Technical and Economic Feasibility of Solar Pump Irrigation in the North-Niayes Region in Senegal

Northern Niayes is an area where agriculture is the main activity. Water used for irrigation in this area comes exclusively from groundwater. Farmers do not have access to electricity, thus fuel is the main source of energy used, which is very expensive. The objective of this study was to assess the techno-economic feasibility of solar irrigation pumps. Regarding technical feasibility, pump sizing was carried out on the basis of irrigation management, irrigation techniques, and water distribution. Also, the economic feasibility was studied on the basis of the Net Present Value, Benefit-Cost Ratio, Internal Rate of Return and Payback Period. Results showed for cultivated area ranging from 0.05 ha to 1.91 ha, pumps’ flow rate does not vary greatly from one irrigation technique to another. It varies between 2.5 m3/h and 31 m3/h. However, pressure and power are higher when using drip and sprinkler irrigation techniques, ranging from 27.8 m to 39.9 m for drip and 40.1 m to 58.5 m for sprinkler irrigation. The power varies between 0.05 kW and 1.6 kW for manual, between 0.05 kW and 2.5 kW for drip and between 0.1 kW and 4.75 kW for sprinkler irrigation. The investment cost is variable (669 euros to 21,400 euros), depending on the cultivated area, pump brands and characteristics, and irrigation techniques. Results show that the investment cost ranges from 669 euros (438,500 CFA) to 4090 euros (2,683,000 CFA) when using the manual irrigation technique, from 1281 euros to 20,600 euros when using the drip irrigation technique and from 819 euros to 21,403 euros when using sprinkler irrigation technique for individual pumps. The investment cost is higher when using reservoirs. In this case, the investment cost varied between €722 and €6062 for manual irrigation, €1532 and €25,882 for drip irrigation and €900 and €28,000 for sprinkling. However, the total investment cost at the entire lowland scale is higher when farmers use the pumps individually and lower when farmers use the pumps in groups when using manual and drip irrigation techniques. NPV varies between 15,993€ (0.75 ha) and 103,139€ (1.41 ha) and between 13,064€ and 86,139€ when using sprinkler irrigation techniques with PVC pipes and when using the drip irrigation technique, respectively. BCR is estimated to average 2.2, 2, and 2 respectively when using manual, drip, and sprinkler irrigation techniques. In addition, PBP is reached more rapidly when using the manual irrigation technique.