WIND TURBINE

A wind turbine is a mechanical device that converts the kinetic energy of the wind into electric energy. It does this by allowing wind to pass through blades attached to a rotor shaft which is connected to a generator rotor causing it to rotate thereby driving the generator rotor to produce electricity.

Wind turbines are classified into two major categories; horizontal axis and vertical axis turbines.

A horizontal axis wind turbine (HAWT) has its blades rotating on an axis parallel to the ground.

A vertical axis wind turbine (VAWT) has its blades rotating on an axis perpendicular to the ground.

The component of a wind turbine are; rotor blades, hub, main shaft, gearbox, generator, control system, tower and foundation.

The rotor blades are long, curved and slender wings that rotate when wind passes over them. They are aerodynamic in design and are typically made of wood, fiber glass, carbon fiber etc. due to its aerodynamic nature and shape, as the wind passes over the rotor blades, and it creates an area of lower air pressure above the blades and an area of higher pressure below. This pressure differentials or difference creates an upward force on the blades, causing it to rotate.

The hub connects the rotor to the main shaft. It is typically made of steel, cast iron or any other suitable material. Its main function is to transfer the rotational energy of the blades to the shaft.

The main shaft is used to transmit the mechanical energy from the rotor blades to the gear box. It is typically made of steel or any other suitable material.

The function of the gear box is to increase the speed from the rotor blade to the desired designed speed to be transmitted to the generator. The gear box consist of interconnecting meshing gears, bearings and a sliding selector that engages the desired gear ratio needed to be transmitted to the generator.

The generator converts the mechanical energy from the input shaft of the gear box into electrical energy. The generator is typically made up of a rotor and stator with copper windings enclosed in a steel cage. The generator uses electromagnetic induction to convert the mechanical energy into electrical energy.

The control system is specifically used to control the operation of the wind turbine and optimize the output. The control system uses sensors built into the necessary hardware such as a computer system and uses dedicated software to monitor the different interacting variables such as the wind speed, direction and turbine performance. It adjust the pitch and yaw of the turbine accordingly to optimize energy production and prevent damage due to hazardous weather conditions.

The function of the tower is to support the wind turbine and elevate it to a suitable optimal design height to capture wind energy. The main function of the foundation is to hold, support and transfer loads from the tower to the ground.

The advantages of wind turbines are; wind turbines use wind energy which is available freely, renewable and sustainable energy source. Wind turbines produce no emissions or greenhouse gases like fossil fuels generators. Wind turbines maintenance and operation cost are minimal once installed. Wind turbines enable the creation of a mixed portfolio of energy generation mix hence reducing the dependence on fossil fuels.

The disadvantages of wind turbines are; wind turbines generate energy intermittently since it depends on the availability of an unpredictable energy source like the wind. Wind turbines can generate noise pollution during operation and can be an irritant to the environment visually. They can also pose significant risk to the wild life such as birds. Though wind turbines have low operational cost, but the initial cost of construction and installation can be high. Despite their numerous advantages the unpredictability of winds as an energy source have minimized their role as a main source of energy and put them as a support energy role only.

The wind turbines have found application and use in various industries for the generation of power for remote off grid locations, residential and municipal city generation and on grid power supply as backup power and a host of other applications.

The future of the wind turbine is based on the trends and developments in the following technologies; design and development of larger turbines, off shore wind turbines, digitalization of the control power infrastructure and the combination of wind turbine in energy generation cocktail or methods that would interface and combine all power generation methods seamlessly and efficiently.

SOURCES:

• Wind turbines by Tony Burton, David Sharpe, Nick Jenkins and Ervin Bossanyi.
• Wind turbine technology by David A. Spera.
• Wind turbine design by David A. Spera.
• Wind turbine control systems by F.D Bianchi, H. D. Battista and R.J Mantz.
• Wind turbine electronics by R. Teodorescu, M. Liserre and P. Rodriguez