wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns a blade, which spins a shaft, which connects to a generator and makes electricity. Modern wind turbines fall into two basic groups, the horizontal axis and the vertical axis design.Horizontal axis wind turbines have blades that spin in a vertical plane like airplane propellers. The blades have a special shape so that when wind passes over them, it moves more rapidly over one side. This creates a low pressure behind the blade and a high-pressure area in front of it. The difference between these two pressures causes the blades to spin.The blades of a vertical axis wind machine work on the same principles as horizontal axis machine. The shape of the blades causes the pressure to differ when the wind blows over them. This causes the assembly to spin. In a vertical axis machine, however, the blades spin in a plane that is parallel to the ground like an eggbeater.Wind turbines are made in a variety of sizes, and therefor power ratings. The largest machine, such as the one built in Hawaii, has propellers that span more than the length of a football field and stands twenty stories high. It also produces enough electricity to power fourteen hundred homes. A small home sized wind machine has rotators between 8 and 25 feet in diameter. It stand upward of 30 feet and can supply the power needs of an all electric home or small business.Wind energy is also a partial solution to environmental problems. The electric Power Research Institute has stated that “ Alone among the alternative energy technologies wind power offers pollution free electricity that is nearly cost competitive with today’s conventional sources”. In 1991, for example, California’s wind power plants offset the emission of more than 2.8 billion pounds of carbon dioxide. These same wind plants offset sixteen ...
