Abstract: A control device for controlling an energy consumption of a load on an electricity grid includes a sensor for sensing over a period of time values of a physical variable of the grid, where the physical variable varies in dependence on a relationship between electricity generation and load on the grid. The control device also includes apparatus for varying the energy consumption of said load.
Abstract: There is provided an electricity grid, system having a substation connecting two grid parts, preferably at different levels in the grid hierarchy, wherein flow control means is provided for controlling the flow of electricity between the two parts in dependence on the level of stress of the respective grid part of the network.