Examples of loads whose power consumption can be varied are speed-regulated heat pumps or battery charge controllers for electric cars. Heating elements, for example for hot water preparation, often have discrete switching states for their power consumption; they have a regulatable power consumption, but only with due regard to the possible power steps. In the industrial sector too, variable loads exist, for example speed-regulated compressors for compressed air stores.
Known solutions to this optimization problem are associated with considerable numerical complexity. An example that may be mentioned is DE 10 2010 042 172 A1, which relates to a method for operating a controller for a domestic appliance on an energy supply system with an associated data network, wherein transmitted data from the energy supply system need to be taken into account for simultaneously available setting data for the domestic appliance. In order to determine manipulated variables for actuators of the domestic appliance, a computer executing a graph algorithm, for example Dijkstra's algorithm, is needed.
In order to map a regulatable energy draw for a load by means of the algorithms cited in DE 10 2010 042 172 A1, a multiplicity of auxiliary variables would need to be introduced, which increase numerical complexity immensely.
There is therefore a need for methods with low numerical complexity that allow an operation of a load with a variable power consumption at optimum cost in the case of multiple energy sources being available to meet the demand for this variable power consumption, especially when these multiple energy sources have different tariff structures and possibly also a different temporal availability.