Abstract: A self-contained device for self-service delivery of electrical energy, comprising a plurality of terminals, each capable of being connected to an electrical appliance, and a central management unit, operable independently of the terminals. The central management unit serves to: (1) manage distribution of electricity from an electrical supply grid to each of the terminals, (2) manage interaction between a prepayment instrument and users of the terminals, and (3) manage connection of the terminals to the electrical supply grid for transmission of electricity therebetween for either a period of time or a quality of electricity, as determined in response to a signal from the prepayment instrument indicating prepayment by a user.