There are times when the source will use up fuel but do no useful work. These cases are handled in physics in the study of thermodynamics when waste is defined. The energy associated with the position of an object in the field of a force. The first potential energy that we define is gravitational potential energy but potential energy can be defined for any conservative force and its associated field. A force for which the work done in moving an object from one place to another does not depend on the path taken from point A to point B .
Gravity is such a force.
A force for which work done depends on path taken as the force moves an object. Friction is such a force. The rate at which work is done. That is power is a measure of how much work is done by a source in each second . This raises the possibility that no work is done if there is no displacement and there is no work done if the force is perpendicular to the displacement .