Comparative Life Cycle Assessment Research Articles

Development of a streamlined framework for probabilistic and comparative life cycle assessment of road pavements

This study presents a novel framework to address the challenges of extensive data requirements and uncertainties in road pavement life cycle assessment (LCA). We introduce a streamlined framework that employs a structured data underspecification approach. In this study, we categorized the required data into four specificity levels (M1 to M4) to manage data uncertainty in a systematic way. Using 10 case studies with various data specificity levels, our method proves effective in adapting to different degrees of data scarcity. The proposed framework supports a confident decision-making process, in which the comparison indicator shows discerned results at least 90 % of Monte Carlo runs by reducing the data collection burden by 85.7 %. For example, in the Boston pavement scenarios, one can achieve a 90 % reliability level by selectively specifying the maintenance and repair (M&R) activities to an M3-level specificity, while maintaining all other data at a lower level of detail, i.e., M2.

Comparative life cycle assessment of organic industrial solid waste co-disposal in a MSW incineration plant

Co-disposal experiments involving industrial solid waste (ISW) are conducted at a municipal solid waste (MSW) incineration plant in this study, investing the environmental impact of co-disposal with different ISW addition proportions using life cycle assessment (LCA). Results show that increasing ISW proportions improves economic indicators, reducing the payback period from 7.92 years (0 % ISW) to 6.58 years (40 % ISW). Environmental impact indicators initially decrease and then increase. The indicator with the greatest environmental impact is Eutrophication Potential (EP), the only major indicator with positive values in all scenarios when considering power output. Its normalization value reaches a minimum at 30 % ISW blending, at 7.85 × 10−12. Contribution analysis reveals that the direct emissions of N-containing gases are the primary cause, while the addition of urea, ammonia water, and quicklime in flue gas treatment, as well as the ash-slag landfill, also have significant effects. Technical optimization of stepwise co-disposal, denitrification system and ash-slag reduction will be the focus. Compared to the existing conventional situation, the co-disposal system exhibits considerable improvements in environmental benefits and carbon reduction potential. Notably, there is a significant reduction in non-CO2 greenhouse gas emissions. This study offers theoretical insights for multi-source waste disposal in MSW incineration plants.

Comparative life cycle assessment of sequential chemical and electrochemical processes for the treatment of industrial textile wastewater

AbstractFenton-based processes, chemical and electrochemical, have attracted the interest of industrial and academic researchers for wastewater treatment. However, the deficiency of rigorous comparison between different methods, including assessment of their impact on the environment, has hindered their large-scale application. This study reports for the first time on the sustainability of raw textile wastewater treatment through two sequential processes, Coagulation-Flocculation-Fenton-Neutralization (CF-F-N) and Coagulation-Flocculation-Electro-Fenton-Neutralization (CF-EF-N), based on Life Cycle Assessment (LCA) approach. The CF-F-N and CF-EF-N were optimized at laboratory scale and compared through LCA, using the IPCC-2013 and ReCiPe-2016 midpoint and endpoint methods. The highest CO2 emissions relied on the wastewater primary treatment by CF. This due to the high amount of hazardous sludge generated and the technology necessary for its disposal (i.e., 16.89 kg CO2-Eq/FU for underground deposit in security cells or 47.52 kg CO2-Eq/FU for incineration) as well as the consumption of reagents required for the treatment (alum, 7.72 kg CO2-Eq/FU; and slaked lime, 5.56 kg CO2-Eq/FU). Regarding the sequential processes, the EF-N presented lower carbon footprint (CFP) than the F-N (14.74 kg CO2-Eq/FU vs. 20.74 kg CO2-Eq/FU). Electricity (87.02% of the total CFP) and reagents (88.63% of the total CFP) denoted the main environmental hotspot during the EF-N and F-N, respectively. The EF-N, compared to the F-N, had an inferior incidence in 14 of the 18 impact categories analyzed using the ReCiPe-2016 method at the midpoint level. This is the result of low consumption of reagents and auxiliary chemicals. The electricity was also found as main environmental hotspot of the EF-N. The ReCiPe-2016 method at the endpoint level showed that the EF-N resulted in lower environmental load in all impact categories. The economic performance (11.91 USD/m3 for CF-EF-N vs. 13.66 USD/m3 for CF-F-N) and LCA demonstrated the competitiveness of the electrochemical sequential process compared to the chemical one. The CF-EF-N can be considered more environmentally sustainable technology.

Energy carrier exports from New Zealand to Japan – A comparative life cycle assessment of hydrogen and ammonia

Hydrogen and ammonia have been promoted as energy carriers for exporting energy from renewables-rich countries. This article presents a life cycle assessment on the export of hydrogen and ammonia from New Zealand to Japan. It encompasses production of hydrogen by electrolysis in New Zealand, conversion to ammonia (where applicable), liquefaction, transport to Japan and combustion in a thermal power station.The life cycle greenhouse gas emissions of energy carriers under present conditions are 0.61 kg CO2eq per kWhe output. This is higher than the carbon intensity of Japan's current electricity generation, so energy carriers provide no climate benefit for electricity generation. The emissions are largely from the supply of electricity for production: for every 1 kWhe output at the power station where the energy carrier is burnt, 5.1 kWhe input is needed for energy carrier production due to energy losses. The findings underscore the importance of decarbonizing the electricity grid in the exporting country if genuine carbon savings are to be realised.

A comparative nutritional life cycle assessment of processed and unprocessed soy-based meat and milk alternatives including protein quality adjustment

Efforts towards sustainable food systems have stimulated the development of plant-based alternatives to meat and milk. However, the debate on the nutritional quality of (processed) plant products compared to animal products remains unresolved, and combined assessments are needed to assess the benefits and trade-offs of these products in future diets. Using life cycle assessment (LCA) combined with nutrient density measurements and the Digestible Indispensable Amino Acid Score (DIAAS), this case study evaluates different processing stages of soy-based products, including cooked soybeans, tofu, soy drink, and a processed soy-based meat analogue (SBMA) produced in Switzerland. The nutritional LCA (n-LCA) showed that the environmental impact of all soy-based meat alternatives was 4–20 times lower than that of beef, especially when locally sourced soy was used. The differences were smaller when compared to chicken meat. All soy-based products showed lower DIAAS compared to animal products, but the results from the combined n-LCA were always less favourable for animal products in this case study. Contribution analyses showed that despite the high level of processing, the raw materials contributed significantly to the environmental footprint of SBMA, exceeding 50% in some environmental impact categories. Moreover, comparisons within the soy-based alternatives revealed a lower environmental impact of the minimally processed products. The higher protein quality and quantity of the processed SBMA were not sufficient to offset its higher environmental impact in this case study. SBMA also contained highest level of sodium and saturated fatty acids, highlighting the need for careful food formulation. Overall, this study showed the potential of soy-based alternatives to meat and milk to reduce the environmental impact of food production whilst highlighting the importance of considering their nutritional quality and the role of processing. Overall, this research provides insight into the potential of plant-based alternatives to meat and milk for sustainable diets amid the global challenge of climate change and changing dietary patterns.

Comparative life cycle assessment of integrated renewable energy-based power systems

Integrated renewable-based power cycles should be employed to produce more sustainable electricity. This is a comparative life cycle assessment (LCA) of three combined power plants, encompassing: case 1 involving combined geothermal and wind, case 2 featuring combined geothermal and solar, and case 3 integrating wind and solar systems. The base case perovskite solar cell (PSC) modelling assumes a 3-year lifespan and a power conversion efficiency of 17 %. However, diverse scenarios are evaluated through a sensitivity assessment involving enhancements in lifetime and efficiency. The base case evaluation emphasizes that the phases with the most significant negative environmental effects which includes the drilling of geothermal wells, construction of wind plants, and manufacturing and installation of PSCs. The midpoint findings indicate that boosting the power conversion efficiency of PSC from 17 % to 35 % yields a notable decrease in environmental impact. Moreover, extending the lifetime from 3 to 15 years led to reduction in CO2 emissions from 0.0373 and 0.0185 kg CO2 eq/kWh to 0.026 and 0.0079 kg CO2 eq/kWh in cases 2 and 3, respectively. Assessing worst and best-case scenarios highlights significant declines in certain impact categories. In case 3, terrestrial ecotoxicity (TE), photochemical oxidant formation (POF), human toxicity (HT), marine ecotoxicity (ME), and marine eutrophication (MU) saw reductions exceeding 88 % compared to worst-case results. The environmental effects observed in cases 2 and 3 stem from toxicity and metal depletion, mainly linked to the PSC. Endpoint results revealed that when considering a PSC lifespan of 10 years or more, the detrimental ecosystem impacts of cases 2 and 3 become less severe than those of case 1. Uncertainty assessment has been done for different cases and impact categories. The study's results are also novel in which it evaluated the innovative PSC technology when integrated with other renewable resources, contrasting it with other integrated plants.

Life cycle greenhouse gas emissions of retrofit electrification: Assessment for a real case study

Nowadays fleet electrification appears the most concrete opportunity to reduce the environmental burdens of the transportation sector. However, Battery Electric Vehicle penetration has to deal with crucial challenges, such as new BEVs high price, customers’ reluctant and scarcity of materials. In this regard, electric retrofit is emerging as a low-cost and short-term solution to deal with these issues. However, to date only few studies focus on regulatory framework of electric retrofit and fewer quantify the environmental benefits of a converted BEV used in a certain context. This paper analyses a retrofit industrial prototype made by a local start up with all features available for a future homologation and it proposes a comparative Life Cycle Assessment, stressing the significant environmental hotspots to suggests in which geographical context governments should promote retrofit conversion. Two scenarios composed by two time-related parts are evaluated: a vehicle replacement with a new Internal Combustion Engine Vehicle and a retrofit conversion process of a SmartForTwo W450. The production stage of conversion kit is assessed mainly through primary data, while operation consumption is calculated through an analytic model implemented in MATLAB- Simulink. A detailed sensitivity analysis is performed in which different options for electricity grid mix, energy consumption, battery pack maintenance and EoL pathways are combined, for a total of 274 scenario combinations. The results reveal that retrofit conversion allows achieving about 45 % Greenhouse Gases saving compared to new replacement, in particular when urban driving and renewable electricity grid mix are considered.

Comparison of life cycle assessment of different recycling methods for decommissioned lithium iron phosphate batteries

The rapid development of China’s new energy industry has dramatically increased the sales of electric vehicles. Frequent charging and discharging will lead to a decline in the service life of the battery, and consequently a large number of lithium iron phosphate (LFP) batteries are discarded. Batteries contain a large number of toxic substances, and the wrong recycling method will produce a large amount of pollution. In China, the question of how to improve the technology for recycling LFP batteries more environmentally friendly is still under investigation. Life Cycle Assessment (LCA) methodology was employed to analyze the environmental impacts of the whole process of recycling LFP batteries by the conventional recycling technologies used in traditional factories in China. The results of the study show that the hydrometallurgy process is superior to the physical recycling process though environmental benefits of the physical recovery process with complete recovery are better than those of hydrometallurgical process with incomplete recovery. Incomplete hydrometallurgical methods release more toxic substances into the environment, whereas traditional physical process only need to focus on the pollution caused by the battery crushing process. The results of the calculation and analysis provide a new direction for the technological update of power battery recycling in China.

Life cycle assessment of lithium carbonate production: Comparing sedimentary deposits

Lithium sedimentary deposits which were once considered impractical to extract, have become increasingly attractive for exploiting and producing high-quality lithium compounds, due to the surge in demand for batteries and from other markets. However, potential environmental impacts are yet to be evaluated for this emerging lithium production route. Therefore, this paper presents a comparative Life Cycle Assessment study for three prominent and near-to-opening lithium clay projects globally: Sonora Mexico, Falchani Peru, and Thacker Pass USA. Specifically, this study used literature, statistical data, expert interviews, and technical reports to develop cradle-to-gate models covering the mining to refining processes. The results suggest that lithium carbonate production in the Thacker Pass project has higher impacts than the two other selected sedimentary projects. Additionally, the impact categories of the Sonora project are significantly influenced by the source of electricity. The sensitivity analysis highlights the pivotal role of a transition to clean energy sources for these emerging lithium production routes. Especially, the Thacker Pass project would benefit significantly from on-site sulfuric acid production and power generation to reduce the associated environmental impacts.

Comparative Life Cycle Assessment of Electric and Internal Combustion Engine Vehicles

This article is devoted to the ecological comparison of electric and internal combustion engine vehicles throughout their entire life cycle, from mining to recycling. A scientifically based approach to a comprehensive environmental assessment of the impact of vehicles on the environment has been developed. To analyze the impact on the environmental situation, aspects such as the consumption of natural resources, waste generation, electricity consumption, emission of harmful substances into the atmosphere, water consumption, and greenhouse gas emissions are taken into consideration. As a result of comparing the environmental impacts of vehicles, it was found that natural resources consumption and production of industrial waste from electric vehicles (EV) is 6 times higher than from internal combustion engine vehicles (ICEV). Harmful substance emissions and greenhouse gas emissions from EV production are 1.65 and 1.5 times higher, respectively. The EV total electricity consumption is 1.4 times higher than that of ICEVs. At the same time, it was revealed that during operation, EVs have higher energy consumption and emit more harmful substances into the atmosphere, but EVs produce less greenhouse gas emissions. It means that at different life cycle stages, EVs have a much higher negative impact on the environment compared to gasoline engine vehicles.

Correction: Requirements for comparative life cycle assessment studies for single-use and reusable packaging and products: recommendation for decision and policy-makers

Correction: Requirements for comparative life cycle assessment studies for single-use and reusable packaging and products: recommendation for decision and policy-makers

Comparative life cycle assessment of excreta management systems through composting and biomethanization: Case of a low-income tropical country.

Low-income tropical regions, such as Haiti, grapple with environmental issues stemming from inadequate sanitation infrastructure for fecal sludge management. This study scrutinizes on-site sanitation systems in these regions, evaluating their environmental impacts and pinpointing improvement opportunities. The focus is specifically on systems integrating excreta valorization through composting and/or anaerobic digestion. Each system encompasses toilet access, evacuation, and sludge treatment. A comparative life cycle assessment was undertaken, with the functional unit managing one ton of excreta in Haiti over a year. Six scenarios representing autonomous sanitation systems were devised by combining three toilet types (container-based toilets (CBTs), ventilated improved pit (VIP) latrines, and flush toilets (WC)) with two sludge treatment processes (composting and biomethanization). Biodigester-based systems exhibited 1.05 times higher sanitary impacts and 1.03 times higher ecosystem impacts than those with composters. Among toilet types, CBTs had the lowest impacts, followed by VIP latrines, with WCs having the highest impacts. On average, WC scenarios were 3.85 times more impactful than VIP latrines and 4.04 times more impactful than those with CBTs regarding human health impact. Critical variables identified include the use of toilet paper, wood shavings, greenhouse gas emissions, and construction materials.

Comparative Life Cycle Assessment on fuel types for a Formula 1 engine in Belgian Grand Prix

Formula 1 racing, known for its speed and innovation, faces an increasingly urgent need to address environmental concerns. This study investigates the environmental impacts of various fuel types used in Formula 1, aiming to bridge a critical gap in the automotive industry's perception of sustainability. With sustainability at the forefront, we conducted a comprehensive Life Cycle Assessment (LCA) of different fuel types, including Gasoline, E5, E10, and E85, specifically analyzing their effects during the Belgian Grand Prix race. Through a thorough literature review and careful scoping, we sought to provide valuable insights into the environmental performance of these fuels in the context of high-performance racing. Our findings reveal a stark contrast between marketed sustainability claims and actual environmental impacts. Contrary to expectations, our analysis demonstrates that E85, often advertised as a sustainable alternative, exhibits the highest emissions across various environmental indicators. Specifically, E85 showed the highest impacts on water consumption, fine particulate matter, ozone formation, and human health. These results carry profound implications for the automotive industry, highlighting the importance of informed decision-making in fuel selection within the racing industry. By prompting further discussions on sustainable practices in motorsports, our study urges stakeholders to reevaluate fuel choices and embrace environmentally responsible alternatives.

Comparative Life Cycle Assessment of Wall Painting Types in a New City Development: Impacts on Environment and Human Health

Comparative Life Cycle Assessment of Wall Painting Types in a New City Development: Impacts on Environment and Human Health

Comparative life cycle assessment of landfill sludge treatment technologies in China.

Reasonable treatment of large amounts of sludge excavated from landfills has gained increasing attention due to the diminishing availability of landfill space in China. In this study, five landfill sludge (LS) treatment technologies using life cycle assessment (LCA) and life cycle cost (LCC) were investigated, i.e., co-incineration in coal-fired power plants (CFPP) and waste incineration power plant (WIPP), co-processing in cement kiln, bricks production, and sintering ceramsite. The LCA results demonstrate that sintering ceramsite outperforms other technologies and LCC results indicate sintering ceramsite also provides the highest economic benefit ($869.94). To further enhance environmental and economic performances of the LS treatment, the substitution of coal with natural gas and biomass can reduce Energy Conservation and Emission Reduction (ECER) index by 74% and 98%, respectively. This substitution can increase economic returns by 24% and 26%, respectively. Furthermore, national-level economic benefit and carbon emission reduction potential of different LS treatment technology alternative scenarios were assessed. Results display that a combination of 50% CFPP, 25% bricks, and 25% ceramsite (biomass) offers the highest economic gain, which is 3.02 times that of 50% CFPP and 50% cement (original case). Conversely, the replacement of 25% brick with 25% cement in the above combination result in the lowest carbon reduction, which is 9.35 times that of the original case.

Design and construction of chemical-biological module clusters for degradation and assimilation of poly(ethylene terephthalate) waste

The rising accumulation of poly(ethylene terephthalate) (PET) waste presents an urgent ecological challenge, necessitating an efficient and economical treatment technology. Here, we developed chemical-biological module clusters that perform chemical pretreatment, enzymatic degradation, and microbial assimilation for the large-scale treatment of PET waste. This module cluster included (i) a chemical pretreatment that involves incorporating polycaprolactone (PCL) at a weight ratio of 2% (PET:PCL = 98:2) into PET via mechanical blending, which effectively reduces the crystallinity and enhances degradation; (ii) enzymatic degradation using Thermobifida fusca cutinase variant (4Mz), that achieves complete degradation of pretreated PET at 300 g/L PET, with an enzymatic loading of 1 mg protein per gram of PET; and (iii) microbial assimilation, where Rhodococcus jostii RHA1 metabolizes the degradation products, assimilating each monomer at a rate above 90%. A comparative life cycle assessment demonstrated that the carbon emissions from our module clusters (0.25 kg CO2-eq/kg PET) are lower than those from other established approaches. This study pioneers a closed-loop system that seamlessly incorporates pretreatment, degradation, and assimilation processes, thus mitigating the environmental impacts of PET waste and propelling the development of a circular PET economy.

Comparative life cycle assessment for the sustainable production of fermentation-based L-methionine

Methionine, essential for human and animal growth, faces increasing demand, contributing significantly to greenhouse gas emissions through animal digestion and nitrogen excretion. This study introduces L-methionine (L-Met) produced biologically from CJ CheilJedang Corp., offering a sustainable alternative to the conventional petroleum-based DL-methionine (DL-Met) due to its higher bioavailability and reduced environmental impact. One of the most important aspects for the sustainable lifecycle of L-Met is to reduce environmental impact during the production stage. Consequently, the aim of this study is to evaluates the environmental impact of L-Met and its environmentally improved product, L-Met Eco, through a life cycle assessment compared to DL-Met. We employed scenario analysis to consider uptake CO2 by bio-based feedstock, bioavailability of methionine, and system expansion of co-products. Our findings indicate that L-Met and L-Met Eco have lower global warming potentials of 0.92 and 0.79 kg CO2/kg Met, respectively, than DL-Met (2.60−3.32 kg CO2/kg Met). Sensitivity analysis further suggests that optimizing renewable energy use and production location can significantly enhance the sustainability of L-Met production. This comprehensive study offers valuable insights for stakeholders in the bio-based material sector, promoting environmentally sustainable practices.

Photovoltaic Manufacturing Factories and Industrial Site Environmental Impact Assessment

Life cycle inventories (LCIs) and life cycle assessments (LCAs) of photovoltaic (PV) modules and their components focus on the operations of PV factories, but the factories and industrial site product and construction stages are either not or only partially tackled. This work contributes through the bottom-up, model-based generation of LCIs and LCAs for setting up a vertically integrated 5 GWp/a PV industrial site, including the manufacturing of silicon ingots, wafers, solar cells, and PV modules, on a 50 ha greenfield location. Two comparative LCAs are performed. The first compares the annualized environmental impacts of the developed LCI sets with four existing inventories in the Ecoinvent v3.8 database. The second comparative LCA explores the environmental impact differences concerning the industrial site when using different building systems for the factories. Here, the reference system with a steel structure is compared with two alternative building systems: precast concrete and structural timber. The results show that the wafer, cell, and module factories’ annualized environmental impacts with the Ecoinvent LCIs are strongly overestimated. For the ingot factory, the opposite result is identified. The impacts of all four factories show reductions of between 11.7% and 94.3% for 14 of the 15 impact categories. High mean environmental impact shares of 79.0%, 78.2% and 79.2% for the steel, precast concrete and timber structural building systems, respectively, are generated at the product stage. The process and facilities equipment generates 54.2%, 54.4% and 58.2% of the total product and construction stages’ mean environmental impact shares. The proposed alternative timber building system reduces the environmental impacts in 14 of the 15 evaluated categories, with reductions ranging from 1.1% to 12.4%.

A comparative life cycle assessment of building sustainability across typical European building geometries

In recent years, significant progress has been made in the sustainability assessment of building materials and buildings. The introduction of Environmental Product Declarations (EPDs), the development of Level(s), and the release of relevant series of standards have helped to improve the sustainability of buildings. However, a research question that remains unresolved is the lack of information related to the comparison of the sustainability performance of building units across Europe and the significance of conducting such research. This study addressed this question by implementing a comparative whole-building Life Cycle Assessment (LCA) across buildings in Europe. The study emphasizes the necessity of considering typical building geometries and thermal performance of buildings across Europe and introduces six typical building geometries for three different European clusters (northern-western, central-eastern, southern cluster). The results of this study revealed that the sustainability performance of buildings is not similar across the EU and that cost-optimal minimum thermal performance requirements for building structures have a significant impact on their environmental performance. Particularly, single-family houses in Central and Eastern Europe are responsible for 324.42 kgCO2e/m2. Contrary to this, Northern and Western European single-family buildings have the lowest environmental impact with 268.97 kgCO2e/m2. Multifamily houses in Southern Europe are responsible for 321.82 kgCO2e/m2, in Northern and Western Europe the environmental impact is 275.37 kgCO2e/m2. The outcome of this study is significant for the scientific community involved in assessing the sustainability of buildings in Europe, as it provides valuable insights into their environmental performance, considering the energy efficiency and sustainability aspects of buildings. The study's findings should be considered when setting minimum LCA-related requirements, in view of the provisions of the new EU policies expressed in the Energy Performance of Buildings Directive (EPBD) recast for defining the Global Warming Potential (GWP) of new buildings.

Combining Fleetwide AviTeam Aviation Emission Modeling with LCA Perspectives for an Alternative Fuel Impact Assessment.

Reducing aviation emissions is important as they contribute to air pollution and climate change. Several alternative aviation fuels that may reduce life cycle emissions have been proposed. Comparative life cycle assessments (LCAs) of fuels are useful for inspecting individual fuels, but systemwide analysis remains difficult. Thus, systematic properties like fleet composition, performance, or emissions and changes to them under alternative fuels can only be partially addressed in LCAs. By integrating the geospatial fuel and emission model, AviTeam, with LCA, we can assess the mitigation potential of a fleetwide use of alternative aviation fuels on 210 000 shorter haul flights. In an optimistic case, liquid hydrogen (LH2) and power-to-liquid fuels, when produced with renewable electricity, may reduce emissions by about 950 GgCO2eq when assessed with the GWP100 metric and including non-CO2 impacts for all flights considered. Mitigation potentials range from 44% on shorter flights to 56% on longer flights. Alternative aviation fuels' mitigation potential is limited because of short-lived climate forcings and additional fuel demand to accommodate LH2 fuel. Our results highlight the importance of integrating system models into LCAs and are of value to researchers and decision-makers engaged in climate change mitigation in the aviation and transport sectors.