Wind Power

Wind Power

Using the elements

People have used the power of the wind for more than 5,000 years. It propelled their sailing boats over rivers, lakes and oceans; it turned the heavy blades of windmills to grind grain and pump water. Wind has energy because it is always moving in one direction or another. This energy can be caught, or harnessed, by large sails or blades.

When electricity was developed in the nineteenth century, wind power did not seem as efficient as this marvelous new source of power, and most windmills disappeared. But wind power is making a comeback. Today, modern versions of windmills called wind turbines are used to generate electricity. Groups of wind turbines with long, thin metal or plastic blades, which look like airplane propellers on top of tall thin towers, are often erected together in wind farms that stretch across the landscape. By the middle of the twenty-first century, one-tenths of the world's electricity could be powered by wind turbines.

Wind-Assisted Tanker

Some ships have stiff fiberglass sails as well as engines. They can save fuel by using sails whenever there is enough wind. Computers calculate the wind speed and indicate when it is time to unfold the sails.

The wind. Photograph by Elena.

Wind Farms

These are buit in very windy areas and are controller by computers that turn their blades into the wind. When the wind turns the blades, the spinning motion is converted into electricity.

Blades: The blades of the turbine are set at an angle that can be changed to suit the wind's speed of direction.

Gearbox: The gearbox, driven by the turbine shaft, controls the speed of the generator.

Generator: The generator converts the spinning motion into electricity.

Turbine shaft: Wind turns the blades, which turn the central turbine shaft. The speed of the shaft varies according to the strength of the wind.

Nacelle: The nacelle (the part that contains the machinery) pivots to keep the blades pointing into the wind. The angle of the blades is set automatically to suit the wind speed.

Tower: The tower holds the blades at a safe height above the ground and contains the cables that cary the electricity underground.

Times past

Windmills were used for many years to grind grain.

Cap: The cap carrying the sails could turn so that the sails faced into the wind.

Canvas-covered sails: Canvas sheeting stretched over the wooden frame of the sails caught the wind and moved the sails around.

Fantail: Wind blowing against the fantail made it spin and turned the mill cap until the sails faced the wind.

Grain hopper: Grain fell from a container, called a hopper, down to the two grindstones below.

Driveshaft: This used the turning motion of the sails to move the grindstones.

Grindstones: Two heavy stones rotated and crushed the grain beneath them.

Make Your Own Windmill

Cut one-third of the way across a square of paper from each corner, and make a small hole in each corner (Step 1). Pull the four corners into the middle of the sheet (Step 2). Fasten pa pushing a tack of drawing pin through the middle. Attach to a drinking straw at the back, making sure your windmill can spin freely (Step 3). Now blow on it or hold it in the breeze.