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WES Windfacts
On this page you will find general information about wind energy. Click on the questions below to read the answers.
Q) How does a wind turbine make electricity?
Q) What influences the output of the wind turbine?
Q) How much of the time do wind turbines produce electricity?
Q) Two-bladed versus Three-bladed Wind turbines, waht is the difference?
Q) How safe is wind energy?
Q) Local law and subsidies
Q) What advantages do I get if I place the wind turbine?
Q) Do I need permission for placing a wind turbine?
Q) How much wind is needed to produce electricity?
Q) How do I read the characteristics?
Q) How much service cost is there?
Q) If I supply the over production to the grid, will I get paid for?
Q) How much will the power company pay per kWh?
Q) Can I use a wind turbine without a connection to the power grid (electricity network)?
Q) What is the life expectancy of a wind turbine?
Q) Who does the service and maintenance on my wind turbine?
Q) Do I need a grid connection?
Q) Can I use a wind turbine in a diesel-powered grid?
Q) My farm/factory uses a lot of electricity. Can I use wind energy?
Q) I live in a hurricane-prone area. What pre-cautions do I take to protect my wind turbine?
Q) Does the wind turbine switch on and off automatically when the wind speed changes?
Q) Does wind energy have an impact on the environment?
Q) Do wind turbines influence birds?
Q) Do wind turbines frighten livestock?
Q) Are wind turbines noisy?
Q) 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!
Q) 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.
Q) 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 WES18:
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 WES30:
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.
Q) 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?
Q) 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 100.000
operational wind turbines.
Q) 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.
Q) What advantages do I get if I place the wind turbine?
Most imporatnt 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
Q) Do I need permission for placing a wind turbine?
Yes. Please contact your local WESdealer for the details.
Q) 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 [ m/sec]
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Annual production [kWh)
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4,5 |
74.000
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5,5
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130.000
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6,5
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193.000
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7,5
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256.000
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8,5
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313.000
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WES30
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Wind speed
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Annual production
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4,5
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205.000
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5,5
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370.000
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6,5
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560.000
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7,5
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753.000
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8,5
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930.000
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Q) 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.
Q) How much does turbine maintenance cost?
Wind
turbines need maintenance. Service costs for WES turbines are low. The
annual estimated service cost for a WES18 is Euro 1.500 and for the
WES30 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.
Q) 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.
Q) 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, your local WESdealer can help to make calculations.
Q) 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?
Q) What is the life expectancy of a wind turbine?
Most medium to large wind turbines have a life expectancy of 20 years.
Q) Who does the service and maintenance on my wind turbine?
When
you purchase a WES wind turbine from a cetified WES dealer, you can
enter into a service contract with the WES dealer 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 dont have to worry
about keeping track of the maintenance. For most wind turbine owners
this is the preferred method.
Q) Do I need a grid connection?
Most wind turbines 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.
Stand-alone:
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 genrator use grid frequency to control energy production.
Q) 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.
Q) 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 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 set up.
Q) 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.
Q) 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.
Q) 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.
Q) 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.
Q) 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.
Q) 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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