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The growing amount of space debris in the low Earth orbit poses a danger to manned as well as uncrewed missions. Additionally, the new business model of providing internet from space is emerging among new space players, making low Earth orbit more crowded. These factors have encouraged the space community to focus on sustainability in space. Satellite manufacturers typically have the capability to perform complete life cycle analysis (LCA) on their own products based on the manufacturing data. However, there is a lack of a method for non-manufacturers such as environmentalists and the general public to predict the carbon footprint of satellite manufacturing using a subsystem-level mass budget. Hence, this paper presents a method to quantify environmental pollution caused by the production of satellite constellations. Starlink is taken as a case study in this paper, and mass budget is predicted based on space systems engineering budget estimation techniques, the parametric method, and Federal Communication Commission orbital data. With the budget table used as an input, space-specific life cycle assessment is performed based on European Space Agency's life cycle inventory database. Finally, the single score for Starlink constellation version 1 was found to be 76 kilo points. This signifies the annual environmental load. These results could be helpful in obtaining an overview of the environmental effects of the production phase of satellite constellations. Further, the results could act as a foundation for further research on implementing more circular approach practices on Earth as well as in space. [ABSTRACT FROM AUTHOR]

Carbon dioxide emissions pose a global issue, with deforestation, forest loss from logging, fires, and construction highlighting the adverse effects of climate change. Urgent action is required to reduce carbon dioxide emissions and preserve forests. Egypt can contribute to reducing greenhouse gas emissions by effectively utilizing its waste resources, especially agricultural waste. The research focuses on developing environmentally friendly and sustainable construction materials with a forward-looking approach. This involves exploring alternative options for synthetic formaldehyde adhesives. This assessment emphasizes the significance of sustainability in the construction sector. The mechanical properties of the developed construction materials demonstrate higher tensile strength and Young's modulus values of 6.95 and 2493.5, respectively. An environmental impact assessment (EIA) was conducted for the production process of manufactured building materials, using 1000 kg of cotton stalk waste, and employing "open LCA software". The assessment includes impact categories such as ecological footprint, greenhouse gas protocol, impact 2002 +, CML IA baseline, and ecosystem damage potential. Results indicate an impact of 179.411 kg of CO2 on global warming and a total ecological footprint of 2382.1722 m2a. The study also considers other impact categories, including carcinogens, respiratory organics, aquatic and terrestrial ecotoxicity, human toxicity, and land occupation and transformation. [ABSTRACT FROM AUTHOR]

Bio‐based polymers may present a sustainable, circular way to reduce the environmental impact of plastics because they are produced from biomass that absorbs CO2 during its growth. However, sourcing (type of biomass used and cultivation location), production, and end‐of‐life affect the environmental impact of bio‐based plastics. We assessed the effect of sourcing and end‐of‐life options on the environmental impact of bio‐based high‐density polyethylene (bio‐HDPE) in 31 sourcing scenarios and five end‐of‐life options. Our study found that careful consideration of biomass sourcing (biomass type and production location) and end‐of‐life is needed to optimize the environmental impact of bio‐based plastics. If these aspects are not considered, the environmental impact of bio‐HDPE may exceed that of its petrochemical‐based counterpart. The direct availability of fermentable sugars indicated a lower environmental impact. The production location affected the resources needed for biomass cultivation and the environmental impact of processing due to the energy mix. Recently published guidelines do not allow biogenic carbon to be accounted for during the production stage, but only upon the incineration of the plastic. Our results show that this way of attributing biogenic carbon results in an apparent disadvantage for bio‐based plastics compared to petrochemical‐based plastics. Furthermore, it disadvantaged mechanical recycling of bio‐based plastics compared to incineration, a result out of line with circular economy principles. [ABSTRACT FROM AUTHOR]

Dairy farming is one of the most important sources of greenhouse gas (GHG) emissions in the livestock sector. In order to identify the key emission links and the best emission-reduction strategies for combined dairy farms, this study selected a typical large-scale combined dairy farm in northeast China, constructed a carbon emission model based on the lifecycle assessment concept, and set up different emission reduction scenarios to explore the zero-carbon pathway for combined dairy farms. The results showed that: (1) enteric fermentation and manure management of cows are important sources of carbon emissions from the seeding-integrated dairy farms, accounting for 38.2% and 29.4% of the total, respectively; (2) the seeding-integrated system showed a 10.6% reduction in carbon footprint compared with the non-seeding-integrated system; and (3) scenarios 1–4 reduced carbon emissions by 9%, 20%, 42%, and 61% compared with the baseline scenario, respectively. Therefore, the integrated-farming model is important for the green development of animal husbandry, and as the "net-zero" goal cannot be achieved at present, integrated-farming dairy farms have the potential for further emission reduction. The results of this study provide a theoretical basis for low-carbon milk production. [ABSTRACT FROM AUTHOR]

This study addresses the gap in the comprehensive literature on the intersection of readiness technology and changes in the manufacturing sector. This study employs a hybrid review (bibliometric analysis and conceptual framework) to offer a panoramic overview of the field. We scrutinised 77 publications from peer-reviewed journals, from 2005 to 2023, using methodological lenses such as keyword co-occurrence networks and thematic maps. The review reveals the major contributors (publication trends, themes, and topics) to integrating 3D printing, additive manufacturing, Tech Competition and Lifecycle Assessment in Manufacturing, and Smart Manufacturing Strategies. Based on these insights, we advocate a focused research agenda to expand scholarly contributions to this field. We introduce a framework that offers a theoretically robust tool for scholars and practitioners studying the impact of technology readiness in the manufacturing sector. Consequently, this study not only distils the existing literature, but also sets the stage for future research. This study places significant emphasis on the implementation of technological solutions as a means to improve production operations. Additionally, this research emphasises the significance of ensuring that investment strategies follow the organisation’s technological preparedness. An additional crucial implication concerns the cybersecurity protocols. This is consistent with the research’s emphasis on investigating cybersecurity concerns in the manufacturing industry.

The global wind energy industry is expected to expand in the context of carbon neutralization. Meanwhile, with the continuous improvement in carbon reduction tools such as carbon market and carbon tariffs, the carbon footprint of renewable energy may impact the cost and development of wind power in the future. Taking China, Europe, and the United States as the research object, this study constructs the lifecycle evaluation process and list of onshore wind power systems, conducts parameter comparison regarding the carbon footprint of onshore wind power in relevant regions, and summarizes the change trends. Moreover, it analyzes the cause of the trend and clarifies the influencing factors. The results indicate that the carbon footprint of onshore wind power shows a downward trend in the aforementioned regions from 2011 to 2022 owing to the large-scale wind turbines, improved generation efficiency, and cleanliness of industrial production. Specifically, the average decrease in China, Europe, and the United States was 49.2%, 46.2%, and 20.8%, respectively, and the decrease was concentrated in the equipment production stage. China has reduced its carbon footprint to a level close to Europe, and its gap with the United States has been reduced to 3.63 g/kW·h. However, China still lags behind Europe and the United States in terms of industrial production cleanliness and fan capacity factor, respectively. In the process of promoting industrial development, China should further promote the power generation efficiency of its wind power system, improve the cleanliness of industrial production, and support the recycling of decommissioned wind power systems, so as to steadily reduce the carbon footprints within the lifecycle of onshore wind power systems.

The North China Plain (NCP) serves as a critical grain-producing region in China, playing a pivotal role in ensuring the nation's food security. A comprehensive analysis of the carbon footprint (CF) related to the cultivation of major grain crops within this region and the proposal of strategies to reduce emissions through low-carbon production methods are crucial for advancing sustainable agricultural practices in China. This study employed the lifecycle assessment (LCA) method to estimate the CF of wheat, maize, and rice crops over a period from 2013 to 2022, based on statistical data collected from five key provinces and cities in the NCP: Beijing, Tianjin, Hebei, Shandong, and Henan. Additionally, the Logarithmic Mean Divisia Index (LMDI) model was utilized to analyze the influencing factors. The results indicated that the carbon footprints per unit area (CFA) of maize, wheat, and rice increased between 2013 and 2022. Rice had the highest carbon footprint per unit yield (CFY), averaging 1.1 kg CO2-eq kg−1, with significant fluctuations over time. In contrast, the CFY of wheat and maize remained relatively stable from 2013 to 2022. Fertilizers contributed the most to CF composition, accounting for 48.8%, 48.0%, and 25.9% of the total carbon inputs for wheat, maize, and rice, respectively. The electricity used for irrigation in rice production was 31.8%, which was much higher than that of wheat (6.8%) and maize (7.1%). The LMDI model showed that the labor effect was a common suppressing factor for the carbon emissions of maize, wheat, and rice in the NCP, while the agricultural structure effect and the economic development effect were common driving factors. By improving the efficiency of fertilizer and pesticide utilization, cultivating new varieties, increasing the mechanical operation efficiency, the irrigation efficiency, and policy support, the CF of grain crop production in the NCP can be effectively reduced. These efforts will contribute to the sustainable development of agricultural practices in the NCP and support China's efforts to achieve its "double carbon" target. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this article was to perform a life cycle assessment (LCA) of industrial meatballs produced in Malaysia, for evaluating the environmental impacts and discussing the adoption of circular economy (CE) principles. It attempted to fill the research gaps of very less related work reported, unavailability of environmental performance data and less discussion on improvement implications for food production in developing countries. Methods: To achieve the objectives, the midpoint environmental impacts of beef meatballs manufacturing were assessed and analyzed. Primary data were collected from a small- and medium-sized food manufacturing company located in Malaysia. The environmental assessment was grounded on the production of food raw materials and packaging materials and industry-based manufacturing of processed food items as the system boundary. The LCA was conducted using SimaPro 7.3.3 as a software tool and CML-IA baseline V3.05 as an impact evaluation method. Results and discussion: The results found that the farm-based production and industrial cooking of beef are the major sources responsible for the environmental burdens. Comparatively, food-based raw materials were having more damaging impact on the environment than the packaging materials. The use of natural gas for meatballs cooking was found to be another environmental hotspot. In addition, from the packaging viewpoint, polystyrene material was the major contributor towards environmental impacts. Based on the results, the potential solutions and CE principles were recommended and discussed in order to improve the environmental performance. Conclusions: By using LCA, this study identified the environmental hotspots for industrial meatballs production in Malaysia and discussed the potential adoption of CE principles in order to reduce the environmental burdens. [ABSTRACT FROM AUTHOR]

Nowadays, all productive sectors, including the construction industry, are facing the challenge of reducing their environmental impact. To achieve this objective, numerous actions are being carried out to access greater levels of environmental and economic sustainability. Techniques as Life Cycle Assessment contribute to quantifying environmental impacts, promoting a circular economy in a sector that consumes a high volume of resources, materials, and energy while generating large amounts of gaseous, liquid, or solid emissions. The present study aims to deepen our understanding of aspects that demonstrate the benefits of using RA instead of natural aggregates. This study not only quantifies the environmental impact but also explores the effects of potential improvements in the productive system and their impact on reducing environmental harm. The Life Cycle Assessment methodology is applied to quantify and compare the environmental impacts generated in the production of a ton of mixed recycled aggregates (MRA) from construction and demolition wastes, based on the data provided by plant managers. This is compared to the environmental impacts generated in the production of one ton of natural aggregates extracted from a quarry. The results revealed that the production of mixed recycled aggregate is more environmentally beneficial, confirming a reduction of 70.66% in environmental impacts during the production of recycled aggregates, in comparison to the natural aggregates extraction. Furthermore, the economic analysis demonstrates the economic advantage since the cost of producing recycled aggregates is over 30% cheaper than natural aggregates, being more competitive even when the transportation distances from the plant to the work sites exceed those of natural aggregates. [ABSTRACT FROM AUTHOR]

Current agricultural energy management methods do not sufficiently account for the environmental impacts related to farm size. This gap limits the ability to accurately predict the ecological effects of sugar beet cultivation, particularly regarding climate change, eutrophication, acidification, human toxicity, and terrestrial and aquatic ecotoxicity. Moreover, optimizing agricultural productivity and integrating artificial intelligence (AI) are necessary to improve energy management and anticipate future consumption patterns, considering current constraints. Our innovative solution combines LCA with AI to better forecast the ecological impacts of sugar beet cultivation across farms of different sizes. By using historical data and advanced neural models, this method anticipates future energy consumption while integrating environmental and energy constraints. The study highlights that medium-sized farms (MF) show the lowest environmental impacts, according to the CML and USEtox methodologies, unlike small (SF) and large farms (LF), which do not significantly differ in their contribution to pollutants. The average energy consumption for beet production was 1,092,000 MJ/ha on small farms, 1,126,100 MJ/ha on medium farms, and 1,107,080 MJ/ha on large farms. The key critical points identified were related to the use of diesel, machinery, seeds, and pesticides. In terms of energy distribution, chemical fertilizers accounted for 41 % of the total energy used, followed by fuel (24 %), pesticides (18 %), and machinery (7 %). Neural models revealed correlation coefficients (R2) ranging from 0.634 to 0.945 for testing, 0.861 to 0.967 for validation, and 0.944 to 0.982 for training. These results suggest good predictive accuracy for our AI-based approach. Finally, to improve energy efficiency, the study proposes modernizing agricultural equipment and developing more sustainable technologies, such as hybrid tractors, robotic and automated weeding systems, and cultivation techniques that reduce carbon emissions.

In an era of resource scarcity and environmental concerns, integrating Internet of Things (IoT) technology into the circular economy (CE), particularly for household appliances like microwaves, is crucial. The lack of systematic assessment of their post-use residual values often reduces utilization and shortens lifespans. Inadequate disposal and management contribute to electronic waste and environmental pollution. Addressing these challenges is vital for efficient appliance management within resource constraints, ensuring meaningful contributions to sustainable resource management. Thus, this study addresses these concerns by integrating IoT technology into microwave ovens, enabling real-time monitoring of key parameters such as voltage, current, door closures, and motor/blade rotations. Data from integrated sensors enables performance analysis and trend tracking, offering potential for advancing CE practices and sustainable product management. Subsequently, utilizing the insights stored from IoT data analysis and tailored surveys, a predictive maintenance model is developed, aiming to predict the life cycles of microwave oven components and categorize them within the CE principles, including reuse, repair, remanufacturing, and cascade. Finally, to mitigate the challenges of lower effective utilization and shortened operating lifespans observed in household appliances, this research employs machine learning models such as Random Forest, Gradient Boosting, and Decision Tree to accurately predict the residual values of IoT-enabled microwaves. Notably, Random Forest demonstrates superior accuracy compared to the other models. Therefore, these technological advancements allow household appliances to be utilized more effectively, thereby enhancing resource utilization.

The wind energy sector faces a persistent challenge in developing sustainable solutions for decommissioned Wind Turbine Blades (WTB). This study utilises Lifecycle Assessment (LCA) to evaluate the gate-to-gate carbon footprint of high-profile disposal and recycling methods, aiming to determine optimal strategies for WTB waste treatment in the UK. While this article analyses the UK as a case study, the findings are applicable to, and intended to inform, recycling strategies for WTB waste globally. Long-term sustainability depends heavily on factors like evolving energy grids and changing WTB waste compositions and these must be considered for robust analysis and development strategy recommendations. In the short to medium term, mechanical recycling of mixed WTB waste is sufficient to minimise Global Warming Potential (GWP) due to the scarcity of carbon fibre in WTB waste streams. Beyond 2040, carbon fibre recycling becomes crucial to reduce GWP. The study emphasises the importance of matching WTB sub-structure material compositions with preferred waste treatment options for the lowest overall impact. Future development should focus on the extraction of carbon fibre reinforced polymer (CFRP) structures in WTB waste streams, commercialising large-scale CFRP structure recycling technologies, establishing supply chains, and validating market routes for secondary carbon fibre products. In parallel, scaling up low-impact options, like mechanical recycling, is vital to minimise WTB waste landfilling. Developing viable applications and cost-effective market routes for mechanical recyclates is necessary to displace virgin glass fibres, while optimising upstream recycling processes based on product requirements. [ABSTRACT FROM AUTHOR]

Buildings are a basic requirement for human beings and an essential part of the built environment, with significant environmental impacts. In addition to their complex and diverse material use, buildings are expected to have a long lifespan, typically more than 50 years. This paper aims to evaluate the environmental performance of materials and construction activities for a typical residential building. Life cycle assessment methodology was applied using Simapro©software. A cradle-to-gate analysis was carried out. The results were analyzed based on the Ecoinvent 3.8 database and Eco-Indicator 99. The results show that reinforcing steel (21%) and concrete production (16%) are the most dominant processes, accounting for almost 37% of the overall environmental impact. Transportation also had an overall impact of around 15%. Brick production and use accounted for 11.23% of the overall impact, followed by lime mortar production (11%). Asphalt coating production and use had the 6th highest impact with 9.7% of the overall impact. Ceramic production accounted for 5% of the overall impact, followed by cut stone products with 3.58% of impact. Steel use, plaster mixing, excavation processes, laminate, fiberboard, paint, and glass production and use had around 7% of the overall impact in total. Besides, the resource depletion impact category showed the highest value among the three main impact categories. On the other hand, fossil fuels and respiratory inorganic impact categories were the most affected sub-impact categories among the 11 study impact categories. As material and designing codes, technology, and construction methods differ based on regions and countries, this paper demonstrates the importance of even smaller portions of materials such as Laminate production in the Land use and asphalt felt production in the Fossil fuels impact categories in, especially for countries with insufficient studies and databases for construction activities. [ABSTRACT FROM AUTHOR]

The process of coal-to-methanol conversion consumes a large amount of energy, and the use of the co-production method in conjunction with carbon capture, utilization, and storage (CCUS) technology can reduce its carbon footprint. However, little research has been devoted to comprehensively assessing the carbon footprint of the coal-to-methanol (CTM) co-production system coupled with CCUS-enhanced oil recovery technology (CCUS-EOR), and this hinders the scientific evaluation of its decarbonization-related performance. In this study, we used lifecycle assessment to introduce the coefficient of distribution of methanol and constructed a model to calculate the carbon footprint of the process of CTM co-production of liquefied natural gas (LNG) as well as CTM co-production coupled with CCUS-EOR. We used the proposed model to calculate the carbon footprint of the entire lifecycle of the process by using a case study. The results show that the carbon footprints of CTM co-production and CTM co-production coupled with CCUS-EOR are 2.63 t CO2/tCH3OH and 1.00 t CO2/tCH3OH, respectively, which is lower than that of the traditional CTM process, indicating their ability to achieve environmental sustainability. We also analyzed the composition of the carbon footprint of the coal-to-methanol process to identify the root causes of carbon emissions in it and pathways for reducing them. The work described here provided a reference for decision making and a basis for promoting the development of coal-to-methanol conversion and the CCUS industry in China. [ABSTRACT FROM AUTHOR]

Wave energy, as a significant renewable and clean energy source with vast global reserves, exhibits no greenhouse gas or other pollution during real-sea operational conditions. However, throughout the entire lifecycle, wave energy convertors can produce additional CO2 emissions due to the use of raw materials and emissions during transportation. Based on laboratory test data from a wave energy convertor model, this study ensures consistency between the model and the actual sea-deployed wave energy convertors in terms of performance, materials, and geometric shapes using similarity criteria. Carbon emission factors from China, the European Union, Brazil, and Japan are selected to predict the carbon emissions of wave energy convertors in real-sea conditions. The research indicates: (1) The predicted carbon emission coefficient for unit electricity generation ( E F co 2 ) of wave energy is 0.008–0.057 kg CO2/kWh; when the traditional steel production mode is adopted, the E F co 2 in this paper is 0.014–0.059 kg CO2/kWh, similar to existing research conclusions for the emission factor of CO2 for wave energy convertor (0.012–0.050 kg CO2/kWh). The predicted data on carbon emissions in the lifecycle of wave energy convertors aligns closely with actual operational data. (2) The main source of carbon emissions in the life cycle of a wave energy converter, excluding the recycling of manufacturing metal materials, is the manufacturing stage, which accounts for 90% of the total carbon emissions. When the recycling of manufacturing metal materials is considered, the carbon emissions in the manufacturing stage are reduced, and the carbon emissions in the transport stage are increased, from about 7% to about 20%. (3) Under the most ideal conditions, the carbon payback period for a wave energy convertor ranges from 0.28 to 2.06 years, and the carbon reduction during the design lifespan (20 years) varies from 238.33 t CO2 (minimum) to 261.80 t CO2 (maximum). [ABSTRACT FROM AUTHOR]

The relevance of digital solutions to enable sustainable value creation, the monitoring and ultimately the reduction of the environmental footprint has increased. New information technologies and increased data availability along a product's lifecycle offer more tools to assess product sustainability than ever before. This paper presents how a Digital Twin needs to be designed to help monitor product-level energy efficiency and how such a Digital Twin can be implemented. State-of-the-art research on Digital Twins and their development, lifecycle assessment, and energy efficiency are introduced. There is a lack of evaluated implementations of methodical DT development in different scenarios, especially for the evaluation of product-level energy efficiency during production. Results of a research project with the focus on the development and implementation of Digital Twins are presented. The use case is set within the scenario of the sequential development of a product simultaneously with the development of the Digital Twin. The focus is put on the implementation of an energy consumption prediction and product carbon footprint analytics module as part of the Digital Twin. The development approach is presented and recommendations for the development of future Digital Twins are derived. [ABSTRACT FROM AUTHOR]

The results of the most prevalent environmental lifecycle assessments represent the relative impact on the environment caused by the object being assessed. Hereby, the object is compared to its alternatives (to derive: Which is the better solution?) rather than to the carrying capacities of nature (to determine: Is it ultimately sustainable or not?). This poses a problem for implementing and assessing the progress towards sustainable development. In connection to this, prior research has started categorizing the constitutive research on lifecycle-based absolute environmental sustainability assessments. This paper adds to these efforts and provides a new point of view by categorizing the absolute environmental sustainability assessment approaches within the driver-pressure-state-impact-response framework. Hereby, we focus on the absolute environmental sustainability assessment approaches of (1.) the precedent methods of absolute pressures, and (2.) the state-of-the-art approaches of the impacts on nature. Their common challenges and limitations are discussed, along with a theoretical example. From there, we conclude the proposal of incorporating the absolute environmental sustainability pressure methods into the current discussion on lifecycle-based absolute environmental sustainability assessment approaches. Ultimately, we conclude that further research is required to connect the approaches to the level of application. [ABSTRACT FROM AUTHOR]

The identification of environmental impacts through Life Cycle Assessment (LCA) has become a prevalent approach in recent years. However, the utilization of software tools for LCA analysis poses challenges, particularly in terms of cost, time consumption, and complexity, especially for industries operating in emerging economies. Despite these challenges, such industries are compelled to adhere to new policies and regulations when exporting products to European countries. This paper delves into the implementation of a comprehensive approach to identify the environmental impact of the product lifecycle in the textile industry, with a specific focus on recognizing circular economic potential to mitigate environmental impacts. The methodology employed includes value chain analysis, environmental impact identification, lifecycle thinking to pinpoint sustainability hotspots, prioritization of these hotspots, and identification of potential circular economic approaches to alleviate associated impacts. The paper presents a case study applying this approach to the textile industrial sector. By scrutinizing the intricacies of circular economy frameworks, the study provides insights into the challenges and opportunities associated with transitioning towards a more sustainable and circular textile industry. The findings aim to contribute valuable knowledge to global endeavors in achieving environmentally friendly practices within the textile and apparel sector.

Switchgrass is a promising feedstock for cellulosic biorefineries, due to its ability to maintain comparatively high biomass yields across a wide range of soil and climatic conditions. However, there is an incomplete understanding of the economic and environmental tradeoffs associated with cultivating switchgrass on low-productivity land for conversion to biofuels. This study surveys prior literature and demonstrates a new integrated assessment framework, including agroecosystem, ecosystem services valuation, technoeconomic, and life-cycle assessment models, to quantify and contextualize the economic and environmental impacts of switchgrass cultivation on marginal land with downstream conversion to biofuels. Monetizing and incorporating the value of ecosystem services, such as improved water quality benefits from nitrate and sediment reductions, climate change mitigation benefits from CO2 emission reduction, and recreational and pollination benefits from increased biodiversity, the modeled multifunctional landscape reduces the ethanol production cost by 33.3–58.9 cents/L-gasoline-equivalent ($1.3–2.2/gge). Planting switchgrass in low productivity land improves soil health, resulting in the carbon footprint reduction credit of 12.8–20.2 gCO2e/MJ. For an improved switchgrass-to-ethanol conversion pathway with the maximum benefits from ecosystem services, the minimum ethanol selling price and carbon footprint of ethanol, respectively, could reach to 31 cents/L-gasoline-equivalent (47% reduction relative to average gasoline price) and 3 gCO2e/MJ (97% reduction relative to gasoline). This low carbon renewable ethanol leads to substantial State and/or Federal policy incentives (∼$1/L-gasoline-equivalent) providing a large benefit to biorefinery operators, farmers, and the public as a whole.

Portland cement (PC) is the most commonly used binder material for producing concrete. Nonetheless, increasing concerns have been attached to its manufacture which is highly energy-intensive and generates a large quantity of greenhouse gases. Developing alkali-activated materials as eco-binders is a sustainable replacement for PC and many investigations have been reported successfully utilizing industrial wastes as precursors. However, owing to the low reactivity, studies regarding biomass wood ashes (BWA) are still limited. To produce a green cementless alkali-activated mortar material, in this study, biomass fuel by-products – biomass wood bottom ash and biomass wood fly ash – were binarily used as precursors. Sodium hydroxide NaOH at 10 mol/L and calcium hydroxide Ca(OH)2 at 20 % by binder mass were applied as alkali activators. Recycled sand, substituting natural sand, was adopted as fine aggregate with an aggregate/binder ratio of 2 to reduce the consumption of non-renewable natural resources. Compressive and flexural strength were tested to evaluate the mechanical performance. A cradle-to-gate lifecycle assessment was conducted to analyse the environmental impacts. The results reveal that the alkali-activated mortar has less environmental impact compared to the traditional PC mortar. NaOH solution is the primary source of environmental influence and BWA only contributes to very limited impacts. The usage of Ca(OH)2 effectively improves the mechanical strength and compared to NaOH, it leads to decreased energy demand, requires fewer preparation steps and is less dangerous for operation.

There is a growing interest in the production of biofuels and biochemicals from renewable biomass. Biomass in the form of woody and agricultural residues, municipal solid waste and other organic refuse is becoming popular as a feedstock for biofuel and biochemical production through thermochemical and biological routes. Methanol, a widely used industrial chemical, also has clean fuel properties due to its high-octane number, low flammability, low emissions and high engine performance. This paper performs a comprehensive review of different thermochemical and biological processes able to sustainably convert waste biomass to methanol. This article also evaluates the techno-economic assessment and lifecycle analysis of different processes used for methanol production. The article discusses the effects of process parameters and biomass properties on methanol production and utilization. Finally, the article concludes with recommendations on the eco-friendly aspects of methanol for use as a clean fuel and chemical derived from renewable organic bioresources. [ABSTRACT FROM AUTHOR]

Much focus of dual energy-storage systems (DESSs) for electric vehicles (EVs) has been on cost reduction and performance enhancement. While these are important in the development of better systems, the environmental impacts of system and component-level choices should not be overlooked. The current interest in EVs is primarily motivated by environmental reasons such as climate change mitigation and reduction of fossil fuel use, so it is important to develop environmentally sound alternatives at the design stage. Assessing the environmental impact of developmental and mature chemistries provides valuable insights into the technologies that need to be selected now and which to develop for the future. This paper presents a cradle-to-gate (i.e., all raw material and production elements are considered; however, the "use" phase and recycling are not) lifecycle assessment of a DESS with Li-ion and aqueous Al-ion cells and that of one with Li-ion cells and supercapacitors. These are also compared to a full Li-ion EV battery in terms of their environmental impact for both a bus and car case study. Key findings show that the use of a DESS overall reduces the environmental impacts over the vehicle lifetime and provides an argument for further development of aqueous Al-ion cells for this application. [ABSTRACT FROM AUTHOR]

Context. The Western Australian (WA) Government has set ambitious emission reduction targets and is developing strategies to reduce emissions across the state economy, including agriculture. Aims. This study determined the product carbon footprint (CF) and total emissions of the WA beef industry, to establish a baseline for emission reduction planning. Methods. A cradle-togate attributional life-cycle assessment with a reconciled livestock inventory of herd numbers and turnoff, was used. Emission reduction strategies were examined and included herd management, enteric-methane mitigation, and removals via carbon sequestration in vegetation and soils. Key results. Modelled livestock numbers were found to be 36% higher than reported in the Australian Bureau of Statistics (ABS), resulting in an emission profile of 4.7 million tonnes (Mt) of carbon dioxide equivalent (CO2-e) (excluding land use (LU) and direct LU change (dLUC)). This profile was 26% higher than emissions reported in state inventories. LU and dLUC were estimated to be a greenhouse-gas removal of -2.6 Mt CO2-e, although with high uncertainty. The mean CF for WA was 15.3 kg CO2-e per kg liveweight (LW) (excluding LU and dLUC). State-wide removals from LU and dLUC were estimated to be -8.5 kg CO2-e/kg LW. The CF was 11.7, 19.2 and 18.2 kg CO2-e/kg LW for the Agricultural, Kimberley and Arid regions respectively. The implementation of herd-management strategies and anti-methanogenic supplements resulted in a maximum 25% reduction. Conclusions. Herd productivity and market specifications were key drivers of regional differences in CF. Opportunities exist to reduce the CF in northern herds through diverting cattle to Australian backgrounding and feedlot supply chains to reach slaughter weight at a younger age. Adoption of anti-methanogenic feed supplements were important; however, achieving major reductions in the next decade will rely on removals via carbon sequestration in soil and vegetation. Implications. Considering the magnitude of removals and elevated uncertainty in this result, further research and new datasets are needed to refine this analysis. New datasets are required to accurately report livestock numbers and track and reduce future GHG emissions from this higher baseline. Technical, cost and adoption barriers will need to be addressed by developing actionable pathways to achieve emission reduction in the mid-to long term. [ABSTRACT FROM AUTHOR]

There is a growing interest in the production of biofuels and biochemicals from renewable biomass. Biomass in the form of woody and agricultural residues, municipal solid waste and other organic refuse is becoming popular as a feedstock for biofuel and biochemical production through thermochemical and biological routes. Methanol, a widely used industrial chemical, also has clean fuel properties due to its high-octane number, low flammability, low emissions and high engine performance. This paper performs a comprehensive review of different thermochemical and biological processes able to sustainably convert waste biomass to methanol. This article also evaluates the techno-economic assessment and lifecycle analysis of different processes used for methanol production. The article discusses the effects of process parameters and biomass properties on methanol production and utilization. Finally, the article concludes with recommendations on the eco-friendly aspects of methanol for use as a clean fuel and chemical derived from renewable organic bioresources.

Dairy farming is one of the most important sources of greenhouse gas (GHG) emissions in the livestock sector. In order to identify the key emission links and the best emission-reduction strategies for combined dairy farms, this study selected a typical large-scale combined dairy farm in northeast China, constructed a carbon emission model based on the lifecycle assessment concept, and set up different emission reduction scenarios to explore the zero-carbon pathway for combined dairy farms. The results showed that: (1) enteric fermentation and manure management of cows are important sources of carbon emissions from the seeding-integrated dairy farms, accounting for 38.2% and 29.4% of the total, respectively; (2) the seeding-integrated system showed a 10.6% reduction in carbon footprint compared with the non-seeding-integrated system; and (3) scenarios 1–4 reduced carbon emissions by 9%, 20%, 42%, and 61% compared with the baseline scenario, respectively. Therefore, the integrated-farming model is important for the green development of animal husbandry, and as the “net-zero” goal cannot be achieved at present, integrated-farming dairy farms have the potential for further emission reduction. The results of this study provide a theoretical basis for low-carbon milk production.

The North China Plain (NCP) serves as a critical grain-producing region in China, playing a pivotal role in ensuring the nation’s food security. A comprehensive analysis of the carbon footprint (CF) related to the cultivation of major grain crops within this region and the proposal of strategies to reduce emissions through low-carbon production methods are crucial for advancing sustainable agricultural practices in China. This study employed the lifecycle assessment (LCA) method to estimate the CF of wheat, maize, and rice crops over a period from 2013 to 2022, based on statistical data collected from five key provinces and cities in the NCP: Beijing, Tianjin, Hebei, Shandong, and Henan. Additionally, the Logarithmic Mean Divisia Index (LMDI) model was utilized to analyze the influencing factors. The results indicated that the carbon footprints per unit area (CFA) of maize, wheat, and rice increased between 2013 and 2022. Rice had the highest carbon footprint per unit yield (CFY), averaging 1.1 kg CO2-eq kg−1, with significant fluctuations over time. In contrast, the CFY of wheat and maize remained relatively stable from 2013 to 2022. Fertilizers contributed the most to CF composition, accounting for 48.8%, 48.0%, and 25.9% of the total carbon inputs for wheat, maize, and rice, respectively. The electricity used for irrigation in rice production was 31.8%, which was much higher than that of wheat (6.8%) and maize (7.1%). The LMDI model showed that the labor effect was a common suppressing factor for the carbon emissions of maize, wheat, and rice in the NCP, while the agricultural structure effect and the economic development effect were common driving factors. By improving the efficiency of fertilizer and pesticide utilization, cultivating new varieties, increasing the mechanical operation efficiency, the irrigation efficiency, and policy support, the CF of grain crop production in the NCP can be effectively reduced. These efforts will contribute to the sustainable development of agricultural practices in the NCP and support China’s efforts to achieve its “double carbon” target.

This review presents a broad exploration of the techno economic evaluation of different technologies utilized in the production of hydrogen from both renewable and non-renewable sources. These encompass methods ranging from extracting hydrogen from fossil fuels or biomass to employing microbial processes, electrolysis of water, and various thermochemical cycles. A rigorous techno-economic evaluation of hydrogen production technologies can provide a critical cost comparison for future resource allocation, priorities, and trajectory. This evaluation will have a great impact on future hydrogen production projects and the development of new approaches to reduce overall production costs and make it a cheaper fuel. Different methods of hydrogen production exhibit varying efficiencies and costs: fast pyrolysis can yield up to 45% hydrogen at a cost range of $1.25 to $2.20 per kilogram, while gasification, operating at temperatures exceeding 750 °C, faces challenges such as limited small-scale coal production and issues with tar formation in biomass. Steam methane reforming, which constitutes 48% of hydrogen output, experiences cost fluctuations depending on scale, whereas auto-thermal reforming offers higher efficiency albeit at increased costs. Chemical looping shows promise in emissions reduction but encounters economic hurdles, and sorption-enhanced reforming achieves over 90% hydrogen but requires CO2 storage. Renewable liquid reforming proves effective and economically viable. Additionally, electrolysis methods like PEM aim for costs below $2.30 per kilogram, while dark fermentation, though cost-effective, grapples with efficiency challenges. Overcoming technical, economic barriers, and managing electricity costs remains crucial for optimizing hydrogen production in a low-carbon future, necessitating ongoing research and development efforts.

Much focus of dual energy-storage systems (DESSs) for electric vehicles (EVs) has been on cost reduction and performance enhancement. While these are important in the development of better systems, the environmental impacts of system and component-level choices should not be overlooked. The current interest in EVs is primarily motivated by environmental reasons such as climate change mitigation and reduction of fossil fuel use, so it is important to develop environmentally sound alternatives at the design stage. Assessing the environmental impact of developmental and mature chemistries provides valuable insights into the technologies that need to be selected now and which to develop for the future. This paper presents a cradle-to-gate (i.e., all raw material and production elements are considered; however, the “use” phase and recycling are not) lifecycle assessment of a DESS with Li-ion and aqueous Al-ion cells and that of one with Li-ion cells and supercapacitors. These are also compared to a full Li-ion EV battery in terms of their environmental impact for both a bus and car case study. Key findings show that the use of a DESS overall reduces the environmental impacts over the vehicle lifetime and provides an argument for further development of aqueous Al-ion cells for this application.

The Intergovernmental Panel on Climate Change's sixth assessment report (AR6) allocates 15% to 43% of global primary energy to biomass in 2050 across multiple mitigation scenarios. The report also emphasizes the importance of electrification. For increased reliance on electricity and on biomass, bioelectricity is expected to play a major role. It is therefore vital to know whether the energy generation potential of biomass electricity can support the removal of its environmental impact, particularly as generation at large scale is expected to rely almost solely on energy crops. This paper evaluates the potential of short-rotation woody crops in generating green electricity. This is performed using the "Green Energy Return on Investment (EROIg)" methodology, which indicates the net energy generated after investing in ecosystem maintenance energy (ESME). This study found that the EROIg of bioelectricity is marginally larger than unity when converted to its primary equivalent form (EROIg-PE). Three design options were proposed to improve bioenergy's EROIg. Among these options, pelletizing wood chips has the largest advantage with an EROIg of 1.11 and an EROIg-PE of 3.17. We conclude with a discussion of the indirect advantages of growing energy crops, and discuss how this technique can be used alongside others to help generate cleaner energy. [ABSTRACT FROM AUTHOR]

Water treatment technologies are striving to retain their ecological and economic viability despite the rising demand, conventional infrastructure, financial constraints, fluctuating climatic patterns, and highly stringent regulations. This study evaluates the lifecycle environmental impact of urban water treatment systems within the two densely populated South Asian municipalities of Islamabad and Rawalpindi, Pakistan. The scope of this study includes a process-based Life Cycle Assessment (LCA) of the entire water treatment system, particularly the resources and materials consumed during the operation of the treatment plant. The individual and cumulative environmental impact was assessed based on the treatment system data and an in-depth lifecycle inventory analysis. Other than the direct emissions to the environment, the electricity used for service and distribution pumping, coagulant use for floc formation, chlorine gas used for disinfection, and caustic soda used for pH stabilization were the processes identified as the most significant sources of emissions to air and water. The water distribution consumed up to 98% of energy resources. The highest global warming impacts (from 0.3 to 0.6 kg CO2 eq./m3) were assessed as being from the coagulation and distribution processes due to extensive electricity consumption. Direct discharge of the wash and wastewater to the open environment contributed approximately 0.08% of kg-N and 0.002% of kg-P to the eutrophication potential. The outcome of this study resulted in a thorough lifecycle inventory development, including possible alternatives to enhance system sustainability. A definite gap was identified in intermittent sampling at the treatment systems. However, more stringent sampling including the emissions to air can provide a better sustainability score for each unit process. [ABSTRACT FROM AUTHOR]

Food waste (FW) increases with urbanization and population growth, which puts pressure on the treatment system, causing a variety of harmful impacts on the environment. Proper FW treatment is imperative for ecological integrity and public health. Even though FW treatment is an extensively studied topic, the sustainable FW treatment considering holistic-lifecycle-based environmental impacts has rarely been evaluated. This study addresses this gap through a comprehensive analysis of various FW treatment methods, including co-treatment with sewage, anaerobic digestion, incineration, and aerobic composting. The impacts of greenhouse gas (GHG) emission and energy use efficiency are assessed by analyzing diverse FW treatment methods in Shenzhen, China. The study indicates that FW addition to sewage does not adversely affect the current sewage treatment plant, but benefits GHG avoidance and energy recovery. Compared with the other FW treatment methods, FW anaerobic digestion avoids the most GHG emissions with −71.3 kg CO2 eq/FU and recovers the most energy with −223 kWh/FU, followed by FW co-treated with sewage. The energy conversion efficiency of the combined heat and power (CHP) unit greatly affects FW incineration, while energy consumption in incineration and anaerobic digestion (AD) process is relatively minor. Perturbation analysis pinpoints key parameters influencing outcomes, including CHP efficiency, GHG emission factor of local electricity, and chemical oxygen demand (COD) in FW with ratios of −13~−0.942, −0.518~0.22, and −13~1.01, respectively, that should be given special attention. This study sheds light on sustainable FW management strategies, not only in China but also transferrable to regions confronting similar challenges. Advocating ecologically balanced and resource-efficient approaches, the study aligns with broader aims of fostering sustainable development. [ABSTRACT FROM AUTHOR]

The use of new vehicle technologies such as fuel cell hybrid electric and fully electric powertrains for biomass feedstock supply is an unexplored solution to reducing biofuel production cost, greenhouse gas emissions, and health impacts. These technologies have found success in light-duty vehicle applications and are in development for heavy-duty trucks. This study presents the first detailed stochastic techno-economic analysis and life-cycle assessment of biomass feedstock supply systems with diesel, fuel cell hybrid electric, and fully electric trucks and determines their impacts on biofuel production considering butanol as a representative biofuel. This study finds that fuel cell hybrid electric and fully electric trucks consume less energy relative to the diesel-powered truck regardless of the evaluated circumstances, including payloads of truck (loaded and empty), pavement types (gravel and paved), road conditions (normal and damaged), and road networks (local and highways). The use of fuel cell hybrid and fully electric trucks powered by H2-fuel and renewable sources of electricity, respectively, results in a large reduction in cost and carbon footprint, specifically for a long-distance hauling, and minimize other economic and environmental impacts. While the economic advantage of fuel cell hybrid electric vehicle is dependent on the price of H2-fuel and road conditions, use reduces the GHG emissions of biobutanol per 100 km-trucking-distance by 0.98–10.9 gCO2e/MJ. Results show that converting to fully electric truck transport decreases the biobutanol production cost and GHG emissions per 100 km-trucking-distance by 0.4–7.3 cents/L and 0.78 to 9.1 gCO2e/MJ, respectively. This study establishes the foundation for future investigations that will guide the development of economically, socially, and environmentally sustainable biomass feedstock supply system for cellulosic biorefineries or other goods transportation systems.

The wind energy sector faces a persistent challenge in developing sustainable solutions for decommissioned Wind Turbine Blades (WTB). This study utilises Lifecycle Assessment (LCA) to evaluate the gate-to-gate carbon footprint of high-profile disposal and recycling methods, aiming to determine optimal strategies for WTB waste treatment in the UK. While this article analyses the UK as a case study, the findings are applicable to, and intended to inform, recycling strategies for WTB waste globally. Long-term sustainability depends heavily on factors like evolving energy grids and changing WTB waste compositions and these must be considered for robust analysis and development strategy recommendations. In the short to medium term, mechanical recycling of mixed WTB waste is sufficient to minimise Global Warming Potential (GWP) due to the scarcity of carbon fibre in WTB waste streams. Beyond 2040, carbon fibre recycling becomes crucial to reduce GWP. The study emphasises the importance of matching WTB sub-structure material compositions with preferred waste treatment options for the lowest overall impact. Future development should focus on the extraction of carbon fibre reinforced polymer (CFRP) structures in WTB waste streams, commercialising large-scale CFRP structure recycling technologies, establishing supply chains, and validating market routes for secondary carbon fibre products. In parallel, scaling up low-impact options, like mechanical recycling, is vital to minimise WTB waste landfilling. Developing viable applications and cost-effective market routes for mechanical recyclates is necessary to displace virgin glass fibres, while optimising upstream recycling processes based on product requirements.

This study assesses and compares lifecycle (LC) greenhouse gas (GHG) emissions from the two main railway track construction types: ballasted track and slab track. In this study, preexisting soil conditions are considered, as they significantly influence necessary measures during the construction phase for each type. This study is executed for Austrian boundary conditions with speeds up to 250 km/h. The results show that ballasted track is associated with 11–20% lower LC GHG emissions, whereby the variation in relative emission reduction is associated with additional soil reinforcement treatments due to varying preexisting soil conditions. Poor preexisting soil conditions increase LC GHG emissions by 26%, underlying the necessity to integrate this parameter into the lifecycle assessment of railway track. In contrast to the higher service life of slab track construction, this type amounts to higher masses of concrete and demands more extensive measures for soil enhancement due to the higher stiffness of the track panel. Only in tunnel areas does slab track cause lower GHG emissions since soil reinforcements are not necessary due to an existing concrete base layer after tunnel construction. For both construction types, over 80% of the GHG emissions stem from material production. Hence, circular economy as well as innovations within steel and concrete production processes hold significant potential for reducing GHG emissions. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper was motivated to review and discuss the current issues and challenges for decarbonisation in the international shipping sector. It was mainly focused on international and local efforts to reduce greenhouse gas (GHG) emissions from shipping activities while introducing new strategies, agreements, and regulations to meet the target on GHG reduction levels. It firstly reviewed the impact of the Clydebank Declaration made at 26th UN Climate Change Conference in Glasgow, 2021. Then, the review was moved to UK and EU policies and activities. Findings from this research offer some insights into local governmental authorities and shipping companies in terms of how to respond to gradually stringent environmental regulations as well as their roles to make the shipping sector cleaner.

The coal-to-liquid coupled with carbon capture, utilization, and storage technology has the potential to reduce CO2 emissions, but its carbon footprint and cost assessment are still insufficient. In this paper, coal mining to oil production is taken as a life cycle to evaluate the carbon footprint and levelized costs of direct-coal-to-liquid and indirect-coal-to-liquid coupled with the carbon capture utilization and storage technology under three scenarios: non capture, process capture, process and public capture throughout the life cycle. The results show that, first, the coupling carbon capture utilization and storage technology can reduce CO2 footprint by 28%–57% from 5.91 t CO2/t oil of direct-coal-to-liquid and 24%–49% from 7.10 t CO2/t oil of indirect-coal-to-liquid. Next, the levelized cost of direct-coal-to-liquid is 648–1027 $/t of oil, whereas that of indirect-coal-to-liquid is 653–1065 $/t of oil. When coupled with the carbon capture utilization and storage technology, the levelized cost of direct-coal-to-liquid is 285–1364 $/t of oil, compared to 1101–9793 $/t of oil for indirect-coal-to-liquid. Finally, sensitivity analysis shows that CO2 transportation distance has the greatest impact on carbon footprint, while coal price and initial investment cost significantly affect the levelized cost of coal-to-liquid. [ABSTRACT FROM AUTHOR]

Purpose: The purpose is to describe and demonstrate the applicability of a bottom-up methodology to build the lifecycle inventory of industrial equipment ubiquitous in chemical processes. The analysis describes concepts of the methodology and demonstrates its functionality in the context of carbon footprint assessment of methanol production. Methods: The methodology proposed assumed unit operations are composed of macroscopic components, six structural including steel, concrete, insulation (glass wool), aluminum, powering, and electronic, and one functional, catalyst. Unit operations included heat exchangers (shell-and-tube and air-cooled systems), separation units (flash tanks and distillation column), and a methanol reactor. Sets of equations were provided to estimate the lifecycle inventory (LCI), while relying on scaling parameters as reported in techno-economic assessment techniques (i.e., surface area to estimate heat exchangers costs). A Power-to-X case study (system boundary) was selected to demonstrate the methodology functionality to build the equipment LCI to estimate the CO2 equivalent emissions to produce 1.0 kg of methanol at 25 °C and 1 atm (functional unit). Results and discussion: The case study showed emissions associated to capital goods amounted to 4146 tonnes of CO2 equivalent, with the methanol reactor having the largest share (67.9%), followed by heat exchangers (23.5%) and separation units (8.6%). Regarding components, steel and concrete comprised the largest contribution for most unit operations (> 53.8% of emissions) excluding the methanol reactor (9.9%). The share of powering and electronics was relevant in the carbon footprint (CF) exercise due to the components intrinsic CF (5.74 and 36.25 kg-CO2 eq./kg-component, respectively) when compared to other major components (i.e., steel, 0.58 kg-CO2 eq./kg-component). The component catalyst had a significant impact on the reactor emissions (80.7%) which originated from the need of being renewed every 2.5-year period. For the system boundary, capital goods only amounted to 0.221% of methanol production emissions or 0.0005 kg-CO2 eq./kg-MeOH. Conclusion: This study described a novel methodology to estimate the LCI and subsequent CF of capital goods. This new methodology has been used in a specific case study for methanol production using PtX. Ultimately, the authors of this study seek to create the basis of a simple but comprehensive methodology to reduce data gaps associated to lifecycle inventory and assessment of industrial equipment in literature. [ABSTRACT FROM AUTHOR]

Reducing wheat and bread loss and waste is crucial for ensuring global food security and sustainability. The importance of reducing wheat and bread loss is particularly significant in Iran, where wheat is a staple crop and a vital component of the country's food security. A value stream mapping study was conducted to identify loss and waste hotspots and critical data gaps along the wheat and bread lifecycle (WBL). In October 2018, 14 experts were surveyed in Fars province, Iran's second-largest wheat producer. The study presents a detailed cradle-to-grave overview of WBL and identifies farms, foodservice, and households as the loss and waste hotspots. The results revealed significant data gaps regarding on-farm wheat loss and household bread waste. Additionally, although data exist in other segments of WBL, they are not readily accessible nor utilized to report loss and waste, highlighting the need for transparency within the WBL system and further research to compile existing data and analyze wheat and bread loss and waste. Other researchers can employ the holistic approach of the present study to investigate loss and waste throughout the lifecycle of other food items in different geographical contexts. The methodology adopted in this study offers advantages for defining the scope of research in lifecycle assessment and circular economy studies. [ABSTRACT FROM AUTHOR]

Rapid industrial developments and rising population are mounting concerns, leading to increased greenhouse gas (GHG) emissions and resultant climate change. Therefore, to curb such drastic trends, it is necessary to adopt and develop a sustainable environment. Among the most effective ways to lower GHG emissions is carbon capture. Absorption is one of the most mature methods of reducing CO2 due to its high processing capacity, excellent adaptability, and reliability. This study aims to evaluate the most recent advancements in various CO2 capture techniques, with an emphasis on absorption technology. The techno-economic analyses of absorption-based CO2 capture processes were meticulously discussed. These include studies on solvent screening as well as techno-economic analysis methods. Economic estimators such as the payback period, rate of return and net present value are discussed. The research progress in absorption-based capture compared to other separation methods, is elucidated. Advances in the applications of various absorption solvents including aqueous, phase change solvents and deep eutectic solvents are presented. Finally, key recommendations are provided to tackle the challenges for efficient utilization of the absorption technique.

Due to high toxicity, thermal instability at high temperature, low availability, and the high cost of raw metallic alloys such as Bi2Te3 for thermoelectric (TE) applications, there has been a drive to develop earth-abundant and eco-benign TE materials suitable for high-temperature applications. Oxide-based TEs have lately been touted to satisfy these criteria, but a lifecycle assessment (LCA) and energy payback period (EPBP) assessment of both classes of materials have not been conducted. This paper presents a comparative LCA of two laboratory-based TE modules namely, non-oxide n-type selenium-doped Bi2Te3 and p-type antimony-doped Bi2Te3 (Module A) versus oxide-based n-type lanthanum-doped SrTiO3 and p-type layered Ca3Co4O9 (Module B). Electrical energy consumption (EEC) during fabrication constitutes the largest impact for both modules, even under a decarbonised grid scenario, although Module B has an overall lower EEC. Nonetheless, for Module A, the use of tellurium and antimony exhibited noticeable environmental toxicity impacts, but smaller compared to EEC. The rare earth elements contained in the n-type component of Module B, showed negligible environmental toxicity impact, but those from its p-type component is noticeably high due to the presence of cobalt oxide. Computations of performance characteristics based on the material configurations of both modules showed that Module A yielded a higher power output compared to Module B, and as the power output increases, the EPBP becomes almost identical for both modules, underscoring its integral role to EEC offsetting. Key challenges, therefore, once EEC is diminished for large-scale applications are raw materials availability and cost, alongside performance.