Apparatus and method for generating power

An apparatus (100) couples to a vehicle (101) movable in relation to a medium (103). The vehicle (101) comprises a vehicle wheel (105) attached to an axle (107). The apparatus (100) comprises a driving wheel (110) configured to couple to the vehicle wheel (105) or to a vehicle axle (107) or to couple directly to the medium (103); a generator (120) configured to generate electrical power based on a rotation of the driving wheel (110), wherein the vehicle wheel (105) rotates upon a motion of the vehicle (101) as consequence of a friction of the vehicle (101) with the medium (103); a battery (130), configured to store the generated electrical power; and a control unit (140) configured to transform the generated electrical power to a predetermined level used for charging the battery (130).