Wikipedia’s entry for the Gorlov Helical Turbine explains that the design was originally designed for use in tidal and in-stream hydro applications. Nevertheless, the design has been frequently adapted for use in wind energy since the early to mid-2000s. One example is Quiet Revolution.
The helical rotor design is reputed to reduce or eliminate the torque ripple encountered in traditional two-blade Darrieus or eggbeater turbines.
Because of its dramatic aesthetic appeal, the helical or Gorlov rotor has become the preferred wind turbine design by architects when adding architectural features to their buildings or development sites.
In the US, the addition of a wind turbine to a building or as part of a building’s development gives the building design extra “points” toward its LEED certification. Architects seeking LEED platinum are notorious for adding small wind turbines—often helical—as an architectural element or kinetic sculpture.