TRANSCRIPTS
people claim that wind turbines are ugly, kill birds and hardly generate any power. But that just isn’t true. It’s quite clear that the benefits far outweigh the perceived problems. Most of the research has concluded that, if turbines are sited correctly – out of sight, in areas with sufficient average wind, and away from major bird migration routes – they do not create extra problems. The evidence lies in the increasing use of wind power for electricity generation, from around 28 quadrillion BTUs (British Thermal Units) in the year 2000 to more than 40 quadrillion in 2009.
Unit 11, Lesson 11.4, Exercise E ≤2.23
Extract 1 MAJED: Our lecture on wind turbines last week raised a number of interesting issues. In my part of the seminar, I would like to start by discussing very small domestic wind turbines, the type you might attach to the side of your house. The question is: Are they worthwhile? How do they compare to big turbines? I found a recent report which suggests that, unfortunately, they are usually not a good idea compared to big turbines. There seem to be two problems: The first is that in urban environments the wind resource is simply insufficient. The wind speeds are not high enough and the wind is too unsteady. The second problem is that often the performance of these domestic wind turbines does not match expectations, and there is no suitable standard for performance testing to make sure that manufacturers are all talking about the same thing.
Extract 2
EVIE: OK, following on from what Majed has said, I’d like to mention that, from a financial point of view, small wind turbines in urban areas are not a very good investment. If you combined the two factors that Majed talked about, you find from the report that small wind turbines in urban areas produce about 10–30 times less energy than large wind turbines in windy areas. So, if I was an investor who wanted to produce as much renewable energy as possible and make a return, I would rather invest in large wind projects.
Extract 3
JACK: Right. Thank you, Evie. I’m going to expand the topic by mentioning another issue related to wind turbines in general, whether small or large. This is the issue of intermittency. Wind turbines produce power when it’s windy, but it’s not always windy, so the power output varies. How do we
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cope with this? Well, electricity companies are already used to coping with massive short-term swings in demand in household consumption – the classic example is when everyone in the country is watching a football match. At half-time, everyone wants a cup of tea and the electricity demand rockets! So, although it will take some thought, engineers are already used to solving this kind of issue.
Extract 4
LEILA: As well as short-term intermittency, we should also look at longer-term lulls. This is when the wind speed over the whole country drops for a period of a few days. In this scenario, if we are heavily depending on wind as an energy source, we need a way to store the energy for days. There are a few options out there, but I want to suggest that pumped storage is probably a good way of solving this problem, combined with very large specialized battery systems called flow batteries.
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