Renewable energy potential for irrigation in Kilombero

In May 2012 MSABI initiated a research project in partnership with the Tanzanian Rural Energy Agency (REA).  The aim of the project is to evaluate the potential of solar powered water extraction for irrigation of rural agriculture in Kilombero.  Specifically we want to understand the costs and logistics associated with importing equipment to Tanzania, and to evaluate performance of the solar equipment in the field, to provide data that can be used for a cost benefit analysis for this method of irrigation for small scale farmers.

Selection of solar pump & panel equipment

There is great potential for irrigation to improve the livelihoods of Tanzania's subsistence farmers.  In the Kilombero Valley a shallow water table and plentiful ground water resources mean that with access to simple, cheap, sustainable irrigation technologies, small-scale farmers may be less dependent on seasonal rains for crop growth, more versatile in the range of crops they can cultivate, and more resilient to unpredictable seasonal variation due to climate change.  

Abundant tropical sunlight is readily available, and this wonderful natural resource can be harnessed in a clean, safe, sustainable manner for the benefit of rural Tanzanians.

The approach of the study is to install submersible pumps in MSABI hand-drilled boreholes, using solar power to extract water to the surface, where it can be distributed via an irrigation network – in this case drip tape. 

The first step of the project was to find suppliers and order the pumps and solar equipment for shipment to Tanzania.  The second step was to receive the shipments into Tanzania, and have the equipment transferred from Dar Es Salaam to Ifakara.   This was a long process that provided some interesting challenges, and good learning opportunities.

Consignment landed on the wharf in Dar Es Salaam
Consignment awaiting clearance from TRA

Phase 1 testing involved setting up a closed loop pumping system to confirm the equipment was serviceable and fit for purpose.  This was done in Ifakara, using a nominal pressure head of 4m – meaning the pumps would lift water to a height of 4m, and the volume of water being pumped recorded against the rated capacity of the pump, and the amount of available solar irradiation available at the time of testing.
This first round of testing allows for evaluation of the equipment quality, and helps inform decisions on suitability of each pump/solar panel combination for use in the field.
The photos below show the basic set up of testing in Ifakara, with water being circulated via a 2000l tank, using locally available materials typically used for water distribution in the region.

A flow meter allows water volume measurement
Closed loop pump testing in Ifakara

The second phase of testing has started in Idete, and includes a selection of the equipment and a borehole, allowing evaluation of the performance of the pumps at depth for capacity to lift water.  The volume of water will again be recorded against rated capacity and irradiation.  The irrigation distribution system will be installed shortly and tested to evaluate the suitability of the drip tape under local environmental conditions, and when paired with the solar pump system.

Laying out equipment for installation in Idete
Lotte and some helpers - potential beneficiaries of the project...

Measuring flow rate at the head of the borehole

Testing will continue through March and April, when we look forward to submitting the results to REA for evaluation and feedback.