An industrial-scale wind turbine is a lot bigger than one you might see in a schoolyard or behind someone's house. The blades sweep a vertical airspace of just under an acre. (Turn the page for great pictures!)
An industrial-scale wind turbine is a lot bigger than one you might see in a schoolyard or behind someone's house. The widely used GE 1.5-megawatt model, for example, consists of 116-ft blades atop a 212-ft tower for a total height of 328 feet.
The blades sweep a vertical airspace of just under an acre. The 1.8-megawatt Vestas V90 from Denmark is also common. Its 148-ft blades (sweeping more than 1.5 acres) are on a 262-ft tower, totaling 410 feet. Another model being seen more in the U.S. is the 2-megawatt Gamesa G87 from Spain, which sports 143-ft blades (just under 1.5 acres) on a 256-ft tower, totaling 399 feet.
Many existing models and new ones being introduced reach well over 400 feet high, the higher towers and extra-long blades being necessary to turn the generator in sites with lower average wind speeds.
The steel tower is anchored in a platform of more than a thousand tons of cement and steel rebar, 30 to 50 feet across and anywhere from 6 to 30 feet deep. Shafts are sometimes driven down farther to help anchor it, and mountain tops have to be blasted for it. The platform has to stabilize the immense weight of the turbine assembly. The gearbox -- which transforms the slow turning rate of the blades to a faster rotor speed --and the generator are massive pieces of machinery housed in a bus-sized container, called the nacelle, at the top of the tower. The blades are attached to the rotor hub at one end of the nacelle. Some nacelles include a helicopter landing pad. On the GE 1.5-megawatt model, the nacelle alone weighs more than 56 tons, the blade assembly weighs more than 36 tons, and the tower itself weighs about 71 tons -- a total weight of 164tons. The corresponding weights for the Vestas V90 are 75, 40, and 152, total 267 tons; and for the Gamesa G87 72, 42, and 220, total 334 tons.
Besides the noise and vibrations such huge moving machines unavoidably generate, they must be topped with flashing lights day and night to increase their visibility.
This information was taken from here and presented to the Ellis County Zoning Board in March 2007 in regard to the proposed Hays Wind Farm to be constructed west and south of Hays, Kansas.