Wind energy is a form of solar energy. In this topic we describe the process by which the wind is used to generate electricity. Wind turbines convert the kinetic energy of the wind into mechanical power that rotate the fan. A generator is used to convert mechanical power into electrical power. Mechanical energy can also be utilized directly for specific tasks like pumping of water.
How do winds form?
This can be explained in terms by the daily wind cycle.
We know that the earth’s surface has both water and land. When the sunshine the air on the land heats up faster than that over water. The heated air has lighter in weight and it rises up. The cooler air is denser or heavier and it falls downward and replaced the air over the land. In the night the reverse process happens. Air that is present over the water is hotter and rises up, and is replaced by cooler air from land.
The moving air or wind has huge amounts of kinetic energy, and this can be converted into electrical energy by using wind turbines. The wind turns the blades, which rotate a shaft, shaft is connected to a generator that makes electricity. The electricity is sent through transmission lines to a substation, then send on to schools, homes, business offices e.t.c.
Wind turbines cannot perform work if there is no or less wind. If the speed of the wind is so high it would damage the system.
Wind turbines are usually making on high hills and mountains to take advantage of the prevailing winds.
windmills have also been used for grinding grain.
The major types of wind power are:
- Utility-scale wind power
Wind turbines that produce larger than 100 kilowatts are developed with electricity delivered to the grid power station and distributed to the end user by electric utilities or power system operators.
- Distributed or “small” wind power
The wind power stations which uses turbines of 100 kilowatts or smaller to directly supply power to homes schools and small business for it primary use
Wind Energy Basics
The wind is caused by the uneven heating of the atmosphere by the sun, rotation of the earth and variations in the earth’s surface. Mountains, vegetation, and bodies of water all affect the wind flow patterns. Wind turbines convert the kinetic energy of wind to electrical energy by rotating blades around a rotor. The rotor turns the shaft, which turns an electric generator. Three key factors that affect the amount of energy a turbine can harness from the wind: swept area wind speed and air density.
The equation for Wind Power
The energy in the wind varies with the cube of the speed of the wind. In other words, if the wind speeds twice then there is eight times more energy in the wind
(). Small changes in wind speed make a large impact on the amount of energy available in the wind.
The density of the air
If the air is denser then more energy received by the turbine. Air density varies with height factor and temperature. Air is less dense at higher places than at sea level, and warm air is less dense than cold air. All else being equal, turbines will produce more energy at a lower height and in locations with cooler average temperatures.
The swept area of the turbine
If the size of the area through which the rotor spins this means that if the swept area is larger than the more power the turbine can capture from the wind.