What is wind
energy?
How is wind energy a good
alternative?
What are the problems with using wind
energy?
Simply put, wind energy is the utilization of the
energy that moves the air. The uneven heating of the earth by the
sun causes differences in air pressure and produces wind. The
wind's mechanical energy is usually captured by wind turbines and
turned into electricity. However, for several centuries now, it
has been and still is used as a method of boat propulsion and
water pumping.1
Two types of turbines are used: horizontal-axis wind
turbines and vertical-axis wind turbines. The horizontal-axis
turbine looks similar to windmills used to pump water; the
vertical-axis turbine looks like an eggbeater. A wind turbine
usually consists of rotors or blades, an electrical generator, a
speed control system, and a tower. Wind turbines are in many
different sizes. The rotor of a big turbine can be as wide as a
football field and as tall as a 20 story building. A small wind
turbine can be just five feet wide and 30 feet tall. A large size
turbine can produce electricity for 1400 homes and they are
usually grouped together to form a wind farm. The small size
generator is ideal for a home, cottage or small business that is
remote from the local utility grid.2
Wind resources are the main factor in electricity production
efficiency. Wind resources are generally graded by the wind-power
density classes. Class 3 and above are considered good wind
resources. Details of the classification3
are as follows:
| Wind Power Class | Wind Power Density (Watts/m2) | Speed (m/s) |
| 1 | < 200 | < 5.6 |
| 2 | 200 - 300 | 5.6 - 6.4 |
| 3 | 300 - 400 | 6.4 - 7.0 |
| 4 | 400 - 500 | 7.0 - 7.5 |
| 5 | 500 - 600 | 7.5 -8.0 |
| 6 | 600 - 800 | 8.0 - 8.8 |
| 7 | > 800 | > 8.8 |
How is wind energy a good alternative?
Like many other alternative energies, wind energy does not require any fuel therefore it can generate electricity as long as the wind blows. Wind energy is also one of the cleanest forms of alternative energy. In fact, according to the United States Department of Energy's Wind Energy Program, "A single utility scale wind turbine (500 kW) displaces approximately 500 tons of CO2 emissions annually, based on the current U.S. energy mix's average emissions."4 The Department of Energy also gave an example, California's wind power plants offset more than 2.5 billion pounds of carbon dioxide emissions in 1990, which would take a forest of 90 million to 175 million trees to provide the same air quality.5
What are the problems with using wind energy?
There are quite a few problems with wind energy. Economically, the initial cost for wind turbines is greater than that of conventional fossil fuel generators. Also, from an environmental point of view, there is noise produced by the rotor blades, there is interference on television signals, and there are birds flying into the rotors, all of which are potential problems. Along with that, dozens of wind turbines standing in a big field or coastline do damage the view presented by nature (however, by some this could be seen as a beautiful sight). Furthermore, wind resources might not be available near cities and, even so, the space might be used for other purposes that can generate larger profits. In addition, wind does not blow consistently 24 hours a day and that could cause a problem when the demand for electricity peaks.6
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