Unlike the old-fashioned rural windmills used to pump water, which whipped back and forth with every gust, today's wind turbines rely on an electronic nervous system that allows them to predict the force and direction of the wind up to 24 hours in advance, and adjust the orientation of the rotor and even the pitch of each individual blade in order to wring the maximum energy out of a passing breeze.
Electricity is generated at the top of the windmills, in a boxlike structure called the nacelle, to which the rotors are attached. "The rotors can be as large as the wingspan of a 747," said Jim Lyons, the advanced-technology leader for GE Wind Energy, the biggest domestic maker of turbines. At the bottom of the tower that supports the nacelle and rotor is a cylindrical space housing the computers that collect data from throughout the turbine. The collection of computers is known as a Scada system, for Supervisory Control and Data Acquisition.
The Scada system can supply 200 or more pieces of data related to the turbine's operation, Mr. Lyons said. Information about higher-than-normal vibration levels or oil temperature can alert a wind farm's staff to problems before they happen. Typically, the wind turbines are connected by fiber-optic cable to a control center. Many problems can be solved remotely, but staff members must climb up through the tower to the nacelle on occasion.
