Search Results (1,275)

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

Higher education institutions are increasingly expected to reduce greenhouse gas emissions while maintaining reliable educational, laboratory, and administrative operations. This challenge is particularly relevant in transition economies, where university campuses often depend on fossil-fuel-based electricity systems, natural-gas heating, and aging infrastructure. This study presents a campus-scale decarbonization assessment for the Tashkent Institute of Chemical Technology in Uzbekistan. The quantified inventory covered Scope 1 emissions from natural-gas combustion and Scope 2 emissions from purchased electricity. Paper use, digital services, behavioural measures, and campus greening were assessed as supplementary institutional indicators and were excluded from the quantified total because consistent pre- and post-intervention activity data were unavailable. The assessment combined institutional utility records for 2023–2025 with information on renewable-energy deployment, heating modernization, digital transformation, sustainability awareness, and campus greening. A 300 kW solar photovoltaic system comprising 666 modules was commissioned in May 2023, with a documented annualized generation potential of approximately 520,000 kWh. Purchased grid electricity amounted to 711,402, 745,947, and 749,060 kWh in 2023, 2024, and 2025, respectively, while annual natural-gas consumption was 144,775, 161,200, and 142,031 m³. Using a conservative standard-based net calorific value of 31.8 MJ/m³ together with IPCC stationary-combustion factors, annual Scope 1 and Scope 2 emissions were estimated at 637.53, 685.29, and 652.65 tCO₂-eq, respectively. The 2025 total was 4.76% below the 2024 value but 2.37% above the 2023 value. The annualized PV technical potential corresponds to a theoretical maximum Scope 2 displacement of 276.64 tCO₂-eq/year under 100% self-consumption. This value does not represent measured generation or a realized emission reduction and was not included in the quantified inventory. Digitalization, behavioural engagement, and greening were evaluated as complementary measures rather than assigned separate emission-reduction credits. The study provides a transparent and regionally relevant framework for universities in transition economies seeking to strengthen campus carbon management under incomplete data conditions. Full article

The urgent need for bio-based functional materials has driven a shift away from fossil-fuel-sourced materials toward renewable lignocellulosic biomass (LCB). This comprehensive review explores the advancements in LCB carbonization between 2020 and 2026, marking a shift from traditional, low-yield combustion processes toward highly selective and sustainable thermochemical conversion pathways. The primary objective of this review is to evaluate the integration of green pretreatment strategies, conversion technologies, and efficient valorization of the aqueous effluents and by-products. The goal of green pretreatment is to overcome the inherent recalcitrance of LCB without the use of harsh chemicals and reaction conditions, specifically highlighting the effectiveness of deep eutectic solvents (DESs) and ionic liquids (ILs). The review also evaluates the emerging conversion technologies, including hydrothermal carbonization (HTC), microwave-assisted pyrolysis (MAP), and the synergistic co-pyrolysis of LCB with synthetic polymeric wastes. Another novel concept in preparing hard carbon and other related materials is the “lignin-first” biorefinery strategy, which facilitates the subsequent production of high-value aromatic monomers, platform chemicals, and biofuels. The engineered carbon materials are increasingly utilized well beyond their traditional use as solid fuels. The products have been proven to be excellent for use in high-performance energy conversion and storage, serving as renewable bio-based electrode materials for supercapacitors and carbon electrodes in next-generation batteries. Full article

Provincial power systems must decarbonize while sustaining rapid demand growth and improving air quality; yet, few integrated assessments separate the contributions of renewable expansion and carbon capture, utilization, and storage (CCUS) for China’s less-developed regions. We apply the Low Emissions Analysis Platform (LEAP) to model Guangxi’s power system to 2060 under four scenarios—Reference (BAS), Renewable-driven (RES), CCUS-intensive (CCS), and an Integrated comprehensive-policy scenario (ICS). Under ICS, solar photovoltaic generation rises from 38 TWh in 2025 to 408 TWh in 2060 (close to half of all generations), non-fossil capacity grows by about 730%, and power-sector CO₂ falls by roughly 95% relative to BAS. A counterfactual decomposition shows that CCUS provides about 75% of the CO₂ reduction along the coal-retaining CCS pathway but only about 5% along the renewables-led ICS pathway and reduces neither SO₂ nor NO_x. The air-quality co-benefits—up to 82%, 78%, and 73% lower SO₂, NO_x, and PM_2.5 than BAS—arise mainly from renewable substitution, which also abates carbon more cheaply (about 120–190 versus 300 CNY t⁻¹ CO₂) while sharply raising flexibility needs. Once avoided fuel and carbon-market costs are included, the renewables-led pathways become net cost-saving on a full-system basis and yield a monetized air-quality health co-benefit roughly twice that of the CCUS-intensive route. The findings give policy-relevant guidance for sustainable low-carbon transitions in Guangxi and comparable emerging regions. Full article

Global energy-related carbon dioxide (CO₂) emissions reached approximately 37.4 Gt in 2023, reflecting continued dependence on fossil fuels. In the Philippines, coal accounted for about 62% of total electricity generation in 2023, highlighting the need for renewable and lower-carbon fuel alternatives. At the same time, increasing urbanization has intensified municipal solid waste generation, with fruit and vegetable residues (FVRs) comprising a substantial biodegradable fraction. This study investigated the effects of torrefaction temperature and residence time on the physicochemical properties, fuel quality, and structural transformation of heterogeneous market-derived FVR to assess its potential as a renewable torrefied solid fuel. Torrefaction was conducted in a batch, crucible-based muffle-furnace system using a full factorial 2² design at 200 and 300 °C and residence times of 30 and 90 min, with three replicates per condition. Each covered 100 mL alumina crucible was loaded with 50.0 g of oven-dried, milled, and homogenized feedstock. The crucibles were initially purged with nitrogen, and residence time was counted after the furnace reached the target temperature. Product performance was evaluated through mass and energy yields, proximate analysis, higher heating value (HHV), fuel ratio, visual comparison, Fourier Transform Infrared (FTIR) spectroscopy, and analysis of variance (ANOVA). Temperature exerted the largest statistical effect on mass yield, HHV, and fuel ratio. Mean mass yield decreased from 96.05 ± 1.00% at 200 °C/30 min to 46.97 ± 0.51% at 300 °C/90 min, while HHV increased from 20.75 ± 0.06 MJ kg⁻¹ in the untreated feedstock to 25.97 ± 0.80 MJ kg⁻¹. Volatile combustible matter decreased from 76.30 ± 0.36% in the untreated feedstock to 41.60 ± 2.40% at 300 °C/90 min, whereas fixed carbon increased from 18.13 ± 0.49% to 45.50 ± 3.42%. The fuel ratio increased from 0.238 ± 0.007 in the untreated feedstock to 1.099 ± 0.142. FTIR spectra showed weaker hydroxyl and aliphatic C–H bands and a more pronounced aromatic C=C band near 1600 cm⁻¹ as severity increased, consistent with progressive darkening and carbonization. Lower torrefaction severity favored solid and energy retention, whereas higher severity improved energy density and carbonization. The products should be regarded as potential renewable solid fuels or co-firing materials; ultimate analysis, combustion performance, and NO_x/SO_x emissions require further evaluation before direct coal-substitution claims can be made. Full article

This study presents a mathematical programming approach for the optimal design of a renewable energy system in a grid-connected public building, incorporating green hydrogen production for surplus energy storage. The system includes wind turbines, solar panels, batteries, a hydrogen unit, and a grid connection. Hydrogen can also be sold as vehicle fuel, generating revenue and reducing the environmental impact. Unlike traditional hydrogen smart grid models that rely on continuous capacity variables—which often yield non-commercial fractional unit sizes—our MILP framework strictly enforces discrete equipment capacities matching real-world procurement specifications. The methodology is applied to the Chemical Engineering Department Building at the University of Patras, Greece, with two objectives: minimizing annual cost and minimizing carbon dioxide emissions. While higher grid electricity tariffs increase absolute total energy costs, they significantly enhance the economic competitiveness and payback of local renewable energy and green hydrogen installations, shifting the optimal system configuration toward self-sufficiency and deep decarbonization. Emission minimization achieves substantial reductions with acceptable economic trade-offs, mainly through hydrogen replacing fossil fuels in transport. A GAMS-based model demonstrates that integrating renewables and hydrogen storage can enhance energy security, lower costs, and reduce the environmental impact in public buildings. Full article

This paper evaluates whether hydrogen-based marine fuels were financially feasible in the European maritime sector in mid-2026 without subsidies, grants, contracts for difference, preferential carbon-price treatment, or other public subventions. A techno-economic model compares pure hydrogen fuel cells, hydrogen internal combustion, ammonia combustion and fossil marine fuels for general cargo ships, container ships and passenger liners. The model combines 2026 bunker quotations, fuel-energy properties, EU ETS exposure, FuelEU Maritime requirements, ammonia cost evidence and scenario assumptions for delivered renewable hydrogen. Results show that fossil-fuel-equivalent useful propulsion costs remain substantially lower than hydrogen and ammonia alternatives under a no-support baseline. Current EU policy narrows the gap but does not close it. The hypothesis is confirmed: in mid-2026, hydrogen-based propulsion is not commercially feasible without public support, except for exceptional pilots and premium fixed-route niches. Under the paper’s central scenarios, unsubsidised parity is unlikely before 2032–2035 for short routes and 2035–2040 for larger vessels. Green methanol is treated as a complementary hydrogen-derived pathway whose easier storage and handling may favour selected services, although its lifecycle benefit depends on renewable hydrogen and a sustainable carbon source. Full article

India’s rapid expansion of utility-scale solar photovoltaic (PV) capacity is increasingly constrained by aging assets and the temporal mismatch between generation and peak demand. This study develops a techno-economic framework integrating battery energy storage systems (BESSs) with repowered solar PV projects, using repowered electricity as a low-cost charging source. A capacity-based assessment estimates national repowering potential of 7.2 GWp under power purchase agreement constraints and 10.9 GWp under technical limits. The levelized cost of repowered electricity is ₹1.40/kWh, significantly lower than prevailing utility-scale solar tariffs under stated assumptions. Levelized storage costs range from ₹5.08 to ₹4.12/kWh for 2–6 h durations, declining with improved inverter and balance-of-system utilization. Financial analysis under a ₹10 per kWh peak tariff arbitrage scenario yields internal rates of return between 17.5% and 24.2%, with positive project viability across configurations. Sensitivity analysis identifies capital cost as the dominant economic driver. Environmental benefits include annual greenhouse gas reductions of 13.8–17.2 MtCO₂, accumulating to 411–514 MtCO₂ over the project lifetime. These findings demonstrate that repowering-integrated battery storage offers a cost-effective, scalable pathway to enhance renewable integration, displace fossil fuel peak generation, and support India’s low-carbon transition, highlighting a viable framework for improving system flexibility and overall system performance. Full article

Despite rapid global growth in renewable energy capacity, fossil fuels still dominate the energy mix. Renewable energy firms often face limited access to bank credit because their asset-light, technology-intensive business models provide little collateral, constraining investment in clean energy deployment. This study examines whether China’s Fintech Reform Pilot Zones, which introduce digital technology-based credit evaluation, can alleviate these financing constraints and accelerate corporate energy transition. Using a staggered difference-in-differences design on a panel of Chinese listed renewable energy firms, we find that pilot zone designation significantly improves firms’ access to external financing and increases Energy Transition Depth (ETD) by approximately 3.6 percentage points, equivalent to 24.7% of the sample mean, indicating economically meaningful improvements in corporate energy transition. The strongest effects are observed in solar photovoltaic deployment and battery storage penetration. Greater energy transition is also associated with lower firm-level greenhouse gas emission intensity, suggesting potential environmental benefits. Mediation analysis identifies two complementary pathways: an innovation-accumulation route which advances renewable energy technology, and a capital-deployment route which supports renewable energy capacity expansion by relaxing firms’ general financing constraints. Regions with more developed renewable energy industries also exhibit lower fossil energy consumption and carbon emissions, suggesting potential regional spillover effects. These findings demonstrate that Fintech-enabled financial reform can facilitate renewable energy deployment and support broader energy transition and decarbonization, with important implications for emerging economies. Full article

This study examines the association between the fossil fuel share in electricity generation, energy-related climate change mitigation technologies, and CO₂ emissions in four selected major emitting economies—China, the United States, India, and Russia—over the period 1990–2023. Using an extended STIRPAT framework, the analysis considers both consumption-based and territorial CO₂ emissions per capita to distinguish between demand- and production-side perspectives on environmental responsibility. The fossil fuel electricity variable is measured as the combined share of electricity generated from coal, oil, and gas in total electricity generation and is further disaggregated into coal-, oil-, and gas-based shares. Energy-related technological innovation is proxied by the share of climate change mitigation technologies related to energy generation, transmission, or distribution among environment-related technologies. The baseline ECM and Driscoll–Kraay fixed-effects estimates indicate that the aggregate fossil fuel share in electricity generation is positively associated with both emissions measures, while the technology variable is negatively associated with emissions. However, the FMOLS estimates are less consistent, suggesting that long-run coefficients are sensitive to estimator choice. Country-level disaggregated estimates reveal substantial heterogeneity across fuels and countries, with coal-based electricity generation showing the most consistent positive association with emissions in China, India, and the United States. The findings suggest that electricity sector decarbonization in major emitters should prioritize coal substitution, renewable-energy deployment, grid modernization, and targeted energy-technology innovation, while climate responsibility assessments should consider both territorial and consumption-based emissions. Full article

The decarbonization of essential water supply infrastructure is a critical challenge for water-stressed and geographically constrained regions, particularly islands where both water and electricity systems are highly dependent on external or fossil-based resources. In Northern Cyprus, approximately 70% of domestic water demand is met through imported water via pipeline, while electricity generation relies predominantly on fuel oil, resulting in high greenhouse gas emissions and environmental burden. This study evaluates an integrated renewable energy-based supply system using a medium-scale concentrating solar power (CSP) plant with parabolic trough collectors coupled to thermal desalination. The proposed configuration is assessed as an alternative energy-driven infrastructure option for reducing dependence on imported water and fossil-based electricity. System performance was evaluated by estimating electricity and freshwater production under local climatic conditions, demonstrating that the proposed configuration can meet both the associated electrical energy requirements and domestic water demand in the selected region. A cradle-to-gate life cycle assessment (LCA) was conducted to quantify the environmental impacts of the integrated system and support sustainability-oriented decision-making. The LCA results identify residual fossil-based electricity, phosphoric acid consumption, and brine discharge as the main environmental hotspots. Overall, the findings show that CSP-driven desalination can provide a viable and more sustainable option for integrated energy and water supply in water-scarce coastal regions with high solar potential, highlighting its relevance for renewable energy integration, water-energy nexus planning, and resource-efficient infrastructure development. Full article

This research evaluates the feasibility of implementing photovoltaic solar systems in the Ecuadorian Amazon to harness solar energy and increase energy security in the region. It is based on the need to reduce direct dependence on fossil fuels and existing hydroelectric systems. The overall framework is to transform the energy matrix to utilize incident solar energy, integrating it with current hydroelectric and thermal generation. The fundamental goal is to evaluate the energy resource using specialized software such as Homer Pro and develop designs for the proper operation of photovoltaic solar technology, which will contribute its surplus energy to the National Interconnected System (SNI) and, therefore, reduce the country’s high dependence on the hydrological cycle. The results obtained demonstrate that solar power plants can be of great benefit to the country, especially when combined with wind and existing hydroelectric power. This will contribute to the diversification of energy sources and, consequently, to energy security through the increase in renewable energy. In the worst-case scenario, the cost of energy can be 7 cents per kWh, and in the best-case scenario, in a combined dispatch, 3 cents per kWh. Full article

Achieving the Sustainable Development Goals (SDGs) requires countries to simultaneously advance renewable energy transitions, environmental innovation, carbon efficiency, and sustainable governance mechanisms. Although previous research has extensively examined sustainability transitions and environmental sustainability, comparative assessments integrating renewable energy, environmental innovation, carbon efficiency, fiscal instruments, and fossil fuel dependency remain limited. Using 2023 data from 31 OECD countries, the study analyzes eight sustainability-related indicators through an integrated CRITIC-ARAS multi-criteria decision-making framework. The CRITIC method is employed to determine objective criterion weights, while the ARAS method evaluates countries’ performance relative to an ideal sustainability profile. The findings reveal considerable differences in sustainability performance across OECD countries. CO₂ emissions from air transport per capita emerge as the most influential criterion within the weighting structure. According to the results, Slovenia, Iceland, and Norway demonstrate the strongest transition performance. Countries with higher renewable electricity generation, stronger environmental innovation support, lower transport-related emissions, and lower fossil fuel dependency generally achieve better outcomes. Sensitivity analysis supports the overall stability of the ranking structure under alternative weighting scenarios, although the exclusion of the highest-weighted criterion produces noticeable ranking shifts for some countries. The results indicate that sustainability performance depends not only on environmental outcomes but also on countries’ ability to coordinate renewable energy policies, environmental innovation, fiscal instruments, and decarbonization strategies. From a policy perspective, the findings emphasize the importance of renewable energy expansion, environmental taxation, transport decarbonization, environmental R&D support, and fossil fuel subsidy reform for strengthening long-term sustainable development strategies. This study contributes to the sustainability assessment literature by providing a comparative and policy-oriented framework for benchmarking sustainability-oriented green transition performance across countries through integrated environmental, energy-related, and innovation-based indicators. Full article

Energy security has become a central policy challenge because decarbonisation must be achieved without weakening the reliability, affordability and resilience of national energy systems. This article examines whether and how energy transition policies contribute to national energy security, with particular attention to aggregate policy stringency, individual policy instruments, and renewable electricity deployment. The analysis uses a panel of 49 countries over 23 observed years between 2000 and 2023, excluding 2002, comprising 1127 country-year observations, and applies two-way fixed-effects models with Driscoll–Kraay standard errors. The aggregate Energy Policy Stringency Index has a positive but statistically insignificant coefficient in the contemporaneous model (0.421) and remains insignificant with one-, two- and three-year lags (0.187, 0.128 and –0.026, respectively). Renewable electricity generation is consistently positive and significant, with coefficients ranging from 0.071 to 0.090, indicating that actual renewable deployment is more closely associated with energy security than formal policy stringency. Policy-instrument decomposition shows that fossil fuel excise taxes have the strongest positive association, with coefficients from 1.554 to 1.082 in full-instrument models and from 1.614 to 1.077 in one-by-one robustness checks. Air emission standards have delayed positive effects, while some renewable-support and cross-sectoral tools show mixed results, indicating dependence on design and system readiness. Full article

This study investigates the asymmetric and heterogeneous effects of renewable energy, non-renewable energy, capital stock, labour, and trade openness on CO₂ emissions in BRICS countries over the period 1991–2022. The study applies a panel nonlinear autoregressive distributed lag (PNARDL) model to capture short- and long-run asymmetries, complemented by a panel quantile nonlinear ARDL (QNARDL) to assess distributional heterogeneity. Robustness is ensured using Fully Modified Ordinary Least Squares (FMOLS) and Robust Least Squares (RLS) estimators. The study is grounded in the Environmental Kuznets Curve (EKC) and Just Energy Transition Theory. The results reveal a stable long-run cointegrating relationship among the variables, with a significant error correction mechanism confirming convergence toward equilibrium. Renewable energy consumption consistently reduces CO₂ emissions in both the short and long run, while non-renewable energy significantly increases emissions, exhibiting strong asymmetric effects. Capital stock shows mixed dynamics, increasing emissions in the short run but reducing them in the long run when directed toward productive and efficient investments. Labour is found to reduce emissions in the long run, highlighting the role of human capital in supporting cleaner production. Trade openness generally increases emissions, reflecting energy-intensive trade structures. Quantile results confirm heterogeneity, with stronger renewable energy effects at higher emission levels and greater environmental gains from reducing fossil fuel dependence than from increasing it. The FMOLS and RLS estimations confirm robustness, reinforcing the negative relationship between renewable energy and emissions and the positive impact of non-renewable energy. The study recommends accelerated renewable energy deployment, fossil fuel phase-down strategies, and targeted green capital investment. It further emphasizes grid modernization and energy storage systems to enhance renewable integration, alongside labour reskilling and green trade policies. These coordinated strategies are essential for achieving sustainable decarbonization in BRICS economies. Full article