Last Friday I highlighted an extreme form of wind power, flying windmills. This update from MIT's Technology Review shows how the state of the art of stationary windmills is advancing, with power output increasing from under 4 MW per turbine to nearly 7 MW. There is a direct relationship between wind turbine size, power output, and the cost per kilowatt-hour of the electricity generated, and the industry has made great strides moving down this curve. Unfortunately, there is another curve that wind developers must keep in mind: the relationship between wind turbine size and negative public perceptions.
While Europe has forged ahead with wind technology as its fastest growing new electricity source, many US wind projects have been delayed or derailed due to public objections against the intrusion of windmills in favored viewscapes. These clashes are unfortunate, because they divide supporters of the environment over a technology with fewer environmental drawbacks than most other ways to generate the electricity we all consume so eagerly. But even in areas that are more receptive to wind power and its visual profile, there must surely come a point at which bigger is simply too big, regardless of its other benefits.
The trick will be finding the optimal size at which power output is high, cost low, and public acceptance good. As wind turbines approach blade diameters of 140 meters (460 feet--more than twice the wingspan of a Boeing 747), we can't be too far from that point. Finding the right balance is important, if wind power is to remain as a viable alternatives to more coal- or gas-fired power plants and and their associated emissions, greenhouse and otherwise.