Abstract: A power apparatus comprising an input connectable to a mains electrical supply; an energy storage device; a supply converter selectively connectable to an electrical supply to convert electrical power from the electrical supply to energy for storage in the energy storage device; a load converter arranged to convert energy from the energy storage device to electrical power for supply to an electrical load; an output, selectively connectable to either of the input or the load converter, by which the electrical load is coupled to the apparatus to receive electrical power; and a control device, coupled to a communications network, configured to: receive, from the communications network, time-dependent electrical pricing data associated with the mains electrical supply; determine a schedule using at least the received time-dependent electrical pricing data for each of (i) charging the energy storage device, (ii) supplying power from the input to the output, and (iii) discharging the energy storage device to the ou