•Recent updates in recycling carbon fibre reinforced composites are reviewed.•Mechanical, thermal and chemical methods along with influential parameters are discussed.•The methods of manufacturing ...yarns and nonwovens from dry carbon fibre scraps are reviewed.•The environmental impacts of processing CFRC wastes are discussed.
Carbon fibre reinforced composites (CFRC) continue to play a key role in the growth and development of many weight sensitive industries. However, their proliferation has raised increasing concerns regarding the required practices and strategies to deal with these expensive engineered structures at the end of their life cycle. This has brought into focus the need to develop more sustainable and efficient recycling solutions for these products. Similarly, the necessity of managing dry carbon fibre scraps generated during the manufacturing process of CFRC has attracted more attention in recent years. This review article provides an overview on recent advances in recycling CFRC as well as processing dry carbon fibre scraps. Influential parameters, advantages, drawbacks, and possible environmental impacts of the main technologies of processing CFRC waste including mechanical, thermal (pyrolysis and fluidised bed), and chemical (solvolysis and low temperature chemical processing) will be evaluated. Their potential effects on mechanical characteristics and surface chemistry of fibres are assessed. Moreover, recent processing methods of dry and semi-finished carbon fibre scrap are also reviewed. Specific attention is paid to the recent developments in producing hybrid yarns and nonwovens made of waste carbon fibre. The methodologies developed in this area, their processing conditions, as well as other important findings are discussed. This review paper provides a valuable platform for researchers and decision makers working in the field of carbon fibre by providing a clearer picture on the options available to recycle CFRC, and the methods of developing value-added products using waste carbon fibre.
The life cycle sustainability assessment (LCSA) is a tool to assess sustainability from a life cycle perspective, which has been receiving increased attention over the years. This work presents a ...systematic review of the current application of LCSA, presenting the foundations, main methods, current operationalization state, and major challenges to its broad implementation. The review protocol considered the search of keywords in Scopus and Web of Science databases. The search has considered the literature published or in the press until December 2018, resulting in the selection of 144 articles written in English. Of those, 71 articles operationalize LCSA in real case studies, while the remaining consist of review, viewpoint, and methodological development articles. This review demonstrates that the use of LCSA has been increasing in recent years. Today, the most applied approach is to consider LCSA as the sum of life cycle assessment, life cycle costing, and social life cycle assessment because it is built on the methodologies that already exist and are under continuous development. However, the lack of harmonization of the methodology is a central challenge to its operationalization. Therefore, LCSA still requires further improvement in, among others, definition of coherent system boundaries, the development of robust databases to allow the assessment of economic and social perspectives, definition of impact categories that allow comparability between studies, development of impact assessment methods, development of methods to carry out uncertainty analysis, and communication strategies. Besides, further case studies should be developed to support the improvement of the methodology and a better understanding of the interaction of the environmental, economic, and social aspects.
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•There are several approaches to conduct LCSA.•LCSA = LCA + LCC + SLCA is the most used approach.•Multi-criteria decision analysis (MCDA) methods are widely used to assess LCSA.•Methodological challenges for operationalization of LCSA are identified.
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•Methanol is firstly produced by CO2 electroreduction with a CuO/ZnO/Al2O3 catalyst.•CO2-to-methanol conversion is scaled-up from lab data process simulation results.•Electrocatalytic ...CO2 conversion is sustainable with 90% of FE and 200 mA/cm2.•CO2-to-Methanol could be economically competitive at productivity >20 kg/hmethanol.•The carbon footprint is 62% lower for both processes using 100% of renewable energy.
Electrocatalytic (EC) and thermocatalytic (TC) conversion of CO2 to methanol are promising carbon capture and utilization technologies. Herein, these CO2-to-methanol conversion processes are analysed in terms of technical, environmental and economic feasibility. To this purpose, the catalytic performance of the same catalyst (CuO/ZnO/Al2O3) was evaluated in both EC and TC processes. Here is showed for the first time that this catalyst is (apart from TC route) also able to generate methanol through CO2 EC reduction. This work presents lab scale tests, scaled-up simulations and evaluates the environmental and economic performance of these processes.
The carbon footprint of the TC and EC processes, scaled-up to the same productivity of ~ 3 kg/h methanol, scored ~ 8 kgCO2 eq/kgCH3OH. Strategies to reduce this impact are presented, such as improving the current density of the EC cell (i.e. 200 mA/cm2 results in a reduction of 68% to 2.72 kgCO2 eq/kgCH3OH) and the availability of 100% renewable electricity (saving up to 62% carbon footprint of both processes). Considering an effective allocation of the methanol productivity on a real market scenario, both the TC and EC processes would start to be economically competitive at methanol productivities > 19.1 kg/h and 3.3 kg/h, respectively. Moreover, if O2 valorisation, a low price of the renewable electricity and a carbon tax are considered, the economic profitability will rise; e.g. the minimum levelised cost of product (LCOP of 1.45 €/kg and 1.67 €/kg, respectively) could be reduced by 53%. Finally, our results pointed out that the CO2 electroreduction process must be optimized (e.g. improving catalysts performance and EC cell design reducing mass transfer limitations) to achieve industrially relevant rates and the maturity of the thermocatalytic technology.
The increasing pressure to reduce greenhouse gas emissions from buildings has motivated specialists to develop low-carbon products incorporating bio-based materials. The impact of these materials is ...often evaluated through life-cycle assessment (LCA), but there is no clear consensus on how to model the biogenic carbon released or absorbed during their life-cycle. This study investigates and compares existing methods used for biogenic carbon assessment. The most common approaches were identified through an extensive literature review. The possible discrepancies between the results obtained when adopting different methods are made evident through an LCA study of a timber building. Results identified that land-use and land-use-change (LULUC) impacts and carbon-storage credits are not included in most existing methods. In addition, when limiting the system boundary to certain life-cycle stages, methods using the –1/+1 criterion can lead to net negative results for the global warming (GW) score, failing to provide accurate data to inform decision-making. Deviation between the results obtained from different methods was 16% at the building scale and between 35% and 200% at the component scale. Of all the methods studied, the dynamic approach of evaluating biogenic carbon uptake is the most robust and transparent.Practice relevanceThis critical review identified key methodological differences between the most commonly used methods and recommended standards for biogenic carbon accounting in buildings. This indicates a lack of consensus and guidance for conducting LCAs of bio-based construction products and buildings using bio-based materials. A case study applying four different LCA approaches on a timber building identified the inability to compare results and create proper benchmarks. Moreover, different methods lead designers to pursue different strategies to reduce a building’s carbon footprint. Regulators, the construction industry and the construction products industry are directly affected by this lack of comparability. This research highlights the flaws and benefits of commonly used methods. A clear and grounded recommendation is for practitioners to adopt dynamic biogenic carbon accounting for future assessments of bio-based materials and buildings.
Annually, 8.3 million tonnes of mismanaged plastic waste enter oceans, prompting the food packaging industry, a major contributor, to minimize its environmental footprint. Within the seafood sector, ...a nascent number of studies are exploring the impacts of various packaging solutions for distribution, yet clear insights remain elusive. This study tries to fill the gap by comparing the impacts of two seafood packaging options: disposable expandable polystyrene (EPS) boxes and, for the first time, reusable plastic crates (RPC) crafted from high-density polyethylene. Using the life cycle assessment methodology with a ‘cradle to grave’ approach, the research evaluates the distribution of 1260,000 t of fish from port of Vigo (Spain) to various markets. Similar climate change values emerge in local (5.00·107 kg CO2 eq.) and regional trade (1.20·108 kg CO2 eq.) for both options, but RPCs exhibit around a 12 % increase (6.15·108 kg CO2 eq.) during national distribution, emphasizing package weight and load significance. The findings across all impact categories exhibited general consistent trends. The sensitivity analysis suggests relocating washing facilities to port could enhance RPCs´ environmental benefits for transport within a 160 km range. These findings underscore reusable packaging's potential as an eco-friendlier alternative in specific contexts, aligning with heightened environmental concerns and regulatory pressures surrounding plastic usage.
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•Packaging comparison: RPCs vs. EPS boxes in seafood distribution impact.•Transportation key: Weight and distance crucial for environmental impacts.•Future focus: Optimize packaging shelf life, enhance reuse cycles, and develop effective collection/washing.
There is pressure on the global shipping industry to move towards greener propulsion and fuel technologies to reduce greenhouse gas emissions. Hydrogen and electricity are both recognised as pathways ...to achieve a net-zero. However, in the evaluation of the environmental performance of these alternative marine power configurations, conventional life cycle assessment (LCA) methods have limitations reflecting the varied nature of ship design and operational modes. The integration of LCA with experimental assessment could remedy the shortcoming of conventional approaches to data generation. The system energy demand data in this study was generated based on specific ship design and directly fed into life cycle assessment. To demonstrate the effectiveness and potential the approach was applied to a case study of inland waterway vessel. Suitable hybrid PV/electricity/diesel and hydrogen powered fuel cell systems for the case vessel were modelled; and hydrodynamic testing and dynamic system simulation was undertaken to provide ship performance data under various operational/environmental profiles. Lifecycle assessment (LCA) indicated hydrogen and electrical propulsion technologies have the potential for 85.7 % and 56.2 % emissions reduction against an MGO base case, respectively. The results highlight that implementation of both technologies is highly dependent on energy production pathways. Hydrogen systems reliant on fossil feedstocks risk an increase in emissions of up to 6.3 % against the MGO base case. Sensitivity analysis indicated an electrical system with electricity production from 79.5 % renewables could achieve savings of 82.2 % in GHG emissions compared to the MGO base case. Crucially, the results demonstrate a further development of the LCA approach which can enable a more accurate environmental performance evaluation of alternative marine power configurations considering specific ship design and operational characteristics. Ultimately this addition makes the results more meaningful for commercial operations and decision making in the selection of alternative marine power systems to support the transition to net-zero.
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•Lifecycle benefits/harms of vessel energy systems fuelled with alternative energy sources/fuels are quantified.•Demonstration of a life cycle framework for marine propulsion system performance evaluation and optimal selection.•Improved accuracy of life cycle assessment application with integration of experimental-based dynamic system evaluation.•Lifecycle environmental evaluation of low-carbon fuel transportation, necessary to avoid mismanagement of emissions.
Improving the food supply chain efficiency has been identified as an essential means to enhance food security, while reducing pressure on natural resources. Adequate food loss and waste (FLW) ...management has been proposed as an approach to meet these objectives. The main hypothesis of this study is to consider that the “strong fluctuations and short-term changes” on eating habits may have major consequences on potential FLW generation and management, as well as on GHG emissions, all taking into account the nutritional and the economic cost. Due to the exceptional lockdown measures imposed by the Spanish government, as a consequence of the emerging coronavirus disease, COVID-19, food production and consumption systems have undergone significant changes, which must be properly studied in order to propose strategies from the lessons learned. Taking Spain as a case study, the methodological approach included a deep analysis of the inputs and outputs of the Spanish food basket, the supply chain by means of a Material Flow Analysis, as well as an economic and comprehensive nutritional assessment, all under a life cycle thinking approach. The results reveal that during the first weeks of the COVID-19 lockdown, there was no significant adjustment in overall FLW generation, but a partial reallocation from extra-domestic consumption to households occurred (12% increase in household FLW). Moreover, the economic impact (+11%), GHG emissions (+10%), and the nutritional content (−8%) complete the multivariable impact profile that the COVID-19 outbreak had on FLW generation and management. Accordingly, this study once again highlights that measures aimed at reducing FLW, particularly in the household sector, are critical to make better use of food surpluses and FLW prevention and control, allowing us to confront future unforeseen scenarios.
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•A multivariable analysis on FLW behavior for the COVID-19 outbreak in Spain was done.•Short-term disruptions on eating habits influence food loss and waste (FLW) patterns.•Higher FLW generation rates (+12%) during early stages of the outbreak were observed.•Economic and environmental impacts rose notably, while nutritional quality decreased.•FLW reduction policies must consider future unexpected food disruption scenarios.
Wind turbine structures have become increasingly popular due to global trends in renewable energy policies. However, more than 3800 failures are reported annually, and resultant maintenance and ...repair costs are significant. Previous studies have mainly focused on structural failures from the historical perspective, but there is a lack of discussion on condition-based maintenance to reduce life-cycle costs. Furthermore, the studies on disposal after end-of-life are limited. To face these challenges, this study aims to optimize wind turbine structures throughout their life cycle, from design to disposal with four key approaches. From parts to system level, wind turbines are investigated (i) theoretically and (ii) experimentally under dynamic stress and various environmental conditions for optimized and safe operation. Health monitoring, damage diagnosis, and prognosis approaches are highlighted to ensure their reliable and secure operations. Maintenance strategies are reviewed from repair to maintenance perspective (iii). Finally, recycling and life cycle assessment studies are discussed, along with current challenges in condition-based maintenance (iv). Advanced condition-maintenance with four approaches will lead to enhanced sustainability and efficiency of wind turbine systems to achieve the goal of carbon neutrality. Lastly, scientific recommendations and guidelines for future research towards sustainable net-zero life cycle of wind turbine structures are proposed.
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•State-of-the-art-review on wind turbine systems was conducted.•Liable failure locations, mechanisms, and the detection methods were investigated.•Damage countermeasures and long-term maintenance strategies were reviewed.•Recycling methods and life cycle assessment were reported.
An array of emerging technologies, from electric vehicles to renewable energy systems, relies on large‐format lithium ion batteries (LIBs). LIBs are a critical enabler of clean energy technologies ...commonly associated with air pollution and greenhouse gas mitigation strategies. However, LIBs require lithium, and expanding the supply of lithium requires new lithium production capacity, which, in turn, changes the environmental impacts associated with lithium production since different resource types and ore qualities will be exploited. A question of interest is whether this will lead to significant changes in the environmental impacts of primary lithium over time. Part one of this two‐part article series describes the development of a novel resource production model that predicts future lithium demand and production characteristics (e.g., timing, location, and ore type). In this article, part two, the forecast is coupled with anticipatory life‐cycle assessment (LCA) modeling to estimate the environmental impacts of producing battery‐grade lithium carbonate equivalent (LCE) each year between 2018 and 2100.
The result is a normalized life‐cycle impact intensity for LCE that reflects the changing resource type, quantity, and region of production. Sustained growth in lithium demands through 2100 necessitates extraction of lower grade resources and mineral deposits, especially after 2050. Despite the reliance on lower grade resources and differences in impact intensity for LCE production from each deposit, the LCA results show only small to modest increases in impact, for example, carbon intensity increases from 3.2 kg CO2e/kg LCE in 2020 to 3.3 kg CO2e/kg LCE in 2100.
•CO2 recovery from waste-to-energy was investigated in a LCA perspective.•The CO2 was then exploited for e-fuel (methanol) and liquid CO2 production.•About 490 kgCO2eq can be saved per each tonne of ...methanol produced.•About 20% of EU methanol demand can by supplied by the proposed system.
This study investigates an integrated approach in which CO2 captured from waste-to-energy (WtE) facility flue gases is exploited to produce methanol (CH3OH), via a catalytic reaction with H2, and liquid CO2 for industrial applications. The integrated system is fully powered by energy from WtE, including the facility for alkaline electrolysis for hydrogen production. The amount of energy necessary for producing 1 tonne of CH3OH was 10.2 MWh, which can be generated by the combustion of approximately 25 tonne of waste in a typical European WtE. Under these conditions, 18.1 tonnes of liquid CO2 can also be recovered. Compared to the conventional production of CH3OH, the proposed system achieves a significant reduction in greenhouse gas emissions, about 492.3 kg CO2eq per tonne of CH3OH. Other environmental impacts, such as particulate matter, acidification, and freshwater ecotoxicity, were found to be quite similar between the two scenarios. Furthermore, the EU27 WtE systems have the potential to meet about 22 % of the current methanol demand in the area significantly contributing to the EU’s goals for a circular and carbon–neutral economy.
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