Greenhouse Gas Reduction Potential Research Articles

Prediction greenhouse gas emissions from road freight flow in South Korea for sustainable transportation planning.

Road freight modeling was conducted to project freight flow and greenhouse gas (GHG) emissions in 16 administrative regions of South Korea through 2050. Origin-destination matrices were constructed using a gravity model for each region. The modeling covered seven product categories for both inter-regional and intra-regional freight transportation and was validated using 2017 data. The total future freight flow is projected to increase from 1399 million tons in 2019 to 1701 million tons by 2035. However, after peaking in 2035, it is expected to decline to 1618 million tons by 2050, indicating that population decline will impact product demand, causing a reduction in freight flow despite continued economic growth. GHG emissions are projected to slightly decrease from 19.0 million kgCO2eq. in 2025 to 18.6 million kgCO2eq. in 2035, followed by a steeper reduction to 15.5 million kgCO2eq. by 2050. This decline is attributed to both population decrease and long-term reductions in emission factors. Changes in freight flow between 2019 and 2050 are expected to be more pronounced within five regions in the capital and extended capital areas, which will account for approximately 50.3% of the total freight flow due to population concentration. As a result, these five regions contribute 26.5% of the total GHG reduction potential. The minimum economic growth rates required to maintain the same freight volume as in 2035 are estimated at 5% for 2040, 13% for 2045, and 26% for 2050.

Life Cycle Greenhouse Gas Reduction Effects Induced by Turbocharger Multiple Remanufacturing in South Korea

In light of growing global supply chain instability and carbon neutrality initiatives, South Korea has highlighted the need for a circular economy to reduce its reliance on natural resources. As a critical strategy for promoting a circular economy, remanufacturing has become essential because of its ability to improve resource efficiency and reduce environmental impacts. The automotive sector, which accounts for 80% of the remanufacturing industry, plays a critical role in these efforts. Turbochargers, primarily made of cast iron, represent approximately 20% of sales in this sector and are significant contributors to greenhouse gas emissions, making them an important target for emission reduction. This study examined the greenhouse gas emissions associated with turbochargers across multiple remanufacturing cycles using the LCA method. The results indicated an approximate decrease of 50%, 48%, and 46%, based on a comparative analysis between brand-new products and those remanufactured one to three times. Comparing brand-new and remanufactured products does not fully capture the key advantage of remanufacturing. This advantage lies in its ability to extend a product’s life cycle by using core parts as primary raw materials and reducing the consumption of new resources. Therefore, it is important to consider the environmental impact of remanufacturing within an expanded process, where brand-new products are included in the entire life cycle. Using this approach, the accumulated annual greenhouse gas reduction effect for multiple remanufacturing indicated decreases of approximately 25%, 32%, and 35% for remanufacturing one, two, or three times, respectively, compared to using only brand-new products. This study shows that multiple remanufacturing reduces greenhouse gas emissions compared to the use of brand-new products. In particular, as remanufacturing is repeated, the product lifespan can be extended from 3 years to up to 12 years with a concomitant decrease in annual greenhouse gas emissions. These findings provide valuable data for modeling and encouraging the greenhouse gas reduction potential driven by remanufacturing across various industrial sectors.

Compressive strength and regional supply implications of rice straw and rice hull ashes used as supplementary cementitious materials

Substituting Portland cement (PC) with supplementary cementitious materials (SCMs) is a key strategy for reducing greenhouse gas (GHG) emissions. Considering alternative SCMs requires a holistic understanding of changes to material performance, emissions reduction potential, and regional availability. Four rice hull ashes (RHAs) and one rice straw ash (RSA) were evaluated to replace PC in mortars (10% untreated ash and 30% blast furnace slag; 15% untreated ash; or 15% milled ash). The 28-day compressive strengths with 0.59 water-to-binder ratio for fly-RHAs (38.0–49.8 MPa) and RSA (37.7 - 44.1 MPa) did not vary significantly from the PC control (43.2 MPa) based on an ANOVA. Modeling rice biomass generation in six U.S. states shows RSA could triple the supply of rice-biomass ash, but in states with substantial PC demand, i.e., California and Texas, the potential GHG reduction may remain small (∼1–2%). RSA and RHA may hold promise in lowering concrete GHG emissions.

Reductions in GHG and unburned ammonia of the pilot diesel-ignited ammonia engines by diesel injection strategies

How to reduce the exhaust NH3 and N2O emissions is very crucial for bridging the gap between the high greenhouse gas (GHG) reduction potential and the engineering application of ammonia engines with high ammonia energetic ratios (AER). In this study, experiments were conducted to explore how the diesel injection pressures and the split injections affect the characteristics of combustion, emissions, and thermal efficiency for the AER of 80 % in a LPDF (i.e., low-pressure injection ammonia-diesel dual-fuel) engine. As for the split injections, both the early first injection during the compression stroke and the postponed second injection after the top dead center (TDC) were detailed investigated. With the injection pressure of the pilot diesel increasing from 60 to 150 MPa, about 28 % reductions in the unburned NH3 and about 13 % reductions in the N2O are achieved. With the optimized split injections before the TDC, about 11 % reductions in the unburned NH3, 13 % reductions in N2O, and 1.1 % enhancements of the indicated thermal efficiency can be simultaneously achieved. For the split injections with the second injection after TDC, the exhaust temperature can be to some degree increased but result in more NH3 and N2O, alongside a decline in thermal efficiency. Numerical simulations show that the diesel spray targeting and mixture reactivity stratification can explain the mechanism behind the improved performance of the optimized split injections, suggesting the potential for further improvement by the co-optimization of diesel injection strategy and combustion chamber geometry for the LPDF operations with high AERs.

A Hybrid Pre-Assessment Assists in System Optimization to Convert Face Masks into Carbon Nanotubes and Hydrogen

With extensive attention being paid to the potential environmental hazards of discarded face masks, catalytic pyrolysis technologies have been proposed to realize the valorization of wastes. However, recent catalyst selection and system design have focused solely on conversion efficiency, ignoring economic cost and potential life-cycle environmental damage. Here, we propose an economic-environmental hybrid pre-assessment method to help identify catalysts and reactors with less environmental impact and high economic returns among various routes to convert discarded face masks into carbon nanotubes (CNTs) and hydrogen. In catalyst selection, it was found that a widely known Fe–Ni catalyst exhibits higher catalytic activity than a cheaper Fe catalyst, potentially increasing the economic viability of the catalytic pyrolysis system by 38%–55%. The use of this catalyst also results in a carbon reduction of 4.12–10.20 kilogram CO2 equivalent for 1 kilogram of discarded face masks, compared with the cheaper Fe catalyst. When the price of CNTs exceeds 1.49 × 104 USD·t–1, microwave-assisted pyrolysis is the optimal choice due to its superior environmental performance (in terms of its life-cycle greenhouse gas reduction potential, eutrophication potential, and human toxicity) and economic benefits. In contrast, conventional heating pyrolysis may be a more economical option due to its good stability over 43 reaction regeneration cycles, as compared with a microwave-assisted pyrolysis catalyst with a higher conversion efficiency. This study connects foundational science with ecological economics to guide emerging technologies in their research stage toward technical efficiency, economic benefits, and environmental sustainability.

CH4 and CO2 Reductions from Methanol Production Using Municipal Solid Waste Gasification with Hydrogen Enhancement

This study evaluates the greenhouse gas (GHG) impacts of converting municipal solid waste (MSW) into methanol, focusing on both landfill methane (CH4) emission avoidance and the provision of cleaner liquid fuels with lower carbon intensity. We conduct a life cycle assessment (LCA) to assess potential GHG reductions from MSW gasification to methanol, enhanced with hydrogen produced via natural gas pyrolysis or water electrolysis. Hydrogen enhancement effectively doubles the methanol yield from a given amount of MSW. Special attention is given to hydrogen production through natural gas pyrolysis due to its potential for lower-cost hydrogen and reduced reliance on renewable electricity compared to electrolytic hydrogen. Our analysis uses a case study of methanol production from an oxygen-fired entrained flow gasifier fed with refuse-derived fuel (RDF) simulated in Aspen HYSYS. The LCA incorporates the significant impact of landfill methane avoidance, particularly when considering the 20-year global warming potential (GWP). Based on the LCA, the process has illustrative net GHG emissions of 183 and 709 kgCO2e/t MeOH using renewable electricity for electrolytic hydrogen and pyrolytic hydrogen, respectively, for the 100-year GWP. The net GHG emissions using 20-year GWP are −1222 and −434 kgCO2e/t MeOH, respectively. Additionally, we analyze the sensitivity of net GHG emissions to varying levels of fugitive methane emissions.

Carbon Footprint and GHG Reduction Potential of Bioethanol Production in the Philippines

Abstract As the Philippine bioethanol industry concluded its first decade, it is in due time to assess whether the objectives of the Biofuels Act of 2006 (Republic Act No. 9367) are being met. Specifically, the law aims to reduce the country’s dependence on oil importation, mitigate toxic and greenhouse gases (GHGs), and promote the use of biofuels from indigenous resources to boost the country’s rural economy, by mandating biofuels blending to fossil-based fuels for transport use. This study examined the contribution of seven bioethanol production systems to the country’s climate change mitigation efforts by assessing the environmental impacts, particularly the carbon footprint and GHG emission reduction potential of each bioethanol distillery through life cycle assessment (LCA). Results of the environmental impact assessment revealed that the weighted average carbon footprint of the seven bioethanol production systems is at 1,415.66 gCO2e L−1, which ranges from 287 to 1,726 gCO2e L−1, translating to an average GHG reduction potential of 47.54% or an average avoided GHG of 268,091.15 tons CO2e yr−1 for CY 2019-2020. With the environmental hotspots identified, recommendations were made to improve the distilleries’ carbon footprints, and a sensitivity analysis was conducted to quantify the benefits from the recommended strategies. By applying all strategies, the average GHG reduction potential of the seven bioethanol production systems can get as high as 85.63%, which can be translated to an average avoided GHG of 482,933.91 tons CO2e yr−1.

Enhancing carbon reduction and sustainable agriculture in Thailand: An assessment of rice straw utilization strategies

This research explores strategies for carbon reduction through the utilization of rice straw waste in Thailand, focusing on three project approaches: (1) converting rice straw into biomass fuel pellets for power plants, (2) transforming rice straw into biochar using high-tech systems and blending it with fertilizers, and (3) using conventional systems for biochar production. The study assesses the greenhouse gas (GHG) reduction potential of these approaches compared to traditional open-field burning of rice straw. The results indicate that Project 2, which involves high-tech biochar production, exhibits the highest potential for GHG reduction and carbon sequestration, with a potential to reduce emissions by approximately 12.19–13.05 MTCO2e/year. This approach also has potential for generating valuable carbon credits due to biochar’s long-term carbon sequestration and soil enhancement benefits. In contrast, Project 1 yields a reduction of about 4.06–4.35 MTCO2e/year, while Project 3 results in negative emission reduction. The study recommends prioritizing and incentivizing biochar production projects, upgrading low-tech systems, balancing the use of biomass fuel pellets, leveraging carbon credits for funding, and enhancing public awareness.

Optimizing the greenhouse gas emissions of waste transfer and transport: An integration of life cycle assessment and vehicle routing problem

This study presents a comprehensive analysis of greenhouse gas (GHG) emissions associated with waste transfer and transport, incorporating derived leachate treatment—a factor often overlooked in existing research. Employing an integration model of life cycle assessment and a vehicle routing problem (VRP) methods, we evaluated the GHG reduction potential of waste transfer and transport system. Two Chinese counties with different topographies and demographics were selected, yielding 80 scenarios that factored in waste source separation as well as vehicle capacity, energy sources, and routes. The functional unit (FU) is transferring and transporting 1 tonne waste and treating derived leachate. The GHG emissions varied from 12 to 39 kg CO2 equivalent per FU. Waste source separation emerged as the most impactful mitigation strategy, not only for the studied system but for an integrated waste management system. Followings are the use of larger capacity vehicles and electrification of the vehicles. These insights are instrumental for policymakers and stakeholders in optimizing waste management systems to reduce GHG emissions.

Evaluation of greenhouse gas emission and reduction potential of high-food-waste-content municipal solid waste landfills: A case study of a landfill in the east of China

This study proposes a comprehensive evaluation method based on a two-stage model to assess greenhouse gas (GHG) emissions and reductions in high-food-waste-content (HFWC) municipal solid waste (MSW) landfills. The proposed method considers typical processes such as fugitive landfill gas (LFG), LFG collection, flaring, power generation, and leachate treatment. A case study of an HFWC MSW landfill in eastern China is considered to illustrate the evaluation. The findings revealed that the GHG emissions equivalent of the case landfill amounted to 21.23 million tons from 2007 to 2022, averaging 1.03 tons CO2-eq per ton of MSW. There was a potential underestimation of LFG generation at the landfill site during the initial stages, which led to delayed LFG collection and substantial fugitive LFG emissions. Additionally, the time distribution of GHG emissions from HFWC MSW was significantly different from that of low-food-waste-content (LFWC) MSW landfills, with peak emissions occurring much earlier. Owing to the rapid degradation characteristics of HFWC MSW, the cumulative LFG production of the landfill by 2022 (2 years after the final cover) was projected to reach 77 % of the total LFG potential. In contrast, it would take until 2030 for LFWC MSW landfills to reach this level. Furthermore, various scenarios were analyzed, in which if the rapid LFG generation characteristics of HFWC MSW are known in advance, and relevant facilities are constructed ahead of time, the collection efficiency can be improved from 31 % to over 78 %, resulting in less GHG emissions.

Technology-driven carbon-neutral pathway analysis for Urban Wastewater Treatment Plants

Carbon-neutral pathways for China's wastewater sector is of great significance, but technical carbon reduction pathways for single wastewater treatment plant (WWTP) are not yet clear. This study develops a framework to design technology-driven carbon-neutral pathways at plant-level up to 2050 through four steps. Results shows that the average greenhouse gas (GHG) intensity was assessed at about 0.29 kgCO2eq/m3 from 2011 to 2021. Techno-economic analyses of various low-carbon technologies reveal Sharon-anammox as an effective option for carbon reduction. Additionally, the sensitivity of GHG reduction potential to changes in electricity emission factors highlights the importance of the power sector's clean energy transition. Scenario simulations suggest that approximately 39% of the carbon-neutral target by 2050 will require technological advancements, achievable with a 0.37 $/kgCO2eq investment. This study presents an analysis of the carbon-neutral pathways for a single WWTP system, providing insights into sustainable wastewater treatment practices.

GHG emission quantification and reduction pathway of subway shield tunnel engineering: a case study on Guangzhou Metro, China.

The shield method is a commonly used construction technique in subway tunnel engineering. However, studies on greenhouse gas (GHG) emissions specifically in subway shield tunnel engineering are lacking. This study aims to investigate the GHG emission characteristics and GHG reduction pathways during the construction period of subway shield tunnels. Firstly, based on the life cycle assessment (LCA) method, a greenhouse gas (GHG) emission quantification model for the shield tunnel construction period was developed using a multi-level decomposition of construction. Then, the GHG emission level and intensity during the construction period of a case project are quantified, and its emission characteristics and GHG reduction potential points are assessed. Finally, a comprehensive path for GHG reduction in subway shield tunnel engineering is proposed. The research results indicate that constructing 1 km of subway shield tunnel can generate 19,294.28 t CO2eq. Among these, material production element dominates the emissions with a percentage of 89.05%, while transportation and mechanical construction elements contribute 1.81% and 9.14%, respectively. From the structure perspective, the main structure contributes 88.73% of total emissions, while the ancillary structure contributes 11.27%. Among them, the working shaft and tunnel segments are the main sources of emissions for the main structure, accounting for 23.65% and 65.08%, respectively. Connecting channel and end reinforcement are the main emission sources of the ancillary structures, accounting for 43.63% and 31.30%, respectively. These findings provide a scientific foundation for the environmentally friendly transformation of urban railway development regarding pursuing "carbon peaking and carbon neutrality" strategic goals.

The greenhouse gas (GHG) reduction potential of ICT: A critical review of telecommunication companies’ GHG enablement assessments

AbstractFor about a decade, telecommunication network operators (TNOs) have explored the potential greenhouse gas (GHG) reductions their customers can achieve by using TNO services (e.g., by substituting physical travel with video conferencing), the so‐called GHG enablement. Some TNOs also calculate a GHG enablement factor, which is the ratio between the GHG enablement and their own GHG footprint. Since GHG enablements usually exceed the footprint, they create the narrative that TNOs contribute to GHG reductions across society. In this paper, we systematically analyze TNO GHG enablement claims and the underlying methodological approaches. We find several methodological shortcomings and inconsistencies, such as different sets of TNO services considered, inconsistent system boundaries, potential double counting of GHG reductions, and a disregard for rebound effects. Most importantly, TNO assessments focus exclusively on those services likely to yield GHG reductions, neglecting possible GHG‐increasing services. We conclude that current GHG enablement (factors) do not accurately and comprehensively represent TNOs’ overall GHG impacts and create a flawed picture. To provide a reliable decision basis to stakeholders such as TNOs themselves, customers, investors, and policymakers, we provide eight recommendations on how to substantially improve the methodological basis.

Greenhouse gas footprint and reduction potential in a typical Chinese tea-producing area

Tea is an important cash crop in China but also contributes significantly to greenhouse gas (GHG) emissions. Understanding and mitigating the GHG footprint of tea production is essential for transitioning to cleaner and more sustainable, low-carbon agriculture. This study developed a comprehensive life cycle inventory of tea production using diverse data sources and calculated the GHG footprint of the tea industry in Songyang County, Zhejiang Province. The analysis encompassed multiple scopes of GHG emissions related to tea production. The findings revealed that the average GHG footprint of fresh tea leaves was 3.5 kgCO₂e/kg, with nitrogen fertilizer identified as the primary emission source. For the “from cradle to factory gate” scope, the GHG footprint was 23.5 kgCO₂e/kg, while for the “from cradle to grave” scope, it was 0.04 kgCO₂e per cup. The data quality pedigree matrix indicated an acceptable level of uncertainty in the results. This study also examined the statistical variation among tea growers and the spatial distribution of the GHG footprint. In addition, this paper explores the decarbonization potential of the tea industry, highlighting key strategies such as optimizing nitrogen fertilizer usage, advancing energy transformation, and establishing a tailored personal emission trading system for smallholders. Implementing these measures is critical for the sustainable development of the tea industry, reducing GHG emissions, and ultimately achieving carbon neutrality.

Exploring the green and low-carbon development pathway for an energy-intensive industrial park in China

Energy-intensive industrial parks (IPs) with the distinct characteristics of high energy consumption, substantial greenhouse gas (GHG) emissions, and huge pollution, are facing enormous pressure to realize the synergistic mitigation of GHG and air pollutants. Exploring the green and low-carbon transformation of energy-intensive IPs is urgently required to achieve the dual strategies of “carbon peaking and carbon neutrality” and “Beautiful China”. Taking a typical energy-intensive industrial park (IP) in Henan Province—the Red Flag Cannel Industrial Park (RFCP) as the research object, an integrated evaluation framework including multi-objective optimization model alongside the synergistic mitigation potential of carbon and air pollutant emissions, was established in the energy-intensive IPs. Five scenarios were designed to quantify the GHG and air pollutant mitigation potential, while synergistic emission reduction control effects were evaluated under four measures of industrial structure adjustment, energy structure adjustment, energy efficiency improvement, and industrial symbiosis. The scenario analysis indicates that the integrated scenario (S4) shows the most significant emission reduction potential by 2030. Compared to the baseline scenario (S0), the GHG emission reduction is 11.66 Mt CO2eq (53% reduction rate), and the emission reduction rate of air pollutants ranges from 38% to 69% in S4. The findings indicate that industrial structure adjustment and energy structure adjustment are the primary measures for reducing GHG and air pollutants of IPs. Additionally, the evaluation of synergistic effect demonstrates that industrial structure adjustment shows the most significant synergistic effect on GHG and air pollutant by 2030. Finally, some policy recommendations regarding the transformation direction of energy-intensive IPs were proposed. This study will provide valuable references for the green and low-carbon development of energy-intensive IPs.

Transforming the transportation sector: Mitigating greenhouse gas emissions through electric vehicles (EVs) and exploring sustainable pathways

Transportation-related emissions in Pakistan have been rapidly increasing in recent years. This study aims to determine how important it is to electrify road transportation in Pakistan to reduce greenhouse gas (GHG) emissions from the transportation sector. Motivated by the need to tackle the growing environmental issues related to conventional fuel-powered automobiles, this research explores the application of electrification techniques in the context of Pakistan’s transportation system. During the 2019 fiscal year, the transportation industry in Pakistan consumed 23 × 106 tonnes of energy from the burning of fossil fuels and produced 52.9 × 106 metric tons of CO2, which made up 31% of the country’s total carbon emissions. In this research, different scenarios, such as business as usual, low carbon, strengthen low carbon, and Pakistan National Electric Vehicle Policy 2040, are evaluated for the transportation sector of the country. Using the LEAP model, this study projects the effects of electrification on Pakistan road transportation over 30 years. When estimating how electrification will affect road transportation in Pakistan over the next 30 years, several factors were taken into account, including policy frameworks, changing consumer behavior, technology advancements, and infrastructure improvements. The analysis covered the emission levels, adoption hurdles, and possible advantages of transitioning to electric vehicles (EVs). The outcomes illustrate that adopting EVs can produce substantial drops in fuel consumption and environmental emissions, providing a sustainable solution to mitigate global warming. This work is directly associated with various Sustainable Development Goals, including SDG3 (good health and well-being), SDG7 (affordable and clean energy), and SDG13 (climate action). The results of this study highlight the considerable potential for GHG reduction associated with the widespread adoption of EVs, offering crucial insights to stakeholders and policymakers.

Reduction Method of Carbon Emission in Chemical Plants: Comparison of Middle East, Southeast Asia, and Korea

There are various methods to reduce greenhouse gas emissions in the construction and operational processes of chemical plants; however, the greenhouse gas reduction effects, investment costs, and benefits of their application have not been evaluated. Therefore, this study proposes greenhouse gas reduction measures that can be applied to chemical plant projects, including photovoltaic power generation, power factor improvement, VSD (Variable Speed Drive) motors, LED (Light Emitting Diode) lighting, and minimizing on-site business trips. Subsequently, the potential greenhouse gas reduction, estimated costs, and expected benefits for each measure were calculated by region. Among these measures, power factor improvement demonstrated the highest CO<sub>2</sub> reduction potential, with an estimated investment cost as low as 27 USD/tCO<sub>2</sub>, making it an effective greenhouse gas reduction strategy. Additionally, LED lighting and minimizing on-site business trips, which require little initial investment, should be implemented promptly. The proposed five measures, considering the potential reduction in greenhouse gas emissions, estimated investment costs, and benefits, can be applied to identify ways to significantly reduce greenhouse gas emissions in new chemical plants.

Exploring the GHG reduction potential of pilot diesel-ignited ammonia engines - Effects of diesel injection timing and ammonia energetic ratio

Ammonia-diesel dual-fuel engines have been demonstrated as a promising technology to reduce the greenhouse gas (GHG) emissions. However, understandings of the operational boundaries and combustion mechanism in the ammonia-diesel dual-fuel engines are far from adequate, and the published works are mostly done with relatively low ammonia substitution ratios. To bridge the gap between the technology status and the potential in engineering applications, a series of engine bench tests of the pilot diesel-ignited ammonia combustion with detailed analysis of the combustion performance and exhaust gas emissions are conducted in this study to explore the GHG reduction potential. As the first report, the effects of the diesel injection timing and ammonia energetic ratio on the performance and exhaust gas emissions of the dual-fuel engine at various loads and a fixed speed are evaluated in this paper. As the ammonia energetic ratio increases, the diesel injection timing for the stable engine operation becomes narrower. Increasing the ammonia energetic ratio decreases the indicated thermal efficiency. The ammonia-diesel dual-fuel engine can maintain the stable of COVIMEP below 3% at a wide ammonia energetic ratio range, the indicated thermal efficiency with the tested upmost 90% ammonia energetic ratio can reach about 34% if an optimized diesel injection timing is implemented. The unburned ammonia increases linearly with the ammonia energetic ratio while the unburned ammonia ratios of total input ammonia are similar at the different ammonia energetic ratios. In comparison to the conventional pure-diesel mode, while the CO2 emission decreases by 50% and 72%, the equivalent CO2 emission (i.e., CO2 + 265 N2O, labelled as CO2e) decreases by 24% and 55% at the 60% and 80% ammonia energetic ratios in the ammonia-diesel mode, respectively. In the ammonia-diesel dual-fuel mode, the specific CO2e, N2O and unburned ammonia decrease with the engine load increasing from 50% to 100%, while the highest indicated thermal efficiency is reached at the 75% load.

Life cycle assessment of sludge anaerobic digestion combined with land application treatment route: Greenhouse gas emission and reduction potential

Sewage sludge treatment and disposal is essential for water environment protection and pollution management. Coupling anaerobic digestion with land application offers a promising solution to recycle energy and resources to reduce greenhouse gas(GHG) emissions. However, the comprehensive assessment of the anaerobic digestion treatment route on GHG emissions and reduction potential is lacking. This study used life cycle assessment(LCA) to evaluate the GHG emissions based on two cases. The GHG emissions resulting from the digested sludge land application was considered, and the reduction potentials resulting from biogas utilization and substituting chemical fertilizers were also analyzed. The results showed the net GHG emissions of the two cases were 178.92 and − 26.33 kg CO2-eq/tDS, respectively. When excluding the reduction, the GHG emissions of the two cases were 519.32 and 352.97 kg CO2-eq/tDS, respectively, where the dewatering, digested sludge drying, and land application were the main contributors. The GHG emissions associated with the digested sludge land application accounted for 28% and 45% of the total GHG emissions in two cases, respectively. The GHG emission reduction could be achieved by sludge substitution for chemical fertilizer, which could offset 65.5% and 107.5% of the total GHG emissions in two cases, respectively. While the biogas utilization could only offset less than 10% of the total GHG emissions of both cases. Likewise, improving organic content or specific biogas yield rates could only offset up to 26.2% and 40.3% of the total GHG emissions. These findings provide understanding into evaluating GHG emissions of the sludge anaerobic digestion treatment route.

Technological assessment of greenhouse gas reduction potential of power generation in Türkiye

Climate change is one of the most pressing issues of the 21st century and transformation of power generation infrastructure is essential to achieve the long-term temperature goals set by the Paris Agreement, given that it accounts approximately 34% of global anthropogenic greenhouse gas emissions. Türkiye, as a developing country, has committed to reducing its greenhouse gas emissions by up to 41% from the business-as-usual level by 2030. To explore potential pathways for the mitigation of emissions from power generation in Türkiye, a model was developed using the TIMES (The Integrated MARKAL-EFOM System) modelling framework within this study. This model utilized national datasets to conduct a comprehensive assessment of current infrastructure of power generation in Türkiye, and emission trends were estimated under various scenarios. TIMES model allowed for an analysis of the energy, economy, and environment relationships based on technological development. Results were obtained for the reference scenario and three alternative scenarios for the period of 2020–2045. A mitigation potential of 18–50% from business as usual levels was obtained across scenarios. Total system costs were increased around 4%–24% as compared with reference scenario, which resulted in higher unit cost for electricity production.