A method and apparatus for control

A method of controlling the connection of a collection of a plurality of electricity providing devices to an electrical power network is described. In this, the plurality of electricity providing devices having a communication line therebetween and the method comprises receiving a message at a first electricity providing device from a controlling device and, in response to the message: connecting the first electricity providing device to the electrical power network; and sending, from the first electricity providing device to a second electricity providing device, a second message containing data in response to which the second electricity providing device is connected to the electrical power network.