The adjustment of the angle of a wind turbine in the front row can significantly dampen the wake effect on the fans in the back row, thereby boosting the overall power output of a wind farm by 28-47%, according to a study from Stanford University.
A major flaw of the existing mainstream blade-type wind turbines is the lower power-generation efficiency of the back-row fans, which is generally 40% lower than that of the front-row fans. This is mainly because of the blockage of wind by the latter fans, which is known as the "wake effect."
To dampen the wake effect, the site of the individual wind turbines will need to be very far away from each other. This not only expands the overall space that is necessary for the wind farms, but also boosts the costs of the cables.
As a result, there have been various efforts in recent years to find an alternative method for alleviating the wake effect, including the proposal by a research team at the University of Texas at Dallas that calls for the determination of an optimal revolution speed for turbine blades via the simulation of a computerized model.
The approach of the Stanford University team is actually quite simple, as it only proposes to slightly slant the fans in the front row to avoid the direct impacts of the upcoming wind. This helps to reduce the wake effect on the back-row fans, and can boost the overall power output and generation efficiency of the wind farm. A field test at a wind farm in Alberta, Canada, shows that the approach can augment the total power output of the wind farm by up to 28-47%.
The Stanford team’s findings and statistics can all be found in the "Proceedings of the National Academy of Sciences" journal.
(Collaborative media: TechNews, first photo courtesy of Thomas Kohler via Flickr CC BY 2.0)