A Viability Analysis of Multipurpose Dam System in Rwanda - Renewable Energy for Irrigation, Electricity and Clean Water

Abstract

Abstract In Rwanda, where agriculture accounts for a quarter of the national GDP, improv ing productivity is essential due to limited opportunities to expand cultivated land. In parallel, expanding access to both electricity and clean drinking water remains a central development challenge. National strategies promote a diversified energy system, with off-grid solutions widely encouraged for rural electrification. This the sis investigates the feasibility of implementing a multipurpose dam system that supports irrigation while simultaneously enabling electricity generation and water purification through an integrated infrastructure. The analysis is based on a case study conducted in Tabagwe, Rwanda. A linear optimisation model was developed to identify the most cost-effective setup of the multipurpose dam in the focus area. The result showed that a multipurpose dam providing irrigation, electricity, and clean water could be a viable solution for Tabagwe. These functions can be adapted to local needs and economic conditions. The most advanced configuration offered electricity access of 1 kWh capacity, available for at least 8 hours per day, sufficient to power appliances such as a refrigerator, fan, or television. It also provided 50 litres of clean water per person and was nearly 60% more expensive than the pri mary setup. The primary setup delivered the same amount of clean water but only provided electricity under 0.012 kWh for around 4 hours per day, enough for lighting and phone charging. UV water purification was technically feasible without system resizing, but its high capital cost made the solution financially demanding. At the same time, the system demonstrated substantial solar surplus energy, highlighting the potential to integrate alternative water purification technologies with higher en ergy requirements but lower costs. Further investigation into how this surplus can be better utilised or stored could enhance overall system efficiency. be better utilised or stored could enhance overall system efficiency