California Institute of Technology researchers believe that a new approach to wind farm design may provide significant efficiency gains. The Caltech team is focusing on the efficiency of the entire wind farm, rather than the efficiency of individual turbines.
John Dabiri, Professor of Engineering and Applied Science, at Caltech observed that "because conventional, propeller-style wind turbines must be spaced far apart to avoid interfering with one another aerodynamically, much of the wind energy that enters a wind farm is never tapped. In effect, modern wind farms are the equivalent of ‘sloppy eaters.’ To compensate, they’re built taller and larger to access better winds."
The Caltech design uses vertical-axis wind turbines placed much closer together than is possible with horizontal-axis propeller-style turbines.
According to Professor Dabiri, this provides several immediate benefits, including effective operation in turbulent winds like those occurring near the ground, a simpler design (with no gearbox or yaw drive), lower costs of operation and maintenance and a lower profile that reduces environmental impacts.
Although vertical-axis turbines are less efficient individually, the researchers initial field data sugests that an entire vertical-axis wind farm can result in a lower total cost of wind energy.
Professor Dabiri says that "Since the basic unit of power generation in this approach is smaller, the scaling of the physical forces involved predicts that turbines in our wind farms can be built using less expensive materials, manufacturing processes, and maintenance than is possible with current wind turbines."