An electrical generation system is based upon sail craft that move between towers through wind power. The system includes at least two support towers (or support structures on buildings, for example), and upper and lower cables extending from one tower to another. At least one sail craft is coupled to the upper and lower cables such that wind moves the sail craft along the cables. Each sail craft is coupled to the upper and lower cables with respective upper and lower modules, one or both of which includes a wheel that rotates as the craft moves along the cables. The wheel is coupled to an electrical generator that that feeds one or both of the cables for further distribution through at least one of the towers. A structure at each tower causes the craft to reverse its direction and travel back and forth between the towers in such a way that sail craft travelling in opposite directions to not block the wind to other craft.