вЂњWe like to think of the controller as essentially the brain of the system,вЂќ said Pao, senior author on the study and fellow at the Renewable and Sustainable Energy Institute (RASEI). Key to PaoвЂ™s innovative contributions are improvements to the controller-the part of the turbine that determines when to be more or less aggressive in power production. The inconsistency of wind speed has plagued wind energy since its inception the lost time spent shutting down the system leads to less energy generated and less efficient production. When gusts are too fast, they can push the limits of a turbine's capacity, causing it to shut down to avoid a system overload. When wind speeds are too low, a turbine canвЂ™t produce a useful amount of energy.

One of the trickiest elements of wind energy generation is dealing with not enough or too much wind at one time.

Bottom: Lucy Pao at the NREL Flatirons Campus, with the SUMR-D directly to her right. Top: A close-up of the 53.38 kilowatt demonstrator (SUMR-D) at the National Renewable Energy LaboratoryвЂ™s (NREL) Flatirons Campus, just south of Boulder, Colorado. Hurricane activity this year in the Atlantic is predicted to be above average, with NOAAвЂ™s Climate Prediction Center estimating up to six major hurricanes with winds of 111 mph or higher from June 1 to November 30. Climate change not only demands that we quickly scale up more cost-effective and reliable renewable energy, but rising global temperatures are also likely causing hurricanes to intensify. This innovative work couldnвЂ™t come at a better time. That way, we can reduce the cost of the blades and bring down the cost of energy,вЂќ said Mandar Phadnis, lead author on the new study in Proceedings of the 2022 American Control Conference, and a graduate student in electrical, computer and energy engineering. вЂњThe blades are manufactured to be lightweight and very flexible, so they can align with the wind loads. They found that their turbine performed consistently and efficiently during periods of peak wind gusts-a satisfactory result. On June 10 at the American Control Conference, the CU researchers presented results from a new study of four years of real-world data from testing their 53.38 kilowatt demonstrator (SUMR-D) at the National Renewable Energy LaboratoryвЂ™s (NREL) Flatirons Campus, just south of Boulder, Colorado. Over the past six years, in conjunction with collaborators at the University of Virginia, the University of Texas at Dallas, the Colorado School of Mines, and the National Renewable Energy Laboratory, PaoвЂ™s team has collaborated to develop the SUMR (Segmented Ultralight Morphing Rotor) turbine, a two-bladed, downwind rotor to test the performance of this lightweight concept in action. These downwind blades can also then bend instead of break in the face of strong winds-much like palm trees. This means they can be lighter and more flexible, which requires less material and therefore less money to make. Turbine blades on downwind rotors, however, face away from the wind, so thereвЂ™s less risk of them hitting the tower when the winds pick up. It requires a lot of material to build these relatively thick and massive blades, which drives up their cost. Traditional upwind turbines face the incoming wind, and to avoid being blown into the tower, their blades must be sufficiently stiff. вЂњWe are very much bio-inspired by palm trees, which can survive these hurricane conditions,вЂќ said Lucy Pao, Palmer Endowed Chair in the Department of Electrical, Computer and Energy Engineering. To make those turbines more hurricane-resilient, a team of CU Boulder researchers are taking a cue from nature and turning the turbine around. Off the east coast, where offshore turbines are located in the U.S., increasingly powerful Atlantic hurricanes pose risks to the structures themselves and to the future of wind energy. TodayвЂ™s offshore wind turbines can tower more than 490 feet above ground, their spinning blades churning out up to 8 megawatts (MW) each-about enough to power 4000 homes in the U.S.Д«ut with their increasing size comes challenges. From left to right: Lucy Pao and Mandar Phadnis of CU Boulder, and Dan Zalkind (former graduate student of PaoвЂ™s) of NREL.

Banner image: Researchers at the NREL Flatirons Campus, posing in front of the two-bladedВ SUMR-D in the background.

Palm trees image with copy space