When man discovered the nuclear and the fossil fuels, man thought he has finally arrived. The amount of energy generated by only small quantity of fossil and nuclear fuel was so much that man decided to focus all it resources to only this kind of energy, forgetting the other sources he derived energy from like the sun and the wind, before he made that great discovery.
Fast forward, few years later, what he thought was manna have become poison. He never knew that the energy generation will come with a price. The by-products of energy generation using fossil fuels had severe consequence to man and his surroundings. The by-product destroyed man's ozone layer which normally acts as a protective covering which protects man from the direct emissions from the sun. The by product also resulted to acid rains which destroyed and poisoned man's crops. Thank God man finally learnt his lesson and decided to go back to his roots. Right now, man now harnesses energy from the sun and the wind.
Nature has so much secrets, man haven't been able to fully harness the power of the wind, till a man called Dr Fish discovered the ways of the humpback whales which performs acrobatic maneuvers which is impossible for other whales. This had lead to the advancement in wind energy harvesting.
Before we get to how man managed to make this discovery and how he applied it, we really need to get to know how the old turbines worked and how lacking it was. We will also see what this improvement really effected in energy production.
WIND TURBINE
A wind turbine is just a device that generates electricity by converting the kinetic energy of the wind to electrical energy. Wind turbines are of different types, orientation, shapes and sizes, but they all aim at achieving one thing. It is worth noting that a larger sized wind turbine tends to generate a higher amount of electricity than a small turbine. Thus, the small turbines are used for powering of simple devices, while larger turbines are used to generate electricity for a whole city. Wind energy is one of the best energies in the world, though not as efficient as the nuclear and fossil fuels, the energy production of the wind turbine had the lowest greenhouse gas emission, the lowest water consumption and doesn't cause any harm to the environment.
HOW A CONVENTIONAL WIND TURBINE WORKS
Generally, all turbines work with the basic principle of generating electricity when the rotor blades are rotated by any kind of fluid. In wind turbines, the rotor blades are rotated by the wind. The idea is all aerodynamics, the blades are shaped into a curved thus making the air flow over the blades laminar. When the wind blows past the rotor blades, it causes them to spin around. Remember that energy can't be created neither be created nor destroyed, it doesn't just generate electricity from thin air, but rather, the wind loses some of its kinetic energy to the blade, while the wind turbine now converts this energy to electrical energy.
The size of the rotor blades is a crucial factor in determining the amount of energy that can be generated by the wind turbine. Thus, the longer the blades is, the more the energy that can be generated by the turbine. And also, the faster the wind blows, the more energy generated. The energy of the wind is proportional to the cube of its speed, thus if the wind speed doubles, we would be expecting an energy generation eight times the normal amount.
Pxhere.com: The rotor blades are pushed by the wind
Now as the rotor blades are pushed by the winds, it causes the rotor to spin which in turn turns the central drive shaft which supports the rotor. Lest I forget, even though the rotor blades spins really fast, the drive shaft doesn't spin that fast too, rather it spins slowly about 16rpm. This is due to how it is designed to rotate.
Inside the body of the turbine, the part behind the blades, (also called the nacelle) you will find the gear box, whose work is to convert the low speed at which the drive shaft rotates to a very high speed about 1600rpm. This is because the generator requires a fast rotation for it to function properly. It is this generator that takes this kinetic energy and converts it into electrical energy. A 2MW turbine generator can be able to generate a higher amount of power of about 2 million watts at a voltage of 700V, if it is running at its highest capacity.
Also the wind turbine has other devices like the anemometer and wind vanes on the nacelle's back. Their job is to measure the winds speed and it's direction too. Now with this measurement, the yaw motor rotates the entire top part of the wind turbine such that it faces the direction the wind blows the highest so as to catch the maximum energy that can be supplied by the wind. The wind turbine also have brakes for stopping the rotor blades in case the wind becomes too much that it can destroy the wind blades.
Now, this electricity generated by the generator flows down through a wire that runs within the turbine casing to a step-up transformer, which steps up the voltage generated to a high voltage to enable the efficient transmission of the electric current into the power grid. This voltage generated is stepped up further when it gets to a substation even up to 130,000volts.
TYPES OF WIND TURBINES.
Horizontal axis wind turbines:-
These turbines are the most common of the wind turbines. In this type of turbine, blades, shaft, generator and other components of the turbine are placed on the top of a very top tower, while the blades are made to face in the direction of the wind, while the shaft is positioned in such a way that it appears horizontal to the ground.
Ducted Wind Turbines
This types of wind turbines are placed on top of buildings. Mainly, it makes use of the air that flows along the side of a building. As it flows up, it flows very close to the wall of building touching it, as if the building wall guides it till if enters the front of the duct. These type of turbines are small when compared to the other types and it has a diameter of about 600mm.
Vertical axis wind turbines
The blades are connected to a shaft which is positioned perpendicular to the ground. Unlike the horizontal turbines which are mounted on a very high towers, the vertical turbines are not that high. In fact, all the main components of the vertical turbines are mounted closer to the ground. Vertical axis wind turbines are of two types: The lift based type and the drag based type. The lift based designs have more efficiency than the drag based design.
Picture by Spiritrock4u - wikicommon CC BY-SA 3.0
A vertical axis wind turbine
HOW TO HARVEST THE MAXIMUM AMOUNT OF ENERGY FROM A CONVENTIONAL WIND TURBINE
The rotors blades are made so long (about 70m tall) so as to enable it capture a lot of wind energy. This is because the amount of energy captured by the blade is proportional to its length. The idea is more like that of a couple, as the wind blows past the rotor blades, despite their length, it turns. It is worth noting that the wind turbine doesn't work all the time, atleast, 14% of the time, it is idle. It is the way it is designed to enable it to adapt to the winds nature of constant change. Also all the winds do not work at the same speed, some designed to function at a larger speed than others, invariably generating more speed than others.
The wind turbine is made to stand quite tall, sometimes, it's total length is about 85m. It is a general knowledge that the wind travels faster at a higher height than when its close to the ground. This is because trees, buildings and other high structures prevent the free flow of air, but at greater height, these obstructions to flow are not experienced. Due to this, turbines are made quite tall, and at this height, they can capture a considerable amount of wind energy more than it can capture if it was placed closed to the ground.
Also, another factor that is worth noting in the factors that influences maximum harvest of wind energy is the position of the wind turbine. The wind turbine are normally placed at a position that enables it to recieve the maximum kinetic energy of the wind. Since a higher number of turbines are required to generate a large amount, it is necessary that each turbine should be kept a distance away from the other, to prevent them from affecting themselves.
ADVANTAGES OF WIND TURBINES
Energy generated by wind turbines are clean and it doesn't poses any harm to the environment, unlike water happens in burning of fossil fuels and nuclear power plants which always result to emissions that are harmful to the environment.
Wind energy is a self renewal energy. Thus, once a wind turbine is built, you can make limitless energy from it from now till forever, only pausing for a while for maintenance. Its running cost is not high, since all that is requires is just the initial cost of acquiring the equipment.
Wind turbines are quite easy to construct, and since the cost of production is low, the selling price for the energy is cheaper than those of fossil and nuclear fuels.
Pxhere.com: Use of fossil fuels causes air pollution
DISADVANTAGES OF A WIND TURBINE
Wind turbines doesn't generate as much power as nuclear plants and other fossil fuels does. A nuclear power plant or a coal-fired power station generates 2000MW of power while a wind turbine produces 2MW of power. What this means that to produce the same amount of power produced by the power plant, about 1000 wind turbine is needed to achieve that. This is also a huge problem, as it would consume a lot of space. Imagine mounting 1000 poles of wind turbines, while bearing it in mind that they should be kept at a long distance away from each other. Surely, that would consume a lot of space.
That's not even all, remember that that these vast area of land that would be covered by wind turbines just to generate electricity can be used for other things even more beneficial to man like farming e.t.c. Thus, this poses as a great disadvantage, and because of this, wind energy have not been considered as a reliable source for future energy. It wasn't until Dr fish made his amazing discover on how to improve on wind turbines did we start putting our hopes on wind turbine as a reliable source of energy for the future.
INSPIRATION FROM NATURE:- THE HUMPBACK WHALES
One of the largest mammals in the sea is the humpback whales. The humpback whale is a member of the animal family known as cetacea. They are known for their majestic songs which the males sing to the females so as to lure them for mating. They are also known for their acrobatics abilities they display in the sea. Humpback whales grow quite tall, the adults grow about 40-60ft in length, and weigh about 44 tons. They don't have teeth like sharks, in place of teeth, they possess baleen plates. Since they don't have teeth, they swallow their food whole, while using their baleen plates to separate the seaweeds from the fishes.
pixabay.com: A humpback whale with its flippers visible
But I must tell you that all none of these makes this black/grey animal with patches interesting. If you have ever studied whales before, you will notice that during feeding, the whales first startle the smaller fishes. This startling causes them to become immobile, due to shock. Then, the whale open its mouth wide like a basket while the krills and other smaller fishes (now immobile) flows with the water into its mouth. The humpbacks doesn't just depend on that. Unlike their brethren, the humpback whales have this special ability that enables them to catch many fishes than others of its brethren. This ability is due the tubercules they possess in their flippers.
EXPLAINING THE MECHANISMS INVOLVED
Like I said, the humpback whales are quite different from their brethren. While other species of whales depend only on catching the krill by simply open their mouth and letting the fish flow with the water right into its mouth, the humpback whales make manoeuvre to catch fishes.
If a whale wants to make a turn to be able to catch a fish, it will require more lift. For this, it positions itself at a maximum angle of attack, but if the angle it needs to make is more than this maximum angle of attack and it tries to turn itself in that angle, it stalls.
Stalling means that it losses control and it starts to spin while it falls downwards.
The humpback has this special characteristics that prevent it from stalling. It doesn't stall easily due to the tubercules in its flippers. This tubercles gives it a higher maximum angle of attack than that of other whales. At first, the world really wondered what this bumps in the flippers was for. It wasn't until Dr Fish made an amazing discovery that it was this bumps known as tubercles that enables humpbacks to make increase their angle of attack without stalling. Humpback whales can increase their angle of attack up to 42%. This enables them to position themselves accurately to the position that will aid them catch the maximum amount of fishes.
APPLICATION OF THIS DISCOVERY
Wind Turbines
Normally, the angle of attack of wind turbines are made very small, to prevent it from stalling. (As gust from two seperate directions can cause the blades of a windmill to stall and even blow up.). Now, with the the addition of tubercles into the design of wind rotor blades, the windmills can be positioned at a higher angle of attack which will enable it to experience a higher lift and thus spin at a faster speed than the speed we obtain from conventional turbines, (without blowing up) resulting to a higher energy generation.
Other Applications
This discovery has an application in almost every part of aerodynamics. Now, fans with tubercles are now been made, and it is observed that they are more efficient than the normal fans. Currently, engineers are designing an aeroplane in that will have tubercles in its wings. It is theorized that the aeroplane is going to experience a higher lift and it will be able to travel a very fast distance with a lesser amount of fuel.
WIND ENERGY, THE ENERGY OF THE FUTURE
Man have suffered a lot from the damages done to our surrounding due to the emission of harmful substances by fossil fuels and nuclear plants. There is need for renewable energies which won't be of any harm to our surrounding. Since the discovery made by Dr Fish, the hopes for wind energy becoming one of the dependable sources of energy for the future has increased.
But wind energy can't be a general solution to the world's energy problem. This is because, it is weather influenced, it varies from place to place. Thus, a place that is windy will result to higher generation of wind energy than a place that experiences less wind. For that reason, It has to work hand in hand with other renewable energy like solar energy. If an area (like Scotland) has more wind flow and less sunlight, it should depend on wind energy.
Also, with Dr Fish new designs for rotor blades, wind turbines will be able to supply energy to the whole country, even with a lesser number of turbines. In other areas that experience more sunshine than wind, like in Australia, the cost of solar energy would be more cheaper there, thus, it is more advisable to use solar energy in those areas than wind energy.
CONCLUSION
This is one of the biggest breakthrough man have made in his search for a better solution to power generation. Right now, man's dependence on fossil and nuclear energy is reducing as the day goes by, which is quite goodness. If man will reach the peak of generating electricity using wind turbines imagine how the world would be like.
Nature is living, and just like a living thing, if man will stop the use of all fossil and nuclear fuel completely, I believe that nature will heal itself. Nature will find a way to correct all the damages done to it by man.
There are still quite a lot of other things man can learn from nature. I recently learnt from someone that man is on limited by himself. Mr Fish allowed himself to think, now man is thinking of a way to build the fastest plane using an idea Mr fish found in nature. Imagine what we will soon enjoy just because someone allowed himself to think. If only man will allow himself to see the secrets of nature hidden in plain sight; eyes have not seen what man will achieve.
REFERENCES
Wind turbines inspired by Humpback whale