The three-bladed egg-beater turbine looks like the standard FloWind machine, but is elongated to 178 feet tall. It was partially developed using Department of Energy funds at Sandia National Laboratories. The elongated design is more elliptical in shape than previous FloWind machines but still has a 17 metre rotor diameter, thereby achieving a greater swept area without diminishing the number of machines that can be installed on a site, says FloWind.
The San Rafael-based company maintains that VAWTs are cheaper to manufacture. It says there is less blade mass, no yaw mechanism is required, the machine can accommodate wind blowing from any direction and the drive-train, generator and gearbox are located in a box on the ground for easy maintenance. Since the turbine is also secured at the ground and the top by guy wires, less overall mass is required and there is greater structural reliability.
FloWind says that at least one bird study suggests that VAWTs kill fewer birds than horizontal-axis turbines on lattice towers. The 17 EHD has a cut-in wind speed of 10 mph, a cut-out wind speed of 60 mph, a survival wind speed of 130 mph, a rated power of 300-375 kW, and fail-safe redundant brakes.