Wind Energy

Wind-mills were a fixture on the Ontario country-side at the turn of the century – they functioned first to pump water then later to generate electricity. At their peak, there were about 600,000 farm windmills in operation across North America.

Once again windmills are catching the attention of farmers and food processors as they look for energy and environmental solutions. The next generation of windmills – wind turbines are banking on old-ideas with breath-taking results. The size and contrast to natural landscapes take your breath away.

According to wikipedea, a wind turbine is a machine that converts the kinetic energy in wind into mechanical energy. If the mechanical energy is converted to electricity the machine is called a wind generator. Wind turbines can be separated into two types based on the axis about which the turbine rotates. Turbines that rotate around a horizontal axis are more common. Vertical-axis turbines are less frequently used.

Horizontal-axis wind turbines (HAWT) have the main rotor shaft and electrical generator at the top of a tower, and must be pointed into the wind. Small turbines are pointed by a simple wind vane, while large turbines generally use a wind sensor coupled with a servo motor. Most have a gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable for generating electricity.

Since a tower produces turbulence behind it, the turbine is usually pointed upwind of the tower. Turbine blades are made stiff to prevent the blades from being pushed into the tower by high winds. Additionally, the blades are placed a considerable distance in front of the tower and are sometimes tilted up a small amount.

Common modern wind turbines are usually three-bladed, sometimes two-bladed or even one-bladed (and counterbalanced), and pointed into the wind by computer-controlled motors. The rugged three-bladed turbine type has been championed by Danish turbine manufacturers. These have high tip speeds of up to 6x wind speed, high efficiency, and low torque ripple, which contributes to good reliability. This is the type of turbine that is used commercially to produce electricity. The blades are usually colored light gray to blend in with the clouds and range in length from 20 to 40 metres (60 to 120 feet) or more.