Rwanda’s electricity system historically dependent on hydropower, regional imports, and localized thermal generation faces growing pressure from rapid economic expansion and long-term development goals under Vision 2050. This thesis investigates the least cost techno-economically optimal electricity capacity expansion pathway for Rwanda through 2050, while meeting rising energy demand and integrating green hydrogen production for industrial heat. Using the Open Source Energy Modelling System (OSeMOSYS) and the Modelling User Interface for OSeMOSYS (MUIO), a long-term optimization model was developed for the period 2025–2050. Electricity demand was disaggregated into residential (47%), industrial (31%), and commercial/public (21%) sectors and assessed under three GDP driven growth scenarios: Low (7.3%), Medium (10%), and High (12%).