As the renewable energy plays a significant role in power generation industry, there are thousands of wind farms around the world. Most of the wind farms adopt horizontal axis wind turbines, but there are also a few wind farms use vertical axis wind turbines. No matter what types of wind turbines they use, one common thing for all the wind farms is they use tall wind turbine towers.
As we all know, higher altitude has higher wind flow rate, and higher wind flow rate brings higher wind kinetic power. To match the industrial electricity generation requirements, the wind turbine towers for industrial wind farm must has a certain height.
Table 1 Wind data and wind turbine tower height
|Height above ground||Mean wind speed||vref||Tower height as number of turbine diameters||Annual production MWh|
Industrial Wind Turbine Tower Height Status
During the last 20 years, the height of industrial wind turbine towers keep increasing constantly. Take some European countries as an example, in 2000, the average wind turbine tower height is 60m in France, Netherlands and Belgium. But in recent years, the average height of wind turbine towers in France, Netherlands and Belgium is 120m.
In 2013, three quarters of the industrial wind turbine systems that installed in Belgium adopts the wind turbine towers with a height that over 100 meters. The same thing happens in 70% of the wind energy generation systems in France.
This trend is definitely mean to happen as people would certainly expect larger wind energy production with the constantly developed technologies. Moreover, as the size of wind turbine rotors keep increasing, and the clearance between ground and the rotor must keep in a certain rate, so the height of wind turbine towers also need to grow.
As the wind turbine tower height keep increasing, the stiffness of wind turbine towers over 100m is a main focus. From the design point of view, as the height of the wind turbine towers increases, the design technology changes to make the wind turbine tower cost effectively. Moreover, onshore wind turbine towers suffer more restrictions than offshore wind turbine towers. For onshore wind turbine towers, the complete transportation is on road, and there are regulation about maximum production weight and dimension to transport. For example, if the wind turbine tower sections need to go through a tunnel, the wind turbine tower diameter must under 4 or 5 meters, or it can not pass the tunnel. But as we all know, when the wind turbine tower height increased, the diameter of wind turbine tower will also increase, so that the wind turbine tower can keep its stiffness. But with the restriction of transportation, the only solution is to reduce the thickness of steel to keep the wind turbine tower diameter. And for the over 100 meters wind turbine tower project, the wind farm owners can still choose a steel and concrete hybrid tower to reduce the construction input.
Highest Wind Turbine Tower In the World
During the last decade, there is a new highest wind turbine tower had been installed in each year. In 2016, a German company had installed a world highest wind turbine tower in Germany which has a total height of 164 meters. This wind turbine tower is a steel & concrete hybrid wind turbine tower with a 100 meters concrete tower and 64 meters steel tubular tower. This hybrid wind turbine tower adopts a rotor with the rotor length of 65.5 meters, and the maximum wind turbine tower height can be 230 meters.
But in the beginning of 2017, a Danish company built a complete steel wind turbine tower to test that if the high wind turbine towers can sustain the vibration of their new wind turbine product. This high wind turbine tower is 220 meters, and with the rotor length of 80 meters.
As the development of wind turbine technology, the vibration of wind turbine will definitely reduce, and the stability of high wind turbine towers will improve significantly. Therefore, there is no doubt that we will see more and more wind turbine towers that over 100 meters later.