Quantifying the economic feasibility of solar irrigation in sub-Saharan Africa

An erratic water supply is a limiting factor for crop production. In several world regions, switching from rainfed to irrigated agriculture has allowed farmers to increase production robustly and stabilise agricultural yields. Yet, in sub-Saharan Africa - the world region with the fastest demographic growth - extensive rain-fed still agriculture accounts for more than 90% of agricultural land, more than one-in-six people are undernourished, and electricity access mostly lacks in rural areas. Previous assessment revealed significant solar irrigation technical potential in the region thanks to the large availability of water supply sources and high solar irradiance. To assess the economic feasibility of this large-scale transformation, here we conduct a high-resolution assessment of solar irrigation solutions, comparing system costs with potential revenues. We estimate and locate the share of rainfed cropland in SSA could be equipped with solar irrigation while ensuring groundwater sustainability and calculate the relative payback time. In addition, we estimate how and to what extent the transition could positively impact food security, in term of kilocalories, and protein and fat grams per capita per year. Our analysis supports public and private actors working along the water-energy-food-economy nexus wishing to identify economic feasibility areas, quantifying the potential net economic benefit of developing solar irrigation, and fostering investment for a synergetic achievement of the Sustainable Development Goals.