What do dinosaur tails have to do with the rotor blades of wind turbines? It’s very simple: Serrations on the trailing edges of rotor blades reduce noise and increase wind turbine efficiency, and the jagged edges make the blades look a little like dinosaur tails. These serrations are only one of Peder Bay Enevoldsen’s (44) inventions for optimizing wind turbines.

Working with real objects is very important to this inventor from Brande, Denmark. “I’m not the type of person who only fiddles around at a computer,” he explains. He invented his “dino tails,” i.e. the flexible serrated design for the trailing edges of rotor blades — which also look like giant saw teeth — twelve years ago. The teeth are either produced with the rotor blade in one part or they can be affixed on elder rotorblades in order to improve them. Their size along the edge of the rotor blade is variable and depends on the length of the rotor blade. Even though other producers had experimented with saw-toothed designs for reducing noise, no one had realized before that serrated edges could improve performance. Actually, he too was simply looking for a way to reduce the noise generated by wind turbines. Noise reduction solutions are important for onshore wind turbine facilities. Thanks to the development of new high-performance turbines, rotor blade tips can reach speeds of 350 kilometers per hour. But turbines with traditional rotor blades are too loud for onshore installation. So Enevoldsen finally had the chance to test his designs. However, testing made it clear that the “dino tails” were doing a lot more than just greatly reducing the noise. “We also routinely measured the efficiency of the turbines. When we found that it was unexpectedly high, we were delighted,” he says. There was a four percent improvement in energy production per year — a substantial increase for a wind turbine. One of Enevoldsen’s English colleagues christened the rotor blades with the serrated edges “dino tails” the first time he saw them. This is only one of Enevoldsen’s 21 inventions for optimizing wind turbines. He holds 53 individual patents in 21 patent families.

Enevoldsen considers his contribution to the fabrication of rotor blades to be much more important than his dinosaur tails. “It’s really exciting to develop a new production method from scratch. That’s a much bigger challenge than optimizing existing processes,” he says. Using the patented integral blade process, Siemens Wind Power was the first company in the world to successfully manufacture an entire blade in one piece, made of balsawood and fiberglass-reinforced epoxy resin. These rotor blades can be up to 75 meters long, and they are significantly more robust than traditional blades because they don’t have seams or adhesion points. Enevoldsen’s other inventions include improvements in rotor blade design and ways of increasing the overall output of an entire wind farm by optimizing the interaction between the individual wind turbines.

Enevoldsen has always been fascinated by wind energy. This fascination is a bond he has with Henrik Stiesdal, the wind turbine pioneer and current Chief Technological Officer of Wind Power. Stiesdal hired Enevoldsen right out of college, 19 years ago. The company that Stiesdal was in is now a part of Siemens Wind and Power. Like Stiesdal, Enevoldsen is an inventor who focuses strongly on practical applications. He still recalls a certain Christmas holiday during his student days, when he constructed an experiment dealing with water flow in the basement of his parent’s house. “My father, a fisherman, looked at me and said, ‘Anyone can see that the water will go in this direction. You don’t have to go to college to know that.’” Enevoldsen often went to sea with his father to fish. “But I discovered that this job was too exhausting for me,” he says, smiling. He is still an avid sailor and surfer, though. “You've got the wind in your hands. It’s a perfect situation for thinking about wind power,” says Enevoldsen, who believes that wind power has a bright future. He is convinced that wind turbines will continue to be improved and that one day soon wind power will be competitive with fossil fuel-based power. His career has also clearly not suffered from the fact that he has only worked part-time for years. “My wife is a doctor and we have three children. That means we have to be well organized to make sure everything’s properly taken care of,” he says. ​