Yesterday, we visited the Danish Technical University's Large Turbine Test Center, a facility on Denmark's western coast that gives Siemens, Vestas, and other wind turbine manufacturers a place to test their new, large turbines that can generate a megawatt or more. The center has five permanent towers in a location with known good wind characteristics, so if a company wants to test a new generator type or new blade configuration, they can just bring a crane out and lift it on, rather than finding a site, pouring a foundation, and constructing a tower.
The wind turbines of the Large Turbine Test Center
To find all the power characteristics of a wind turbine, the engineers need to figure out its reaction to all possible wind conditions, so they need to use instruments to measure the temperature, pressure, and relative humidity of the air throughout the test period, as well as the exact wind speed and direction. For older turbines, it was sufficient to measure the air at the hub and assume it would be the same for the whole turbine area. However, modern turbines can have rotors that more than 100 meters (325 feet) in diameter! The wind can change a lot with a three hundred foot difference in altitude, so the Test Center has several meteorological masts that have arrays of instruments at various heights, to get a wind profile for the full height of the tallest turbines.
a 150 meter (500 ft.) tower with instruments on it at 10 meter (33 ft.) intervals.
Today, we followed up yesterday's visit by traveling to the Offshore Test Center, a brand new facility for testing turbines intended for installation in the open ocean. With no obstructions to the wind (or neighbors to complain), these turbines can be larger than their onshore cousins, and the two installed here are the largest in the world. Their rotors are 150 meters (500 ft.) in diameter, and they each generate 6.5 megawatts, enough to power more than 1500 homes. Though the rotors appear to be moving slowly, the tips are slicing through the air at more than 260 feet per second, or 178 mph.
The largest wind turbine in the world