Nexus Perspective Research Articles

Assessment of floating solar photovoltaic potential in China

Solar energy has expanded rapidly in recent years, and China is the largest market in terms of installed capacity. With the aim of achieving carbon neutrality by 2060, solar power will play an increasingly important role in China. However, like many other countries, the low energy density of solar photovoltaics is one of the major drawbacks of its further development. The emergence of floating photovoltaic systems (FPV) can not only break this threshold but also generate a series of cobenefits from a brand-new energy-land-water nexus perspective. Using a GIS-MCDA model, an evaporation model, combined with a cost-benefit analysis, this paper estimates the development potential of FPV in China, and its energy-land-water cobenefits are further analyzed. Moreover, to reveal the current land constraint for developing solar photovoltaics in China, the potential of traditional terrestrial solar photovoltaics has also been evaluated. The results show that the potential installed capacity of FPV in China can reach 705.2 GW–862.6 GW with an annual 1164.9 TWh to 1423.8 TWh of potential power output, and most potential FPV stations can obtain positive financial returns. The annual water evaporation reduction is approximately 5.8 km3. In the meantime, around 7117.3 km2 of the land could be conserved, which would alleviate the land constraint for terrestrial solar photovoltaic systems, especially in the highly urbanized eastern and southern coastal areas in China.

Process analysis and mitigation strategies for wetland degradation caused by increasing agricultural water demand: an ecology–economy nexus perspective

BackgroundFarmland expansion has played a major role in wetland degradation in Heilongjiang Province, China in recent decades. Farmland expansion increases the demands for water, thereby affecting wetland water cycles, and promoting the shrinkage of wetland areas and degradation of ecosystem functions. As an open system, agricultural production is limited by both ecological and socioeconomic conditions. However, our understanding of wetland degradation caused by farmland expansion from the perspective of the ecology–economy nexus is limited.MethodsA correlation between farmland expansion and agricultural economic activities was established, and wetland degradation driven by agroeconomic activities was inversely derived using a multi-regional input–output (MRIO) analysis. We developed an ecology–economy nexus framework to explore the ecological process of the area and water demand tradeoffs between wetland degradation and farmland expansion, the economic process of wetland degradation driven by food consumption, and the nexus between the two processes. We finally explored strategies to mitigate wetland degradation due to increased agricultural water demand.ResultsFarmland expansion contributed to 93.76% of the total degraded wetland area. There was a significant negative correlation between wetland area and the water consumption for crop production, but no significant correlation between wetland area and the ecological footprint of croplands. The direct wetland degradation caused by local final demand accounted for 63.02%, while the indirect degradation caused by non-local final demand accounted for 36.98%. Hebei, Shandong, Liaoning, Inner Mongolia, and Shanghai were the top five provinces contributing to indirect wetland degradation in Heilongjiang. Our findings indicated that a mixed scenario combining water footprint reduction per unit yield with food export reduction could maximize wetland restoration while reducing local farmland–wetland competition for water.ConclusionsOur research highlights the effects of economic processes in the agricultural sector on wetland degradation, and showed that the adjustment of food trade patterns can effectively promote wetland restoration.

Analyzing carbon source-sink nexus for green and sustainable transition at the local scale

The pursuit of green and sustainable transition at the local level holds great significance for achieving high-quality development, particularly in developing countries and regions. An in-depth understanding of the intricate relationship between carbon sources and sinks can assist in identifying the key influencing factors of low carbon development. Therefore, this study takes Chongming District of Shanghai in China as an example and proposes a novel methodology to assess the relationship between carbon sources and sinks from the nexus perspective. Our results reveal that: 1) From 2000 to 2020, the overall carbon sink level in Chongming has increased gradually, but its growth rate lags behind its carbon emissions level. Both the intensity of carbon emissions and the extent of high-carbon emission areas have significantly increased. And the trend of carbon balance change is consistent with the original planning goals. 2) In order to achieve a dynamic balance between carbon sources and sinks in temporal and spatial scales, integrated source-sink plan and associated measures must be taken. Additionally, to promote the green, low-carbon, and sustainable transition, it’s crucial to maintain a dynamic equilibrium between the natural ecological interface and the socio-economic interface. 3) This study aims to enhance our understanding of regional carbon peaking and neutrality from the perspective of source-sink nexus and can serve as a decision-support tool for other developing countries and regions seeking to achieve net-zero carbon transition within the constraints of local energy-resource endowments.

Assessment of agricultural adaptations to climate change from a water-energy-food nexus perspective

Adapting agriculture to climate change without deteriorating natural resources (e.g., water and energy) is critical to sustainable development. In this paper, we first comprehensively evaluate six agricultural adaptations in response to climate change (2021–2050) through the lens of the water-energy-food (WEF) nexus in Saskatchewan, Canada, using a previously developed nexus model—WEF-Sask. The adaptations involve agronomic measures (early planting date, reducing soil evaporation, irrigation expansion), genetic improvement (cultivars with larger growing degree days (GDD) requirement), and combinations of individual adaptations. The results show that the selected adaptations compensate for crop yield losses (wheat, canola, pea), caused by climate change, to various extents. However, from a nexus perspective, there are mixed effects on water productivity (WP), total agricultural water (green and blue) use, energy consumption for irrigation, and hydropower generation. Individual adaptations such as early planting date and increased GDD requirement compensate for yield losses in both rainfed (0–60 %) and irrigated (18–100 %) conditions with extra use of green water (5–7 %), blue water (2–14 %), and energy for irrigation (2–14 %). Reducing soil water evaporation benefits the overall WEF nexus by compensating for rainfed yield losses (25–82 %) with less use of blue water and energy consumption for irrigation. The combination of the above three adaptations has the potential to sustain agricultural production in water-scarce regions. If irrigation expansion is also included, the combined adaptation almost fully offsets agricultural production losses from climate change but significantly increases blue water use (143–174 %) and energy consumption for irrigation while reducing hydropower production (3 %). This study provides an approach to comprehensively evaluating agricultural adaptation strategies, in response to climate change, and insights to inform decision-makers.

An inexact bi-level multi-objective modeling approach for managing agricultural water-food-carbon-land-ecology-nutrition nexus in an arid area

Multiple subsystems such as water, food, land, carbon, ecology, and nutrition are closely intertwined, and the resulting complexity and uncertainty pose challenges to water resource management. This study proposes an optimization framework from a novel water-food-carbon-land-ecology-nutrition (WONDER) nexus perspective for the integrated management of agricultural and ecological water resources. Firstly, the irrigation priority ranking of decision-making units (DMU) is obtained based on the remote sensing indices from the Google Earth Engine (GEE) platform. Secondly, the ecological satisfaction degree, which aggregates carbon sink satisfaction degree and ecological water demand satisfaction degree, is proposed to characterize the degree of achieving the pre-given ecological objectives. Then, the above two indicators (i.e., the irrigation priority ranking and the ecological satisfaction degree) are integrated with a fuzzy-interval credibility-constrained bi-level multi-objective programming model to realize: (1) reconciling conflicts in food nutrition, food security, economic development, and ecological conservation; (2) making trade-offs among the positions and preferences of different decision-makers; (3) dealing with the dual uncertainties of fuzzy-interval parameters; (4) obtaining optimal agricultural and ecological water allocation schemes. The applicability of the model is verified by taking Hongyashan Irrigation District of Minqin County as an example. The results show that: (1) the irrigation priority ranking for the DMUs is: DMU 10 > DMU 9 > DMU 4 > DMU 5 > DMU 1 > DMU 11 > DMU 6 > DMU 8 > DMU 7 > DMU 2 > DMU 3; (2) the ratio of agricultural to ecological water allocation in the irrigation district is about 3:1, which is consistent with the water use characteristics of this area; (3) the total water allocation during the whole growth period for different crops is mainly determined by planting area, and the ranking of the water allocation is: sunflower > maize > wheat > seed melon. Moreover, compared with the single-level models, the inexact bi-level multi-objective model can well coordinate the upper and lower decision-makers and the multiple decision objectives under the WONDER nexus. Therefore, the proposed framework can provide the scientific basis for balancing agricultural and ecological water management and conflicting objectives in similar irrigation districts through involving multiple subsystems and perspectives.

Potential of technological innovation to reduce the carbon footprint of urban facility agriculture: A food–energy–water–waste nexus perspective

As an emerging form of agriculture, urban facility agriculture is an important supplement to traditional agriculture and one of the ways to alleviate the urban food crisis, but it may generate a high carbon footprint. A comprehensive assessment of urban facility agriculture is a necessity for promoting its low-carbon development. In this study, the carbon footprint of urban facility agriculture under four different technological innovation models was simulated by life cycle assessment and a system dynamics model for a carbon footprint accounting without considering economic risk. Case 1, as the basic case, is Household farm facility agriculture. Case 2 is the introduction of vertical hydroponic technology based on Case 1, Case 3 is the introduction of distributed hybrid renewable energy micro-grid technology based on Case 2, and Case 4 is the introduction of automatic composting technology based on Case 3. These four cases demonstrate the gradual optimization of the food–energy–water–waste nexus in urban facility agriculture. This study further uses the system dynamics model for carbon reduction potential considering economic risk to simulate the diffusion (promotion) scale and carbon reduction potential of different technological innovations. Research results show that with the superposition of technologies, the carbon footprint per unit land area is gradually reduced, and the carbon footprint of Case 4 is the lowest at 4.78e+06 kg CO2eq. However, the gradual superposition of technologies will further limit the diffusion scale of technological innovation, thereby reducing the carbon reduction potential of technological innovation. In Chongming District, Shanghai, under theoretical circumstances, the carbon reduction potential of Case 4 is the highest at 1.6e+09 kg CO2eq, but the actual carbon reduction potential is only 1.8e+07 kg CO2eq due to excessive economic risks. By contrast, the actual carbon reduction potential of Case 2 is the highest with 9.6e+08 kg CO2eq. To fully achieve the carbon reduction potential of technology innovation, it is necessary to promote the scale diffusion of Urban facility agricultural technology innovation by raising the sales price of agricultural products and the grid connection price of renewable electricity.

Alert in the dynamics of water-energy-food production in African countries from a nexus perspective

In African countries, limited knowledge about the co-production of water, energy, and food (WEF) resources and their sectoral interaction makes it problematic to define sufficient policy options to ensure their efficient and sustainable production. This study proposes a new approach to assess the WEF sectors' co-production in 47 African countries from 2000 to 2020. The study shows low and varied co-production between resource sectors in African countries. At the continental level, the water sector contributes 91.3% of its share to food and energy production and gets 10.5% back from these two sectors. Similarly, the energy sector contributes 17.7% of its share to food and water production and receives 39.1% from these two sectors. The food sector contributes a small percentage of 6.7% to the total production of the water and energy sectors, compared with the 79.5% it receives back from those two sectors. Limited and unsustainable collaboration between resource sectors is a major concern in all African countries, particularly between the food and energy sectors, and seems to be a continuous challenge for WEF security. Applying the co-production approach provides a dynamic pathway capable of helping practitioners identify opportunities and gaps among WEF production and plan investments to achieve their respective SDGs.

Energy-water nexus in low-carbon electric power systems: A simulation-based inexact optimization model

Energy and water resources are closely linked in electric power systems, and the application of low-carbon technologies further affects electricity generation and water consumption in those systems. The holistic optimization of electric power systems, including generation and decarbonization processes, is necessary. Few studies have considered the uncertainty associated with the application of low-carbon technologies in electric power systems optimization from an energy-water nexus perspective. To fill such a gap, this study developed a simulation-based low-carbon energy structure optimization model to address the uncertainty in power systems with low-carbon technologies and generate electricity generation plans. Specifically, LMDI, STIRPAT and grey model were integrated to simulate the carbon emissions from the electric power systems under different socio-economic development levels. Furthermore, a copula-based chance-constrained interval mixed-integer programming model was proposed to quantify the energy-water nexus as the joint violation risk and generate risk-based low-carbon generation schemes. The model was applied to support the management of electric power systems in the Pearl River Delta of China. Results indicate that, the optimized plans could mitigate CO2 emission by up to 37.93% over 15 years. Under all scenarios, more low-carbon power conversion facilities would be established. The application of carbon capture and storage would increase energy and water consumption by up to [0.24, 7.35] × 106 tce and [0.16, 1.12] × 108 m3, respectively. The optimization of the energy structure based on energy-water joint violation risk could reduce the water utilization rate and the carbon emission rate by up to 0.38 m3/104 kWh and 0.04 ton-CO2/104 kWh, respectively.

Online job scheduling scheme for low-carbon data center operation: An information and energy nexus perspective

As the digitalization of the economy and society accelerates, the enormous and fast-growing energy consumption of data centers is becoming a global concern. With the unique power consumption flexibility introduced by computing job scheduling, data centers could play an important role in enhancing the capability to integrate renewable generation as a demand-side resource. In this paper, we propose an online job scheduling scheme for low-carbon data center operation from an information and energy nexus perspective. We formulate the job scheduling problem as a Markov decision process in which job dependencies, job heterogeneity, and quality of service are considered comprehensively. To address the challenges of large-scale heterogeneous computing jobs, we propose a deep reinforcement learning-based approach to solve the energy-aware scheduling problem and achieve an optimal online policy. The case study results based on real-world data illustrate that the proposed scheme can effectively reduce the carbon footprint and energy cost of a data center while maintaining the quality of service for cloud products.

A new city's water–energy nexus implications: The case of Sejong City in South Korea

Cities’ impact on water, energy, and greenhouse gas (GHG) emissions is increasing as the world becomes more urbanized. Focusing on Sejong City, which was developed as a new administrative hub in South Korea in 2012, this study scrutinizes its development path from water–energy nexus perspective by developing a system dynamics model that describes the interactions among numerous components related to water and water-related energy consumptions. Furthermore, this study reimagines the city's potential development trajectories by constructing nine policy scenarios that combine different degrees of water conservation ambitions with different amounts of decarbonization in the power sector. The results confirmed the potential of water conservation policies. The expansion of rainwater use has the potential to cut water use by 50% from the 2050 baseline levels. Although the use of harvested rainwater is negligible compared to wastewater reuse, its overall effect on water conservation would be substantial if it is increased. The maximum reduction in GHG emissions from the water sector would be 9.36% from the 2050 baseline scenario when combined with decarbonizing the power sector. Although this study does not fully account for the water conservation potential, including the efforts at the end-use stages, the possibility of carbon neutrality in Sejong's water sector by 2050 is presented. It affirms that local governments can significantly reduce cities’ environmental footprints and complement national efforts for the transition to a carbon-neutral society.

Linking spatial and temporal contexts to multi-contextual segregation by hukou status in urban China

The paradigm in segregation research is shifting from a place-based to a people-based perspective and from static spatial segregation to dynamic spatiotemporal segregation. However, empirical studies measuring individual-level segregation from a space–time nexus perspective are quite limited, and the effects of various geographic and temporal contexts in people's daily lives on segregation are not clear enough. Drawing on activity-travel diary data in Shanghai, China, we considered hukou (“household registration”) status as the key dimension in this research. Accordingly, we employed an individual-level spatiotemporal proximity index (i-STP index) to measure multi-contextual segregation and then examined the associations between various spatial and temporal contexts with regard to hukou segregation. In this study, we found that migrant and rural populations experience higher levels of segregation, not only in residential neighborhood or activity spaces, but also in various space–time contexts in their daily lives. Moreover, it reveals temporal variations in hukou segregation, which is correlated with the arrangement of daily activities and the temporal rhythm of the city. Our study also shows the various roles of geographical contexts within residential spaces and activity spaces that are segregated, indicating that improved facilities within activity spaces could help mitigate hukou segregation. Therefore, it contributes to the current literature with people-based dynamic measurements of hukou segregation and offers insight regarding the understanding of the relationship between spatial and temporal contexts as well as activity attributes with multi-contextual segregation.

Sustainability assessment of Cerrado and Caatinga biomes in Brazil: A proposal for collaborative index construction in the context of the 2030 Agenda and the Water-Energy-Food Nexus

The 2030 Agenda framework represents an opportunity for the co-development of local indicators and shares the same principles of cross-sectoral integration and universality as the water–energy–food nexus. This research aimed to develop a quantitative-collaborative methodology for constructing indicators and indexes for the sustainability of the Cerrado and Caatinga Brazilian biomes, considering the connection and synergies between the Nexus perspective and the 2030 Agenda’s SDG–target framework. The study was applied in 2,512 municipalities that make up the total of the mentioned biomes. The methodology consists of four major blocks: i) identification and construction of indicators based on the association of them with one or more 2030 Agenda’s targets, in a collaborative way from expert groups; ii) generation of weights by an indicator considering leverage, according to the number of target assignments, and importance, attributed by experts for each indicator to the target; iii) generation of sustainable development goal indexes, considering the performance of the SDGs; Nexus performance, considering different weights between the SDGs; Nexus synergistic, the standard deviation between the SDGs; and Nexus overall, a combination of the last two; and iv) sensitivity analysis for performance indexes considering the assignment of zero values to the governance indicators. In general, the regions of MATOPIBA, northern and western of Cerrado and the Caatinga, are, on average, the areas of greatest vulnerability. The targets that respond to this inequality are related to eradicating hunger, sustainable and climate-resilient production systems, universal access to water, water quality, efficiency of multiple water uses, access to energy, and the participation of renewable energies. We found that in areas of better average nexus performance, there is also greater inequality between nexus dimensions; therefore, the Nexus overall index is penalized. The federal units and areas with the worst Nexus dimension performances and with insufficient governance measures are north and northwest of Bahia and municipalities bordering the State of Tocantins—food; Maranhão and Piauí, northeast of Mato Grosso, northwest of Goiás, Rio Grande do Norte and Paraíba—water; and Maranhão, extreme southeast of Pará, and more sparsely in Paraíba—energy.

Multi-objective optimization of concentrated solar power plants from an energy-water-environment nexus perspective under distinct climatic conditions – Part B: Environ-economic analysis

The objective of this study is to include environmental impact in optimization of concentrated solar power plants previously limited to techno-economic analysis only. Performance of solar towers and parabolic trough collectors equipped with dry and wet cooling is numerically investigated at 10 min interval for three climatic zones. Based on electricity generation profiles pertinent to variation of design variables of solar multiple and thermal energy storage, the water usage is quantified techno-economically, considering water scarcity levels. Besides, five different potential impacts over lifecycle of concentrated solar and natural gas-based power plants are compared after unifying them into metric of net environmental impact avoided. Additionally, utilizing techno-economic solutions and eco-friendly solutions, multi-objective ‘balanced’ solution is proposed. It is found that levelized cost of water increases five-fold for areas with extreme water scarcity and is higher for trough than solar tower. Net environmental impact of troughs is higher and lower electricity generation causes the avoided impact to be higher than solar towers, when compared with natural gas-fired power plants. For eco-friendly solutions, solar multiple varies from 3.5 to 4 with thermal energy storage of 24 h. Dry-cooled solar towers with optimal solar multiple in range of 3–3.2 and thermal energy storage of 18.8–19.9 h are evaluated for pareto-optimality based ‘balanced’ solutions for all zones. These solutions offer minimum net levelized cost of electricity, alongside maximized electricity generation, huge return on invested capital and energy, and reducing environmental impact by over 94%. Lastly, semi-arid climates are found suitable for concentrated solar power plant installation.

Systematic Modeling and Policy Analysis on the Urban Water–Energy Nexus for Sustainable Resources Management

Urbanization in developing countries has imposed great pressure on the availability of water and energy (WE) resources, while single-sector strategies may cause several unanticipated consequences. To find sustainable solutions for resource management, this study develops an integrated approach to assess urban WE from a nexus perspective. With the city Shenzhen as a case study, the existing WE nexus on the supply and demand sides of urban areas is first quantified. Subsequently, a system dynamics model (SDM) is constructed to reveal the complex interactions in the urban nexus, and the trends of WE supply and demand by 2035 are simulated. To narrow the potential resources gap, a policy analysis considering the interest and influence of various stakeholders is conducted to formulate policy scenarios. As revealed from the results, the resources gap will expand continuously by 2035, especially for water resources. Compared to the demand side, the policies implemented on the supply side exhibit a better performance, and the scenario of import expansion could independently achieve the desirable result. Moreover, as the demand side displayed more complexities, the implementation of future policies should rigorously weigh the priorities and difficulties of a range of stakeholders’ involvements.

Remarriage migration of women in Asia: The case of Japan

AbstractThis study aims to confirm the diversity of intra‐Asian female marriage migrants in Japan with comprehensive statistics. Methodologically, I used quantitative method, collecting appropriate data from local demographic and immigration statistics in Japan. Simultaneously, I reviewed related empirical studies on the various factors affecting marriage migration, including those written in the local language (Japanese). Results indicate that 42.9 per cent of intra‐Asian female marriage migrants in Japan were middle‐aged women whose marriages to Japanese men were their second. Beyond a simple development–migration nexus perspective on marriage migration in Asia, middle‐aged women entering Japan for their second marriage often aim to escape social stigmatization and poverty and to overcome the difficulties of marrying late or remarrying in their own countries. A more complex intersectionality of gender–class–age stigmatization should be considered to understand marriage migration. The findings have important policy implications for both origin and destination countries.

Navigating the nexus: The role of intermediaries in charting a new frontier of policy integration for agrifood and energy systems transformation

The effects of climate change are instigating a discourse shift towards net-zero emissions agriculture. However, a sectoral silo paradigm of policy design is incompatible with a systems approach to address complex global environmental challenges. This study introduces a social cartography approach that amalgamates network theory with a nexus perspective to identify social relation changes in the making. The study examines the role of an advisor-led initiative promoting the discourse of climate-smart farming in Scotland and identifies the impacts upon farmer knowledge networks. The social cartography comprises of a survey, farm meeting observations, and social network analysis of the agriculture, climate change, and energy (ACE) policyscape. As a visualization method, the social cartography provides a conceptual compass to navigate social relation changes of farmer knowledge networks amidst discursive transition. The results demonstrate that the advisor-led initiative acts an intermediary of discursive transition by introducing new knowledge frames and practices of farming that facilitate network shifts. However, voluntary measures fall short of instigating cross-sectoral interplay to actualize transformation towards systems integration. Furthermore, the study presents policy design elements to chart a new frontier of integrated agrifood and energy systems governance in Scotland.

Coupling Efficiency Assessment of Food–Energy–Water (FEW) Nexus Based on Urban Resource Consumption towards Economic Development: The Case of Shenzhen Megacity, China

The population aggregation and economic development caused by urbanization significantly influence the efficiency of urban resource consumption. However, the coupling interactions between crucial resource consumptions such as food, energy and water (FEW) and urbanization processes within highly urbanized areas has not been well-studied. In this study, we constructed an assessment framework for the coupling efficiency measurement of FEW resource consumptions in 10 administrative districts across Shenzhen megacity during 2012–2020, based on the data envelopment analysis (DEA). This study demonstrated that, from the perspective of the FEW nexus, increasing efficiencies in the energy consumption of most districts improved the municipal FEW efficiency, while more than half of the districts did not achieve water resource efficiencies throughout the period. Concerning regional economic development, 80% of the districts improved coupling FEW efficiencies by 2020, the average values of which were higher for Yantian, Nanshan, Luohu and Dapeng, and lower for Baoan, Longgang and Guangming, with a downtrend only being observed in Guangming. Overall, the value of the coupling FEW efficiency of Shenzhen megacity rose by 35% from 2012 to 2020. Correlation analysis showed that synergistic effects of efficient resource consumption occurred in most districts, and economic urbanization was the main driving factor of regional FEW efficiencies within Shenzhen megacity. This study provides instructive insights into the status of urban resource consumption and suggests that the coordination of FEW management should be further improved by fiscal intervention to maintain economic development with the limited resources available, which would have valuable implications for synergistic FEW governance in megacities in China and elsewhere.

A Critical Appraisal of the Sustainability of Bangladesh’s Water Governance from Nexus Perspectives

Demographic change, coupled with industrialization, urbanization, and economic activities, has vastly increased the demand for water in Bangladesh in different sectors. This has resulted in the over-exploitation of water resources, leading to cross-sectoral competition among water, energy, food, and the environment. Since water is a crucial element for the national developmental activities, a vital necessity for its citizens’ life and livelihood, and a lifeline for its ecosystem and biodiversity, water governance remains a top priority for the government, the sustainability of which largely depends on the integrated nexus perspective with multi-sectoral priorities. Based on a comprehensive literature review and expert interviews, this paper critically analyzes Bangladesh’s water governance sustainability from a nexus perspective. The findings suggest that the nexus perspective is partially integrated into the regulatory and policy framework as well as the institutional mechanism of Bangladesh’s water governance. To increase the sustainability of the system, it is vital to integrate the nexus perspective into every aspect of the country’s water governance and harmonize the water policies with other sectors, bearing in mind their interdependency, in order to abate cross-sectoral conflict and align each sector through defining shared objectives based on the exploitation of their complementarities.

Low-Carbon Development from the Energy–Water Nexus Perspective in China’s Resource-Based City

Energy crises, water shortages, and rising carbon emissions are constantly posing new demands and challenges to global economic development. Considering the problem of high emissions and high water consumption in the process of energy production and transformation in resource-based cities, this study established the LEAP-Jincheng model based on the low emissions analysis platform (LEAP) model. Taking 2020 as the base year, the baseline scenario (BS), policy scenario (PS), and intensified scenario (IS) were set to predict future energy and water consumption and carbon emissions of Jincheng from 2021 to 2050. The results show that both PS and IS can achieve energy conservation and emission reduction to some extent. The total energy consumption of PS will be 32.89 million metric tons of coal equivalent in 2050, 15.62% less than the BS. However, the carbon emissions in 2030 will reach 8221 metric tons CO2 equivalent, which is significantly higher than that in other scenarios. In PS, carbon emissions after 2030 will not be significantly reduced, and the energy–water elasticity coefficient is −0.77, which fails to achieve effective emission reduction under energy–water synergy. The total energy consumption of the IS will be 22.57 million metric tons of coal equities in 2050, which has a total decrease of 31.38%, compared to BS. In the IS, the carbon emissions will reach a peak in 2030 (68.77 million metric tons CO2 equivalent) and subsequently reduce to 50.72 million metric tons CO2 equivalent in 2050, which has a total decrease of 50.64%, compared to BS. Furthermore, water consumption and energy–water synergy results show that the elastic coefficient is 1.37 in the IS. The IS is the best scenario for Jincheng to achieve coordinated development of energy and water resources from a low-carbon perspective. This study can provide a scientific basis for decision-making departments of Jincheng to formulate targeted sustainable development policies for energy and water and has an essential promoting significance for China to achieve the “double carbon” goals.

Multi-objective optimization of concentrated solar power plants from an energy-water-environment nexus perspective under distinct climatic conditions – Part A: Techno-economic analysis

In the current article, which is first to a two-part study, techno-economic evaluation, viability and optimization of concentrated solar power plants considering design parameters of solar multiple and integration of thermal energy storage is performed. High frequency (10 min), validated ground datasets are used for numerical simulations using System Advisor Model. Techno-economic performance analysis of dry and wet cooling system equipped solar tower and parabolic trough collectors is assessed for three different climatic zones i.e. temperate, semi-arid and sub-tropical. The optimization problem intends to maximize technical potential alongside minimizing net cost of electricity production. It is found that on average, 60 and 75% increase in annual electricity generation, and 5 and 7% decrease in levelized cost of electricity is observed with addition of 6 h of storage for solar tower and trough plants, respectively. For cost-effective solution, optimal solar multiple and thermal energy storage combination is in range of 3–3.2 and 15.4–15.9 for solar tower, and 2.3–3 and 10.6–11.6 h for trough plants. Wet-cooled solar towers perform the best in each climatic zone offering 5–6% lower cost of electricity production and 3–7% higher electricity generation potentials. Moreover, for mutually exclusive projects, levelized cost of electricity is a better metric to gauge economic viability than net present value. The follow-up study (Part B) focuses on environ-economic optimization of concentrated solar power plants. Furthermore, outcomes from both optimization objectives are utilized for multi-objective optimization based ‘balanced’ solution assessment in the next part.