Optimization approach for achieving sustainable development goals in agricultural energy-water-food nexus system

Sustainable Development Goals (SDGs) take the global challenges into a new phase, calling for reasonable resources management from holistic perspectives. This study develops a novel integrated modelling framework for sustainable agricultural energy-water-food nexus (EWFN) management, with the objectives of maximum social welfare of water resources allocation, maximum hydroelectric generation, maximum grain crop production, maximum positive farmland ecosystem service value, and minimum negative farmland ecosystem service value. The proposed framework is capable of: (1) balancing benefit efficiency and allocation equity using social welfare function; (2) reconciling conflicting targets among socio-economic, resource, and eco-environmental spheres; (3) generating sustainable water and land resources allocation strategies considering complex and uncertain environment. The optimization model directly contributed to achievement of SDG 2 (food security), SDG 6 (water security), SDG 7 (energy security), SDG 8 (economic growth), and SDG 13 (climate change mitigation), whilst indirectly supported other SDGs by providing safe energy, clear water, and nutritious food, and sustainable management. The proposed model was applied to the Zhanghe Reservoir irrigation area, located in the Yangtze River Basin, central China. Flexible water and land resources allocation schemes among different sectors, crops, and periods were generated, as well as managerial insights into what efforts should be done were provided for decision-makers. After optimization, efficiency-equity tradeoff was balanced with social welfare index reaching [0.94, 0.99]. Optima results show that GHGs emission contributed majority of the total loss, which cannot be totally neutralized by carbon sequestration, causing negative eco-environmental impacts of [2.3, 3.4] ×10⁸ CNY. The proposed model performs well on generating robust and coordinated solutions according to scenarios analysis and models comparison. The proposed approach has potential on achieving SDGs in agricultural EWFN system, and is portable to other agriculture-centered areas suffering from similar resources crisis.