A power distribution control system having a string of power assets comprising at least two different power assets selected from sources, stores and responsive loads is disclosed. The assets and associated local routers communicate with a central server and attempt to fulfil high level aims of the server by negotiating times and quantities of power transfer between themselves. Preferably a database stores parameters in relation to the power assets. Preferably a control system at the server anticipates future activity, such as future peaks in demand or supply, in the grid, and local power assets prepare in response. Preferably the power assets communicate between themselves on a peer-to-peer basis and collectively confirm to the server their ability to modify their collective behavior in response to an event in the grid.