What is Wind?

The Earth is surrounded by air, which is made up of a mixture of gas, liquid particles and solids. Cold air contains more air particles than that of warm air, causing it to sink through the atmosphere, which in turn creates areas of high pressure. Warm air rises through the atmosphere and creates areas of low pressure. The air tries to balance out the areas of high and low pressure, and this movement of air is known as wind

What is a Wind Turbine?

A Wind Turbine is a machine that is made up of a foundation, a tower, a nacelle and a rotor. It is used to convert kinetic energy into mechanical or electrical energy. Please refer to the below image as to how a Wind Turbine looks like.

wind turbine diagram

Nacelles contain the primary parts of a Wind Turbine, such as the gearbox, axle, transformer, generator and control system. Rotors are made up of the blades and the hub, which holds the blades in the position that they will turn. In general, most commercial wind turbines have 3 rotor blades (as demonstrated in the diagram above).

Want to learn a little more about Wind Turbines? Take a look at the following interactive diagram below, courteousy of European Energy Association.

What are Wind Turbines made of?

The blades of the turbines are usually made of either reinforced polyester, fiberglass or wood-epoxy. The towers are usually made of either concrete or steel, tubular in shape and mostly painted light grey. Light grey is often used due to the inconspicuousity under most lighting conditions. Finishings are usually matte, to decrease the amount of reflected light.

How big is a Wind Turbine?

On average, the size of onshore wind turbines are around 2.5 - 3 MegaWatts (MW). Offshore wind turbines currently reach just over 6 MW, with a rotor diameter of approximately 120 meters.

How efficient are Wind Turbines?

Wind Turbines generally start operating around wind speeds of 4-5 meters per second. Maximum power of a Wind Turbine is reach at 15 meters/second. Wind Turbines cannot function and will shut down during periods of very high wind speeds, such as for example during gale winds, which are around 25 meters/second. Modern Wind Turbines can produce around 70-85% of the time, but output is dependent upon the wind speed.

How are wind farms designed?

A few factors need to be considered when designing a wind farm. One main factor to consider is that the area that is desired for the wind farm should be as wide and open as possible in the prevailing wind direction, with as minimum of obstacles as possible. The turbines must also be easily accessible for maintenance and repair. Noise levels can be calculated as well so that they fall within the levels of sound that are required by national legislation.

The type of wind turbine selected is all dependent upon certain conditions such as the landscape where the wind turbine is to be located, the wind conditions, the noise levels, the national/local rules on the heights of the wind turbines, how easily can it be transported to the site location, the possibility of earthquakes occuring at the farm location, etc.

How long does it take to design a wind farm and how much does it cost?

Construction of a wind farm can take about 2 months for a 10 MW wind farm and around 6 months for a 50 MW wind farm.

The actual costs in building a wind farm vary. However, the major cost is for the wind turbine itself. This is typically a capital cost and usually is paid for upfront and may account for roughly 75% of the costs.

How does a Wind Turbine produce electricity?

Wind pass over the blades, creating a lift, which causes the rotor to turn. Once the blades start to turn, it turns a low-speed shaft within the nacelle. The gears within the nacelle connect the low speed shaft of the rotor with a high speed shaft that in turn moves the generator. As the shafts continuing spinning, it drives the generator to produce electrical energy. Electricity within the generator is then transported to a transformer which converts the electrical energy into the right voltage required for the electrical grid.

How much electricity can one Wind Turbine produce?

Electrical output of a wind turbine depends on the wind speed and the size of the turbine. Wind Turbines manufactured today have an output range anywhere between 250 watts and 7 MW.