The Global Energy System Model (GENeSYS-MOD) is an open-source energy system model, originally based on the Open-Source Energy Modeling System (OSeMOSYS) framework. While still part of the OSeMOSYS family of models, various aspects have been redesigned, expanded, or added. GENeSYS-MOD is a linear program, minimizing total system costs. Energy demands are exogenously predefined and the model needs to provide the necessary capacities to meet them. The modeling framework is very flexible in its use cases. Based on research question and input data, calculations can be done from a household-basis to a global aggregation of regions. In essence, GENeSYS-MOD can be