Wind Energy Basics

Since wind is a converted form of solar energy, wind energy and solar energy go hand in hand. The radiation from the sun heats the various parts of the earth at differing rates. This occurs because the different surfaces of the earth, e.g. water and land, absorb or reflect the sun’s radiation at different rates. Consequently, sections of the atmosphere warm differently. As hot air rises, the atmospheric pressure at the earth’s surface is reduced, causing cooler air to be drawn in to replace it; the result of which is wind.

The energy that the wind then produces can be transformed by a wind energy system into mechanical or electrical energy, which can then be harnessed for functional use. Mechanical wind energy is most often used to pump water in the form of a farm windmill found in rural locations. The farm windmill is one example of a mechanical wind pumper which can be used for many other purposes as well, such as sawing, grinding grain, and pushing a sailboat. Electrical wind energy is generated through the use of electrical turbines, which create electricity for homes and businesses and to sell to utilities.

Electrical wind turbines come in two basic designs: vertical-axis, or “egg-beater” style, and horizontal-axis, or “propeller” style. The horizontal-axis wind turbines constitute almost all of the “utility-scale” turbines in the global market, which consequently makes them the most common type of wind turbine used today.

Utility-scale wind turbines used on land-based wind farms are available in a variety of sizes. The rotor diameters of these turbines range from 50 to 90 meters with towers of roughly the same size. A turbine that has a 90-meter rotor and a 90-meter tower for a total height of approximately 135 meters would definitely fall on the large end of the size spectrum for wind turbines. Offshore turbine designs, however, are currently under development to have even larger rotors.

Turbines that are intended to be used for homes or small business are much smaller. The rotor diameters of these turbines are typically 8 meters or less and are placed on towers measuring 40 meters or less in height.

The electrical output of a wind turbine depends on both the size of the turbine and the speed of the wind through the rotor. Wind turbines manufactured today have a range of power ratings from 250 watts to 5 megawatts. Not surprisingly, wind speed is a crucial factor in determining the efficiency of a turbine. For small turbines, an annual average wind speed that is greater than 9 miles per hour is required, while utility-scale turbines necessitate a minimum speed of 13 miles per hour.

The Basics of Wind Energy

The phrases wind power and wind energy describe the means of harnessing the faculties of the wind to create mechanical power or electricity. This act is carried out by way of wind turbines, which function in a fashion similar to the way that windmills operate. Wind turbines are typically found grouped together on what is called a wind farm. The mechanical power or electricity that is generated by the wind turbines is able to be used for things like grinding grain, pumping water, and providing electricity to homes, offices, and schools.

Wind turbines have propeller blades akin to those found on an airplane. These propellers rotate as the wind blows, thus, powering an electric generator, which provides an electric current. In other words, wind turbines operate in the opposite way that a fan functions. While fans use electricity to create wind, wind turbines utilize the wind to create electricity. The wind causes the propellers to move, which in turn causes a shaft to revolve, which then hooks up to a generator that creates the electricity.

There are two basic groups of types of wind turbines. First, there is the vertical-axis type. This variety is just like the egg-beater Darrieus model. The second type is the horizontal-axis. This variet is exactly like the traditional windmills that are found on farms and are used to pump water. Most of the modern wind turbines are the horizontal-axis type of turbines. These turbines consist of three major components. These components are comprised of a blade or rotor, which transforms wind energy into rotational shaft energy; a drive train, which typically incorporates a gearbox as well as a generator; and a tower, which provides support to the rotor and drive train. Other more minor pieces of equipment include controls, electrical cables, ground support equipment, and interconnection equipment.

Wind turbines are available in many different sizes and power ratings. The largest type of wind turbine reaches more than 20 stories in height, has propellers that extend farther than the length of a football field, and the quantity of electricity that it produces is enough to power 1,400 homes. The type of wind turbine that is most commonly suited for individual homes has propellers that are between 8 and 25 feet long and stands around 30 feet high. This home-sized type of turbine supplies an adequate amount of electricity to sustain an all-electric home or office.

In the long-run, wind turbines are a very cost-efficient source of energy. The initial cost of preparing and installing wind turbines, however, is a more substantial investment than fossil-fueled generators. Yet, since wind turbines have minimal operating expenses and it is not necessary to purchase fuel in order for them to function, wind turbines are a significantly more competitive energy source than other types of technology. Moreover, the energy produced by wind turbines is an entirely a free and renewable form of energy. Plus, wind turbines do not emit any damaging air pollutants the way other energy sources do.