Search Results (9,649)

Maritime transport is a major component of global supply chains, but reducing its atmospheric emissions remains essential to improving the environmental sustainability of shipping. This study analyzes onboard emission data reported for the MV Ilshin Green Iris under real-world operating conditions to assess how fuel selection affects the direct-emission performance of a dual-fuel marine propulsion system. The vessel is equipped with a MAN B&W 6G50ME-C9.5-GI engine employing high-pressure dual-fuel (HPDF) technology. A quantitative comparison between heavy fuel oil (HFO) and liquefied natural gas (LNG) was performed at 50% of the maximum continuous rating (MCR). At 50% MCR, LNG reduced CO₂ emissions by 27.0%, NOx emissions by 20.7%, and CO emissions by 18.2% relative to HFO, while PM showed an indicative reduction of approximately 69%; its precise magnitude remains uncertain because a complete PM uncertainty budget was unavailable. Over the 900 s measurement period, the estimated reduction in CO₂ mass was 154 kg. During LNG operation, the specific CH₄ emission at 50% MCR was approximately 0.6 g/kWh. Using a 100-year global warming potential of 29.8 for fossil CH₄, this corresponds to approximately 17.9 g CO₂-eq/kWh, equivalent to about 10.5% of the direct CO₂ reduction between HFO and LNG at this operating point. The results are representative of the analyzed stabilized operating point rather than of the vessel’s complete operational profile. The main contribution of this study is a structured matched-load analysis of HFO and LNG emissions from the same HPDF marine engine. The analysis combines measurement-derived specific emissions with energy-based mass estimates, methane-related limitations, data-quality considerations, and regulatory and sustainability implications. Because both fuels were evaluated in the same engine at the same 50% MCR operating point, the study provides a consistent basis for assessing fuel-related differences within the limits of the available dataset. Full article

Geopolitical instability can reshape trade routes, prices, and energy-security risks. Using a monthly country-level panel from January 2015 to June 2025, this study estimates a difference-in-differences (DID) model for the logarithm of China’s fossil-fuel import values (USD) from Russia and four Central Asian suppliers relative to seven comparison suppliers. The corrected benchmark coefficient is −0.582. This estimate means that after March 2022, import values from the treated suppliers were lower relative to the counterfactual trend represented by the control group; it does not mean that every treated supplier experienced an absolute decline. Indeed, several country- and commodity-specific import values increased in levels, partly because the outcome combines quantity and price effects. Commodity-specific international price benchmarks are included as controls, but physical-volume data are not available in the submitted dataset. With only 11 country clusters, conventional clustered significance levels are interpreted cautiously. A 500-assignment placebo exercise provides a randomization-based robustness check, with no simulated coefficient as extreme as the benchmark estimate (empirical p ≤ 0.002 under the stated assignment scheme). Logistics performance, government stability, and energy OFDI are positively associated with import values in conditional regressions; because the article does not report interaction terms, these results are not interpreted as moderation effects. The findings support targeted attention to corridor reliability and supplier diversification, while broader operational policies require additional evidence. Full article

The addition of hydrogen to diesel engines is increasingly being seen as a promising interim solution to reduce fossil fuel consumption and carbon emissions without changing the basic architecture of the compression-ignition engine. This study experimentally evaluated the effect of hydrogen addition on the combustion, performance and emissions characteristics of a single-cylinder AVL 5402 Common Rail diesel engine when hydrogen was supplied via the intake manifold and diesel injection parameters were kept constant. The tests were performed at engine speeds of 1200, 1500, 2000 and 2500 min⁻¹ and loads of 5, 10, 15, 20 and 25 Nm, using a hydrogen mass replacement level of up to 10%. It was found that the addition of hydrogen in many modes increased the maximum cylinder pressure, accelerated the pressure rise, brought the pressure peak earlier and increased engine power, especially at higher loads and speeds. At the same time, fuel consumption decreased in all modes, and CO₂ emissions decreased by 3–22.7%. However, it was found that the addition of hydrogen usually increased NOx emissions; in some modes, it increased particulate and hydrocarbon emissions and extended the total combustion duration due to the reduced oxygen concentration and the formation of a richer mixture. The results showed that the effect of hydrogen on the operation of a diesel engine is strongly dependent on the load and speed; therefore, the benefits of its application can be achieved only under carefully coordinated operating conditions that ensure a favorable compromise between combustion intensification, fuel economy and emission control. Full article

Global population growth, climatic extremes and rising resource pressures necessitate innovative agricultural methods to boost food, feed, fibre and fuel production sustainably. Seed enhancement technologies (SETs), such as seed coating and priming, have emerged as effective strategies to improve seed viability and vigour, seedling establishment and overall crop yield. Conventional seed treatments include seed coating (film coating, encrusting, pelleting) and seed priming (hydro-, osmo-, halo- bio-, nutri-, hormonal-, chemical- and solid matrix priming). They offer advantages such as improved seed handling, uniform germination and promotion of early growth. However, they also have significant drawbacks, including on soil health and off-target pollution from synthetic polymers and pesticides, seed longevity issues from re-drying and outcomes that can vary among different crops, soils and environments. To tackle these issues, new non-traditional SETs are being investigated, including nanotechnology, novel biodegradable coatings and agrichemical-free biostimulants, such as plant growth promoting microorganisms. These innovative methods demonstrate great promise in enhancing active and crop performance while minimising environmental impacts by providing alternatives to materials derived from fossil fuels and that contribute to waste and pollution. This review critically examines both conventional and novel SETs, discusses their pros and cons and outlines strategic research and industry directions to enhance agricultural sustainability and productivity in light of global food and resource security challenges. Full article

The combined elasticity, processability, and recyclability of thermoplastic elastomers (TPEs) has enabled their widespread adoption across diverse industrial sectors. In particular, TPEs have emerged as attractive alternatives to chemically crosslinked elastomers, contributing to extended product lifetimes and reduced waste generation. Their performance arises from the presence of physical, reversible crosslinks, which allow the integration of elastomeric behaviour with thermoplastic reprocessability. This review provides an overview of recent advances in ABA thermoplastic elastomer (TPE) design, focusing on three major classes: styrenic block copolymers, acrylic-based TPEs, and emerging bio-based systems, with particular emphasis on the latter. Special attention is given to structure–property relationships and the influence of molecular architecture on thermomechanical behaviour. Styrenic block copolymers remain the most established class, offering well-defined phase-separated morphologies and tuneable mechanical properties. Acrylic-based TPEs have attracted increasing interest owing to their superior thermal and oxidative stability and versatile molecular design. We also discuss recent progress in bio-based TPEs derived from renewable resources, which aim to reduce reliance on fossil feedstocks without compromising performance. Finally, we examine current challenges and future perspectives, highlighting the need for sustainable synthetic strategies and advanced TPEs with lower environmental impact. Full article

Digital empowerment has become deeply embedded in global production networks, yet its implications for sectoral energy systems remain insufficiently understood. This study investigates whether digital empowerment is associated with sectoral energy-structure transition and through which channels. Using matched World Input–Output Database accounts for 2000–2014 and applying the Hypothetical Extraction Method (HEM), we measure digital empowerment at the country–sector level and examine its association with sectoral energy-use outcomes. The estimates indicate that digital empowerment is associated with a lower fossil-fuel share and lower total sectoral energy consumption in the full sample, although the associations differ across non-fossil energy categories, sectors, and development stages. Additional channel-based tests show that digital empowerment is associated with lower energy intensity, improved global value-chain positioning, and higher export technological sophistication. Both domestic and foreign digital inputs contribute to this relationship, and manufacturing sectors show a clearer association with lower total energy consumption than service sectors. Developing economies exhibit weaker compositional adjustment than developed economies. These findings provide empirical evidence for integrating digitalization into energy transition strategies and offer practical pathways for aligning digital economic development with sustainable energy objectives. Full article

Industrial legacy cities are trapped in carbon lock-in—a self-reinforcing condition where fossil-fuel infrastructure, industrial structures, and institutional inertia collectively resist urban energy transition. Yet whether and how industrial upgrading policies (IUP) can effectively disrupt this lock-in remains unclear. Using panel data from 148 Chinese legacy cities over 2012–2022, we employ a staggered difference-in-differences model combined with policy-text quantification to evaluate the effects of IUP. Results show that IUP significantly raises urban energy transition by 2.52 percentage points, with technology-enabling instruments delivering the strongest leverage among the three policy tool categories. Mechanism analysis uncovers a co-evolutionary mismatch: green technology innovation mediates 42.21% of the total effect, while the mediating pathway through energy consumption structure remains statistically insignificant—evidence that production-side innovation and energy-side infrastructure exhibit systematically divergent adjustment elasticities in response to industrial upgrading policy. Policy effects also differ across city types, with stronger responses in old industrial base, regenerative, and single-type cities. These findings advance carbon lock-in theory by identifying co-evolutionary mismatch as a distinct source of structural friction in urban industrial transitions and provide actionable pathways for aligning urban industrial restructuring with decarbonization goals. Full article

Rapid population growth, urbanization, and industrialization are continuously increasing global energy demand while intensifying climate change associated with fossil fuel consumption. In this context, renewable energy production from organic waste has gained increasing attention as a sustainable and environmentally friendly strategy. Anaerobic digestion (AD) offers significant potential for simultaneous waste stabilization and biomethane generation. However, many previous studies investigating lignocellulosic or nutrient-rich substrates have relied on physical, chemical, or thermal pretreatment methods to enhance biodegradability, despite their additional operational costs, energy consumption, and environmental impacts. Therefore, developing low-cost and pretreatment-free co-digestion strategies remains an important research need. This study investigated the biomethane production potentials of untreated chicken manure (CM) and duckweed (Lemna minor-LM) collected from the final sedimentation tanks of wastewater treatment plants under mono-digestion and co-digestion conditions. The study hypothesized that rapidly growing and widely available LM biomass could enhance methane production without requiring pretreatment. Among all reactors, CM0.75 (75% of the total TS derived from CM and 25% from LM and inoculum) achieved the highest performance with a cumulative biogas production of 5350 mL (74.2% of CH4) and a methane yield of 327 mL CH4/g VS, while mono-digestion of CM resulted in the lowest methane yield of 104 mL CH4/g VS. The results demonstrated that LM biomass naturally proliferating in wastewater treatment plants can be directly utilized as an effective co-substrate to improve biomethane production from poultry wastes. The proposed approach provides a cost-efficient, eco-friendly, and circular-economy-oriented alternative by eliminating the need for pretreatment while simultaneously valorizing problematic biomass generated in wastewater treatment facilities. Full article

This research presents a comprehensive diagnosis of Ecuador’s electricity generation (2003–2024), focusing on structural vulnerabilities, fuel dependence, and Greenhouse Gas (GHG) emissions from electricity generation. The technological composition of the grid, including installed and effective capacity, as well as the share of fossil and organic fuels, is analyzed to construct a coherent analytical framework. GHGs (i.e., CO₂, CH₄, and N₂O) are estimated from fuel consumption in Non-Conventional Renewable Energy (NCRE) and Non-Renewable Energy (NRE), in accordance with the 2006 IPCC Guidelines. Conversion to CO₂ equivalent utilizes the AR5 GWP factors, in agreement with AR6. The results present annual series for each gas and their corresponding CO₂ equivalents, showing that NREs dominate the CO₂ profile, while NCREs contribute significantly to CH₄ and N₂O. Despite the expansion of installed capacity, a gap persists with effective capacity, reflecting the structural vulnerabilities of Ecuador’s electricity generation system, including exposure to hydrological variability (Kraftnōt, referring in this research to electricity shortages caused by reduced hydropower generation under adverse hydrological conditions), insufficient thermal backup, a high concentration of hydropower plants, fluctuating fossil fuel subsidies, and limited diversification. This manuscript provides a technical and quantitative basis using annual CO₂, CH₄, and N₂O values and their CO₂ equivalents to inform future decarbonization scenarios that strengthen NCRE integration within international climate commitments and a sustainable electricity transition. Full article

The energy transition of post-mining regions requires not only the replacement of fossil fuel-based technologies but also the restructuring of infrastructures, institutions, labour markets, local economies and social relations shaped by mining and conventional energy production. This article develops a conceptual framework of cascading lock-ins through a critical literature review and conceptual synthesis of research on path dependence, carbon lock-in, socio-technical transitions, just transition and regional governance. The framework distinguishes infrastructural, technological, institutional and social lock-ins and examines the mechanisms through which constraints are transmitted and reinforced across these domains. Cascading is defined as a context-dependent process in which a mechanism operating in one domain changes the incentives, capabilities, decisions or expectations in another, potentially generating cumulative effects and feedback. The main contribution of this study lies in shifting attention from the classification of individual barriers to the cross-domain transmission mechanisms through which they reproduce regional transition inertia. The conceptual synthesis suggests that addressing cascading lock-ins requires coordinated interventions linking infrastructural modernisation, technological and economic diversification, institutional reform, skills development and meaningful community participation. Full article

Understanding how globalization, energy transition, and resource dependence shape environmental pressure remains critical for resource-rich economies seeking sustainable development. This study investigates the determinants of ecological footprint per capita in the United Arab Emirates from 1992Q1 to 2020Q4 by extending the STIRPAT framework to incorporate scale effects, structural composition, technological mitigation, and a globalization–renewable energy interaction channel. The empirical strategy combines ARDL cointegration modeling, Ridge regression and annual frequency estimations for robustness assessment, wavelet coherence analysis, and ARDL-ECM Granger causality tests. The results show that economic growth increases ecological footprint in the short run, reflecting persistent affluence-related scale effects. In the long run, economic globalization and natural resource rents significantly increase ecological footprint, suggesting that trade- and hydrocarbon-driven composition effects outweigh potential efficiency gains during the study period. Renewable energy consumption exerts a negative long-run elasticity, indicating its technological mitigation role. However, the positive globalization–renewable energy interaction indicates that expanding economic integration partially offsets the environmental benefits associated with renewable energy deployment. Wavelet coherence analysis reveals that these relationships vary across time and frequency horizons, with globalization exhibiting leading associations with ecological pressure at medium-term frequencies, while Granger causality identifies significant predictive pathways toward ecological footprint dynamics. The findings remain consistent across robustness assessments and suggest that renewable energy contributes to reducing ecological pressure, but achieving substantial ecological decoupling requires both fossil fuel substitution and structural transformation in globalization and resource-dependent development pathways. This study provides evidence-based insights for supporting sustainability transitions in resource-dependent economies and advancing progress toward the SDGs. Full article

Considering carbon neutrality and fossil fuel depletion, biomass is becoming increasingly important as a renewable and sustainable energy source. However, understanding of process-dependent characteristics relevant to char production remains limited. This study investigated the carbonization of mushroom waste medium (MWM) via conventional carbonization (CC; i.e., pyrolysis), hydrothermal carbonization (HTC), and microwave-assisted carbonization (MAC), and evaluated their suitability for desired char properties and target applications. For all methods, increasing reaction temperature led to carbon densification, with decreased oxygen and hydrogen contents and increased carbon and fixed carbon fractions. However, the extent of these transformations depended on the reaction environment. HTC achieved carbon enrichment and the highest higher heating value (HHV) at relatively low temperatures. In contrast, CC required higher temperatures to achieve comparable carbonization levels but showed a marked increase in BET surface area at higher temperatures. MAC exhibited intermediate characteristics under moderate conditions. HTC also facilitated potassium and chlorine removal, which may reduce operational issues during thermal utilization. These results indicate trade-offs among carbon densification, char yield, surface structure, and inorganic matter content. Rather than identifying a universally superior process, this study demonstrates that the suitability of each method depends on the desired properties and applications of MWM-derived char, providing a practical basis for appropriate process selection. Full article

Sustainable finance increasingly treats green assets as instruments for climate-risk hedging; however, it remains unclear whether they protect investors during energy-market shocks and financial-market stress or merely transmit different transition, equity-market, and growth risks. This study asks whether green assets hedge better than brown assets, or whether the two asset classes hedge different risks across market states. Using daily data from 2010 to 2025 on exchange-traded clean-energy, fossil-fuel, green-bond, ESG, and market-risk instruments, we construct green and brown portfolios and analyze the green–brown return spread across normal conditions, high-volatility regimes, market-stress days, positive and negative oil-price shocks, the COVID-19 crisis, and the recent energy-crisis period. The empirical design combines performance and downside-risk metrics, rolling correlations and betas, Newey–West regressions, stress-state comparisons, quantile regressions, portfolio allocation tests, and supplementary machine-learning classification. The results reveal strong oil-shock asymmetry: brown assets outperform during positive oil-price shocks, while green assets perform relatively better when oil prices fall sharply. However, green assets do not function as broad safe havens during financial-market stress, reflecting persistent equity-market downside exposure and growth-factor repricing. Quantile regressions confirm nonlinear and state-dependent risk transmission, while portfolio tests show weak full-sample return-risk performance for clean-energy equity exposure alone. Shorter-sample suggests that green bonds and ESG assets display more defensive characteristics, whereas machine-learning models show limited short-horizon predictive power. Green assets are therefore not universal hedges but conditional transition-risk assets whose value depends on the shock source, market regime, and sustainable instrument. Full article

The global plastic pollution crisis demands a fundamental re-evaluation of materials systems beyond incremental improvements to fossil fuel-based polymers. Bioplastics, polymers derived from renewable biological feedstocks, biodegradable under defined conditions, or both, offer a chemically diverse and rapidly evolving platform for transitioning toward circular materials economies in which the value of carbon, energy, and material is retained across multiple use cycles. This review provides a comprehensive and critically organized account of the bioplastics field, spanning three generations of feedstock development from food crops through lignocellulosic residues to algae and waste streams; primary production pathways including microbial fermentation, ring-opening polymerization, and biosynthesis; forming processes from extrusion and injection molding to additive manufacturing; and the mechanical, thermal, and barrier properties that determine application fitness. Particular emphasis is placed on life cycle assessment, which reveals that bioplastics’ climate benefits are conditional on feedstock choice, land-use management, energy source at manufacturing, and end-of-life pathway, and that burden-shifting from greenhouse gas emissions to land use, water consumption, and eutrophication is a systematic risk requiring integrated LCA evaluation rather than single-metric optimization. The review further examines end-of-life recycling, composting, and biodegradation pathways; market applications across packaging, agriculture, automotive, biomedical, and electronics sectors; and the growing role of artificial intelligence and machine learning in accelerating materials design, process optimization, and lifecycle data management. Critical barriers to scale, such as cost premiums of 20–75% over conventional plastics, inadequate composting infrastructure, recycling stream contamination, regulatory fragmentation, and consumer labeling confusion, are systematically analyzed alongside mitigation strategies. The review concludes with a forward-looking discussion of emerging feedstocks, smart and functional bioplastics, and the policy and infrastructure investments required to translate the environmental promise of bio-based polymers into realized circular economy impact. Full article