Integrated scenario analysis under energy, water and decarbonization stress: the case of Rwanda

Compounding crises increasingly expose hidden fragilities in socio-technical systems. At the same time, they generate political momentum and practical urgency for institutional and governance innovation, as emergency measures often become prototypes for routine practice. This paper develops a national-scale, multi-sector water-energy-emissions (WEE) scenario model for Rwanda and uses it to test how demand growth, hydrological stress, and supply-side choices jointly shape future energy security and emissions trajectories through 2050. Water enters the framework in two directions: as a determinant of energy supply, through the translation of river-discharge seasonality and drought stress into monthly hydropower availability, and as a consumer of energy, through the electricity required to supply, distribute, and treat water and wastewater. The analysis shows that, under SSP2 and especially SSP5 growth conditions, emissions remain strongly demand-driven; therefore, even ambitious demand-side and supply-side measures are best interpreted as pathways that moderate, rather than fully reverse, emissions growth. A scenario decomposition further indicates that demand-side energy efficiency is the single most influential lever, while supply-side measures primarily reshape the electricity mix and system resilience rather than aggregate emissions. The contribution of the study is to identify which combinations of efficiency, electrification, renewable deployment, thermal retirement, water-service efficiency, and hydrological risk management most effectively reduce system stress and improve resilience under compound crises.