A flowchart of a process plant is compiled by linking graphical process objects representing operator-controllable and observable facilities of the plant when planning a process plant, wherein the process in the process plant is simulated with reference to simulation models assigned to the graphical process objects during a simulation phase, where simulation models include energy consumption models that describe the electrical energy consumption of the respective facilities to be described as a function of measurable or known process variables in the plant and hence enable simulation and optimization of the automation with respect to electrical energy consumption and energy efficiency.