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 How long does it take for a turbine to 'pay back' the energy used to manufacture it?
The comparison of energy used in manufacture with the energy produced by a power station is known as the 'energy balance'. It can be expressed in terms of energy 'pay back' time, i.e. as the time needed to generate the equivalent amount of energy used in manufacturing the wind turbine or power station.
How safe is wind energy?
Wind energy is one of the safest energy technologies. It is a matter of record that no member of the public has ever been injured during the normal operation of a wind turbine, with over 25 years operating experience and with more than 70,000 machines installed around the world.
How big are they?
Large modern wind turbines have rotor diameters ranging up to 65 meters while smaller machines (around 30 meters) are typical in developing countries. Towers range from 25 to 80 meters in height
How does a wind turbine make electricity?
The simplest way to think about this is to imagine that a wind turbine works in exactly the opposite way to a fan. Instead of using electricity to make wind, like a fan, turbines use the wind to make electricity.
Almost all wind turbines producing electricity consist of rotor blades which rotate around a horizontal hub. The hub is connected to a gearbox and generator, which are located inside the nacelle. The nacelle is the large part at the top of the tower where all the electrical components are located.
Most wind turbines have three blades which face into the wind; the wind turns the blades round, this spins the shaft, which connects to a generator and this is where the electricity is made. A generator is a machine that produces electrical energy from mechanical energy, as opposed to an electric motor which does the opposite
How strong does the wind have to blow for the wind turbines to work?
Wind turbines start operating at wind speeds of 4 to 5 metres per second (around 10 miles an hour) and reach maximum power output at around 15 meters/second (around 33 miles per hour). At very high wind speeds, i.e. gale force winds, (25 metres/second, 50+ miles/hour) wind turbines shut down.
How fast do the blades turn?
The blades rotate at anything between 50-10 revolutions per minute at constant speed. However, an increasing number of machines operate at variable speed.
How much space do wind turbines require?
The wind is a diffuse form of energy, in common with many renewable sources. A typical wind farm of 20 turbines might extend over an area of 1 square kilometre, but only 1% of the land area would be used to house the turbines, electrical infrastructure and access roads; the remainder can be used for other purposes, such as farming or as natural habitat.
To obtain 10% of our electricity from the wind would require constructing around 12,000 MW of wind energy capacity. Depending on the size of the turbines, they would extend over 80,000 to 120,000 hectares (0.3% to 0.5% of the UK land area). Less than 1% of this (800 to 1,200 hectares) would be used for foundations and access roads, the other 99% could still b used for productive farming. For comparison, between 288,000 to 360,000 hectares (1.2-1.5% of the UK land area) is covered by roads and some 18.5 million hectares (77%) are used for agriculture.
How long do wind turbines last?
A wind turbine typically lasts around 20-25 years. During this time, as with a car, some parts may need replacing.
The very first of the mass-produced turbines celebrated its 20th birthday in May 2000. The Vestas 30kW machine has operated steadily throughout its lifetime, with none of the major components needing to be replaced.
How efficient are wind turbines?
The theoretical maximum energy which a wind turbine can extract from the wind blowing across it is just under 60%, known as the Betz limit. However the meaning of efficiency is a redundant concept to apply to wind energy, where the fuel is free. The primary concern is not the efficiency for its own sake, but to improve productivity in order to bring the price of wind energy down.
How much of the time do wind turbines produce electricity?
A modern wind turbine produces electricity 70-85% of the time, but it generates different outputs dependent on wind speed. Over the course of a year, it will generate about 30% of the theoretical maximum output. This is known as its load factor. The load factor of conventional power stations is on average 50%.
Could I put a turbine in my garden or on the roof of my house?
More and more householders, communities and small businesses are interested in generating their own electricity by using small scale wind turbines, either on their roofs or in their back gardens. With AES wind turbines it is possible to have a wind turbine right in your backyard or garden or on your rooftop. |