Wind Turbines

A wind turbine converts the kinetic energy of moving air into mechanical rotation and, in most modern machines, into electricity. The wind pushes against blades or vanes mounted on a rotor; the rotor turns a shaft connected to a generator. The power a turbine can capture rises steeply with wind speed and with the area swept by its blades, which is why larger rotors and windier sites yield much more energy.

Turbines fall into two broad families defined by the orientation of their axis. Horizontal-axis turbines, the familiar propeller-like machines, have blades that face into the wind and usually need a mechanism to turn the rotor toward the wind's direction. Vertical-axis turbines spin about an upright shaft and accept wind from any direction without reorienting. The Savonius type is a drag-driven vertical design built from curved, scoop-like surfaces; it starts easily in light wind and is simple to build but is comparatively inefficient. The Darrieus type uses aerofoil blades and works by lift, reaching higher efficiency but often needing help to start turning.

Because vertical-axis designs such as the Savonius are easy to construct from simple materials, they are popular for do-it-yourself and educational projects. Experimental and conceptual designs have also been proposed over the years, including variations aimed at improving efficiency or capturing wind at height. For small home systems, a turbine typically charges batteries through a controller, and output depends heavily on having a consistently windy location clear of obstructions that create turbulence.

Frequently asked questions

What is the difference between horizontal-axis and vertical-axis turbines?

Horizontal-axis turbines have a propeller-like rotor that must face into the wind, while vertical-axis turbines spin about an upright shaft and accept wind from any direction without turning to face it.

How does a Savonius turbine differ from a Darrieus?

A Savonius is a drag-driven design with curved scoops that starts easily but is less efficient. A Darrieus uses lift on aerofoil blades for higher efficiency but often needs help to start.

Why does site location matter so much for a wind turbine?

Available power increases sharply with wind speed, so a steady, unobstructed wind is essential. Nearby buildings and trees create turbulence that reduces output and stresses the machine.