Search Results (1,269)

Controversy persists on a global scale regarding the trade-offs between greenhouse gas (GHG) emissions, yield, the global warming potential (GWP), and GHG intensity (GHGI) following organic fertilizer substitution within vegetable cropping systems. This study aimed to quantify these effects under diverse conditions and elucidate the direct and indirect drivers governing these outcomes through a meta-analysis and structural equation modeling (SEM). We synthesized 655 paired observations from 69 published studies using random-effects meta-analysis, finding that organic fertilizer substitution significantly increased CH₄ emissions and GWP compared to inorganic fertilizer controls. Although this was the general trend, organic fertilizer could reduce GWP under specific climatic and soil conditions by reducing N₂O emissions, such as mean annual precipitation <400 mm or soil total nitrogen ≥3 g kg⁻¹. These conditions were also associated with substantially higher yield and lower GHGI. Furthermore, SEM demonstrated that field management practices exerted significant direct effects on N₂O emissions, GWP, and GHGI. Reductions in N₂O emissions, GWP, and GHGI could be achieved with fertilizer application duration ≥10 years, total N application rate ≥300 kg ha⁻¹, and field cultivation or plowing. GHGI was also reduced through yield enhancement under a moderate organic substitution rate (33–66%) or irrigation ≥300 mm. Our study provides a scientific basis for moving beyond universal recommendations towards precision organic management, which is essential for optimizing fertilization strategies to mitigate agricultural GHG emissions. Full article

To address the climate impact of maritime transport, the International Maritime Organization (IMO) has implemented regulations targeting ship emissions, particularly greenhouse gases (GHGs), to achieve net-zero emissions by 2050. Meeting these goals requires accurate estimates of air pollutant emissions and a clear understanding of emission trends. This study estimated air pollutant emissions from ships registered in Republic of Korea between 2021 and 2023 using a bottom-up approach. The methodology incorporates ship specification data, regression models, and correction factors based on actual fuel consumption. For ships lacking engine power data, power was estimated using a regression of gross tonnage by ship type. Annual fuel consumption was calculated using engine power, fuel type, engine configuration, and ship age, and emission factors were applied to estimate CO₂, CH₄, N₂O, and other air pollutants. The results showed that CO₂ accounts for over 98% of GHG emissions, while cargo ships, which represent only 10% of the fleet, contribute more than 60% of total GHG emissions. These findings highlight the importance of prioritizing cargo vessels in CO₂ reduction strategies. This study provides baseline data to align policy development with IMO regulations and underscores the need for a continuous national framework for estimating ship emissions. Full article

The maritime sector accounts for approximately 3% of global greenhouse gas (GHG) emissions and faces binding decarbonization obligations under the International Maritime Organization’s (IMO) Net-Zero Framework and the FuelEU Maritime Regulation. Conventional marine fuels, including very low sulphur fuel oil (VLSFO) and liquefied natural gas (LNG), are insufficient to meet long-term regulatory intensity targets on a well-to-wake (WtW) lifecycle basis, creating an urgent need for credible fuel alternatives. This study investigates ethanol as a primary fuel for marine dual-fuel propulsion systems, assessed across four distinct production pathways, sugar beet, corn, sugarcane, and wheat straw, to determine its full decarbonization potential relative to VLSFO and LNG benchmarks. A simulation-based multi-dimensional evaluation framework is developed and applied, integrating dynamic operational simulation, energy analysis, environmental lifecycle modelling, and regulatory compliance assessment. The framework is calibrated against a high-resolution dataset from an active container ship, with scenario-specific engine data. While ethanol requires 39.1% more fuel mass than VLSFO due to its lower energy density, all four ethanol pathways deliver substantially superior WtW GHG reductions: from 50.2% (corn) to 76.9% (wheat straw), compared with 20.6% for LNG. All ethanol scenarios satisfy FuelEU compliance limits across the 2026–2045 horizon, with wheat straw ethanol achieving a GFI of 22.52 gCO₂e/MJ, compliant marginally with the 2040 IMO target. These findings demonstrate that bio-based ethanol, particularly from lignocellulosic feedstocks, is a technically viable and regulatorily superior alternative to LNG for maritime decarbonization, warranting accelerated research into production scale-up and bunkering infrastructure development. Full article

Compact urban form can reduce road transportation GHG emissions and mitigate resource supply bottlenecks associated with mass EV adoption. Global databases from Climate TRACE and the Global Human Settlement Layer are utilized to develop the Compact Urban Form Estimation Tool or CUFET for calculating the reduction in VKT and road transportation GHGs from shifting toward CUF. The CUFET does not explicitly account for mechanistic changes in driving (e.g., modal shift) but rather uses settlement density as a coarse proxy for walking and transit urban fabrics. VKT was modeled using weighted least squares regression from the independent variables settlement population, settlement population density, and country fixed effects. Population size banding was introduced to the model to improve explanatory power. The model was developed using 10,495 settlements in the 2021 Climate TRACE dataset. The CUFET VKT model was able to explain 78% (p < 0.001) of the variation in the VKT of test settlements and improved with the addition of a country fixed effect. The CUFET on average gave estimates of VKT within 24% of Climate TRACE-calculated VKT for countries with a GDP per capita between $20,000 and $45,000 and average estimates within 20% for countries with a GDP per capita above $45,000. Increased settlement density was associated with more substantial reductions in VKT in small (50,000 to 88,335) and medium (88,335 to 329,480) sized settlements relative to large (>329,480) settlements. Higher variability was observed in VKT estimates of small settlements. The CUFET VKT was validated by backcasting historical VKT data from 1960 to 2000. The backcasting exercise used historical administrative boundaries and only included high economic output nations (GDP per capita above $20,000 in 2021 USD). Despite these limitations, backcasting achieved a % difference of ~20% for settlements after 1990, suggesting the model can make useful estimates within 30 years of the model calibration year for high economic output nations. The VKT model was used to calculate emissions using a settlement-specific emissions factor. Settlements with annual road transportation emissions per capita greater than 2 t CO₂eq have the lowest population densities relative to their populations and are mostly located in the United States, Japan, Canada, and Australia. The nations with the highest transportation emissions are also nations where the CUFET provides the most accurate VKT estimates. The CUFET aims to bridge the gap between academic consensus and local decision-making practice by reducing the barriers to estimate VKT and transportation GHG reduction from shifting to compact urban form. Full article

As the second most important anthropogenic greenhouse gas (GHG), methane (CH₄) has received wide attention in the mitigation of global climate change. China’s Sichuan Basin has been identified as one of the world’s hotspot regions with very high CH₄ emission intensity. Winter-flooded paddies are considered as potential significant sources of CH₄ emissions among various cropping systems in Sichuan. However, current studies are limited to the field scale, and there is a lack of research conducted over a large spatiotemporal scale. Here, we simulated CH₄ emissions from 1980 to 2023 at region scale using the Denitrification–Decomposition (DNDC) model and evaluated the associated climate impact using the radiative forcing-based climate footprint (RFCF) metric. We found that CH₄ emissions have recently decreased, from 0.53 billion tonnes in 2019 to 0.28 billion tonnes in 2023, representing a 47.20% reduction. Moreover, the climate footprint peaked in 2019 at 1.25 mW m⁻² and decreased to 1.08 mW m⁻² in 2023, and the system achieved net zero increase in radiative forcing (RF) in 2020. This means that Sichuan’s winter-flooded paddies no longer contribute to the additional RF in the atmospheric system. Overall, our findings demonstrate that the reduction in CH₄ emissions from winter-flooded paddies has been mainly attributed to a reduction in the cropping area and a decrease in average temperature during the rice growth season. These results provide a scientific basis for region-specific CH₄ mitigation policies and demonstrate how these spatiotemporal changes in CH₄ emissions from winter-flooded paddies in Sichuan can support sustainable agriculture. Full article

As declared in the European Green Deal, the decarbonization of the EU energy system is essential for achieving Europe’s climate neutrality targets, demanding a substantial expansion of renewable energy sources and the rapid phase-out of coal and gas. It is therefore essential that newly installed PV products within the EU are designed to avoid creating additional environmental burdens due to environmental impacts during production and at the end of life (EOL) of photovoltaic (PV) modules. This study presents a life cycle assessment (LCA) of sustainable/green PV module designs in terms of recyclability using advanced high-quality recycling technologies. It compares two product systems both based on mono c-Si PV technology and the glass–glass (G–G) module design: 1. Passivated Emitter and Rear Contact (PERC) and 2. Tunnel Oxide Passivated Contact (TOPCon) cell technologies, which are assessed under production scenarios in China and Germany, and two recycling scenarios (hypothetical high-recovery recycling and partial recycling) using inventory data from eco-invent and literature sources. The results across most impact categories show that the PERC and TOPCon module designs produced in Germany with high-recovery recycling as the end-of-life strategy exhibit lower impacts than those produced in China with partial recycling as the end-of-life strategy under the adopted assumptions such as electricity mix and end-of-life modelling choices for module-only impacts (excluding BOS components). The climate change results show that TOPCon cell design under high-recovery recycling yields 10.4% lower emissions than the PERC cell design under partial recycling in Germany and 9.7% lower in China. However, both module designs emit 26.6% and 27.2% less GHG emissions when produced in Germany compared to production in China, respectively, which is line with earlier studies. With the exception of human toxicity, both PERC and TOPCon cell technologies perform better in this study than previously reported in reviewed LCA studies, reflecting the use of more recent state-of-the-art industry data concerning manufacturing requirements. The sensitivity analysis carried out on the design changes and electricity grid mix available shows that any improvements in the design process and increases in renewable energy penetration into the grid corresponds to a proportional reduction in environmental impacts across all impact categories. Full article

This study investigates whether the optimal utilization of the biomass potential contained in municipal solid waste (MSW) can support the implementation of circular economy (CE) principles and contribute to climate policy objectives, particularly the reduction in greenhouse gas (GHG) emissions in the waste management sector. The analysis evaluates whether waste-to-energy recovery can support the objectives of the European Green Deal, including a 55% reduction in GHG emissions by 2035 and the achievement of climate neutrality by 2050. The assessment was conducted for two MSW streams generated in a Polish municipality: separately collected biowaste and residual MSW remaining after meeting European reuse and recycling targets. The study summarizes the results of detailed experimental investigations of the physicochemical and fuel properties of these waste streams. Proven and commercially available energy recovery technologies, including anaerobic digestion (AD) of biowaste and incineration of residual waste, were analyzed. GHG emissions were assessed using a life cycle assessment (LCA) approach, taking into account both direct emissions and avoided emissions resulting from the substitution of conventional energy and fertilizer production. The experimental results revealed significant variability in the biodegradability and energy potential of individual biowaste fractions, with the highest biogas yields observed for kitchen waste. Residual waste exhibited a considerable calorific value and a significant share of renewable energy due to its biomass content. The results indicate that the share of renewable energy in electricity generated from waste is expected to increase from 46.1% in 2025 to 49.9% in 2040. In relation to the total electricity demand of the analyzed city, energy recovered from waste accounts for 1.8 ± 0.3% in 2025 and 1.3 ± 0.2% in 2040. Scenario-based modeling demonstrated that the target system, maximizing energy recovery from both biowaste and residual waste, achieves a consistently negative GHG emission balance throughout the analyzed period (2025–2040), ranging from −72 ± 15 kg CO₂-eq/ton in 2025, through the most favorable value of −81 ± 17 kg CO₂-eq/ton in 2035, to −57 ± 12 kg CO₂-eq/ton in 2040, expressed per ton of total managed biowaste and residual waste. Full article

The industrial sector accounts for a significant share of global energy consumption and greenhouse gas emissions, making the optimal operation of industrial parks a key pathway for sustainable energy transition. This study proposes a day-ahead coordinated optimal scheduling framework for a multi-sector Industrial Park Energy Hub (IPEH) that integrates electricity, heating, and cooling systems with renewable generation and multi-energy storage. The model captures sectoral diversity across industrial, commercial, residential, and administrative sectors, enabling coordinated inter-sector operation through electricity and heating energy sharing. The scheduling problem minimizes total operating cost, including penalties for greenhouse gas (GHG) emissions and for power curtailment from photovoltaics (PV) and wind turbines (WT), while considering the physical constraints of the heating network and power tie-lines. The optimization problem is solved using the CPLEX solver in MATLAB. Results under three scenarios show that, compared with independent operation, electricity sharing alone reduces operating cost by 3.22% and renewable curtailment by 58.19%. Coordinated electricity and heat exchange further improves system performance, achieving a 6.95% reduction in operating cost, a 58.19% decrease in renewable energy curtailment, and emission reductions of 18.11% for CO₂, 23.80% for SO₂, and 38.42% for NO_x. Full article

Achieving deep decarbonization of the residential building sector is essential for meeting Canada’s climate commitments and Net Zero targets. However, large-scale residential retrofit planning is often constrained by the time, cost, and expertise required for detailed building energy modelling. This study evaluates the applicability of a typology-based retrofit planning tool developed by Homes to Zero (HTZ) as a simplified alternative to conventional simulation-based analysis. Two representative Canadian residential archetypes—a detached bungalow and a two-storey semi-detached home located in Toronto—were analyzed using both the HTZ platform and detailed hourly energy simulations conducted in eQuest (DOE-2.2 engine). Baseline energy consumption and greenhouse gas (GHG) emissions were first compared across the two modelling approaches. Results show strong agreement for the bungalow case, with differences of less than 1% for electricity and natural gas consumption and approximately 4% for total emissions. For the two-storey dwelling, baseline electricity estimates were identical while natural gas consumption differed by approximately 17%, highlighting the sensitivity of physics-based simulations to envelope and operational assumptions. Retrofit scenarios were then compared using single-measure GHG reductions derived from HTZ and incremental simulation results from eQuest. While both tools identified electrification through air-source heat pumps as the dominant emission-reduction strategy, differences were observed in the magnitude of savings for envelope upgrades and secondary measures. The HTZ platform also provides approximate retrofit cost estimates, enabling order-of-magnitude budgeting, whereas eQuest requires separate costing analysis. This study is framed as a screening-level benchmark rather than a full validation exercise, highlighting the trade-off between scalability and modelling fidelity in residential retrofit planning. The results suggest that typology-based tools can provide credible screening-level guidance for residential retrofit planning and large-scale policy analysis, while detailed simulation remains valuable for evaluating integrated retrofit packages and design-level decisions. Full article

One of the most critical challenges in maritime transport decarbonization, as part of the EU greenhouse gas (GHG) neutrality strategy, is the reduction in GHG and harmful emissions from the energy systems of existing vessels. Furthermore, the potential for implementing decarbonization technologies in operating vessels remains significantly more limited compared to newly constructed ships. Selecting appropriate decarbonization measures requires a comprehensive evaluation of technological feasibility, economic viability, and environmental performance, in accordance with the regulatory frameworks established by the IMO and the EU. A major limitation in such decision-making processes is ensuring the representativeness and reliability of expert judgments. In order to improve the reliability of results by expanding and structuring the information base, this study proposes and implements a method based on the integration of SWOT analysis with multi-criteria decision-making (MCDM) methods. The objective of this study was to examine the methodological aspects of testing the integrated application of comprehensive analysis and ranking methods for decarbonization technologies as applied to a prototype oil tanker. Based on the SWOT analysis method, technological solutions that are available for practical application were identified for the medium-term decarbonization period considered in the study, up to 2030–2035. Subsequent rating based on several applied multi-criteria (MCDM) analysis methods (TOPSIS, COPRAS, SAW) allowed us to examine the range, stability and sensitivity of the obtained solutions in relation to the methods themselves and scenarios with variations in the weighting factors of the evaluation criteria. The complete match of the ratings obtained using the TOPSIS and COPRAS methods confirms the stability of the multi-criteria decision-making process (priority-compromise order): CCS, kite, air lubrication, Flettner rotor. The performed sensitivity analysis showed that the technology rankings remain relatively stable when the weighting factor for the CO₂ reduction criterion varies within a range of approximately ±10%, while larger deviations result in an increasing difference between all three MCDM methods. For the TOPSIS method, the change limits for the critical values of the threshold indicators were ±20%, the COPRAS method showed intermediate results, and changing the weighting coefficients within a ±20% range did not alter the selection of the best technology. The results obtained allow for a positive assessment of the effectiveness of the proposed integrated methodology when applied as an alternative in the initial stage of ranking decarbonization methods for in-service ships. Full article

Electrification of road transport is widely promoted as a pathway to reduce greenhouse gas (GHG) emissions; however, its effectiveness depends critically on electricity carbon intensity, renewable energy share, charging behavior, and grid capacity constraints. This study develops a multi-objective analytical and optimization framework to evaluate cost and carbon-optimal electric vehicles electrification by jointly minimizing system cost and carbon emissions under coupled transport–energy system conditions. A closed form cut-off condition is derived to determine the minimum renewable electricity share required for electric vehicles to achieve lower emissions than internal combustion engine vehicles, and the formulation is extended to mixed fleets including battery electric and plug-in hybrid electric vehicles. The framework integrates fleet-level emissions, electricity demand, renewable capacity limits, charging losses, carbon taxation, and peak charging constraints to define a feasible electrification region. Feasibility mapping, Monte Carlo exploration, and evolutionary multi-objective optimization are employed to characterize trade-offs between CO₂ emission and total system cost, and to identify Pareto-optimal and knee point solutions. The results show that electrification without sufficient renewable support or coordinated charging can increase emissions and violate grid limits, whereas integrated planning enables significant emission reduction within economically viable regions. These findings provide a quantitative and decision-oriented basis for cut-off-informed and grid-aware electrification planning in carbon-constrained power systems. Full article

Purified terephthalic acid (PTA) is an extremely important bulk organic raw material; it plays a central connecting role in the PX–PTA–polyester industry chain, while its significant carbon intensity remains poorly quantified. Through process-level life cycle assessment (LCA) based on in situ industrial data, this study establishes a comprehensive material-energy inventory for PTA production. The results show that the total greenhouse gas (GHG) emissions of the entire PTA process reached 1600.9 kg of CO₂ eq·t⁻¹, exceeding those of common primary chemicals, like aromatics, butadiene and styrene. The end process of the PTA unit (PU) dominates GHG emissions, reaching 365.6 kg CO₂ eq·t⁻¹, accounting for 22.3%, driven by extra xylene input, various catalyst consumption, auxiliary chemicals, and energy intensity. After allocating steam-related emissions from coal-fired power stations, the GHG emissions of the PU rise to 400.9 kg CO₂ eq·t⁻¹. Sensitivity analysis demonstrates that replacing conventional hydrogen with green hydrogen slashes hydrogen-related global warming potential (GWP) contribution by 61.5%. In addition, a 10% increase in electricity, coal, or steam elevates system GWP by 0.80%, 0.036% and 2.48%, respectively. The findings demonstrate that energy structure optimization and green hydrogen integration represent decisive levers for PTA decarbonization, providing data-driven insights for industrial transition under a carbon reduction policy framework. Full article

The global food system (FS) contributes one-third of anthropogenic greenhouse gas (GHG) emissions, yet evidence remains heavily skewed toward temperate-climate cities, leaving cold-climate cities in the Northern Hemisphere understudied. Here, the GHG footprint (GHGF) of the entire FS in Ulaanbaatar, Mongolia, is assessed, accounting for six subsystems spanning food production, processing and storage, retail, transportation, consumption, and food waste. The baseline indicates that the food waste (FW) subsystem dominates the total GHGF (47.13 kg CO_2eq/kg), contributing 49.3% of overall emissions. It exceeds those from agricultural food production (AFP) (18.5%) and, food & food waste transportation (FFWT) (22.6%). We further evaluate two mitigation scenarios. (1) Under a dietary shift scenario aligned with national dietary guidance, the total GHGF decreases 14.4% while the FW subsystem remains the largest contributor, (2) but the food waste reduction scenario yields a comparable reduction of 15.9%. The findings revealed that decarbonisation lever efficiency can be done through food waste reduction while supporting a circular valorisation strategy, including waste-related GHG liabilities as an energy source in cold-climate cities. Full article

There is an important debate about the appropriate policy measures for reducing greenhouse gas (GHG) emissions in the transport sector. Strong expansion of battery electric vehicles (BEVs) following a ban on the registration of new vehicles with internal combustion engines (ICEs) by 2035 is a prominent but controversial proposal. To evaluate achievable GHG emission reductions, it is essential to understand the temporal dynamics of such a fleet transition. This study provides a time-resolved, policy-oriented quantification of annual and cumulative lifecycle GHG emissions during this process. Therefore, it uses an annual simulation model to assess GHG emissions from vehicle production and use during the transition of Germany’s passenger car fleet between 2019 and 2060. The analysis compares an ICE registration ban by 2035 with alternative scenarios and evaluates the effects of electricity decarbonization, greener BEV production, and the supply of additional Zero Emission Fuels (ZEFs). This study reveals a substantial time lag of 10–20 years between changes in new vehicle registrations and effective emission reductions. Even with a complete ICE ban by 2035, annual GHG emissions decline by only 3.7% by 2030 relative to 2025, while cumulative emissions over this period fall by just 1.6%. Larger reductions occur later, reaching 39% in 2040, 77% in 2050, and 82% in 2060 compared with 2025; cumulative emissions until 2060 decrease by 45%. Without an ICE ban and with a 75% BEV share from 2035 onward, cumulative reductions fall to 34%. Introducing additional ZEFs equivalent to 10% of 2030 fuel demand increases this value to 41%, compensating for much of the lower BEV uptake. Full article

The energy transition is widely regarded as one of the most significant challenges in achieving global climate goals, given that the energy sector is responsible for approximately 73% of greenhouse gas (GHG) emissions. Therefore, the integration of ESG criteria is emerging as a strategic lever for guiding companies, investors, and public decision-makers towards low-emission models. The present study employs a multi-case comparative approach, analyzing two utilities at differing stages of maturity: Ørsted, a global leader in the field of renewable energy transition, and Enel, a major European incumbent in the advanced stage of transformation. The methodology employed is founded upon the utilization of publicly available data and ESG indicators, encompassing the environmental, social and governance dimensions. The results underscore Ørsted’s position as a frontrunner in the field of climate leadership, as evidenced by their 91% reliance on renewable energy sources and an emission intensity of 60 gCO₂/kWh. In comparison, Enel’s figures stand at 49.4% and 237 gCO₂/kWh, respectively. The analysis further reveals a convergence trend across the social and governance pillars. Notably, Enel has demonstrated improvements in safety, inclusion, and leadership diversity. A ten-year scenario analysis suggests significant convergence for Enel, with an expected renewable generation share of 90% and a reduction in emissions to around 60 gCO₂/kWh. The present study makes a contribution to the extant literature by means of the proposal of a replicable, intensity-based ESG comparative framework that integrates normalized indicators with forward-looking scenario analysis. This enables a dynamic assessment of ESG convergence trajectories in the energy sector. Full article