Wind energy is renewable source of energy and available all around the globe in abundance. So to harness this natural resource in the best possible way wind turbines are designed. Wind turbine can operate from 14km/hr to 90km/hr of wind speed, and are being vastly used all around the world. The wind power plant is used for the generation of electricity in high wind area with the help of wind turbines. Almost 2% of the solar energy coming to the earth is converted into wind energy. It is due to the uneven heating of the earth surface that causes different low pressure zones and air molecules move from high pressure zone to low pressure zone thus creates the wind. The rotation of the earth and surface irregularities causes the wind to follow a random path all around the earth. This flowing of this wind is extracted at wind power plant to rotate generators that produces electricity.
The process of wind-produced electrical generation begins when the force of the wind pushes against the turbines blades, causing them to rotate, creating mechanical energy. The spinning blades, attached to a hub and a low-speed shaft, turn along with the blades. The rotating low-speed shaft is connected to a gearbox that connects to a high-speed shaft on the opposite side of the gearbox. This high-speed shaft connects to an electrical generator that converts the mechanical energy from the rotation of the blades into electrical energy. Spinning between 11 and 20 times per minute, each turbine can generate a maximum 1.5 megawatts of electricity enough to power, on average, more than 500 residential homes.
Types of Wind Turbines
Modern wind turbines fall into two basic groups:
- Horizontal-Axis Turbines:Horizontal-axis wind turbines (pictured right) are what many people picture when you think of wind turbines. They most commonly have three blades and are operated "upwind," with the turbine pivoting at the top of the tower so the blades faceinto the wind.
- Vertical-Axis Turbines:Vertical-axis wind turbines (pictured left) come in several varieties, including the eggbeater-style Darrieus model, named after its French inventor. These turbines are unidirectional, meaning they don't need to be adjusted to point into the wind to operate.
Wind turbine components:-
- Turbine blades – propellers with two, three or five blades mounted on the horizontal shaft (this gives higher output than when they are mounted on the vertical shaft) and made of a lightweight material such as carbon fibre, fibreglass or wood, that is strong enough to resist wind forces.
- A tail section – generally a fin that rotates the body of the wind generator to turn the turbine into the direction of the wind, with the fin directly downwind
- An alternator – AC electricity is generated by rotor windings connected to the shaft from the turbine
- A rectifier – converts AC to DC for electricity that is being sent to a battery storage system (the rectifier may be located in the alternator or in a separate control box away from the tower)
- Electricity cables – transfer the electricity from the generator to the electricity supply or battery storage system
- Slip rings – stop the cables twisting as they will otherwise twist within the tower as the turbine body rotates
- Electric element – power is always produced when the turbine spins, so if the power is excess to storage capacity, it must be redirected to a dummy load (generally an electric element that gets very hot) or sold (if permitted under the district plan) to an electricity retailer
- Tower – the structure (usually steel, concrete or wood) that holds the turbine high in the air, and allows the turbine assembly on top to rotate into the wind – for residential applications, it is typically a mast pole with guy wires
- Guy wires – hold the mast pole in operating position
- Gin pole and winch – allow the turbine to be lowered for maintenance
- Concrete foundation – a 2–3 kW turbine on a 10–15 m tower will typically require a 3–5 m3reinforced concrete foundation.
- Air as a fuel is free and inexhaustible.
- It is clean source of energy and does note pollute the environment.
- The cost of electricity is too low and wind turbine could be used over more than 20 years
- It’s cheap as only the installation and maintenance cost is required.
- It takes a lot of research and effort to decide the location where wind power plant has to be installed, due to fluctuating pattern of wind.
- Its initial setup cost is too high as to setup a turbine you have to go through a survey to determine the wind speed of the location. It all adds up to the cost.
- They are the greatest disadvantage to local bird population as they die due to collision with blades.
- Noise pollution is the one of the major disadvantage.
- Wind power plant is only useful to the countries with coastal or hilly areas.
- It is mostly used for electricity generation.
- It is also used for water pumping through multi blade turbine.
For more:- https://mnre.gov.in/wind