WIND BREAKTHROUGHS

The sight of propeller-like rotating blades positioned high up the pole of a tall horizontal-axis wind turbine (HAWT) may be familiar to many. Often grouped in wind farms, HAWTs provide significant amounts of energy for local communities. One drawback to HAWTs is the large space they take up, needing to be placed far apart from each other. If placed too close together, the turbulence and wind velocity deficit caused by one HAWT can make a neighboring HAWT output much less power. To address this, researchers are looking at vertical-axis wind turbines (VAWTs), which could be either arranged in groups or interspersed within HAWT arrays. A VAWT has an overall cylindrical shape, with the blades aligned parallel to, and rotating around, the pole on which the rotor is mounted. These "egg-beater" VAWTs tend to be much smaller than the "propeller" HAWTs, typically about 10 times shorter in height, and output only about 0.1 percent as much power per turbine.