Validating PyPSA for Generation Expansion Planning: A Comparative Study with Microsoft Excel and HOMER

Generation Expansion Planning is a critical aspect of energy system planning to ensure the sustainability of energy supply. While various tools such as HOMER, PLEXOS, and Microsoft Excel have been widely used, their limitationssuch as cost and scalability-have prompted the exploration of alternative solutions. This study introduces PyPSA (Python for Power System Analysis), a free and open-source tool, as a flexible and effective alternative for both multi-period and single-period investment planning. Validation compares PyPSA results with Excel Solver for multi-period cases and HOMER for single-period cases, showing an error value of below 0.45 percent in each comparison. These findings demonstrate that PyPSA produces consistent and accurate solutions, offering a cost-free open-source option for energy system planning. This study serves as a reference for researchers and practitioners considering PyPSA as a viable GEP tool.