Wind is the movement of air around our planet. It is created by the effects of the sun on the atmosphere and the earth’s surface. As the ground is heated by the sun, the air above it becomes lighter and rises, creating vacuums that are filled by cooler air. Wind is essentially caused by differences in atmospheric temperature and pressure.
Local winds are produced as the sun heats the earth in a given area. Prevailing winds are produced by differences in temperature between the polar caps and the equator.
Man has been converting wind into mechanical energy for thousands of years, as ancient windmills and sailboats can testify. Modern wind farms are converting the kinetic energy of the wind into electrical energy.
Clean, renewable wind energy is the ideal alternative to fossil fuels. Wind turbines produce no atmospheric emissions, no harmful waste nor any other type of air or water pollution. And the noise produced by a wind turbine, as measured outdoors close to nearby houses, is no more than 40 dB, which is equivalent to the hum in a library.
Wind energy is therefore particularly reliable and has multiple economic, environmental and social benefits. Not surprisingly, the wind is one of the fastest growing energy sources in the world.
At the top of the tower sits the rotor, the main components of which are the blades. The blades are attached to a horizontal shaft connected to a generator inside the nacelle. When the wind blows it turns the blades, and the rotation generates electricity: as they turn, the blades activate a gearbox in the nacelle that runs the generator. The electricity produced is transmitted to a step-up station and then delivered to consumers through the grid.
The amount of energy produced depends on three main factors: wind speed, air density and the area swept by the blades.
Generally speaking, one megawatt (“MW”) of wind energy can produce enough electricity to meet the annual needs of about 240 Canadian homes (consuming an average of 12 megawatt-hours (“MWh”) per year).