Walalera Power Supply Feasibility Study.

EFOD West Midlands have been asked by Jenga Uganda
( Link to their website ) to consider the provision of
mini hydro power for the benefit of the community of Walalera,
a village set in a cwm 500m above Mbale on Mount Elgon.

Walalera is a trading centre with a population of 1000 with no electrical power, an Irish potato store and a potable water supply just about to be commissioned. A 75mm diameter pipe drawing water from the north hills above the village provides water for this and several other nearby settlements. The original request was to try to generate power from the water supply pipe, but this would only be possible when water is being drawn.

The main road through the village.

A couple of streams to the south of the village flow down the nearby rock slopes, and pass through the village all year round, before flowing down the slope beneath the village. It could generate power to provide light throughout the trading centre, and possibly to gind maize and to pulp coffee cherrys in season. All local produce is currently moved in sacks on the back of motorbikes down to Mbale for processing, before returning to Walalera, together with petrol & kerosene for sale in local stores. The provision of power would save fuel for transport and lights, improve safety, and possibly grind crops. A possible project for EFOD from water flowing down the hillside all year round?

There is a need for a visit to establish a likely power demand for the community, and and to set up a flow monitoring system for the water courses. At least three visits of EFOD volunteers in pairs will be necessary.

Pipe under construction.

Here is a simple power demand estimate :

For lighting - there are thought to be 1000 residents - so at eight per family - about 125 houses. With possibly 25 businesses this suggests 150 buildings. At six LED lights per building at 5w, we'd be looking at generating 4.5kw for around six hours - and 27kwh batteries are expensive! - so is it possible to store water to release on demand?.. In terms of grinding and pulping, we need to assess a power demand - grinding & pulping would occur in daylight, so this would not be in addition to the lighting demand. The work is to assess the viability of mini hydro provision and to estimate its cost of provision, operation and power distribution to the user.

So the question to address is this - is hydro power from the streams viable?

The picture above was taken the day after the rains began in April 2016, showing the stream flowing from the hills above the village. I was advised that the water is slightly contaminated, and so unsuitable for drinking and unlikely to be needed for other use. The water flows constantly through the village, obviously more in wet season. The 2016 dry season was very dry, the rains came late, arriving on 6th April - they normally arrive in mid March. This suggests river flow all year round is realistic, but an assessment will be necessary to establish both dry and wet weather flows to see if there is an adequate baseline flow to power mini hydro.

This needs to be compared with the provision of say 150 mini solar sets, one for each property. These can be purchased for 300,000 ugx
( £ 10,000 ) plus fitting for each. An example kit is shown below :

There are obvious restrictions here. Whilst such an installation will provide light for two to three years, the durability of the battery needs to be considered. The likelyhood of recipents selling the system for gain also needs to be considered. In addition to this we'd ideally need power for grinding, although a small water mill may be viable for this. The Jenga Charity have a staff of 30 locals and about ten expats, so any provision here should be well maintained, and EFOD would have support during research, installation and for subsequent maintenance.

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