Obtaining energy from wind turbines

We like turbines spinning in the wind very much and we refer to them as a renewable and sustainable source of energy. We like them placed on high sticks and as the newest fashion shows, we also like them, when they float. However, all of the listed options have something in common – to find them a place as high as possible.

I know you are very excited to learn more but first I want to tell and show about producing electricity. The blades of a turbine are attached to a rotor that moves along stator. With described movement, the energy is being generated. In case you are more of an » I need to see this« type of person, here you go.

The amount of obtained energy is highly dependent on many things. The most important ones are how strong the wind flow is, the shape of the blades and their position. Before construction of a wind turbine, there is a lot of research that needs to be done. First of all, we need to find and map suitable areas. These are usually areas, with a constant flow of wind of specific strength. In order to produce electricity, wind speeds must be between 2,5 m/s and 25 m/s (this differs between the turbine types). When the wind speeds are too high, the turbine is shut off to prevent the chance of breaking of the blades. The construction is capable to withstand winds up to about 68 m/s (245 km/h) before it breaks. After the mapping of the area, we need to compare the received data to other locations, since there is a lot of other restrictions we need to follow (settlement, conservation areas, migration routes etc.). When a location is finally chosen, the idea of constructing is presented to the people living nearby. The ”let’s do this!” stage is ready to begin when we get all of the needed approvals.

Scientists are coming up with new ideas, (like this tree-shaped turbine), in order to lower the impact on the environment. Unfortunately, until now, they didn’t manage to come up with an idea of a wind turbine, that would be constructed on the ground and would be able to produce a lot of energy. However, they managed to pull some other strings to make wind turbines better. Some birds (especially the ones we refer to as keystone species or ecosystem engineers) are marked with GPS trackers and they managed to get turbines to shut down when the GPS signal is detected. Unfortunately, this process takes a long time, and the migratory birds sometimes already reach the turbine before it stops rotating. To prevent collisions of bats, they tried replacing the color of the light on the end of the turbine to attract fewer insects. For the same reason, they also tried decreasing the speed at which the turbine starts operating since the bats are most active at low wind speeds. It is still very hard to estimate the total number of deaths caused by the turbines but with making improvements, we are definitely decreasing their numbers.

Related articles:

What are keystone species?

What are ecosystem engineers?

There is also increasing numbers of people, living close to the turbines, complaining about their health problems. How is this possible? The turbines need to be built at least 300 meters away so that the sound doesn’t reach us and there are also measurements done to ensure this! Well, the measurements are done, but unfortunately, they only measure the sound, we actually hear. I found a very good picture showing how the noise pollution is decreasing with distance. The picture also explains why the distance of 300 meters was chosen – at this point the sound is only as loud as our refrigerator (40 Db(A).

Okay.. but so many people probably didn’t make their health problems up just so that the turbines would maybe be removed, right? Right. The problem these people are facing is infrasound. Infrasound is a sound that has short wavelengths (this is the reason, why the barriers are not blocking it out) and it can travel up to 460 meters. Through our evolution, hearing this kind of sound didn’t provide any advantages. Because of this, we didn’t bother to keep it through the process of evolution, but it’s presence still affects our behavior and health.

Turbines spinning in the wind

We can divide turbines into two groups: floating and static. The static turbine is one, we all know very well – the turbine installed on top of a very tall stick. They can be rotating vertical or horizontal but the latter version is very rarely used. The leading reasons for this are, that they can only operate in stable and unshifting winds and they can only operate at low wind speeds. 

The currently biggest wind farm on land is located in China and is capable of producing 6000 mW (6.000.000 kW) of power. To have such a big wind farm, 192000 km2 of land (estimated to be 2% of all China’s land (be sure to zoom out on the link to see the real size)) is used. And yes – this is a lot of completely empty land, occupied only by sticks and blades (and yes, it is a very good starting point for desertification)! We are doing our best to move production of electricity elsewhere (read: offshore or into the sky). The currently biggest offshore power plant is located in the UK, and this country is already planning to make another, even bigger one. The new offshore wind farm would be able to produce 1386 mW (1.386.000 kW) of power.  

Related article: Making broad lands lead to desertification

The floating turbine types can float on the water or in the air. However, the turbine floating on water doesn’t look much different as the one on land.

Now, let’s get to the juicy part. A company called Altaeros is developing a flying turbine (BAT). No, it does not have wings and no it doesn’t have balloons attached to it. Turbine is capable of flying because of the round-shaped body surrounding it and is filled with helium. Helium is very light and therefore capable of lifting the turbine to approximately 600 m above ground. See infographic.

Why there? Because this is where they (the turbines) roll! At this altitude, the wind flow is the strongest and most constant (this is why they all build high turbines). The amount of generated energy is the highest and a single turbine is capable of generating 193 mW (193.000 kW) of energy! Generated energy is then sent to Earth through a power cable and can be used right away.

This turbine is just amazing. Because of its lightweight, it can be transported anywhere, including locations where natural disasters occurred or other locations without electricity. Since the turbine is floating very high, the noise it produces doesn’t reach the surface. Because of the same reason, it also doesn’t have much influence on migratory birds. The last but not least point is, that the area used on the ground is also almost neglectable. This means more space for other things we value as well as smaller interventions in nature.

Wind power should be obtained but we need to start thinking about the possibilities with our hearts and in the long run. Until a few years ago we were mostly making decisions to make a short-term profit and we got used to dealing the with consequences later. Let’s change the thinking and let’s not create the problems in the first place – because maybe later never comes.

Related read:

Offshore wind farms and the impact on the marine predators

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