The Alternative Energy Source
A Student Produced Site for Alternative Energy Education
History of Wind Energy
Mankind has been utilizing the energy of the wind since the beginning of recorded history whether for transportation, food production, or a plethora of other uses. Wind energy has been one of the longest existing forms of energy used by mankind, and continues to grow rapidly today.
Timeline
c. 5000 BC- Ancient Egyptians use wind energy to propel boats along the Nile River
c. 200 BC- In China, simple windmills are used to pump water. In the Middle East and Persia, windmills with woven reed sails are being used to grind grain
c. 1100 AD- In Middle East, windmills being used extensively in production of food, and these ideas spread west into Europe.
1800s- Wind energy technologies move west to the New World along with the settlers. Windmills being used to pump water for farms and ranches. Later on, windmills are used for electrical power.
1900s- Using wind energy to produce electricity expands. Now buildings can be lighted remotely from a central power source. As the century progresses, both small and large-scale wind plants with the ability to connect to electricity grids are developed.
1940s- The largest wind turbine of the time begins operating. Located on the top of Grandpa's Knob in Vermont, the turbine was rated at 1.25 megawatts and produced the energy for the local utility network for several months during World War II.
1950s-1970s- Interest in wind energy wanes due to decreased fuel prices in post-war America.
1970s-1980s- Interest in wind and other alternative energy sources increased worldwide because of oil shortages (and increased oil prices). This period of oil embargos causes increases in R & D of wind turbine technology which refines and introduces ways of turning wind into usable power.
1990s- Wind energy's growth in America slows dramatically coinciding with a drop in oil prices but renewable energy tax incentives in California funds the first large-scale use of wind for utility electricity.
Today- Wind powered producers work in all sizes, from small turbines at solitary houses, to large off-shore wind farms providing electricity nationwide and worldwide. In some places wind power costs are very close to conventional energy costs (natural gas, coal, etc) and wind energy is the fastest growing energy source, providing renewable electricity for years and years to come.
Works Consulted
"Advantages and Challenges of Wind Power." Energy Efficiency and Renewable Energy: Wind Power. U.S.
Department of Energy, 7 Nov. 2011. Web. 13 Nov. 2012. <http://www1.eere.energy.gov/wind/wind_ad.html>.
"History." Wind Energy Foundation. N.p., n.d. Web. 5 Nov. 2012. <http://www.windenergyfoundation.org/about-wind-energy/history>.
"History of Wind Energy." Energy Efficiency and Renewable Energy. U.S. Department of Energy, 23 Sept. 2011. Web. 4 Nov. 2012. <http://www1.eere.energy.gov/wind/wind_history.html>.
National Energy Education Development Project. "How Wind Works." Wind Energy Foundation. N.p., n.d. Web. 4 Nov. 2012. <http://www.windenergyfoundation.org/about-wind-energy/how-wind-works>.
U.S. Department of Energy. Energy 101- Wind Turbines. Energy Efficiency and Renewable Energy. U.S. Department of Energy, 27 July 2012. Web. 4 Nov. 2012. <http://vimeo.com/13759005>.
"Wind Program: How Do Wind Turbines Work?" Energy Efficiency and Renewable Energy. U.S. Department of Energy, 27 July 2012. Web. 4 Nov. 2012. <http://www1.eere.energy.gov/wind/wind_how.html>.
In general, wind energy is a form of solar energy; uneven heating of the earth's atmosphere and irregularities in the surface cause the movement of air which we perceive to be wind. The flow and speed of wind varies nationwide and is affected by bodies of water, vegetation, and localized terrain. As mentioned before, wind energy describes the process of using the power of the wind to generate electricity. The turbines convert the energy of the blades spinning into mechanical energy (to be used for grinding grain or pumping water, for example) or to electrical energy.
The Department of Energy briefly explains how wind turbines produce electricity from the wind; in short, the blades are connected to a shaft which is also connected to a generator that produces the electrical energy as the blades rotate.
Development of Wind Energy
Types and Sizes of Wind Turbines
As the video mentioned, the blades on a wind turbine work much like an airplane wing; they are constructed so uneven air pressure flows over the blades to keep them turning. According to the Department of Energy, there are two basic types of wind turbines both of which are useful for different purposes: horizontal axis and vertical axis turbines.
Horizontal axis turbines are more common and are named because the axis of the blades is horizontal to the ground; the turbines have two to three blades that always face into the wind. Horizontal axis turbines are the turbines primarily used for producing electricity.
Vertical axis turbines which are less common are defined by two main windmill types; the Darrieus model which resembles an eggbeater and its blades move in and out of the wind, and the Savonius model which resembles the letter "S" from above and turns slowly while producing a large torque. The vertical axis turbines are used primarily for grinding grain and pumping water because they have slow rotational speed which makes them unsuitable for producing electricity.
Horizontal Axis Wind Turbines. Source: U.S. Dept of Energy
Vertical Axis Wind Turbine (Darrieus model). Source: Mother Earth News
The size of different wind turbines depends largely on who will directly receive the produced energy.
Utility-scale turbines produce anywhere from 100 kilowatts to several megawatts of electricity and are usually more cost effective because they are grouped together in wind farms and provide bulk energy into the power grid.
Smaller wind turbines produce less than 100 kilowatts and are more commonly used in home electricity, telecommunications dishes, and water pumping. Typically, small wind turbines are used in combination with other systems like diesel generators and photovoltaic systems; the combined systems, or hybrid wind systems, are typically used in areas where connections to a large-scale utility grid is not readily available.
Advantages and Challenges of Wind Energy
The Department of Energy's Energy Efficiency and Renewable Energy section explains some of the commonly discussed advantages and challenges facing wind energy, the fastest growing energy source in the world.
Advantages
Wind energy is fueled by the wind, so it's clean energy; there's no air pollution like with power plants relying on fossil fuels and wind turbines have no emissions of greenhouses gasses
Wind energy provides a domestic source of energy; all of the energy produced from the wind comes from the United States itself and our wind supply is quite rich
Wind energy is completely renewable. As mentioned before, wind energy is a form of solar energy, so as long as the sun is shining we will never run out of wind
Wind energy is one of the cheapest forms of renewable energy technologies available today. Wind energy costs between four to six cents per kilowatt-hour
Turbines can be built on farmlands, benefiting economies of more rural areas where some of the best wind sites can be found. Since the turbines don't take much space, farmers can still use most of their land and wind power plant owners pay rent to the farmers for the use of the land.
Challenges
In many places, wind power fights with conventional sources (coal and natural gas) on the basis of cost. The cost competitiveness of wind turbines in comparison to conventional sources depends heavily on the amount of energy produced by the turbines. The cost of wind energy has decreased largely since 2000, but requires a larger initial investment in comparison to fossil-fueled generators.
Usually the best sites for wind farms are located far from cities, where most electricity in necessary; because of this, transmission lines are necessary to transport the electricity from rural areas to the cities.
Wind turbines may often compete with other activities for the use of land in potential wind farm sites and in some cases, the alternative activities may take precedent over wind energy development.
Finally, even though the wind power plants have little to no impact on the environment as compared to conventional fossil-fueled plants, many people are concerned with the noise produced by the turbine rotors, visual impacts, and the fact that some birds have been killed by flying into the turbines. Further developments in the technology and better siting of wind turbines have helped solve some of these concerns.