electric energy

Electric potential energy, or electrostatic potential energy, is a potential energy (measured in joules) that results from conservative Coulomb forces and is associated with the configuration of a particular set of point charges within a defined system. Not to be confused with the term electric potential (measured in volts), the term "electric potential energy" is used to describe the potential energy in systems with electric fields that change with time (time variant), while the term "electrostatic potential energy" is used to describe the potential energy in systems with electric fields that do not change with time (time invariant).

The reference zero is usually taken to be a state in which the individual point charges are very well separated ("are at infinite separation") and are at rest.[1]:§25-1 The electric potential energy of a system (UE), relative to this zero, is equal to the total work 'W that must be done by a hypothetical external agent in order to bring the charges slowly, one by one, from infinite separation, to the stated system configuration.