FAQ

You can find the answers to the frequently asked questions on this page. Can’t you find the answer to your question? Don’t hesitate to contact us!

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 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.  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!

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 bigger the rotor diameter, the higher the output.
  • The tower height. Wind speeds increase at higher altitudes. So, the higher the tower, the more wind the turbine catches.
  • Turbine type; downwind or upwind. Most wind turbines face into the wind, these are called “upwind turbines” Turbines that face the other direction are called “down wind turbines”. A downwind turbine produces less energy and wears out faster compared with an upwind turbine. The reason is that the airflow around the tower introduces turbulence.

WES turbines are upwind turbines.

Related entries: Two-bladed versus Three-bladed Wind turbines.

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%.

Example calculation for a WES80:
One year has (24 * 365 hours) = 8760 hours. When full power (= 80kW) can be generated all the time, the theoretical yearly output will be 700.800 kWh. In practice this will be around 30% of this amount = 210.240 kWh.

Example calculation for a WES250:
One year has (24 * 365 hours) = 8760 hours. When full power (= 250kW) can be generated all the time, the theoretical yearly output will be 2.190.000 kWh. In practice this will be around 30% of this amount = 657.000 kWh.

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?).

  • 3- bladed turbines are more expensive.
  • 3- bladed turbines need more wind to start.
  • 3- bladed turbines do not have a passive mechanical pitch system, each blade needs a motor and a computer.
  • Two cranes are needed to install a 3- blade turbine.
  • 3- bladed turbines with active pitch need more energy.
  • 3- bladed turbines can be slightly more efficient (up to 4 %) in the midsection of the power curve.

Related entries: What influences the output of the wind turbine?

How safe is wind energy?

When turbine siting and turbine maintenance are done in the right way 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 100.000 operational wind turbines.

About siting: Finding the right location for your turbine is important, it is important to stay away from any obstacle since obstacles disturb the flow of air and cause extensive turbulence near the obstacle. Wind turbines can deal with some turbulence from time to time without a problem. When a wind turbine is exposed to strong turbulence for a long period of time problems or even damage to the turbine can occur. When turbine siting is done it is important to investigate both the current and future situation.

Local law and subsidies

Many countries and local authorities support and stimulate renewable energy. Please contact your local WES dealer to check what kind of subsidies or other support you can get from them when switching to wind energy.

What advantages do I get if I place the wind turbine?

Most important reason:

  • Wind turbines pay back for them selves in 3 to 7 years. After this period wind turbines generate electricity for many more years without significant costs. Contact your local WES dealer to make a calculation for you.

On top of this there are various other 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

Do I need permission for placing a wind turbine?

Yes. Please contact us.

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.

How do I read the characteristics?

  • Nominal Power is measured in kilowatt (kW) or megaWatt (mW). Nominal power tells the maximum amount power that the turbine can produce.
  • Production is measured in kiloWatt-hours (kWh) or megaWatt hours (mWh). Production tells you how much electrical energy will generate during a period of time. Often the time period is one year.

How much does turbine maintenance cost?

Wind turbines need maintenance. Service costs for WES turbines are low. The annual estimated service cost for a WES80 is Euro 1.500 and for the WES250 it is Euro 2.000. 3- bladed turbines are more expensive to maintain. The down-time for a WES turbine during a maintenance job is limited to only a few hours.

If I supply the over production to the grid, will I get paid for?

This depends on your local regulations. In many countries you get paid for the kWh that you supply to the grid, please consult your local WESdealer he is aware of all regulations and possible future changes.

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, contact us, we can help to make calculations.

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?

Related entries: What is a hybrid stand-alone wind/diesel system?

What is the life expectancy of a wind turbine?

Most medium to large wind turbines have a life expectancy of at least 20 years.

Who does the service and maintenance on my wind turbine?

You can enter into a service contract with a local service company, WES will assist you in choosing the right partner. The service contract ensures that your wind turbine gets the regular bi-annual service it needs on time and you do not have to worry about keeping track of the maintenance. For most wind turbine owners this is the preferred method.

Do I need a grid connection?

WES manufactures grid connected and Hybrid Wind/Diesel wind turbines for off-grid purposes.

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 be fed 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.

Off-Grid: In this case the wind turbine feeds electrical energy into a small isolated grid. Often powered by a diesel generator. WES wind turbine and diesel generator use grid frequency to control energy production.

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 90% of the total electricity production.

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 WES80 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 to 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 setup.

I live in a hurricane-prone area. What pre-cautions do I take to protect my wind turbine?

The WES80 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.

Does the wind turbine switch on and off automatically when the wind speed changes?

Yes, the system is fully automatic. It starts 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.

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.

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.

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.

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. The picture on the right gives an overview of different sources of noise, including a wind turbine (click the picture to enlarge).

Do you have a question? Don’t hesitate to contact us!