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 the inventions for optimizing wind turbines devised by Peder Bay Enevoldsen, 44. The teeth are either manufactured as an integral part of the rotor blade or can be retrofitted using glue to improve older blades' performance. They can increase the energy output by up to four percent per year. Enevoldsen works for Siemens Wind Power in Brande/Denmark.