An electrical power generating system includes a wind deflecting structure having a contour at a proximal end formed by a plurality of sail segments that in a first position define the contour, a turbine positioned in proximity to a distal end of the wind deflecting structure such that the turbine is driven by wind passing around the wind deflecting structure, and an energy converter coupled to the turbine that converts rotary motion from the turbine into electrical energy, wherein at least one of the plurality of sails is movable between the first position defining a corresponding portion of the contour of the wind deflecting structure and a second position that reduces a wind drag coefficient of the wind deflecting structure.