The industrial sector offers a promising potential to reduce its immense need for energy. Many strategies to improve energy efficiency focus on the modernization of existing production systems. However, the most important potential lies in early stages of the production planning. To be able to introduce energy consumption as a decision factor in production planning, a methodology for a generic description of production machines is developed. This is methodology builds the basis for energy simulation models which support the determination of consumption values of alternative processes by the representation of whole production machines.