Search Results (1,981)

This study presents a comprehensive techno-economic assessment of offshore wind projects in the Colombian Caribbean, emphasizing the impact of site-specific parameters on development costs and performance. Wind resource conditions were evaluated in four coastal regions (La Guajira, Magdalena, Atlántico, and Bolívar) using hourly meteorological data from 2015 to 2024, adjusted to 100 m above ground level through logarithmic and power law wind profile models. The analysis included wind speed, bathymetry, distance to shore, distance to substation, foundation type, wind power density (WPD), and capacity factor (C_f). Based on these parameters, annual energy generation was estimated, and both capital expenditures (CAPEX) and operational expenditures (OPEX) were calculated, considering the technical and cost differences between fixed and floating foundations. Results show that La Guajira combines excellent wind conditions (WPD of 796 W/m² and C_f of 61.5%) with favorable construction feasibility (bathymetry of −32 m), resulting in the lowest CAPEX among the studied regions. In contrast, Magdalena and Atlántico, with bathymetries exceeding 200 m, require floating foundations that more than double the investment costs. Bolívar presents an intermediate profile, offering solid wind potential and fixed foundation feasibility at a moderate cost. The findings confirm that offshore wind project viability depends not only on wind resource quality but also on physical site constraints, which directly influence the cost structure and energy yield. This integrated approach supports more accurate project prioritization and contributes to strategic planning for the sustainable deployment of offshore wind energy in Colombia. Full article

Digital transformation represents a strategic imperative for enterprises pursuing high-performance growth. This study selects A-share listed enterprises from 2014 to 2023 as the research sample and empirically examines the impact of digital transformation on enterprise risk-taking, as well as its internal transmission mechanisms, using a fixed effects model. The findings indicate that digital transformation has a significant positive effect on promoting enterprise risk-taking, particularly in state-owned enterprises and those with lower media attention. The director network and economic policy uncertainty positively moderate this relationship. Results from the mechanism analysis show that digital transformation enhances enterprise risk-taking through independent mediating channels that alleviate enterprises’ financing constraints and increase innovation investment, as well as through the chain mediation channel of “alleviating financing constraints → increasing innovation investment”. This research clarifies the specific mechanism underlying the impact of digital transformation on enterprise risk-taking and provides new evidence for understanding how digitalization enhances enterprise risk-taking by easing financing constraints and stimulating innovation. It holds important significance for helping enterprises improve their risk-taking capacity and promote sustainable development. Full article

The gas oil hydrocracking process is a cornerstone of modern refining, enabling the conversion of heavy fractions into high-value fuels such as diesel, kerosene, LPG, and naphtha. However, despite its economic significance, its considerable water requirements for cooling, washing, and steam generation lead to high utility costs, which may undermine profitability, representing the problem of the study. This study addresses the issue through a techno-economic assessment and resilience analysis of an industrial-scale, mass and energy-integrated gas oil hydrocracking process, utilizing the novel FP²O methodology. The process was modeled in Aspen HYSYS^® V14.0 with a capacity of 1.94 Mt/year, assuming a feedstock cost of USD 350/t and a primary product (diesel) price of USD 1539/t. The total capital investment (TCI) was estimated at USD 175.68 million, while utility expenses reached USD 1312.18 million/year, representing nearly half of the total product cost (TPC) of USD 2692.20 million/year. A set of twelve techno-economic and three financial indicators was determined, yielding a gross profit (GP) of USD 97.69 million, profitability after tax (PAT) of USD 64.96 million, and a net present value (NPV) of USD 229.62 million. The payback period (PBP) was 1.41 years, with a depreciable payback period (DPBP) of 2.99 years. The return on investment (ROI) was 36.97%, and the internal rate of return (IRR) reached 44.81%, evidencing strong profitability relative to comparable petrochemical operations. Resilience analysis highlighted sensitivities to fluctuations in product prices, feedstock costs, and normalized variable operating costs (NVOC), identifying a critical NVOC of USD 1435/t against the current operation at USD 1384.74/t, which suggests a narrow buffer before profitability deteriorates. Overall, the findings confirm that mass and energy integration enhances resource efficiency but does not fully mitigate exposure to feedstock and utility price volatility. This work constitutes the first application of FP²O to a mass and energy-integrated gas oil hydrocracking facility, establishing a benchmark for holistic techno-economic and resilience assessments in complex petrochemical systems. Full article

This study investigates whether public education expenditure crowds out or complements health investment in influencing life expectancy across 158 countries from 1990 to 2023. Graphical analysis shows that in high-income countries, health expenditure consistently exceeds education spending, reflecting mature complementarity between the two sectors. In contrast, in low- and middle-income countries, education spending often surpasses health expenditure, suggesting potential short-term crowding-out risks where fiscal resources are limited. Using Fully Modified Ordinary Least Squares (FMOLS), Two-Stage Least Squares (2SLS), and bootstrap estimation, the results reveal a predominantly crowding-in relationship that varies by income level. Bootstrap estimates from the life expectancy Model indicate that the coefficient of education expenditure (eexp) is −0.003 for high-income countries (HICs), 0.005 for upper-middle-income countries (UMCs), 0.045 *** for lower-middle-income countries (LMCs), and −0.010 for low-income countries (LICs). Bootstrap estimates show that the effect of education expenditure on life expectancy is insignificant in high- and upper-middle-income countries, strongly positive in lower-middle-income countries, and negative but insignificant in low-income countries. The coefficient of government health expenditure (dgghe) is 0.007 ***, 0.007 ***, 0.017 ***, and 0.035 *** for HICs, UMCs, LMCs, and LICs, respectively. Government health expenditure exerts a consistently positive and highly significant effect across all groups, strongest in low- and lower-middle-income countries. Sobel’s z-statistics (9.62, 8.70, 7.68, and 3.07) confirm a significant indirect effect of education on life expectancy through health expenditure. Health expenditure and GDP per capita enhance life expectancy, while inequality and inflation reduce it. Overall, education and health investments are mutually reinforcing but depend on fiscal capacity and governance quality, necessitating coordinated fiscal frameworks for sustainable human development. Full article

Background/Objectives: Local production is a global priority for increasing access to routine, outbreak, and pandemic vaccines and leads to a variety of direct and indirect benefits for countries. This study aimed to characterize the enabling environment for the sustainable production of influenza vaccines, including for epidemic and pandemic preparedness. Methods: National/local vaccine manufacturers were surveyed to capture data on influenza vaccine market contributions, government support for local production, and involvement in national pandemic preparedness activities. Using a conceptual framework for sustainable local production of influenza vaccines for epidemic and pandemic preparedness, manufacturers described 41 global/regional, national, and institutional sustainability factors across policy, health system, research and development (R&D), and regulatory thematic domains. In addition to the survey, key findings from country-level sustainability assessments of vaccine production in Bangladesh, Brazil, Indonesia, Serbia, and Viet Nam were analyzed to complement survey results. Results: This study included 12 participants representing 11 manufacturers from 10 countries. Of the 11 manufacturers, six reported that their countries have policies that support local production, but most manufacturers reported benefiting from some level of direct or indirect support by the government. Manufacturers considered 40/41 factors as important for sustainable production of influenza vaccines, and among the four domains, influenza prevention and control policies, influenza burden data, quality management, and regulatory filing capacity ranked highly. Additionally, manufacturers ranked factors related to cohesive policies for local production promotion and business/strategic planning at the manufacturer level as the top sustainability factors. Conclusions: Manufacturers broadly agreed on the importance of cohesive policies, evidence-based public health priorities, robust R&D and manufacturing investments, and regulatory readiness, though perceptions varied across contexts and company characteristics. Sustainable local production of influenza vaccines should be driven by the alignment of policies, investments, and demand. Full article

This study focuses on highway service areas. Building upon prior research that identified key influencing factors through surveys and ISM–MICMAC analysis, it constructs a tripartite evolutionary game model involving the government, service area operators, and carbon reduction technology providers based on stakeholder theory. Combined with MATLAB simulations, the model reveals the dynamic patterns of the carbon reduction system. The results indicate that government strategies exert the strongest influence on the system and catalyze the other two parties, followed by service area operators. Carbon reduction technology providers adopt a more cautious stance in decision-making. Government actions shape system evolution through a “cost-benefit-incentive” triple mechanism, with its strategies exhibiting significant spillover effects on other actors. Enterprise behavior is markedly influenced by Xinjiang’s regional characteristics, where the core barriers to corporate carbon reduction lie in the costs of proactive equipment and technological investments. The willingness of technology providers to cooperate primarily depends on two drivers: incremental baseline benefits and enhanced economies of scale. The core trade-off in government decision-making lies between the cost of strong regulation (Cg1) and the cost of environmental governance under weak regulation (Cg2). An increase in Cg1 prolongs the government’s convergence time by 233.3% and indirectly suppresses the willingness of enterprises and technology providers due to weakened subsidy capacity. Enterprises are relatively sensitive to the investment costs of carbon reduction equipment and technology, with convergence time extending by 120%. Technology providers are highly sensitive to incremental baseline returns (Rt), with stabilization time extending by 500%. Compared to existing research, this model quantitatively reveals the “cost-benefit-incentive” triple transmission mechanism for carbon reduction coordination in “grid-end” regions, identifying key parameters for strategic shifts among stakeholders. Based on this, corresponding policy recommendations are provided for all three parties, offering precise and actionable directions for the sustainable advancement of carbon reduction efforts in service areas. The research conclusions can provide a replicable collaborative framework for decarbonizing transportation infra-structure in grid-end regions with high clean energy endowments. Full article

Accelerating urbanization and the intensifying pace of climate change have heightened the occurrence of urban pluvial flooding, threatening urban sustainability. As the preferred approach to urban stormwater management, coupled gray and green infrastructure (GI–GREI) integrates GREI’s rapid runoff conveyance with GI’s infiltration and storage capacities, and their siting and scale can affect life-cycle cost (LCC) and urban drainage system (UDS) resilience. Focusing on Fengxi New City, China, this study develops a multi-objective optimization framework for the GI–GREI system that integrates GI suitability and pipe-network importance assessments and evaluates the Pareto set through entropy-weighted TOPSIS. Across multiple rainfall return periods, the study explores optimal trade-offs between UDS resilience and LCC. Compared with the scenario where all suitable areas are implemented with GI (maximum), the TOPSIS-optimal schemes reduce total life-cycle cost (LCC) by CNY 3.762–4.298 billion (53.36% on average), rebalance cost shares between GI (42.8–47.2%) and GREI (52.8–57.2%), and enhance UDS resilience during periods of higher rainfall return (P = 20 and 50). This study provides an integrated optimization framework and practical guidance for designing cost-effective and resilient GI–GREI systems, supporting infrastructure investment decisions and climate-adaptive urban development. Full article

Blue carbon ecosystems, particularly mangroves, seagrasses, and salt marshes, play a crucial role in climate regulation by capturing and storing huge stocks of carbon. Together with supporting fisheries production, protecting shorelines from erosion, and supplying timber and non-timber products to communities, blue carbon ecosystems offer investment opportunities through carbon markets, thus supporting climate change mitigation and sustainable livelihoods. The current study assessed above- and below-ground biomass, sediment carbon, and the capacity of the blue carbon ecosystems in Kwale and Lamu Counties, Kenya, to capture and store carbon. This was followed by mapping of hotspot areas of degradation and the identification of investment opportunities in blue carbon credits. Carbon densities in mangroves were estimated at 560.23 Mg C ha⁻¹ in Lamu and 526.34 Mg C ha⁻¹ in Kwale, with sediments accounting for more than 70% of the stored carbon. In seagrass ecosystems, carbon densities measured 171.65 Mg C ha⁻¹ in Lamu and 220.29 Mg C ha⁻¹ in Kwale, values that surpass the national average but are consistent with global figures. Mangrove cover is declining at 0.49% yr⁻¹ in Kwale and 0.16% yr⁻¹ in Lamu, while seagrass losses in Lamu are 0.67% yr⁻¹, with a 0.34% yr⁻¹ increase in Kwale. Under a business-as-usual scenario, mangrove loss over 30 years will result in emissions of 4.43 million tCO₂e in Kwale and 18.96 million tCO₂e in Lamu. Effective interventions could enhance carbon sequestration from 0.12 to 3.86 million tCO₂e in Kwale and 0.62 to 19.52 million tCO₂e in Lamu. At the same period, seagrass losses in Lamu would emit 5.21 million tCO₂e. With a conservative carbon price of 20 USD per tCO₂e, projected annual revenues from mangrove carbon credits amount to USD 3.59 million in both Lamu and Kwale, and USD 216,040 for seagrass carbon credits in Lamu. These findings highlight the substantial climate and financial benefits of investing in the restoration and protection of the two ecosystems. Full article

Based on the strategy tripod framework, this study identifies 27 feature variables that influence the persistence of enterprise green innovation. In addition, utilizing data from Chinese listed enterprises between 2012 and 2022, this study employs machine learning models and the SHAP method to analyze the driving factors and their underlying mechanisms. The findings indicate that the persistence of enterprise green innovation results from multiple factors, among which enterprise size, R&D investment, and technological utilization capability rank as the top three most important determinants. Enterprise size has a positive linear effect on the persistence of green innovation, while market competition has a negative linear effect. R&D investment, technological utilization capability, enterprise green culture, financing capacity, and integration capability all show non-linearly positive effects. The conclusions provide theoretical guidance and micro-level evidence for promoting high-quality enterprise green development in enterprises and supporting governmental policy formulation. Full article

To address the challenges posed to the secure and reliable operation of the power grid under the “dual-carbon” goals, an optimal planning and investment return analysis method for grid-side energy storage system (GSESS) is proposed, with multi-dimensional grid security requirements being considered. By this method, a decision-making framework for the scientific planning of GSESS is provided, through which both technical and economic viability are balanced. Firstly, an evaluation indicator system for GSESS demand is established, in which loading stress, voltage quality, and renewable energy accommodation capacity are comprehensively considered. The candidate sites are then prioritized by a hybrid subjective-objective weighting method combined with the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Subsequently, the top 10% most severe scenarios are identified from historical operational data, and a set of typical extreme scenarios is extracted using an improved K-means clustering algorithm. Based on these scenarios, an optimal capacity planning model incorporating multi-dimensional security constraints is formulated, and the final planning scheme is thereby determined. Furthermore, with the objective of maximizing net revenue from multiple application scenarios, an optimal operational model for GSESS is established. The life-cycle costs and benefits are quantified, and a comprehensive investment return analysis is conducted accordingly. Finally, the proposed methodology is validated through a case study based on the 220 kV substations in QZ City of China. It is demonstrated by the results that through the application of the derived planning scheme, the operational security of the power grid is significantly enhanced, and a promising outlook for investment returns is also exhibited. Full article

The specialization of tea gardens represents a significant pathway to enhancing the international competitiveness of agriculture. However, it may also disrupt the supply–demand balance of ecosystem services. This study addresses this gap by focusing on the specialized tea zone of Anxi as a case study. Using the InVEST model, we quantitatively assessed four key ecosystem services between 1990 and 2020: carbon storage, habitat quality, water yield, and soil conservation. The findings reveal that tea gardens perform relatively well in terms of carbon storage and habitat quality. However, their capacity for water conservation is limited, and soil conservation is highly susceptible to human disturbance. Dynamic transitions between tea gardens and forests have exerted considerable influence on changes in ecosystem services, with policies and practices aimed at converting tea plantations back to forest demonstrating a positive role in ecological restoration. Finally, guided by the principles of nature-based solutions, this study proposes targeted strategies to provide scientific support and practical references for sustainable development in specialized agricultural regions. Full article

This study aims to evaluate the operational efficiency of electric vehicle (EV) charging stations and explore optimization strategies to enhance resource utilization and service performance. A systematic review approach was first applied to identify the main evaluation indicators and influencing factors from existing studies. Subsequently, a super-efficiency Data Envelopment Analysis (DEA) model was used to assess the efficiency of six EV charging stations in a certain City, China. The robustness analysis was carried out, and the output variables were replaced, and the evaluation results did not change. The results show substantial disparities in efficiency across stations: C1 exhibits the highest operational efficiency, while C3 performs the lowest. The inefficiencies primarily result from supply–demand mismatches and redundant capacity investment. Based on these findings, the study proposes both overall and localized optimization strategies to improve operational performance. The results provide valuable insights for urban energy infrastructure planning and contribute to the enhancement of high-quality, low-carbon transportation development in China. Full article

The conversion of CO₂ into valuable chemicals such as formic acid offers a promising approach to reducing CO₂ emissions. This study presents a techno-economic assessment of two continuous catalytic processes for formic acid production via carbon dioxide (CO₂) hydrogenation. The processes differ in the type of nitrogenous base used, operating under either homogeneous or heterogeneous catalytic conditions. Process simulations and techno-economic evaluations were performed in SuperPro Designer^TM for a medium-scale facility with an annual CO₂ processing capacity of around 14 kMT. The homogeneous catalysis pathway demonstrated superior plant performance, producing 13.03 kMT of formic acid per year at 99.78% purity. In contrast, the heterogeneous pathway required higher capital investment and exhibited lower overall efficiency. The techno-economic analysis confirmed the economic viability of the homogeneous process, with a production cost of $1.18/kg and favorable investment indicators, whereas the heterogeneous route proved economically unattractive under the evaluated assumptions. Sensitivity analysis identified the selling price of formic acid as the most critical profitability parameter, with the homogeneous process remaining robust across varying conditions. Overall, homogeneous catalytic CO₂ hydrogenation demonstrates a technically efficient and economically promising process for the chemical transformation of CO₂, contributing to carbon management. Full article

To address the problem of uncoordinated operation between distributed generation (DG) inverters and dedicated power quality devices, this paper proposes a coordinated optimization model for harmonic and voltage compensation in microgrids. The model considers the capacity constraints of DG inverters and compensation devices, aiming to realize efficient utilization of multi-resource compensation capabilities. A dual-objective optimization framework is established, which simultaneously minimizes total economic cost and enhances overall power quality performance. The first objective function reflects investment and operational costs, while the second quantifies system performance through total harmonic distortion (THD) and average voltage deviation (AVD). The Normal–Normal Constraint (NNC) method is adopted to ensure optimization stability and feasible trade-offs between the two objectives. The proposed approach is validated on the IEEE 33-bus microgrid system, and its results are compared with traditional heuristic algorithms such as PSO. Simulation results show that the proposed method effectively reduces total operating cost while significantly improving harmonic and voltage compensation performance. This study provides a practical reference for coordinated power quality management in microgrids. Full article

Investigating how drought and flooding stresses interact during drought–flood abrupt alternation events and their impact on rice photosynthetic carboxylation capacity ($V_{cmax}$) is critical for improving crop growth and yield models under environmental stress conditions. However, there is limited research on the specific role of these combined stresses on $V_{cmax}$ in rice. This study aims to address this gap by examining the effects of drought and flooding on rice $V_{cmax}$. Using data from drought–flood experiments conducted in 2017 and 2018, we calculated $V_{cmax}$ by combining observed gas exchange parameters with photosynthetic biochemical models. The results revealed that $V_{cmax}$ damage caused by drought and flooding stresses was eventually repaired. Notably, $V_{cmax}$ recovered more quickly when mild drought preceded flooding stress. In contrast, severe and moderate drought treatments showed synergistic effects, where the preceding drought and subsequent flooding exacerbated the damage to $V_{cmax}$. However, the pre-mild drought stress antagonistically mitigated the damage to $V_{cmax}$ of rice induced by flooding stress, showing an antagonistic effect. Additionally, rice increased intrinsic water use efficiency (${WUE}_i$; $A_n/g_s$) by increasing investment in $V_{cmax}$ after drought and flooding stress, but rice yield was not improved. The preceding drought is probably beneficial for yield of rice experiencing subsequent flooding stress at relatively low $V_{cmax}$, while subsequent flooding stress exacerbated the reduction in yield of rice experiencing preceding drought stress. This research enhances our understanding of how the interaction between drought and flooding affects rice’s photosynthetic capacity and emphasizes that appropriate drought and flooding management may have potential optimizing effects on rice yield and water use, and provides an important theoretical basis and practical guidance for paddy water management. Full article