A downhole tool (100) for wellbore operations comprises a substantially tubular member (130) that is operably positionable in the wellbore and a rotation member (110) that is rotatably disposed within the substantially tubular member (130). The rotation member (110) has a passageway (112) through which objects may pass into the wellbore. The rotation member (110) rotates about an axis of rotation (x) that is substantially perpendicular to the longitudinal axis (y) of the substantially tubular member (130) in response to fluid flow through the passageway (112). The rotation member (110) has magnetic properties such that rotation of the rotation member (110) generates a magnetic field that produces useable power.