Introduction
Wind energy is one of the fastest-growing forms of electric power generation. The search for pollution-free, sustainable energy has promoted this industry worldwide. Additionally, tax incentives for new wind installations in the U.S. have resulted in substantial growth in the industry. This nation ranks first in the world for wind electricity generation. Wind energy accounts for approximately 1% of our electricity supply. Texas leads the U.S. for generating wind energy electric power. Pennsylvania is the leader in the eastern states. The Department of Energy is examining the feasibility of using wind energy to generate 20% of the nation’s electricity by the year 2030. The outlook for increasing the number of wind power plants and wind power technology around the world looks imminent.
Wind Energy Basics
Wind is caused by the uneven heating of the earth’s surface. Simply, wind can be defined as “moving air.” The wind’s energy has been used to do work throughout history from moving sailboats to generating electricity. Simple windmills, used for hundreds of years, were the primary technology that led to the modern wind turbines of today. The moving blades on a windmill rotate as the wind blows, turning a shaft or rod that can pump or crush something. Windmills of long ago were made to pump water and grind grain into flour. Small windmills were used in the 1920’s to generate electricity in remote locations which did not have electric service.
Today, wind is harnessed primarily to generate electricity. The tall towers and large rotating propellers of wind turbines are becoming commonplace. Modern wind turbines, which usually consist of two or three blades, turn according to wind speed. As the blades or wheels rotate, energy is transferred to a shaft or rod to make it spin. The spinning motion drives a generator to produce electricity. The electric power is transported to consumers by way of an electric grid. There are horizontal-axis and
vertical-axis wind machines, the most common being the horizontal-axis. Wind machines vary in size. The largest has blades longer than a football field and is 20 stories tall. One this size has the capacity to generate electricity for 1,400 homes. Wind farms, consisting of several to dozens of wind mills, are placed at strategic locations to harvest wind power.
Environmental Impacts
Wind is a clean and renewable energy resource which has no polluting emissions. The most common environmental concern with wind machines are the effect they have on bird populations. Birds (especially “birds of prey”) and bats are killed when they fly into the rotors. The statistics on the bird mortality rates vary. Better placement of wind power plants has reduced bird mortality rates in some areas. Other concerns of wind power include noise and aesthetic impacts.