MEGA currently has an installed 60kW micro-hydro generator and more than 280 customers connected with some 20km of mini-grid distribution.  The micro-hydro generator uses water from the Lichenya river, and the mini-grid is centred in GVH Bondo on the southern side of Mount Mulanje. 

Figure: Schematic of a micro-hydro power system

The micro-hydro generator is a run-of-the-river scheme. This type of scheme requires no water storage but instead diverts some of the water from the river which is channelled along the side of a valley before being ‘dropped’ into the turbine via a penstock pipe. The Lower Bondo system operates with 300 litres/second of water with a head of 50 metres. The weir is a permanent concrete structure and the channel is some 600 metres long. The turbine is a three-jet pelton wheel manufactured in Zimbabwe. The system is regulated by an electronic load controller that monitors demand and dumps excess power.

The mini-grid network consists of medium voltage (11 kV) transmission and four substations distributing three-phase power at 400 V. The substations are strategically placed at centres in the village; Bondo has a relatively high population density. The powerhouse is 8 km from the National Grid, though the mini-grid extends to within 3km at the closest point. 

Download the file to view the mini-grid in Google Earth. 

Each customer has a pre-payment meter and top-ups up with tokens from MEGA’s vending system. The tariff is higher than from ESCOM, the National Utility, to reflect the high cost of doing business and relatively low demand of rural customers.

MEGA has been issued both a Generation and a Distribution license from MERA and is compliant with national grid codes.  

A second generator of around 100kW is being installed and will be operational in 2017.  Grid densification and extension is ongoing, with a target of 400 new connections by 2018.

Learn more about the technology 

Micro-hydro power Technical Brief

Micro-grids Technical Brief