Alternative Energy Tutorials on Energy Articles

Wind Turbine Generation

How much electricity does a wind turbine generate is one of the main questions asked by homeowners looking to buy a wind turbine generator. While wind turbine generators are environmentally friendly generators that generate electrical energy using wind power, The type of turbine generator, its blade design and efficiency are all factors which determine its annual power generating performance. Location, wind speed, rotor diameter and variable speed designs for small and mid-size wind turbines all affect its power output. Accurate data of wind speeds and direction throughout a yearly cycle will help in understanding the operating characteristics of a wind turbine allowing for a better purchasing choice

Wind power and the environment continues to be a discusion as we use the renewable energy sources available within the environment to power our lives. While wind power is a clean, sustainable and accepted alternative to burning fossil fuels, the environmental imapact of wind power on wildlife and their natural habitats must be taken into consideration when siting a new wind farm. Wind farms built for the production of electricity have the potential to impact the natural and urban environment affecting birds, bats and other fauna and flora at a specific site

Airborne wind energy uses tethered wings, aerofoils, kites or ballons that fly high up in crosswinds to generate electrical energy. Unlike grounded wind turbines, airborne wind energy devices fly freely in the air connected by a tether to the ground exploiting the relative velocity between the crosswinds and the ground. The force of the wind in higher altitudes above the ground are typically much stronger and more consistent than those closer to the ground so using airborne wind energy devices makes it possible to obtain very high power densities

Wind Energy is the largest form of renewable energy generation with hundreds of giga-watts of electrical energy being generated around the world every year. But in order for wind turbine generators to generate such vast quantities of this free and sustainable energy, there has to be some wind. Wind turbines have been around for many years, with their energy capture design, efficiency and reliability improving dramatically. Ideally the rotational speed of wind turbines is almost constant and limited to a narrow range of wind speeds. So ensuring that their is enough wind speed at any given location is important for energy production

Induction generators are electrical machines used in wind turbine and hydro turbine applications to generate electrical energy.
Wind turbines operate over a wide range of wind speeds so any electrical generator attached to the turbines blades must also be able to operate at a variable rotational speed. Induction machines are asynchronous generators meaning that when it is driven or rotated at a higher speed than its synchronous speed, that is the rotational speed determined by the frequency of the supply, its torque will be negative so starts acting as a generator rather than a motor. Then operating an induction machine as a generator it is necessary to turn the machines rotor faster than the synchronous speed

Induction generators are squirrel caged machines responsible for transforming the kinetic energy of the wind into electrical energy. Three-phase induction machines have three electrical windings embedded into its stator so are well suited for wind power and even hydroelectric power generation. Induction machines, also known as asynchronous machines, rotate above synchronous speed when used as an electrical generator producing 3-phase AC electricity. As an induction generator can be synchronised directly with the main utility grid supply, it produces electricity at the same frequency and voltage.

Synchronous generators require an external DC power supply to be applied to the main rotor windings by means of slip-rings and carbon brushes in order to produce a constant magnetic field basically making the main rotating part (the rotor) of a synchronous machine into a large electromagnet. The rotor is rotated by the external wind turbine blades connected to it creating a rotating magnetic field within the generators body. Electrical copper windings are incased into the stationary part (the stator) of the synchronous generators body and are the main windings where the voltage is induced. So by varying the amount of rotor field current, it is possible to vary the staors output voltage.

Permanent magnet DC generators, or PMDC machines, can be used as either conventional motors or as DC wind turbine generators as constructionally there is no basic difference between the two. In fact, the same PMDC machine may be driven electrically as a motor to move a mechanical load, or it may be driven mechanically as a simple generator to generate an output voltage. This then makes the permanent magnet DC generator (PMDC generator) ideal for use as a simple wind turbine generator. The two basic connections for a permanent magnet DC machine are shunt wound and series wound, with each type of DC generator having its own set of advantages and disadvantages.

Wind turbine generators for wind power applications can vary from a small DC voltage dynamo to large AC mains rated synchronous machines. The type of electrical machine used to generate the electrical energy depends alot on the size, complexity and dynamics of the wind power as small machines can operate suscessfully in small-scale home or garden based generating applications with steady state wind conditions, whereas larger machines may be required to supply several households in windy mountainous areas or offshore conditions were the voltage and frequency of generated electricity may need to be synchronised before it can be transferred and used by the grid.

Wind turbine design for wind power applications involves understanding the basic concepts about aerodynamics, mechanics, structural theory as well as the flight mechanics of fixed-wing and rotary-wing blades. People think that the design of a wind turbine is straightforward, erect a pole or structure, add a generator to the top, and connect some blades to it. But the cost of generating electrical power from wind energy is linked to its design, efficiency and reliability of the turbine.

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