Figure 2 shows typical consumption profiles of flexible European household appliances [3] and their adaptation to a typical renewable energy production profile by decentral energy management. Appliance flexibility depends on their available storage capacity, e.g. thermal storage in cooling devices, and customer flexibility, i.e. openness of users to provide a longer time window until dishes are removed from a dish-washer to provide the opportunity to shift the cleaning process in time. The use of such energy flexibility allows to use more renewable energies while respecting typical use constraints.

At the left-hand side, a regular two-point control maintains the temperature in the hot-water buffer in a given range. At the right-hand side the controller also receives and reacts to a price signal (BI). In summer (only hot water) heat pumps shift operation to times of maximum PV production. They learn attractive activation price ranges. Appliances with only partly filled thermal buffers react first due to their limited flexibility. As operation control occurs in real time, control power can also be provided: If power balance is disturbed e.g. by cloud moving over the PV panels, heat pumps switch off immediately of operating parameters (such as minimum run-time) permit. The CHP plant shifts operation to evening hours with highest energy import and reduces its output such that it can run once every day at highest return (lowest BI, highest price).

As little heat is needed in summer, grid stabilisation effect is visible but small. During winter season operating times are substantially longer, with a much larger grid-supporting effect of intelligent operation. The combined effects of large energy demand by heat pumps and similarly large supply by CHP leads to a more stable “price”. This is equivalent to a smaller and more uniform grid load with a BI close to zero, expressing maximum autarky. Coupling the different heating subsystems thermally would even enlarge this effect.