About Wind Power
We have been harnessing the wind's energy for hundreds of years. From old Holland to farms in the United States, windmills have been used for pumping water or grinding grain. Today, the windmill's modern equivalent - a wind turbine - can use the wind's energy to generate electricity.
Wind turbines, like windmills, are mounted on a tower to capture the most energy. At 100 feet (30 meters) or more aboveground, they can take advantage of the faster and less turbulent wind. Turbines catch the wind's energy with their propeller-like blades. Usually, two or three blades are mounted on a shaft to form a rotor.
A blade acts much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is actually much stronger than the wind's force against the front side of the blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller, and the turning shaft spins a generator to make electricity.
Wind turbines can be used as stand-alone applications, or they can be connected to a utility power grid or even combined with a photovoltaic (solar cell) system. For utility-scale sources of wind energy, a large number of wind turbines are usually built close together to form a wind plant. Several electricity providers today use wind plants to supply power to their customers.
Stand-alone wind turbines are typically used for water pumping or communications. However, homeowners, farmers, and ranchers in windy areas can also use wind turbines as a way to cut their electric bills.
Small wind systems also have potential as distributed energy resources. Distributed energy resources refer to a variety of small, modular power-generating technologies that can be combined to improve the operation of the electricity delivery system.
When it comes to size, bigger is better – the bigger the wind turbine, the more wind it reaches and the more electricity it produces.
The turbines at Flying Cloud Wind Plant in northwest Iowa are about 240 feet tall. The largest wind turbine in the world, located in Hawaii, stands 20 stories tall and has blades the length of a football field!
The tower is usually hollow and made of steel. The blades, called rotors, are made of fiberglass and polyester.
A wind farm might have only two or three turbines, or it could have as many as 150 spread across a big field. One of the largest wind farms in the U.S. is in Altamont Pass, California. It has more than 900 wind turbines.
How does a wind turbine works?
A wind turbine works the opposite of a fan. Instead of using electricity to make wind, a turbine uses wind to make electricity.
The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. The electricity is sent through transmission and distribution lines to a substation, then on to homes, business and schools.