Rehabilitation and hybridization of the Semonkong hydropower plant in Lesotho

The Semonkong hydro plant rehabilitation and hybridization project represents a critical energy infrastructure initiative for the remote highland town of Semonkong in Lesotho. Commissioned in 1990, the 190 kW Francis turbine plant has faced significant operational challenges, including reservoir siltation, vandalism, and difficulty adapting to variable river flows and electrical demand. Following flood damage in 2021, the plant has remained out of operation, with the community currently relying entirely on diesel generation. Under the World Bank-funded Lesotho Renewable Energy and Energy Access Project, Multiconsult assessed rehabilitation options and proposed hybrid energy solutions integrating hydro, solar PV, and battery storage systems. This hybrid approach, optimized using the MultiFlow tool, enhances reliability, reduces reliance on diesel, and allows for flexible, demand-driven operation. Modelling shows that combining technologies reduces both storage requirements and operational costs, and ensures year-round energy access. This experience could offer a blueprint for other remote African settlements seeking sustainable and resilient electricity solutions.