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.
Eliminate Solar Rack Ballast and Reduce Rooftop Material Handling. PowerGrip™ Universal (PGU) is a commercial roof mount system designed to secure solar racks and other equipment to any type of commercial roofing system. PGU provides a secure connection directly to the roof deck or structural members and is designed to reduce or eliminate ballast in solar racking systems, so there's less weight on the roof and less material handling. Made of heavy-duty cast aluminum, PGU units include a base ring which is secured through the roofing cover and into the structural roof deck, and a waterproof top plate.