Optimal Sizing of Solar Water Pumping System for Small Scale Irrigation: Case Study of Dangila

Abstract

The diesel driven water pumping systems have a great impact on irrigation in remote areas around the world. However the gradual increase of fuel prices worldwide and high maintenance cost discourages the utilization of the technology. Therefore, it is important to think of an alternative energy source for such application. The optimal sizing of this PV water pumping provides theoretical studies of photovoltaics and modelling of electric power requirement for powering pump to irrigate crops as an alternative to diesel technology. The analysis employs determining the optimum tilt angle of solar panel which can collect the maximum solar energy when irrigation water demand could be higher based on seasonal Variation. The irrigation requirement has been determined by combining climate inputs, hydrology, crop type and developing stage, soil type, moisture and irrigation method etc. at each time stage of irrigation period. The power requirement has been analysed using dynamic programming by relating hydraulic load with the solar radiation energy from the solar panel for each decadal irrigation period. The maximum power has been minimized so as to select the power which can satisfy all irrigation periods with reduced cost of PV system. Furthermore Pumps (Centrifugal surfaces) with high discharge and low heads are selected to minimize water cost for such application as surface water sources from rivers and ponds are mostly applicable for irrigation in Ethiopia.