The kinetic energy in wind can be converted into mechanical or electrical power. For centuries, windmills have converted wind energy into mechanical power to grind wheat into flour. Now, improved turbine technology allows wind generators to affordably produce electricity. Electricity is produced when an electrical conductor moves perpendicularly to a magnetic field. Generators have a conductor (or rotor) that spins inside a magnetic field (or stator). The challenge is to find abundant, low-cost energy to spin the rotor.

Wind generates less than 1 percent of the world's electricity, but is its fastest-growing energy source.

Hydroelectricity is a renewable energy source that uses the potential energy of falling water to turn the rotor. Wind is also a renewable energy source because its supply is not depleted after being ...