One big change in the Midwest landscape I’ve seen on my occasional visits over the last decade: Lots of wind turbines are being installed (hundreds and hundreds of them in Illinois so far, with many more coming). I shot this pair–just off Interstate 80 on the southern outskirts of Geneseo–as we blasted past (my brother Chris was driving) on Labor Day on our way from Iowa City back to the Chicago area.
Chris asked “how much power do those things put out?” My researches have uncovered the following: These two turbines are Vensys 77‘s, each rated with a generation capacity of 1.5 megawatts. How much is that? The math isn’t straightforward: how much power is actually generated depends on weather conditions; the turbines need wind, of course, but they’re apparently also sensitive to high temperatures. In practice, the generators at this site might produced enough power for about 1,000 homes. The city of Geneseo, population roughly 6,500, said before the turbines began operation in October 2009 that it expected the turbines to provide between 12 percent and 15 percent of the electricity the town needs.
And: How big are those things? Big. The rotor diameter, which I take to be the diameter of the circle swept by the turbine blades, is 77 meters. About 240 feet. The top of the tower is about 300 feet.