventually gets exposed. You look at concrete coastal defences. How often do you see the
concrete all crumbling away, and all the steel exposed?
Mike: That’s due to inconsistent quality, though. You only get that problem if there’s insufficient
cover. As long as there’s appropriate cover at design level, and the construction quality’s
consistent, then there shouldn’t be a problem. Loreta: Isn’t inadequate cover more of a problem
in a slender structure, though? You’d probably have less cover, compared with the big lumps of
concrete they use for coastal defences.
Mike: Not if...
Hanif: Just a second.
Mike: Yes, Hanif?
Hanif: Let’s just think about what we’re trying to resolve, here. The key issue is, what’s the most
suitable long-term solution? And in both cases, we’re saying steel is necessary, either in an all-

92