Wind energy is the conversion of the kinetic energy of the wind, by the use of wind turbines, into mechanical energy which is then converted into electricity. Mechanical energy is simply created when the wind turbine blades spin and a generator is turned, thus producing electricity. The result is a green renewable energy ready for us to use. The wind renewable energy, compared to conventional energy produced by installations such as coal, oil and natural gas, produces no greenhouse gas emissions or other harmful emissions during operation.
Although a wind turbine can produce electricity on its own (usually in order to provide
electricity to an individual company or house), wind energy is usually produced by wind farms. A wind farm is a large collection of co-located wind turbines covering an area of several square kilometers. A wind farm is usually connected to the electricity power transmission systems network, whereas an individual wind turbine installation (or a small number of wind turbines) is not. There are two types of wind farm installations, the onshore wind farm installations and the offshore wind farm installations. Onshore wind farm installations are located in land while offshore installations are located in the sea (usually up to 30m water deep). Offshore wind turbines can produce more power than an onshore wind turbine but this comes at a much higher cost, making the onshore solutions more preferable. However due to the evolution of the technology and other environmental issues it is projected that the offshore installations will expand faster in the future.
Wind turbines sit on top of towers at around 80-100m high (offshore wind turbines
are even higher) in order to take advantage of the higher and more constant wind speeds usually found at higher altitudes (due to the reduced influence of drag). The blades begin to spin when the wind reaches 7,5-9,5 miles/h and keep spinning up until 50-55 miles/h at which point the wind is considered too strong. The ideal location would be a place with constant wind flow free of turbulences or other powerful wind bursts. Modern wind turbines blades are controlled by computer controlled motors and are optimized so that they always face the wind irrelevant of its direction, thus sustaining high performance for longer periods of time.
United States is the leader in the deployment of onshore wind energy installations,
whereas Europe is the leader in the deployment of offshore installations. The largest onshore installed project is the Roscoe Wind Farm in US consisting of 627 wind turbines in an area of 400Km2 producing a total of 781,5MW. The largest offshore installed project is the Thanet Offshore Wind Project in the United Kingdom with 100 wind turbines, located 11Km from the shore covering an area of 35Km2 and producing a total of 300MW.
The main advantage of wind power is apparent to all. It is the production of electricity from natural resources, without any impact on the environment (greenhouse gas emissions), in an effort to become more self-sufficient and improve sustainability. The main drawback of the wind energy is the level of noise created from the wind turbines when they spin in order to produce electricity. This drawback is mainly related to the onshore wind farms particularly in densely populated areas. However, in modern wind
turbines the level of noise created from the mechanical parts has been largely reduced leaving only the aerodynamic noise created from the rotating blades. The other major drawback is related to the negative visual impact the wind turbines create in an area. For the offshore installations this drawback is affecting only touristic areas, largely because all offshore installations are near the coast (in less than 30m water deep).