Tons Of CO2-eq Research Articles

Determining the efficiency of local heat recycling wastewater based on a heat exchanger

RELEVANCE. The authors research the potential energy, economic and environmental effects of using local heat recovery from wastewater generated in showers. At the moment in Russia, almost all household wastewater is disposed of in sewer networks without the beneficial use of the heat that they possess. It is important to determine the effect of implementing this method of heat recovery, to identify and analyze the problems that prevent this from being done.THE PURPOSE. The purpose of the work is to determine the potential effect of using local heat recovery from wastewater generated in showers.METHODS. Based on a verified mathematical model of the heat exchanger, the energy effect from the individual use of the shower room is determined. A number of assumptions are applied to the heat consumption structure of an individual building and, based on available data on the average annual heat consumption of residential buildings in Moscow, the economic and environmental effect of energy-saving measures is calculated.RESULTS. Relative savings within the annual heat consumption of a building with a decentralized and centralized hot water supply system were 5,3% and 3,1%, respectively (64 and 37 GCal). Fuel economy amounted to: 9145 toe and 5227 toe for a building with a decentralized and centralized hot water supply system, respectively (14,5 and 8,5 thousand tons of CO2-eq). The payback period for energy-saving measures for the case of a decentralized hot water system based on an instantaneous electric water heater was 1,5 years.CONCLUSION. Local waste heat recovery makes it possible to obtain a significant energy and environmental effect within any locality, but at the moment there are no measures to support consumers implementing energy-saving measures. Currently, this method of heat recovery is of interest only to those consumers whose source of thermal energy for the needs of hot water supply is electricity.

Life Cycle Comparative Assessment of Polyethylene Terephthalate (PET) Plastic Bottles: A Case Study of Drinking Bottled Water in Ramathibodi Hospital, Thailand

In the current context where all sectors aim to promote sustainable development, hospitals, as large organizations with significant human interactions, face challenges in managing not only medical waste but also general waste such as water bottles. Improper management of these wastes can lead to environmental problems and high disposal costs. This study performed a life cycle assessment (LCA) of regular (petroleum-based) and alternative (bio-based) polyethylene terephthalate (PET) bottles used in Ramathibodi Hospital, Thailand, to identify effective strategies for mitigating environmental impacts. The assessment was divided into three scenarios: label-free bottles, bio-based bottles, and 100% recycling. The results indicate that using label-free bottles instead of conventional ones merely reduces environmental impacts by 2%. Transitioning to 30% and 100% bio-based PET can decrease greenhouse gas (GHG) emissions by 7 and 13 tons of CO2 eq per year, respectively. Currently, the hospital's PET bottles contribute 56.2 tons of CO2 eq annually. Health impacts associated with conventional PET bottles amount to 11.70 disability-adjusted life years (DALYs), a comprehensive measure that includes both mortality and morbidity. Meanwhile, 30% and 100% bio-based bottles reduce this to 7.35 and 4.87 DALYs, respectively. Achieving 100% recyclability in bottle management can cut GHG emissions from disposal processes by up to 90%. Moreover, combining the use of 100% bio-based PET bottles with 100% recycling can lower GHG emissions by up to 40% compared to current practices. These findings highlight the potential for significant environmental and health benefits through improved bottled water management strategies in hospitals.

Benefits and challenges in deployment of low global warming potential R290 refrigerant for room air conditioning equipment in California

High global warming potential gases (“high GWP”) are the fastest growing sector of greenhouse gas emissions in the world and in California and are primarily used as refrigerant gases in refrigeration and cooling equipment. Hydrofluorocarbons (HFCs) refrigerants are the dominant type of high GWP gases with GWP values thousands of times larger than CO2 on a 100-year timescale. Refrigerant-grade propane (“R290”) has a very low GWP (GWP = 3.3) with good thermodynamic properties and good cooling equipment performance but the flammability of any leaked refrigerant makes equipment design, handling, and maintenance critical factors to manage. This paper focuses on the potential climate benefits and costs of transitioning to R290 refrigerant in small room air conditioning (AC) units, specifically window AC, packaged terminal AC/heat pumps (PTAC/PTHP), and mini-split heat pumps. Overall climate impact for a transition to all three types of air conditioning units in the 2022–2051 timeframe is found to be from 15 to 64 million metric tons of greenhouse gas (GHG) savings in California with a cost of saved CO2eq that ranges from $14.50 per ton of CO2eq saved to −$50.30 per ton of CO2eq saved (net savings) depending on whether the baseline refrigerant is R32 or R410A and depending on the relative energy efficiency for R290 units compared to baseline units.

Analysis of the Impact of Biomass/Water Ratio, Particle Size, Stirring, and Catalysts on the Production of Chemical Platforms and Biochar in the Hydrothermal Valorization of Coffee Cherry Waste

In Colombia alone, 12.6 million bags of green coffee are produced, but at the same time, 784,000 tons of waste biomass are dumped in open fields, of which only 5% is recovered or used, and 10 million tonnes of coffee emit 28.6 million tonnes of CO2 eq annually. This presents a worrying dilemma, and the need to develop a technology to transform the waste into usable products is increasing. As a response to this, the valorization of coffee waste was explored through the production of biochar and platform chemicals by implementing a set of hydrothermal experiments with different biomass/water ratios (1:5, 1:10, 1:20, 1:40), particle sizes (0.5, 1, 2, 5 mm), stirring rates (5000 and 8000 rpm), and catalysts (H2SO4, NaHCO3 and CH3COOH) at 180, 220, and 260 °C in a batch reactor with autogenous pressure. Notably, the smaller B:W ratios of 1:20 and 1:40, as well as smaller particle sizes of 0.5 and 1 mm, yielded higher amounts of platform chemicals, while stirring showed minimal influence. CH3COOH significantly enhanced the process compared to other catalysts. The biochar was characterized as anthracite, and this obtaining of coal-like materials from biomass itself represents a remarkable feat. Said anthracite presented little to no variation in physical parameters, while catalysts induced functionalization. By optimizing factors like B:W ratio, particle size, and catalyst application, valuable insights have been gained into enhancing the yield of platform chemicals and quality of biochar from coffee waste. The findings not only contribute to sustainable waste management practices but also highlight the importance of exploring innovative solutions for utilizing agricultural by-products effectively.

Impact of renewables on the Peruvian electricity system

Peru is committed by international agreements such as the Paris Agreement and the UN 2030 Agenda for Sustainable Development to reduce its Green House Gas (GHG) emissions. Although Peru began promoting power plant projects based on renewable energies in 2008, the institutional impulse seems to have ceased today. Nonetheless, adopting renewable energy sources not only aids in fulfilling these commitments but also reduces electricity prices, fostering a more competitive economy. This study aims to provide a thorough analysis and evaluation of the impact that integrating Non-Conventional Renewable Energy Resources (NCRER) has on Peru's wholesale electricity market. Specifically, it focuses on the net total savings for the system, calculated as the difference between the reduction in energy costs traded and the cost of the renewable premium. To reach that goal a simplified yet analytical tool has been developed based on a multivariable regression of the real data of the market. The volume of natural gas not consumed and the volume of GHG emissions avoided will also be evaluated. The results show that based on the 2021 scenario, a NCRER share of 28.26 % would lead to a net saving for the final users of 316.04 MUSD in the annual energy traded in the market. The reduction of conventional thermal generation prevents the annual burning of 2.04 normal km3 of natural gas and the emission of 4.99 million tons of CO2-eq. To the authors' knowledge, this is the first time that the impact of NCRER production in the Peruvian electricity system has been quantitatively evaluated.

(Invited) Achieving Robustness and Economic Viability in CO2 Electrolysis Scale-up: Key Results from RenewCO2

RenewCO2 is commercializing processes to convert carbon emissions from chemical manufacturing, which contributes 274 million metric tons of CO2eq annually in the U.S. alone. Our pioneering electrocatalytic Carbon Utilization Technology (eCUT) is adept at upcycling CO2 from hard-to-decarbonize industrial sources. By synthesizing commodity chemicals from CO2 emissions, eCUT promises high energy efficiency while producing carbon-negative materials. The critical innovation of RenewCO2’s eCUT process is deploying catalysts designed with readily available metals, optimizing the process to reduce CO2 into multi-carbon chemicals selectively with impressive energy efficiency.RenewCO2 has significantly advanced CO2 electrolyzer scale-up, focusing on demonstrating process robustness and economic feasibility. Targeting liquid products such as monomers (glycols), RenewCO2 has demonstrated cost-advantaged process economics compared to the incumbent petrochemical and bio-derived routes. We present detailed findings on the enhanced performance of our proprietary catalysts, which have shown remarkable endurance under prolonged operational conditions (1000 h of operation) in a scaled-up stack containing five 500 cm2 electrodes. The RenewCO2 team has demonstrated consistent electrolyzer performance with minimal degradation over extended periods. We also delve into improvements in energy efficiency, showcasing how these enhancements contribute to the overall process economics.The purification process is crucial in making carbon-negative materials from CO2 that do not require a green premium. In this regard, RenewCO2 has achieved remarkable progress in demonstrating a highly energy-efficient product purification. In collaboration with Argonne National Lab, we have developed an advanced electrochemical separation method that removes ionic species from the products to comply with strict industrial standards and increase their market value. A key development in this area is our innovative approach to electrodeionization, which combines ion-exchange membranes with electrically active media. This method exhibits low energy consumption, robustness, and simple operation. These advancements in the purification process are integral to our system’s overall efficiency and are pivotal in our pursuit of creating economically viable and sustainable electrochemical manufacturing solutions.On the economic front, we provide an in-depth analysis of the cost implications of scaling up. This includes a breakdown of the capital and operational costs, along with a comparative analysis with existing technologies. We discuss the main factors contributing to product cost and strategies to minimize them, such as the integration of low-cost materials and judicious choice of operating conditions.Our aim is to provide a transparent and comprehensive overview of the challenges and the state-of-the-art in scaling up CO2 electrolysis to liquid products, offering valuable insights for the scientific community and stakeholders in the field.

Alternative uses for urban autumn tree leaves: A case study in profitability and greenhouse gas emissions for the city of Berlin

Autumn tree leaves collect as waste on many city streets every year. In the city of Berlin, they are usually collected and transported for composting as their final treatment, which emits greenhouse gases (GHG) into the atmosphere. This study assesses alternative end uses of autumn tree leaves in order explore the potential of reducing GHG emissions while producing electric energy from residual biomass. It uses a combination of partial life-cycle assessments and net present value (NPV) to explore the different net GHG emissions and economic benefits of using autumn tree leaves for the following scenarios: anaerobic digestion (biogas), gasification, and co-firing. Assuming the use of 36,000 tonnes of leaves per year, co-firing in existing power plants shows the highest NPV, of between 10.3 million and 12.1 million euros for a 10-year lifetime, in line with the phase-out of coal combustion in Germany. It also results in the lowest net GHG emissions, with savings of between 252,000 and 144,000 tonnes of CO2eq. Gasification in new plants resulted in similar NPVs, estimated at between 9.80 and 9.86 million euros over a 20-year investment horizon, but lower emissions savings of 178,000 to 127,000 tonnes of CO2eq. Biogas production showed high emissions savings of 204,000 to 203,000 tonnes of CO2eq, but a much lower NPV of between 2.3 and 2.5 million euros. Composting was the only scenario with positive net GHG emissions. The amount of energy retrieved from the conversion technologies and the electrical tariff applied were the main drivers of these results. Other aspects that can shape the results include the availability of infrastructure and transport distances. The results are highly sensitive in both cases to the dryness of the leaves, while electricity tariffs influenced the economic performance considerably.

Assessment of Corporate Carbon Footprint and Energy Analysis of Transformer Industry

Transformers are primarily key components in power transmission and distribution systems. In the electrical industry, transformers are becoming increasingly important to increase energy efficiency and reduce environmental impact. In the process from the production to the use of transformers, various strategies and technologies are adopted to reduce the carbon footprint. To achieve decarbonization targets and a future with sustainable energy, ongoing efforts to reduce the carbon footprint of transformers need to continue. Therefore, this study aims to calculate the carbon footprint (CF) of Beta Energy in the Adana Province of Türkiye. A comprehensive inventory is being created to determine and monitor the greenhouse gas emissions of Beta Energy, a transformer manufacturer. This inventory includes direct and indirect greenhouse gas emissions from all of the company’s activities. The findings show that in 2023, the total CF of Beta Energy is equal to 1,799,482.72 tons of CO2-eq and considering the total of 6044 transformers sold in 2023, results in 297 tons of CO2-eq/transformer per product. The results show that the transformer manufacturing industry has a high carbon footprint because it is an energy-intensive process. The areas where the most carbon emissions occur in transformer production are revealed by CF hot spot analysis in this study. To minimize both current and future greenhouse gas emissions during transformer production, the measures to be taken during the R&D, production, transportation, and service stages are revealed. This study aims to establish a foundation for Beta Energy’s efforts to reduce greenhouse gas emissions by managing them effectively.

Optimizing waste leachate treatment for environmental and economic sustainability: Insights from a bottom-up study of over 300 cities

Municipal waste incineration in China reached 232 million tonnes in 2022, with increasing problems in treating waste leachate (WL). However, significant uncertainty exists in the emission performances, cost, and optimization strategies of city-level WL treatment. Herein, a bottom-up approach is utilized to investigate the WL status across over 300 cities and a life cycle thinking is employed to compare the environmental and economic effects of various WL and waste leachate concentrate (WLC) management options. Analysis reveals national production of WL has reached 57 million tonnes, with the top ten cities, including Guangzhou, Shanghai, and Chongqing, contributing 20.6 %. Biological coupled chemical treatment (BCT) demonstrates the best environmental performances in WL treatment technologies, while biologically coupled membrane treatment (BMT) offers the lowest economic expenses, and Mechanical Vapor Recompression (MVR) evaporation excels in treating WLC. In a business-as-usual scenario, the national carbon emissions, energy consumption, and economic costs of WL treatment are 24 million tonnes CO2 eq, 264 million GJ, and RMB 19 billion, respectively. Under the WL and WLC technology optimization scenarios, estimations indicate a reduction in carbon emissions by 80.7 % (equivalent to 55.1 million trees) and 19.7 % (equivalent to 13.5 million trees), respectively. Viewed holistically, replacing BMT with BCT emerges as the optimal mitigation strategy, with the synergistic optimization of BMT and MVR evaporation systems following closely. In the formulation of the technology transition strategies, the urban economy, strategic positioning, and geographic location also should be considered apart from the technological aspects, to steadily achieve sustainable co-benefits across environmental and economic dimensions.

Integrating Mechanistic-Empirical Pavement Analysis in the Life Cycle Assessment Use Phase and Monetization of Environmental Impacts to Promote Low Carbon Transportation Materials

This study attempted to integrate the Mechanistic-Empirical Pavement Design Guide (MEPDG) analysis into the life cycle assessment (LCA) framework to explore the potential of terminal blend rubberized bitumen (TBRB) technology as a sustainable alternative to traditional paving materials in the United Arab Emirates (UAE). In addition, the concept of environmental impact monetization is introduced for quantifying shadow prices to be used in cost–benefit analyses and encourage the adoption of sustainable technologies in pavement construction. The findings demonstrate that hot mixed asphalt (HMA) with TBRB outperforms asphalt mixtures with neat bitumen (NB) and polymer-modified bitumen (PMB) containing 7% linear styrene–butadiene–styrene, with respect to durability and environmental impacts. The cradle-to-grave analysis, which includes maintenance and rehabilitation cycles based on the MEPDG results, alters the hierarchy among scenarios compared to conventional cradle-to-gate analyses, highlighting the importance of the use phase in LCA. Overall, the asphalt mixture with TBRB exhibits 83% and 63% less global warming potential than mixtures with NB and PMB, respectively. The monetization process through the distance-to-target approach returned the shadow price of US$157 per metric ton of CO2eq in the UAE. Based on this value, the HMA with TBRB, if selected over those with NB and PMB, offers environmental savings of US$47,186/km-lane and US$15,852/km-lane for the case study investigated.

Life cycle environmental evaluation of medical oxygen masks in the UK

In a clinical setting, medical oxygen masks (MOMs) are made using lightweight and transparent materials with Polyvinyl Chloride (PVC) being a popular choice. Environmental concerns around the use of PVC have arisen due to the toxicity of plasticisers required; in particular the use of increasingly regulated phthalate (Pht) based plasticisers. Non-Pht plasticisers and alternative materials to PVC are being sought as potential replacements in order to keep MOMs in line with current and expected regulations. This study explores the environmental impacts of three (low-flow) MOMs using a life cycle assessment approach from cradle to grave with a functional unit defined as ‘one single-use low-flow medical oxygen mask for adult use in the UK’. The results account for all 11 impact categories as provided by the CML-IA baseline v3.03 methodology. PVC is the main component of two MOMs: mask A using a non-Pht based plasticiser and mask C (a hypothetical mask) using Pht-based plasticiser DEHP. For Mask B, styrene-ethylene-butadiene-styrene based thermoplastic elastomer (TPE-S) and polypropylene is used instead of PVC. Mask B shows the lowest environmental impact across all impact categories. For six out of 11 impact categories (including global warming potential and ozone depletion), mask C scores highest, whereas mask A is highest for the other five categories (with large impacts in human toxicity and ecotoxicities). Two scenario analyses show the importance of supply chain logistics (i.e., the location of the manufacturing site and location of end user) on overall environmental impact. The results of this study intend to provide evidence to policy makers, healthcare professionals, and manufacturers of MOMs to improve the overall environmental impacts of these products, as they contribute around 4437 tonnes of CO2 eq. yearly in the UK alone. The results show that switching from plasticised PVC to TPE-S would reduce the impacts of the use of MOMS within the UK by 2755 tonnes of CO2 eq. per year.

Techno-economic evaluation of GHG emissions mitigation of biomethane upgrading technologies

The current trend in the European biogas industry is to shift away from electricity production towards the production of biomethane for the need to replace natural gas. The upgrading of biogas to biomethane is normally performed by separating the biogas in a stream containing natural gas grid quality methane and a stream containing mostly CO2. The CO2 stream is normally released into the atmosphere; however, part of the methane may still remain in it, and, if not oxidized, even a small fraction of methane released may jeopardise all the GHG emissions savings from producing the biomethane, being methane a powerful climate forcer. Scope of this work is to assess the opportunity cost of installing an Off Gas Combustion (OGC) device in biomethane upgrading plants. The currently available technologies for biogas upgrading to biomethane and the most common technology of OGC (the Regenerative Thermal Oxidisers, RTO) are described according to their performances and cost. Then the cost per tonne of CO2eq avoided associated to the adoption of RTO systems in relation to the upgrading performance is calculated to identify a potential threshold for an effective and efficient application of the RTO systems. It is found that, in case of upgrading technologies which can capture almost all biomethane in the upgrading off-gas (i.e. 99.9%), currently the adoption of an RTO to oxidise the methane left in the off-gas would add costs and need additional fuel to be operated, but would generate limited GHG emission savings, therefore the cost per tonne of CO2eq emissions avoided would result not competitive with other GHG emissions mitigation investments. While the installation of RTOs on upgrading systems with a methane slip of 0.3%, or higher, normally results cost competitive in reducing GHG emissions. The installation of an RTO on systems with a methane slip of 0.2% results in a cost per tonne of CO2eq emissions avoided of 50–100 euro, which is comparable to the current cost of CO2 emissions allowances in the EU ETS carbon market, representing therefore a reasonable choice for a threshold on methane slip regulation for biogas upgrading systems.

Power Sector Under Climate Scenario: A Study of Climate Policy Impact on Indonesia Electricity System

In the sixth assessment report, the IPCC indicates that global temperature increased by 1.11 (±0.13) degrees Celsius in 2019 due to 6.5 gigatons of CO2eq of greenhouse gas emissions into the atmosphere. The power sector is a major global greenhouse gas emitter, particularly in Indonesia. Indonesia’s electricity sector emitted 149.90 million tons of CO2eq greenhouse gas in 2020, which is expected to increase to 158.30 million tons of CO2eq in 2021. Indonesia has committed to reducing greenhouse gas emissions according to the Paris Agreement. The Paris Agreement has been ratified into national law, accommodating Indonesia’s roadmap to net zero by 2060. The emissions reduction target was published in 2022 through the enhanced Nationally Determined Contribution (NDC). This study aims to analyze the impact of climate policy in Indonesia’s electricity sector to meet the net zero emissions target by 2060. Projection and calculation in this study were conducted using the Low Emissions Analysis Platform (LEAP). Data from 2020, including electricity demand, existing capacity, energy production, energy intensity, lifetime, and capacity factor, were used to support LEAP analysis. The data were obtained from the PLN statistical book, PLN sustainability report, Indonesia’s statistical book, and climate change mitigation and adaptation reports in Indonesia. This study developed three climate scenarios, including business as usual (BAU), sustainable development (SD), and low-carbon development (LCD). These scenarios draw upon current climate policies that have various impacts on electricity generation in Indonesia. Based on LEAP analysis, by 2060, energy demand is expected to increase to 300.36 MTOE (BAU), 200.93 MTOE (SD), and 76.97 MTOE (LCD). Consequently, each climate scenario requires an increase in installed capacity to 821.82 GW (BAU), 727.06 GW (SD), and 334.58 GW (LCD). The renewable energy mix is projected to be 21% (BAU), 69% (SD), and 100% (LCD). Each scenario requires investment to develop capacity to meet energy demand. The investment cost is estimated to be 1,671.58 million USD (BAU), 1,537.64 million USD (SD), and 816.51 million USD (LCD). GHG emissions are projected to rise to 1,746.31 million tons of CO2eq (BAU) and 264.39 million tons of CO2eq (SD). However, the LCD scenario expects to achieve net zero emissions by 2060.

Techno-Economic Assessment of Molten Salt-Based Concentrated Solar Power: Case Study of Linear Fresnel Reflector with a Fossil Fuel Backup under Saudi Arabia’s Climate Conditions

Concentrated solar power (CSP) has gained traction for generating electricity at high capacity and meeting base-load energy demands in the energy mix market in a cost-effective manner. The linear Fresnel reflector (LFR) is valued for its cost-effectiveness, reduced capital and operational expenses, and limited land impact compared to alternatives such as the parabolic trough collector (PTC). To this end, the aim of this study is to optimize the operational parameters, such as the solar multiple (SM), thermal energy storage (TES), and fossil fuel (FF) backup system, in LFR power plants using molten salt as a heat transfer fluid (HTF). A 50 MW LFR power plant in Duba, Saudi Arabia, serves as a case study, with a Direct Normal Irradiance (DNI) above 2500 kWh/m2. About 600 SM-TES configurations are analyzed with the aim of minimizing the levelized cost of electricity (LCOE). The analysis shows that a solar-only plant can achieve a low LCOE of 11.92 ¢/kWh with a capacity factor (CF) up to 36%, generating around 131 GWh/y. By utilizing a TES system, the SM of 3.5 and a 15 h duration TES provides the optimum integration by increasing the annual energy generation (AEG) to 337 GWh, lowering the LCOE to 9.24 ¢/kWh, and boosting the CF to 86%. The techno-economic optimization reveals the superiority of the LFR with substantial TES over solar-only systems, exhibiting a 300% increase in annual energy output and a 20% reduction in LCOE. Additionally, employing the FF backup system at 64% of the turbine’s rated capacity boosts AEG by 17%, accompanied by a 5% LCOE reduction. However, this enhancement comes with a trade-off, involving burning a substantial amount of natural gas (503,429 MMBtu), leading to greenhouse gas emissions totaling 14,185 tonnes CO₂ eq. This comprehensive analysis is a first-of-a-kind study and provides insights into the optimal designs of LFR power plants and addresses thermal, economic, and environmental considerations of utilizing molten salt with a large TES system as well as employing natural gas backup. The outcomes of the research address a wide audience including academics, operators, and policy makers.

Simultaneous achievement of energy recovery and carbon sequestration through municipal solid waste management: A review

Effective municipal solid waste (MSW) management is a crucial component for sustainable cities, as inefficient waste disposal contributes to the release of about a billion tons of CO2-eq in greenhouse gases (GHG) annually. With escalating global waste generation, there is an untapped opportunity to integrate carbon dioxide removal (CDR) technologies into existing MSW management processes. This review explores current research on utilizing MSW for CDR, emphasizing its potential for both energy generation and carbon sequestration. The investigation covers three waste management practices: landfilling, waste-to-energy (WtE), and biochar production, revealing two paths for carbon sequestration. First, MSW serves as a feedstock in bioenergy with carbon capture and storage (BECCS), acting as a carbon-neutral resource that avoids fossil fuel and energy crop use, reducing GHG emissions and generating value through energy production. Second, direct storage of organic MSW and its derivatives, like biochar, in various carbon sinks allows for extended sequestration, offering a comprehensive approach to address the challenges of waste management and climate change mitigation. Moreover, this review advocates for an extended exploration into several subjects including in-depth analysis of waste, research on MSW-derived biochar recalcitrance across different carbon sinks, and understanding the symbiotic connections with GHG-emitting sectors like agriculture and energy. Finally, this review emphasizes the necessity of conducting life-cycle assessment studies to fully discern the benefits and assess the impacts of any future endeavors exploring the role of MSW in carbon sequestration.

Wholesale fruit and vegetable market in Milan: Turning food surpluses into environmental gains

Food redistribution is increasingly recognized as a key strategy for tackling food waste and improving food security. However, a comprehensive assessment of its environmental impacts remains a challenge. This study fills this gap by investigating the role of food redistribution in minimizing waste, reducing production pressures, and mitigating the environmental impacts of the agri-food chain. In particular, this research focuses on mapping the flow of recovered food within the Ortomercato system, Italy's largest fruit and vegetable wholesale market, by third sector associations.A comprehensive cradle-to-grave life cycle assessment was conducted to quantify the recovered fruit and vegetable products, assess their environmental impact, and estimate the associated environmental credits through the prevention of food waste.The findings indicate that the production phase has the largest environmental impact, accounting on average for 63% of the total impact. The study employs a net balance approach to demonstrate the success of food recovery efforts, which have saved over 136 tonnes of food from the market over a 49-day period and generated environmental credits equivalent to 169 tonnes of CO2 eq. per year. These results highlight the environmental impact of food redistribution and provide insights for operational optimization and the establishment of an environmental budget for the system. Furthermore, the potential for regulating these environmental credits and promoting the benefits of food redistribution through public channels is highlighted.While the research addresses the mapping of food flows and their environmental impacts, there is a significant gap in the assessment of the socio-economic impacts associated with food redistribution. Further research is needed to understand how this practice affects local communities, economies and social dynamics, and to contribute to a more comprehensive assessment of its effectiveness.

Carbon Emission Analysis and Reporting in Urban Emissions: An Analysis of the Greenhouse Gas Inventories and Climate Action Plans in Sarıçam Municipality

The urban carbon footprint (UCF) is an important tool for assessing an organization’s ecological impacts and in guiding sustainability efforts. This calculation is usually measured in tons of carbon dioxide equivalent (CO2-eq). Calculations provide important data to determine strategies to reduce the carbon footprint and establish sustainability targets. Various standards and protocols guide UCF calculation, and many organizations aim to make these data transparent to their stakeholders and the public. This study aims to calculate the UCF of Sarıçam Municipality (SM) in the Adana Province of Türkiye. This study includes the greenhouse gas emission inventories resulting from all activities of the SM main service building, guest house, construction site service building, Cultural Center service building, and additional service buildings between 1 January 2022 and 31 December 2022. The calculations include generator fuel consumption, electricity consumption, the refrigerant gas leaks and refills resulting from these activities, the fuel consumed in vehicles owned by the company or whose fuel consumption is under company control, emissions originating from personal travel, emissions originating from customers and visitors, emissions originating from business travel, purchases, etc. Emissions from products purchased and emissions from waste transportation are included. The findings show that, in 2022, the total UCF of SM was equal to 10,862.46 tons of CO2-eq. The Paris Agreement aims to reduce the per capita emissions to approximately two tons of CO2-eq by 2030. The carbon footprint per employee within the municipality was calculated at 12.43 tons of CO2-eq, as derived from the analyzed data. The results reveal the importance of implementing sustainable practices and strategies within SM, such as energy efficiency measures, waste reduction, and the adoption of renewable energy sources, to mitigate its carbon footprint. This study plans to provide a basis for SM’s reduction efforts by keeping greenhouse gas emissions under control.

Tracking a Chinese megacity's community-wide carbon footprint and driving forces from a multi-infrastructure perspective

Many urban deep-decarbonization actions are related to multiple infrastructure provisioning sectors; therefore, it is essential to track carbon footprints associated with these infrastructure sectors to guide urban carbon mitigation actions. However, there are fewer temporal analyses of cities' carbon footprints from a multi-infrastructure perspective. This study applied the community-wide trans-boundary infrastructure-based carbon footprinting (CIF) method to Shanghai, China and adopted the logarithmic mean Divisia index (LMDI) approach to explore driving factors in community-wide carbon footprints from 2000 to 2019. Shanghai's total CIF increased by 85%, from 153.2 million tonne CO2-eq in 2000 to 283.5 million tonne in 2019. The energy and mobility sectors contributed to 89%–93% of the total CIF during this period. Although emitting sources within Shanghai contributed to a large proportion, trans-boundary carbon emissions embodied in imported energy, construction materials, and food provisioning increased from 6% of total CIF in 2000 to 28% in 2019. Shanghai significantly reduced city-wide carbon intensity per GDP from 2000 to 2019. Its city-wide carbon footprint per capita was around 11.4 tonne CO2-eq, of which 17.4% was associated with residential consumption. LMDI results showed that improving energy efficiency in economic production and reducing energy demand in residential sector contributed to reducing carbon footprints of these two sectors. The driving effect of carbon intensity was not monotonic in both economic production and residential consumption, indicating future policy should prioritize actions to reduce the carbon intensity of infrastructure provisioning in its carbon neutrality plan.

Comparison of Embodied Carbon Footprint of a Mass Timber Building Structure with a Steel Equivalent

The main purpose of this study is to quantify and compare the embodied carbon (EC) from the materials used or designed to build the Adohi Hall, a residence building located on the University of Arkansas campus in Fayetteville, AR. It has been constructed as a mass timber structure. It is compared to the same building design with a steel frame for this study. Based on the defined goal and scope of the project, all materials used in the building structure are compared for their global warming potential (GWP) impact by applying a life cycle assessment (LCA) using a cradle-to-construction site system boundary. This comparative building LCA comprises the product stage (including raw material extraction, processing, transporting, and manufacturing) plus transportation to the construction site (nodule A1–A4, according to standard EN 15804 definitions). In this study, GWP is primarily assessed with the exclusion of other environmental factors. Tally®, as one of the most popular LCA tools for buildings, is used in this comparative LCA analysis. In this study, the substitution of mass timber for a steel structure with a corrugated steel deck and concrete topping offers a promising opportunity to understand the GWP impact of each structure. Mass timber structures exhibit superior environmental attributes considering the carbon dioxide equivalent (CO2 eq). Emissions per square meter of gross floor area for mass timber stand at 198 kg, in stark contrast to the 243 kg CO2 eq recorded for steel structures. This means the mass timber building achieved a 19% reduction in carbon emissions compared to the functional equivalent steel structure within the building modules A1 to A4 studied. When considering carbon storage, about 2757 tonnes of CO2 eq are stored in the mass timber building, presenting further benefits of carbon emission delays for the life span of the structure. The substitution benefit from this construction case was studied through the displacement factor (DF) quantification following the standard process. A 0.28 DF was obtained when using mass timber over steel in the structure. This study provides insights into making more environmentally efficient decisions in buildings and helps in the move forward to reduce greenhouse gas (GHG) emissions and address GWP mitigation.

Design and eco-technoeconomic analysis of a natural gas cogeneration energy management center (EMC) with short-term thermal storage

This work proposes a non-islanded cogeneration energy management center (EMC) that can be used to displace grid-level natural gas turbine systems and natural gas combustion systems for heat. The design of the proposed EMC included a weighted multi-objective optimization aimed at minimizing: i) natural gas consumption; ii) capital costs; iii) utility costs; and iv) unmet thermal demand. The decision variables consisted of the existence and capacity of the equipment comprising the EMC, including: i) a natural gas boiler; ii) an internal combustion engine that generates heat and electricity; and iii) a hot water thermal storage system. Four resulting candidates EMC designs were then compared with the status-quo (SQ) in an eco-technoeconomic analysis; The SQ draws electricity from the grid and heating for dwellings come from natural gas boilers. Emissions at grid level change which alternative is favored. The findings showed that, for a system that serves 4–5 dense urban city blocks over a 20-year lifetime, the SQ system had cumulative levelized costs of 9.6 million USD for the final consumer, while the levelized costs of the EMC designs ranged from 12.9 to 15.1 million USD. In terms of emissions, the SQ emitted 959 tonnes of CO2eq per year, while the EMC system produced around 500 tonnes of CO2eq per year depending on the year, yielding a CCA varying between 364 and 653 USD/tonneCO2eq