The invention relates to a method of carrying out heat-consuming processes, wherein the total energy required averaged over a year for the heat-consuming process originates from at least two different energy sources, where one of the energy sources is an electric energy source whose power varies in the range from 0 to 100% of the total power required, and three different energy modes can individually provide the total power required for the heat-consuming process: (i) exclusively electric energy, (ii) a mixture of electric energy and at least one further nonelectric energy source or (iii) exclusively nonelectric energy, where the changeover time in which the change from one energy mode to another energy mode is completed is not more than 30 minutes.