A wind turbine shaft includes tubes that are centered on a longitudinal axis, coupled to rotate together about the axis, and movable telescopically along the axis between a retracted condition and an extended condition. A mounting structure is configured to mount wind turbine vanes on the tubular structure when the tubes are in the extended condition. A generator has a pair of parts including a rotor and a stator, and is configured for coupling with the tubular structure for one of the parts to rotate about the axis with the tubular structure while the other part is stationary.