The Modern Wind Energy Industry

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Many countries began exploring alternative sources of energy during the oil shortages of the 1970s. As improvements in wind energy technology have evolved, the modern wind energy industry has emerged. Increasingly, modern wind turbines produce electric power as efficiently as other power generation technologies. One of the major obstacles for developing wind energy is finding suitable terrain and wind conditions.

Placement of Wind Turbines

Wind Turbines
Wind speeds in the Lake Benton, Minnesota, area average about 26 km/h (16 mph), making it the windiest region in the state. These turbines are equipped with special features to operate in this cold climate.

Location is critical for maximizing the electricity wind turbines can produce. The amount of kinetic energy available in the wind is a cubic function of wind speed—that is, for every doubling of wind speed, there is a corresponding eight-fold increase in available energy. This exponential relationship between wind speed and wind energy makes location extremely important. A site with high average wind speeds can provide considerably more wind energy than a site with only slightly lower wind speeds.

For most continental locations, winds are strongest during winter and spring and weakest during summer and fall. Regional weather patterns and local topographic conditions can also cause wind patterns to vary.

See Wind Power Plants; Reliability of Wind Energy

Reliability of Wind Energy

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Wind energy is a promising source of electrical power because it is a clean and renewable resource. However, because wind speeds vary by time of day, season, and even from one year to the next, wind energy is an intermittent resource. At windy sites it is common for wind turbines to operate 60 percent of the year. Even when operating, however, the wind may be insufficiently strong for wind turbines to generate at full capacity. Overall, turbines installed on windy sites operate at an average of 25 to 35 percent of full capacity. In comparison, coal-fired power plants usually operate at an average of 75 to 85 percent of full capacity.

The intermittent nature of wind energy does not affect consumers when wind turbines are tied to an electrical network, or power grid. Many wind turbines in North America, Europe, and parts of Asia are connected to large electricity networks. The effect of windless days can be offset by production from other power-generating sources, such as coal-fired plants and hydroelectric plants that are connected to the power grid. Such a system helps provide reliable power supplies to consumers. People located in remote sites that rely on electricity from wind turbines often use batteries or a backup generator to provide auxiliary power during extended periods without sufficient wind.

Current Issues and the Future

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With the growing worldwide demand for electric power and the rising concern about global warming, many experts believe that the use of wind energy will continue to increase. As wind power becomes an increasingly cost-effective source of electricity, the market for wind power should continue to expand. Some environmental and political factors, however, will also influence the growth of wind energy.

Wind Energy and the Environment

Although wind energy is a relatively clean means of generating electricity, there are associated impacts. One of these is the potential of an array of turbines to alter the visual quality of the landscape, especially when located in a scenic area. In addition to aesthetic concerns, noise associated with spinning wind turbine rotors has generated complaints from the public. Another environmental concern associated with wind energy is the impact on wildlife. Wind turbines in some areas are responsible for killing birds—including some protected species—that are accidentally caught in the rotor blades.

Some of these environmental concerns are being addressed by more careful siting of wind turbines. Other concerns, such as the noise of spinning rotor blades, may be partially solved by design refinements that successfully reduce aerodynamic and mechanical noise.

Wind Energy

Wind Energy, energy contained in the force of the winds blowing across the earth’s surface. When harnessed, wind energy can be converted into mechanical energy for performing work such as pumping water, grinding grain, and milling lumber. By connecting a spinning rotor (an assembly of blades attached to a hub) to an electric generator, modern wind turbines convert wind energy, which turns the rotor, into electrical energy.

Wind is created when air that has been warmed over sun-heated land rises, leaving a vacuum in the space it once occupied. Cooler surrounding air then rushes in to fill the vacuum. This movement of rushing air is what we know as wind.

Egyptians may have been the first to capture wind energy when they sailed boats up the Nile River beginning around the 4th century bc. For centuries afterward, wind-powered sailing vessels plied the world's seas and oceans, serving as the principal form of commercial transport. Wind energy has been harnessed on land since the first windmill was developed by the ancient Persians in the 7th century ad. Windmills have since been used to mill grain, pump water, saw timber, and provide other forms of mechanical energy.

Topics:

• The Modern Wind Turbine
• The Modern Wind Energy Industry
• Current Issues and the Future