Today, approximately 300,000 three-blade, utility-scale horizontal-axis wind turbines are in operation. Because they are the most effective, they are the winning form of their generation. The average efficiency of these units is 15% for the United States and 25% for Europe. Smaller-scale (up to 10 kW) wind turbines are available for use in homes or on small businesses' roofs. These tend to be less efficient, with average ratings of 7-12%. As we will see below, newer technologies promise improvements in efficiency that may one day exceed 20%.
The first modern wind turbines were large horizontal-axis machines built from steel beams and wood boards. They used a third-rail generator to produce electricity. These were followed by some smaller vertical-axis models using magnetic coupling devices instead. In the early 1980s, the American company Wind Energy Institute developed a new type of wind turbine: the hubless wind turbine. This design uses two counter-rotating shafts coupled to a dynamo to produce electricity. It requires no moving parts inside the casing other than a bearing at the base to support the axis. This makes it extremely durable and reliable.
In 1994, a team led by Dr. Thomas Elliott of Texas A&M University developed a technology called "power capture" which effectively converts wind energy into electrical energy by using magnets.
Wind-powered energy generating Wind turbines generated around 8.4 percent of total utility-scale power output in the United States in 2020. Facilities having at least one megawatt (1,000 kilowatts) of power producing capacity are considered utility size. Smaller facilities may be called microgrids or distributed generators.
This number is fairly stable compared to other electricity sources, which makes wind energy very competitive with other methods of production. In fact, according to the U.S. Department of Energy, between 2007 and 2012, electricity from wind farms was often less expensive than electricity from traditional sources.
The majority of wind energy produced in the United States comes from large-scale industrial wind farms. The first such farm began operating in Massachusetts in 1990. As of 2013, 26 such farms were in operation. Another 102 projects were under construction. This gives America a total of 128 large-scale wind farms. These farms can produce up to 1000 MW or more of power, which is about 10 percent of the nation's demand for electricity at any given time.
However, many smaller communities have begun installing wind turbines in their electric grids to provide green energy while saving money on their utilities bills. In 2014, there were approximately 6,000 wind turbines in use across the United States. This number is expected to increase as more communities adopt this source of renewable energy.
Wind Generators use the wind's force on rotating blades to drive a shaft, which in turn drives a generator to produce electricity. The most common type of wind generator is the horizontal-axis wind turbine (HAWT). This design uses two counter-rotating rotors, each with several curved blades. As the rotors spin they act like air motors and draw power from the wind directly into the rotor axis, where it is transmitted through a gearbox to an electric generator.
Turbines using water wheels or magnets as well as solar-powered generators are also used to create electricity from wind. The amount of electricity that can be produced by wind farms depends on many factors such as size, location, and climate. Wind provides one of the most flexible forms of renewable energy because its availability varies significantly over time and space. It can be used as a baseload source of energy, meaning that it can be relied upon to provide constant power day and night, or it can be used in combination with other sources for peak shaving or intermittent power supply.
The term "wind power" can be misleading because it implies that all wind generators use this type of technology to produce electricity. They do not.
We were able to adapt the turbine and generator for lower wind speed operation and produce a much greater power output than existing commercial turbines at lower wind speeds by starting with a traditional axial flux, direct drive, horizontal axis, 3-blade wind turbine. This type of turbine is commonly found in small wind systems for electricity production because of its high efficiency over a broad range of wind speeds.
Traditional wind turbines have three main parts: a hub that supports the blades; a shaft connecting the hub to the rotor; and a gearbox or other means of transferring rotary motion from the blade tips to an electrical generator. More recently, radial-arm wind turbines (RAWs) have become popular due to their design which uses less material and is therefore more efficient. However, traditional RAWs are still used in conjunction with solar panels as a source of supplementary energy during daylight hours when wind speeds exceed 10 mph.
The first modern wind turbine was developed by Francis Upton in 1872. It used two pairs of magnets and two sets of coils to generate electricity from moving air. In 1882, George Hancock built the first working wind-powered generator, using magnets and copper coils. In 1913, Charles Fitch patented a transformer-based system for generating electricity from wind movement. In 1939, Edmond Becquerel invented the electric motor-generator, which is used in most large-scale wind turbines today.
The greater the number of blades on a wind turbine, the greater the torque (the force that causes spinning) and the slower the rotational speed (because of the increased drag caused by wind flow resistance). As a result, the fewer the blades, the better the system is suited to produce electricity. However many blades on a wind turbine are fixed and cannot be adjusted. This can be a problem if you want to maximize your output or use different parts of the spectrum for different applications.
There are two main types of wind turbines: horizontal-axis turbines and vertical-axis turbines. Horizontal-axis turbines have their axis of rotation perpendicular to the wind direction, while vertical-axis turbines have their axis of rotation parallel to the wind direction. Both types of turbine use rotor blades to convert wind energy into mechanical power for electrical generation. Horizontal-axis turbines require less maintenance and are more efficient at higher speeds than vertical-axis turbines. However, they can only be used in areas with steady winds that aren't too strong or weak. Vertical-axis turbines can operate in much wider conditions than their horizontal-axis counterparts because they don't depend on the direction of the wind.
More blades on a wind turbine mean greater torque and thus greater power production. However, too many blades may also cause other problems such as reduced efficiency due to drag or damage caused by high-speed collisions with birds.
Wind turbines can revolve either a horizontal or vertical axis, with the former being older and more frequent. Most feature a gearbox that converts the slow revolution of the blades into a faster rotation appropriate for driving an electrical generator. The direction of rotation can be clockwise or counter-clockwise.
Generally speaking, the answer is yes, you can rotate a wind turbine. There are two types of rotational mechanisms used in wind turbines: direct drive and gear driven. Direct drive mechanisms use coulters or other components to contact the surface of the blade as it turns, preventing it from moving further but allowing it to continue turning. Gear driven mechanisms use gears or other components to increase the speed of one part of the machine while reducing the speed of another. Both types of mechanism can be rotated in either direction, although they will usually be found on wind turbines that are designed to run counter-clockwise when viewed from above.
There are several reasons why you might want to rotate a wind turbine. The most common reason is if its position is limiting its effectiveness. For example, if it can only turn in a small area because of trees or buildings nearby, it would be better off in a different location. Rotating it so it can take advantage of longer, less obstructive runs is always a good idea.