global briefs

Hurricane-Resilient Wind Turbines Modeled After Palm Trees

Atlantic hurricanes pose risks to renewable energy wind turbines, and researchers at the University of Colorado-Boulder are developing more resilient models. Lucy Pao, the Palmer endowed chair in the Department of Electrical, Computer and Energy Engineering, says, “We are very much bio-inspired by palm trees, which can survive these hurricane conditions.” Traditional upwind turbine blades face into the wind, so the blades must be stiff, which requires more material and increases cost. Blades on downwind rotors face away from the wind, with less chance of hitting the tower when the winds pick up, so they can be lighter and more flexible, requiringless material. Downwind blades can also bend, instead of break, like palm trees do.

Over the last six years, Pao’s team, 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, have collaborated to develop the Segmented Ultralight Morphing Rotor turbine, a two-bladed, downwind rotor, to test the concept in action. The researchers found that their turbine performed consistently and efficiently during periods of peak wind gusts. Mandar Phadnis, lead author of a study in Proceedings of the 2022 American Control Conference, says, “The blades are manufactured to be lightweight and very flexible, so they can align with the wind loads.”

Common California Bumble Bees Go Missing

The Western bumble bee, once easily spotted in California, could not be found in a recent survey led by the University of California-Riverside (UCR). The first statewide census of California bumble bees in 40 years found several other species absent, as well. UCR entomologist Hollis Woodard’s research group collected bees from 17 sites representing six different ecosystems previously known to host a large variety of bumble bees, as documented in the journal Ecology and Evolution. One of the missing species, the Western bumble bee, is an important pollinator of wild plants and crops. “We didn’t find it, even once,” says Woodard.

This study was an effort to document changes in bumble bee populations across large geographic areas in California since the last one in the 1980s. Smaller-scale studies have documented significant declines in bumble bee populations around the world due to climate change, development of wild habitat and the use of bee-killing pesticides, so it is important to have data that documents bee health. Bumble bees can fly in cooler temperatures and lower light levels than many other bees, helping to pollinate crops worth $3 billion annually in the U.S., including tomatoes, peppers and cranberries.