Energy from moving air
Wind is created as the sun heats the earth's surface unevenly. The earth's surface is made of different types of material such as land and water, and absorbs the sun's heat at different rates. The daily wind cycle is a great example of uneven heating.
The daily wind cycle
During daytime, the air above the land heats up faster than the air over water. As warm air over the land expands and rises, and the heavier, cooler air rushes in to take its place, and creates what we know as wind. At night, the the winds are reversed because the air cools more rapidly over land than over water.
In the same way, the atmospheric winds that circle the earth are created because the land near the earth's equator is heated more by the sun than the land near the North Pole and the South Pole.
Wind energy for electricity generation
Today, the Sendero Wind Farm in Hebbronville, Texas, is now online and bringing power to Brownsville residents. The wind farm is capable of producing 78.2 megawatts of electricity.
Generating Electricity from Wind
How turbines work
Wind turbines use blades to collect the wind’s kinetic energy. Wind flows over the blades creating lift (similar to the effect on airplane wings), which causes the blades to turn. The blades are connected to a drive shaft that turns an electric generator, which produces electricity. Use the illustration below to identify the components of a wind turbine.
Wind Energy Terms
Turbine: A turbine converts kinetic energy from the wind into electrical power.
Rotor: A rotor includes three blades, a hub and a spinner, this device converts wind energy into a rotation.
Blade: The blades catch the wind and use it to rotate the shaft of a generator.
Nacelle: A box-like component that houses the generator, gearbox, drive train and brake assembly.
Generator: A device that uses energy to produce electricity.
Gearbox: A device that increases rotational speed to the point where electricity is able to be produced.
Brake assembly: The breke assembly stops a wind turbine from rotating in the event of an emergency or when wind gusts are too strong.
Yaw drive: A device capable of orienting a wind turbine to keep it facing the direction of the wind.
Anemometer: A device that measures wind speed and transmits data to controller.
Controller: The controller starts and stops the wind turbine.
Wind vane: A device that measures wind direction and communicates with yaw drive to orient the turbine toward the wind.