A crucial factor affecting the energy yield of a wind turbine, besides air density and wind speed, is the rotor swept area over which the wind flows. This swept area, in turn, is determined by the length of the rotor blades. The industry trend is clearly heading in the direction of longer and longer rotor blades. The Siemens rotor consisting of three 75-meter rotor blades has a diameter of 154 meters and covers a surface area of approximately 18,600 square meters, equal to about two and a half soccer fields. The Siemens 6 megawatt wind turbine will generate about 65% more energy using the 75-meter rotor blade compared with the Siemens 3.6 Megawatt bestseller using the earlier blade with a length of 58 meter.
Dong Energy ordered a total of 300 6-megawatt wind turbines featuring the record rotor measuring 154 meters in length. These wind turbines are to be installed in wind power plants off the British coast between 2014 and 2017.
Developed in 2017, the STI-H250™ is consists of two linked torsion beams that rotate simultaneously following the sun's path. They are moved by just one motor, cutting supply and maintenance costs. STI-H250™ dual-row tracker includes backtracking mode to avoid shadowing between adjacent rows and stow function to protect the tracker in extreme wind conditions. For cleaning, vehicles can pass between trackers and each row can be placed in a different position.