HOW DOES WIND ENERGY WORK?

Wind turbine blades capture wind energy, a form of mechanical energy, and put it to work turning a drive shaft, gearbox, and generator to produce electrical energy. Many factors affect wind turbine efficiency including turbine blade aerodynamics. Large utility-scale wind turbines can now generate more than a megawatt (1,000,000 watts) of electrical power each and deliver electricity directly into the electric grid. These turbines are over 200 feet high at the rotor hub and have blades which are 220 feet or more in diameter. Thus, the blades of a single turbine may sweep an area 80% of the size of a football field. Utility scale turbines are generally grouped together in “wind farms.” The turbines themselves take up little space, just the area of their bases and access roads, so they are compatible with other land uses including farming. Turbines may also be installed off-shore over water where there is higher and more consistent wind speed. Each wind turbine is controlled by computer and in large projects is connected to a central computer where the turbines can be monitored. Wind turbines are designed with cut-in wind speeds and cut-out speeds (i.e. the wind speeds when the turbines start turning or shut off to prevent drive train damage). Typically, maximum electric generation occurs at speeds of 30-35mph. Over the course of one year, well-sited wind power plants operate at an average of 30-35% of their rated capacity.