Mechanical energy storage for groundwater pumping in rural areas of Uganda: A review of flywheel technologies and the potential of spring-assisted systems

Energy and water access are interdependent challenges for rural development in Sub Saharan Africa. In Uganda, over 90% of the rural population lacks electricity, forcing groundwater pumping to rely on manual boreholes and unsustainable mechanised solutions. Diesel pumps have high fuel costs and emissions, while solar battery systems suffer from short battery life, expensive replacements, and maintenance difficulties. This paper reviews mechanical energy storage technologies for groundwater pumping in rural Uganda, focusing on flywheel energy storage systems (FESS), spring assisted mechanisms, and human powered conversion. The review analyses low speed steel flywheels suitable for local fabrication, spring assist principles (up to 18.2% energy savings), and human power feasibility (25–100W). Uganda specific data (groundwater depth 5–15m, rural grid access 5.2%) and economic analysis set design requirements: 5–10L/min at 10m head, battery free operation, local maintenance, and affordability. The synthesis reveals a critical gap: no study integrates flywheel kinetic storage, spring assist energy sustainment, and manual human input into a single rural water supply system. This gap is addressed by a conceptual framework grounded in local availability, affordability, and maintainability. A systematic development plan (design optimisation, prototype development, field deployment, and scaling) is outlined to guide future research and deployment.