This book describes how a model for optimizing the energy supply system in Germany can be implemented. It focuses on the open energy modeling framework (Oemof) program for modeling energy supply systems. The individual elements of Oemof are described, as well as the model’s structure. The technical components of Oemof are subsequently demonstrated in mathematical calculations, along with sufficient Python code to begin basic modeling. The book will appeal to anyone with an interest in optimization models for energy supply systems, or in the mathematical description of the technical components of such systems in practical implementation, using a real example, Oemof. Thermodynamic descriptions of combustion are provided, so that readers can focus on modeling aspects. Researchers and practitioners will also find the book useful, as it expands on their knowledge of the technical components of energy supply systems, supported with detailed mathematical calculations.