Micro Power Plant at Marangu Hotel, Kilimanjaro

Abstract

Development of micro-hydropower schemes in rural areas of developing countries is largely depended on simple and affordable systems. The contra-rotating pipe turbine, produced by GreenEnergy is a one-piece and easily operated turbine, designed as the Rolls-Royce of turbines with good operational qualities. Suitable for low head sites, this turbine is easily installed in existing plants, for minimum passage flows or independent schemes supplying electricity to rural areas.The contra-rotating prototype will now be donated to a site in a developing country and the river Una, near Marangu Hotel in Tanzania has been chosen as a potential site. Thereby the turbine could produce clean and needed electricity, and at the same time test its versatility and easy operation.Field work was performed in Tanzania in February, to gain necessary groundwork for this thesis. A proper site review was conducted with a focus on head and distance measurements of the potential scheme. An introduction to the local conditions, both technically and socially was also in focus.The contra-rotating prototype was tested in the Waterpower Laboratory, to assess the condition after the generator upgrades performed by BEVI. Results showed a disappointingly increase of efficiency at design operation. This might imply an inaccurate position of the runner and generator hubs. A full scheme design is presented with all components necessary in addition to an economical review and evaluation local conditions. Designed scheme has a goal of easy operation and minimum maintenance demand, which has been ensured by installation of a Coanda intake and simple control system.Hydrological data of the area has been assessed from data of a nearby area, from a PhD thesis on the hydrological study of the area. This turned out to be one of the large uncertainties presented in this project. The adapted data gave a low expected river discharge, compared to what would secure a sustainable installation.Further progress is now dependent on the partners involved, especially GreenEnergy. Eventual future activities will require thorough discharge measurements from Una.