A power generation system for the production of electric power or the accomplishment of other work objectives utilizes kinetic energy derived from the action of the force of gravity on a vehicle that is allowed to move along a power generation path having a downward grade. A tether cable connects the vehicle to a tether member that moves along a downhill line in response to the movement of the vehicle along the path, and the movement of the tether member operates a gearing mechanism that operates a machine to accomplish the work objective.