A method and system of controlling the time dependent transfer of electrical power between a first electrical network and a second electrical network is disclosed. The first electrical network is operable to provide instantaneous electrical power to the second electrical network located at a location, the second electrical network includes electrical generating capacity at the location based on stored energy accessible at die location. The method and system involves receiving at the second electrical network pricing information from the first electrical network, the pricing information associated with the future supply of electrical power by the first electrical network to the second electrical network and then modifying substantially in real time the transfer of electrical power between the first and second electrical networks in accordance with the pricing information and the electricity demand characteristics of the location.