Water, Energy and Food (WEF) are key elements of economic and social sustainable development, and present a complex nexus. Existed WEF nexus research is mainly confined to qualitative analyses, and it needs constant improvement and increases quantitative analyses. In China, water security is the most prominent problem in the WEF-nexus, which is manifested in the competitive relationship between food and energy production for water. Therefore, the matter of alleviating water resources stress has become a difficult and hot issue. After improving the existed water footprint accounting method for food and energy production, this study calculated the food water footprints (blue water footprint and green water footprint) in the 31 provinces of mainland China in 2015, as well as the blue water footprints of major energy systems (coal, oil, natural gas and thermal power generation). This study proposed water resources pressure index (IWS), water resources pressure contribution rate of food and energy (WCR), water consumption rate of food and energy (n) and competition composite index (CCI) of WEF, which were used to evaluate the consumption of water resources in food and energy production in different regions, and assess the intensity of competition for water resources in food and energy production. The results showed that the national food water footprint in 2015 was 690.8 Gm³, and the blue food water footprint was 287.8 Gm³. The main water-consuming blue energy water footprint was 18.5 Gm³, and coal production accounted for 9.9% and thermal power generation accounted for 87.6%. According to the competition indicators, the competition relationship among the administrative regions of the 31 provinces in mainland China was obtained. For example, 5 provinces had serious competition and 19 provinces had weak competition. The water consumption of the energy industry continues to grow rapidly by economic development. Corresponding measures should be taken according to the different competition levels for water resources.

The widespread uncertainty regarding future changes in climate, socioeconomic conditions, and population growth have increased interest in water-energy-food-ecology nexus-based frameworks in relation to the analysis of water resources. A challenge for modeling the water-energy-food-ecology nexus is how to reduce the multidimensional and codependent uncertainties and measure the complicated casual relationships effectively. We propose a methodological solution to the problem, and this solution is demonstrated in this case as an extension to the previous water resource optimization framework. We coupled the water-energy-food-ecology nexus into the Bayesian network, which provides a formal representation of the joint probabilistic behavior of the system, and the method was applied to water resource use analysis and management in the Syr Darya River basin, a transboundary and endorheic basin that has contributed to the Aral Sea ecological crisis as a result of unreasonable water use. The annual scale data of four periods, 1970–1980, 1980–1991, 1991–2005, and 2005–2015, were introduced into the Bayesian network. Before the disintegration of the Soviet Union, the amount of water inflow into the Aral Sea was sensitive to increases in irrigation for agricultural development, increases in water storage of the upstream reservoirs and stochastic runoff. After the disintegration of the Soviet Union, the amount of water inflow into the Aral Sea was sensitive to the inefficient irrigation water use in the downstream areas of Uzbekistan and Kazakhstan and the water storage of the reservoir located upstream of Kyrgyzstan. The change resulted from unresolvable disputes between water use for power generation in the upstream area and irrigation in the downstream area. Comprehensive scenario analysis shows that, in the short term, it would be useful to improve the proportion of food crops, improve the efficiency of water use in relation to salt leaching and irrigation, and prevent drought damage. In the long term, based on the increased use of advanced drip irrigation technology from 50% to 80%, the annual inflow into the Aral Sea will increase significantly, reaching 6.4 km³ and 9.6 km³, respectively, and this technology is capable of ameliorating the ecological crisis within the basin.

Hybrid hydropower and floating photovoltaic power generation has far-reaching effects on the intertwined water, food and energy (WFE) nexus, but the complementary operation is fundamentally challenging especially under high uncertainties of hydro-meteorological conditions. This study proposed an artificial intelligence-based WFE system-overarching solution driven by hybrid hydro-floating photovoltaic power generation for promoting nexus synergies. A multi-objective optimization model grounded upon the Grasshopper Optimization Algorithm was developed to simultaneously maximize hydro-floating photovoltaic power output, the ratio of water storage to reservoir capacity, and the ratio of water supply to water demand. The Shihmen Reservoir watershed and its WFE system in northern Taiwan constituted the case study. The results demonstrated that the proposed optimization model could significantly improve synergistic benefits of the WFE nexus by reaching 13%, 13.3% and 15.1% in water storage, food production and hydro-floating photovoltaic power output, respectively. The optimal tilt angles of floating photovoltaic installation would vary between −11.9° (Summer) and 44.3° (Winter). This study opens up new perspectives on green energy production expansion while stimulating WFE nexus synergies in support of policy-makers with feasible schemes on floating photovoltaic deployment in the interest of social sustainability. In consequence, new niches are exploited for floating photovoltaic deployment and give rise to impact mitigation concerning hydro-meteorological uncertainties on WFE nexus management.

As the critical resources for regional development, water, energy and food (WEF) are highly interdependent. Improving the cognition of the complex interactions of WEF nexus is the top priority of regional sustainable development and decision-making. This paper proposes a novel regional water-energy-food interaction model based on supply and demand to clarify the nexus between WEF resources and its impact on the development of the entire region. An indicator of sustainability index is employed to quantitatively evaluate the interactions between supplies and demands in WEF nexus. The scenario analysis method is used to predict the resources and demands for the future medium and long-term development in a high-tech industrial zone, China, and then the total regional cost is optimized to obtain the suitable development roadmaps. The analysis results indicate that energy is the key to WEF and significant regional development. The collaborative development of WEF, including the supply of external resources, can better promote the sustainability of the region. Appropriate adjustment of energy structures and power generation ratios can not only effectively reduce the total cost, but also control CO₂ emissions. The proposed WEF model with the indicator of sustainability index can quantitatively evaluate the region sustainable development.

To attain sustainable development in Latin Ameica and the Caribbean, where there is a strong dependence on commodity and food price development, priority attention towards energy, water, and food security is critical. In this literature and data analysis, we examined the baseline and trends of resource security based on the Water-Energy-Food Nexus concept. A performance index was developed to evaluate the progress in water, energy, and food security of the region, and a nexus-based index was developed to evaluate the inter-linkages of these resources. Finally, critical issues and challenges for sustainable development were addressed. Results showed that an unprecedented amount of infrastructure is needed to address increasing energy consumption. Emphasis should be placed on gradually replacing high carbon-sources that produce electricity with low carbon-energy systems and clean power production. Results also showed that water scarcity, given unequal distributions of rainfall, will be aggravated by changing climate conditions; improvements in water governance as well as water and sanitation provisions are needed. The region is a net exporter of food, at the expense of water availability and greenhouse gas emissions, and suffers from structural constraints. It is important to foster novel agricultural practices and sustainable food systems.

This article explores the water, energy and food nexus in Central Asia as an avenue to seek regional solutions to common challenges. A benefit-sharing scheme was in place between the countries in the Central Asia in the Soviet Union era, but since independence unilateral action has been the norm. It is concluded that a regional integrative approach would be beneficial in the water, energy and food nexus. Collaborative options include exploring existing regional frameworks with a focus on additional investment in hydropower power generation, regional power market development, irrigation reforms, and addressing regional environmental public goods such as water flows and quality.

The sustainable development goals and the Paris agreement target a global cleaner energy transition with wider adaptation, poverty reduction and climate resilience benefits. Hydropower development in the transboundary Koshi river basin presents an intervention that can support the sustainable development goals while meeting the regional commitments to the Paris agreement This study aims to quantify the benefits of eleven proposed water resource development projects in the transboundary basin (4 storage and 7 run-of-the-river hydropower dams) in terms of hydroelectric power generation, crop production and flood damage reduction. A modular hydro-economic model is constructed by soft coupling hydrological and crop growth simulation models to an economic optimization model. It assesses the potential of the interventions to break the vicious cycle of poverty and water, food, and energy insecurity. Unlike previous studies, the model a) incorporates the possibility of using hydropower to lift groundwater for irrigation as well as flood regulation and b) quantifies the resilience of the stated benefits under future climatic scenarios (from downscaled general circulation models) affecting both river flows and crop growth. The results show significant potential economic benefit generated from electricity production, increased agricultural production, and flood damage control at the basin scale. The estimated annual benefits are around USD 2.3 billion under the baseline scenario and USD 2.4 billion under a future (RCP 4.5) climate scenario, compared to an estimated annual investment cost of USD 0.7 billion. The robustness of the estimated benefits illustrates the climate resilience of the water resource development projects. Contrary to the commonly held view that the benefits of these proposed projects in the Koshi river basin are limited to hydropower, the irrigation and flood regulation benefits account for 40 percent of the total benefits. The simulated scenarios also show substantial irrigation gains from the construction of the ROR schemes, provided the generated power is used for groundwater irrigation. The integrated modelling framework and results provide useful policy insights for evidence-based decision-making in transboundary river basins around the globe facing the challenges posed by the water-food-energy nexus.

Food, energy, and water (FEW) resources are critical concerns to achieve long-term sustainability. Climate change and socio-economic development both affect the FEW Nexus, but the combined impacts of these two factors on a Nexus system is not well understood. An integrated management model was applied to quantify the combined impacts on the FEW Nexus through rice yield, power generation, and water withdrawal. Five scenarios from the Coupled Model Intercomparison Project Phase 6 were chosen as the inputs of the integrated model in the Mekong River Delta (MRD). Results showed that rice yields will be vulnerable to extreme climate events. The minimum autumn rice yield, 4.7 ton/ha in 2023 under the SSP1–2.6 scenario, will be as low as the yield of the 2016 drought year (4.6 ton/ha). Power generation will increase sharply due to socio-economic development. The power generation of SSP5–8.5 in 2050 will be about 10 times higher than that in 2010. The average total water withdrawal in 2050 was estimated to increase by 40% compared to that in the 2016 drought year and will be more than 3 times higher than the average withdrawal of 1995–2010. Nexus analysis found water is a central resource that connects food and energy sectors in MRD. Regional sustainability analysis showed that climate change and socio-economic development both have a significant impact through affecting the FEW Nexus. Specifically, the energy and water sectors will be more vulnerable to the combined impacts than the food sector due to the coal-fired power plants planned in the MRD.

The Water-Food-Energy nexus study identifies developmental challenges and trade-offs present along the transboundary river basins. Intensive reservoir development for hydropower production impacts existing actors in the Lancang-Mekong River Basin. Concerns from these stakeholders highlight three major trade-offs that occur between hydropower and irrigation (HP-AG), hydropower and fisheries (HP-F), and irrigation and fisheries (AG-F). Dam construction has an impact not only on power production but also on ecosystems and ultimately the livelihood of people. In this study, we quantify the effects of reservoir operation on hydropower generation, irrigated crop production and fisheries yield in the Tonle Sap lake through a novel hydro-economic model at the whole basin scale. Our main finding is that trade-offs can be turned into synergetic opportunities. First, the dam operation can increase water availability for irrigation without severely harming hydropower production, raising irrigated crop revenue by 49% and reducing crop losses during droughts by 30%. Second, eco-friendly management increases fisheries yield by up to 75%, but decreases both irrigated crop production (−48%) and power production (−17%). Reservoirs can, therefore, benefit the whole basin by releasing more water in months with high irrigation demand (April and December) and by minimizing the adverse effects of flow fluctuations on the livelihood of farmers and fishers living downstream. Our results also reveal the overlooked trade-off between irrigated agriculture and fisheries. Cross-sectoral and transboundary partnerships should strengthen stakeholder participation in decision-making. Local solutions such as enhanced reservoir operation can respond to the broader global issue of natural resource trade-offs and sharing. Our alternative narrative enhances the dialogue about fair and efficient water use among Mekong riparian countries.

Irrigation in the Mediterranean region has been used for millennia and has greatly expanded with industrialization. Irrigation is critical for climate change adaptation, but it is also an important source of greenhouse gas emissions. This study analyzes the carbon (C) footprint of irrigation in Spain, covering the complete historical process of mechanization. A 21-fold total, 6-fold area-based, and 4-fold product-based increase in the carbon footprint was observed during the 20th century, despite an increase in water use efficiency. CH₄ emissions from waterbodies, which had not previously been considered in the C footprint of irrigation systems, dominated the emission budget during most of the analyzed period. Technologies to save water and tap new water resources greatly increased energy and infrastructure demand, while improvements in power generation efficiency had a limited influence on irrigation emissions. Electricity production from irrigation dams may contribute to climate change mitigation, but the amount produced in relation to that consumed in irrigation has greatly declined. High uncertainty in CH₄ emission estimates from waterbodies stresses a need for more spatially resolved data and an improved empirical knowledge of the links between water quality, water level fluctuations, and emissions at the regional scale.