The diagram shows three possible locations where wind turbines could be
placed. The average wind speed is 1.2 metres per second in the valley, 5.5 metres per
second on the moor, and 7.9 metres per second over the ocean. Which of the three locations is not suitable for wind turbines. Why is this location not suitable for wind turbines?
Okay, so looking at our diagram, we indeed see these three candidate locations
for a wind turbine, the valley, the moor, and the sea. And we’re told that, at these three different spots, the wind speed is not the
same. In the valley, the wind speed is 1.2 metres per second, while on the moor, it’s
5.5 metres per second. And then over the ocean, it’s fastest of all, 7.9 metres per second. Now, wind speed is a major determining factor for where to put a wind
turbine. Up to a certain limit of about 24 metres per second, the faster the wind is
blowing, the more power a turbine can generate.
Not only do turbines have a maximum allowable wind speed which is enforced for
the safety of the turbine materials, they also require a minimum wind speed in
order to generate any electricity at all. That minimum wind speed needed to turn the rotor of the turbine and generate
electricity is about three metres per second. But then look at this. The wind speed in the valley is below that speed. This means that if we put our turbine here and the wind blew at this speed, we
wouldn’t get any electricity out of it. The wind speed is not reaching the minimum value needed to generate
electricity. On the other hand, the wind speeds over the moor and over the sea are high enough
to cause our turbine to generate electricity.
So only one of these three locations is not suitable for a wind turbine; it’s the
valley. And the reason is that in the valley the wind speed doesn’t reach its minimum
required speed. We can write that this way. We can say that wind turbines cannot generate electricity if the wind speed is
below approximately three metres per second. This explains which of the three locations where we wouldn’t install a wind
turbine and why.