Synergies between Renewable Energy and Water Management Systems - A Systems Perspective on Resilient Irrigation in Rwanda

Abstract

Abstract Water, energy and food systems are essential for human development and modern life but face growing, complex and overlapping challenges under climate change. This thesis examines these issues in a case study in eastern Rwanda, focusing on irrigation and water purification under climate change. A linear optimisation model was developed that sized and determined operation for cost-effective electrified irri gation systems using two different set-ups. One set-up combined solar photovoltaics and bio-diesel generators. The other set-up used only solar energy. Both met energy demand sustainably but the bio-diesel system was more cost-effective and flexible. The results showed that slightly oversizing the system enabled water purification at lower cost than separate sizing of each system. Climate change modelling cases revealed cost increases of up to 6% for irrigation alone and 23% when combined with purification. This highlights the need for strategic resilience planning. Fur thermore, prioritisation strategies strongly influenced system performance when not adapted to climate change. The findings highlight that sustainable electrified irri gation is achievable. Although integrated designs and careful trade-off navigation in the Water-Energy-Food Nexus remain critical under climate uncertainty, broader challenges, including infrastructure, materials, and political factors pose other pressures regarding these systems.