Optimisation of the energy, water, and food nexus for food security scenarios

The food security challenge has become a major concern for many countries and regions in the light of changing climatic conditions, unpredictable political instabilities and increasing consumption of resources. To overcome global food insecurity and doing so whilst conserving natural resources, a holistic energy, water, and food (EWF) Nexus approach is proposed, involving the integration of sub-systems representing EWF resources. However, computational challenges associated with Nexus systems usually hinder the consideration of uncertainties governing the three sectors; therefore, deter the comprehensive modelling of such systems. This study suggests a novel methodology that utilises EWF Nexus thinking to influence decision-making within the food sector and considering uncertainty related to energy prices derived from natural gas. It assesses technology alternatives for a domestic food production case in the State of Qatar based on economic performance quantified using capital and operating costs, in addition to environmental performance represented by Global Warming Potential (GWP). Three different scenarios are evaluated; the first scenario consists of the current state of the local food sector responsible for delivering 22% of the total country requirements from perishable food products; the second scenario is illustrated using an enhanced food profile that can achieve a hypothetical 40% self-sufficiency level from the perishable food demand; and the final scenario suggests a hypothetical EWF Nexus configuration comprised of renewable and non-renewable energy sources coupled with diverse water technologies responsible for securing the desired self-sufficiency level. The final case is assessed using a multi-objective stochastic optimisation aimed at identifying the optimum energy and water mix that investigates the trade-off between the cost and environmental burden of the EWF Nexus proposed, whilst hedging against natural gas prices fluctuations. Findings of this research indicate that diversifying the energy and water mix of the Nexus studied through introducing more than 70% of renewable energy technologies and utilising reverse osmosis reduces the environmental impact associated with these two sectors by 60% compared to current technologies. However, the configuration requires additional investments due to the expensive cost of the technologies deployed, such that $1 invested in operating the hypothetical configuration could yield to 0.019 kg of CO_2eq per year. Despite its high cost, the final scenario exhibits a relatively short payback period compared to the overall lifetime of the system, which deems it a sustainable alternative that can be adopted by the food sector in the future.