It’s a new version of the old addage: give a man a fish, he’ll eat for a day, teach a man to fish and he’ll fish for a lifetime, teach a man about fish and he may just help revolutionize renewable energy. The lesson a school of fish recently taught to Dr. John Dabiri, head of Caltech’s Biological Propulsion Laboratory, was all about efficiency. Dr. Dabiri was watching how water swirls off fishes bodies when they swim in schools, and he noticed that the water spun clockwise for some vortices, and counter-clockwise for others. And that got him thinking. Maybe there was a way these rotating whirlpools helped the fish gain efficiencies. And, if so, then maybe, just maybe, that organization could help increase efficiency of wind farms, too.
To understand that last leap, it’s important to realize that the windmills currently undergoing this piscivorous transformation are not the typical horizontal-axis turbines that most of us would imagine. Those spin like giant pinwheels, the blades drawing circles perpendicular to the ground. And they take up a lot of space—one of the reasons wind farms are not yet very efficient. The turbines have to be placed far enough apart to avoid blade collision.
But, they also have to be placed far enough apart that they do not interfere with the wind reaching other turbines.
Vertica-axis wind turbines—aka windspires—the kind that Dr. Dabiri is working with, look like giant, elongated egg-beaters, with the blades running vertically, surrounding a central pole. These take up far less space, already an advantage over the horiztonal wind mills. And, if the theory holds, rotating these wind mills in opposite directions might help to increase their efficiency.
Two graduate students in Dabiri’s lab, Robert Whittlesey and Sebastian Liska, have created computer models to test the idea, and found significant energy gains. But the lessons from the deep didn’t stop here. There was another aspect of fish schooling the researchers found useful to mimic: the arrangement of the fish in a “staircase” pattern, as opposed to the typical straight row formation most wind farms employ. Adding in this detail ripped from our aquatic ancestors, bumped up efficiencies even more so.
The results from the models have been significant enough to warrant field tests. The researchers will move around the windspires and test different configurations on two acres of land north of L.A. Here’s to hoping all goes swimmingly, and we can look for some seriously improved wind farm designs in the near future. Thanks to those fishes in the deep blue sea. And to some smart guys who paid some attention to them.
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