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 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! |
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What influences the output of the wind turbine? |
- The average wind speed. More wind means higher electricity production. It means both how fast it blows and how often it happens. More important is the average speed than the speed at any given moment.
- The rotor diameter – the area which the blades sweep. The bigger it is, the higher the output.
- The tower height. Wind speeds increase at higher altitudes. So, the higher the tower, the more wind the turbine catches.
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How safe is wind energy? |
| Wind energy is one of the safest energy technologies. No member of the public has ever been injured by wind energy or wind turbines anywhere in the world, despite the fact that there are now over 68,000 operational wind turbines. |
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Two-bladed versus Three-bladed Wind turbines |
People do ask about the difference between two-bladed and three-bladed wind turbines. In general the following is true:
The amount of the blades is not a key factor influencing efficiency of the wind turbine(see: What influences the output of the wind turbine?). A three-bladed wind turbine can be more efficient than a two-bladed wind turbine. This difference is minimal (up to 5%) where the cost of the three-bladed turbine is higher. Three-bladed wind turbines may also need a stronger wind to start turning. Two bladed wind turbines simplify rotor assembly on the ground. Unlike three-blades rotors, two-bladed turbines require only one crane to assemble. |
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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%. |
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Local law and subsidies |
| Many countries and local authorities support and stimulate renewable energy. Please contact your local authorities to check what kind of subsidies or other support you can get from them when switching to wind energy. |
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What advantages do I get if I place the wind turbine? |
There might be various advantages depending on the situation you are in.
- A wind turbine may stabilize an instable grid
- You decrease your diesel need and cost
- You decrease the diesel generator noise
- You decrease your electricity cost
- You produce green energy for a better environment
- You “educate” your community by setting an example of a better environment
There may be more advantages that are not discussed here. Many of them are personal advantages.
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Do I need permission for placing a wind turbine? |
| Yes. Please contact your local authorities for the details. |
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How much wind is needed to produce electricity? |
The WES wind turbines will start to produce at 3 m/s, however, with an average wind speed of 5 m/s it gets economically interesting to produce your own electricity with a wind turbine. Stronger wind produces more electricity. For example:
| WES18 |
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wind speed |
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annual production |
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4,5 m/s |
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80.000 kWh |
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5,5 m/s |
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135.000 kWh |
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6,5 m/s |
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200.000 kWh |
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| WES30 |
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wind speed |
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annual production |
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4,5 m/s |
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200.000 kWh |
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5,5 m/s |
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400.000 kWh |
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6,5 m/s |
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580.000 kWh |
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How do I read the characteristics? |
- Nominal Power is measured in kilowatt (kW) or megaWatt (mW). Nominal power tells the maximum amount energy that the turbine can produce at certain moment.
- Production is measured in kiloWatt hours (kWh) or megaWatt hours (mWh). Production tells you how much energy in total you get from the turbine during for example one year.
- Efficiency tells you how much (kinetic) energy from the wind is turned into electrical energy. The maximum value in the modern turbines is approximately 45 %.
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What does my wind-electricity cost? |
| If we take an average wind speed of 6,5 meter/second, then the cost per kWh for the WES18 (80 kW) is an estimated 8 euro cent and for the WES30 (250 kW) it is only an estimated 5 euro cent per kWh. If you have a refurbished WES wind turbine, the cost per kWh will be at least 50% less! |
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How much service cost is there? |
| Service costs are generally low. The annual estimated service cost for a WES18 is € 750,0 and for the WES30 it is € 2.000,00. |
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If I supply the over production to the grid – do I get paid for? |
| This depends on your local regulations. In most European countries you get paid for the kW that you supply to the net. |
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How much will the power company pay per kWh? |
| This all depends on the country you live in. Many governments have rules and regulations regarding the prices per kWh. This should be checked on an individual basis. |
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Can I use a wind turbine without a connection to the power grid (electricity network)? |
There are two types of wind turbines: grid-connected and non-grid-connected. The grid connected wind turbines are the larger ones that produce electricity. The non-grid-connected are usually the very small wind turbines that charge batteries only. The WES turbines are all grid connected, except for our Hybrid stand-alone Wind/Diesel system.
See: What is a hybrid stand-alone wind/diesel system? |
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What is the life expectancy of a wind turbine? |
| A wind turbines life expectancy is 20 - 25 years. The expected life time of a refurbished wind turbine is another 15 years. |
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Who does the service and maintenance on my wind turbine? |
| When you purchase a WES wind turbine, you can enter into a service contract with either WES or a local service company. The service contract ensures that your wind turbine gets the regular bi-annual service it needs on time and you don’t have to worry about keeping track of the maintenance. For most wind turbine owners this is the preferred method. |
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Do I need a grid connection? |
A WES wind turbine is either grid connected or (together with a diesel generator) stand-alone.
Grid connected:
When connected to the grid (the local electricity network) and “behind the meter”, the electricity will be consumed directly by you at your house, farm or factory. Excess electricity produced will “flow” automatically into the grid. In this case a meter keeps track of your supplied kWh to the grid and your power company will pay you a certain amount of money per kWh (net-metering). This price is usually pre-determined and often regulated by the government. In times of insufficient wind, you will automatically draw electricity from the grid.
Stand-alone:
In this case the wind turbine, together with a controller, will be connected to your diesel generator. Shortage of wind-electricity will be leveled by the diesel generator. Overcapacity of wind energy can either be stored (batteries) or dumped. |
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Can I use a wind turbine in a diesel-powered grid? |
| Yes, WES has installed wind turbines in small “diesel-grids” (grids where diesel generators supply the electricity). A wind turbine is never a substitute for the diesel generator in such a system and it can generally supply up to 30% of the total electricity production. |
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What is a hybrid stand-alone wind/diesel system? |
As explained above, the WES wind turbines and most other wind turbines, need a connection to the electricity grid to be able to function. If there is no power, the wind turbine will stop producing. A hybrid stand-alone wind/diesel system is a wind turbine that is not connected to a grid, but that works together with a single diesel generator. The wind penetration is much higher than the previously discussed 30%. For example: you live in an area where there is no electricity network. You work only with one or more diesel generators that run 24 hours a day. The diesel cost is very high and steadily increasing. The hybrid system will produce most of its electricity with the wind turbine and only in times of insufficient wind, will the diesel generator take over and produce electricity. The advantages are that you safe fuel cost, diesel generator maintenance cost, you have less noise and pollution and the electricity is more stable.
WES is developing such a system now and we expect the system to be ready in the third quarter of 2005. |
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My farm/factory uses a lot of electricity. Can I use wind energy? |
| Yes! As a matter of fact, if there is space to install a wind turbine and there is sufficient wind, then any farm or factory can use a wind turbine. For example: A poultry farmer has a house and a large poultry shed and it consumes 120.000 kWh per year. There is sufficient wind available and the local regulations allow you to use a wind turbine. In this case a WES18 with an 80 kW generator can easily produce 150.000 kWh per year. Enough for your own electricity needs. At times when there is not enough wind, you will automatically draw electricity from the power grid. In this case you only pay the power company for the electricity you take from them and the rest you get from your wind turbine. If you produce more electricity (150.000 – 120.000 kWh = 30.000 kWh) then you can sell the over production to the power company and they will pay you a certain amount per kWh delivered. Many factory or farm owners that use WES wind turbines use such a set up. |
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I live in a hurricane-prone area. What pre-cautions do I take to protect my wind turbine? |
| The WES18 wind turbine can be ordered with a special Tilt-Up Tower. This tower enables you to install the wind turbine without a special crane, but more importantly, you can lower the wind turbine before an approaching hurricane. |
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Does the wind turbine switch on and off automatically when the wind speed changes? |
| Yes, the system is fully automatic. It start automatically when the wind speed reaches at least 3 m/s, it follows the wind direction automatically and it slows down and stops automatically when the wind speeds reach or pass the maximum wind speed. |
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Does wind energy have an impact on the environment? |
| Yes, as wind energy is a clean energy it only has a positive impact! Wind energy decreases the use of fossil fuels, nuclear energy and other polluting energy sources. It also decreases CO2 emissions. |
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Do wind turbines influence birds? |
Many people are concerned about the influence wind turbines have on the safety of birds. Extensive surveys show that very few birds are killed by wind turbines and that they have no influence on the bird migratory routes at all. A study made by Dutch institutions in 1999 (Informatie centrum Duurzame Energie, Vogelbescherming Nederland, het Instituut voor Bos en Natuurbeheer van de Dienst Landbouwkundig) show the following data: |
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Do wind turbines frighten livestock? |
| Wind farming is popular with farmers, because their land can continue to be used for growing crops or grazing livestock. Sheep, cows and horses are not disturbed by wind turbines. |
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Are wind turbines noisy? |
| Wind turbines are not noisy. The evolution of wind farm technology over the past decade has rendered mechanical noise from turbines almost undetectable with the main sound being the aerodynamic swoosh of the blades passing the tower. There are strict guidelines on wind turbines and noise emissions to ensure the protection of residential amenity. It is possible to stand underneath a turbine and hold a conversation without having to raise your voice. As wind speed rises, the noise of the wind masks the noise made by wind turbines. For more information, read the facts about noise from wind turbines or why not visit a wind farm and experience it for yourself. |
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Do wind turbines produce low frequency noise? |
| There is always low frequency noise present in any ambient quiet background and it can be produced by a variety of sources, including machinery, transport and natural sources such as the sea, wind and thunder. It has been repeatedly shown by measurements of wind turbine noise undertaken in the UK, Denmark, Germany and the USA over the past decade, and accepted by experienced noise professionals, that the levels of low frequency noise and vibration radiated from modern, upwind configuration wind turbines are at a very low level; so low that they lie below the threshold of perception. |
We hope that this information has given you a general overview on wind energy |
