Development of a System Model for Low-Cost, Solar-Powered Drip Irrigation Systems in the MENA Region

Drip irrigation has the potential to conserve water and increase crop yields. However, existing drip irrigation systems often require high pumping power, making them financially inaccessible to smallholder farmers. Integrating a holistic system model with a cost-optimization scheme can enable the design and implementation of low-cost, solar-powered drip irrigations systems, ultimately making this technology more cost-effective for smallholder farmers. This paper describes the algorithms comprising an integrated model of solar-powered drip irrigation systems, consisting of agronomic, hydraulic, pump, and power system modules. It also introduces a preliminary optimization scheme for the power system, which uses the system hydraulics and pump curve to select an optimal solar array and energy storage configuration that minimizes capital cost. The system model and power system optimization is applied to three case studies, and the resulting power system configurations are compared to outputs from commercially-available software for sizing solar pumping systems. The results show that the model successfully captures the nuances in crop type, local weather patterns, and hydraulic system layout between different cases. This offers a greater level of flexibility than commercially available software, which tends to have broader applications and focuses on larger systems. Future model generations will add more variables to the optimization scheme — including pump selection, variable emitter flow rates and pipe geometries — to provide a versatile design tool for cost-optimized, solar-powered drip irrigation systems.