An assessment of hydrokinetic potential in the Maputo Basins, Mozambique

Abstract

In Mozambique, access to modern energy services in the form of electricity has been limited to most of rural population. 6% of the rural areas are electrified, the country is large with widely dispersed mostly rural populations (70%) and no ambition grid extension plan can reach the entire country in short and medium term. The government of Mozambique has growing interest to promote the use of small hydropower for isolated rural communities. The potential of small hydropower plants is 1000 MW, of which 2.63 MW have been exploited. Hydrokinetic turbines can play a pivotal role in providing electricity access to remote areas, as stand-alone isolated mini-grids. Hydrokinetic turbines convert the energy in moving water into mechanical and electrical energy. The study was done to assess energy generation based on hydrokinetic turbines in the main hydrological basins (Umbeluzi, Maputo and Incomati) of Maputo Province. Frequency analysis using historical data of river streams velocity to generate velocity duration curves (VDC) in excel tool, characterized the rivers flow. Comparison of velocity of the stream versus the design velocity of the hydrokinetic turbine and comparison of the rotor diameter of hydrokinetic turbine to the depth of the river evaluated the feasibility for installation in Maputo main basins. Extractable power was evaluated for stations, which satisfied the minimum requirement water depth considering each technology development. The results show that low flow velocities, hence no considerable potential sites for installations of hydrokinetic turbine, characterize the rivers basins. However, 2.061 kW can be extracted from Maputo River, at western border using ducted. Additional 870 W can be extracted in Maputo main course at Madubula, using dual axial turbine (Under Water Electric kit).