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: A method and apparatus is provided in which the use or provision of a resource or service can be optimised based on data indicative of the benefits of using or providing the resource or service at one or more future times. The service could be the provision of electricity to an appliance or device. A retailer or distributor of the electricity could transmit future prices of the electricity based on the expected supply and demand for the electricity. An apparatus could receive the future prices and set a timing of an appliance or device to use or provide the electricity in order to optimise the cost of the use or provision of electricity. Other resources and services are also applicable, such as road network usage, telecoms or gas provision or usage. The usage or provision of the resource or service by the appliance or device can be metered and the amount of resource or service used or provided can be billed using the given indication of a benefit at particular future times, e.g. using the given future prices.

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.

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.