Vertical-Axis Wind Turbine

A vertical axis wind turbine, or VAWT, is a wind turbine whose main rotor shaft stands upright, transverse to the wind, with its generator and other heavy components mounted at the base of the machine rather than high in a nacelle, unlike the horizontal axis design used by most wind turbines today. Because its shaft is already perpendicular to the wind from every direction, a vertical axis turbine needs no yaw mechanism to turn and face changing wind, unlike a horizontal axis turbine, though early Darrieus and Savonius designs, patented from the 1920s onward, struggled with torque ripple and blade fatigue that limited their reliability. The tallest vertical axis wind turbine ever built, at Cap-Chat in Quebec, Canada, stood 110 meters tall and produced 4 megawatts of power, and recent research, including a 2024 study by the National Renewable Energy Laboratory building a full scale prototype, has found that vertical axis turbines arranged together in a wind farm can generate more than 15 percent more power per turbine than an identical turbine operating alone. Vertical axis designs remain a minority of installed wind capacity worldwide but continue to draw research interest for their mechanical simplicity and ground level maintenance access.