A vertical wind-driven electricity generation device is described, which utilizes a unique segmented Savonius rotor and which is easily handled, transported, assembled and maintained, even by a single person. The blades of the rotor are segmented into a plurality of modest size blade pair segments, each of which comprises two (or optionally, three or four) low height, helically curved blade portions. The blade pair segments are preferably of the same height and diameter. The rotor is mounted on a central vertical shaft connected to a generator. When the plurality of blade portions are installed on the device's central shaft, the overall blade configuration functions as an unitary Savonius rotor. Flow of gas (normally air in the form of wind) causes the segmented Savonius rotor to move, turning the shaft and rotating member of the generator to rotate, causing the generator to generate electricity.