Comparative Environmental Assessment Research Articles

Substitution of Conventional Vehicles in Municipal Mobility

Among the economic sectors, mobility is showing significant environmental impacts, especially in the use phase of vehicles. By substituting fossil-fuelled propelling systems, environmental impacts such as the Global Warming Potential (GWP) can be reduced. The use of properly designed light electric vehicles (LEVs) significantly reduces further environmental impacts, as well as maintenance costs, which are relevant for a circular economy. For example, the use of low-voltage (42 V) propelling systems enables the maintenance of LEVs in a broader range of existing bicycle workshops. Regarding the environmental impacts, the described LCA results indicate the advantage of LEVs compared with EVs and ICVs, e.g., vehicle weight is found to be a main factor related to environmental impact for each type of vehicle. This implies a reduced need for battery capacity and lower emissions of particulate matter from tire and break abrasion. This study aims to present the application potential of LEVs and the related reduction in environmental impacts. Anonymised inventory lists of municipal vehicle fleets are analysed for quantifying the substitution potential of LEVs in specific use cases. For this purpose, the use phase of vehicles is analysed with a focus on product design for repair and recycling and supplemented by the results of a comparative environmental impact assessment of internal combustion engine vehicles (ICEVs), electric vehicles (EVs), and LEVs. The comparison is made on the premise of similar application requirements. These specifications are the ability of each of the vehicles to transport a maximum of three persons (driver included) or one driver and 250 kg of cargo in 3 m3 over a daily distance of 100 km in urban areas. On this basis, the municipal environmental benefits derived from substituting small vehicles in the form of ICEVs and EVs with LEVs are assessed. The results show that in the field of municipal mobility, a relevant number of conventional small vehicles can be substituted with LEVs. The environmental impacts in categories of the highest robustness level, RL I, that is, Global Warming Potential, fine dust emissions, and Ozone Depletion Potential, can be reduced by LEVs by 50% compared with EVs and by over 50% compared with ICEVs. The strong influence of vehicle weight on the abrasive conditions of tires and brakes is considerable, as shown by reduced fine dust emissions.

Comparative Life Cycle Assessment of a centrifugal compressor impeller: Hybrid technology production versus welding production

Sustainable development is one of the main objectives in the turbomachinery sector to achieve the climate neutrality targets set by 2050 protocols. The manufacturing industry consumes an average of 23% of global energy, significantly contributing to the generation of greenhouse gases and other pollutants. Therefore, it is crucial to research technological solutions aimed at reducing consumption for the benefit of the environmental sustainability of the products manufactured. This study presents a comparative environmental impact assessment using the Life Cycle Assessment (LCA) methodology to evaluate the sustainability of two technological alternatives used to produce centrifugal impellers in the industrial sector. The first process analyzed deals with making an impeller by welding the shroud to the impeller body. The second process involves producing the component from a semi-finished product, machined through milling and Electrical Discharge Machining (hybrid solution). The study has been conducted at Nuovo Pignone company. It is based on primary inventory data collected through specific measurement campaigns and modeled using the environmental database Ecoinvent v3.9. The results were produced using the ILCD Midpoint method, and four different impact categories were investigated: Climate Change, Human Toxicity, Cancer Effects, and Freshwater Ecotoxicity. The results demonstrate that the solution produced through hybrid manufacturing is generally less impactful compared to the welded one. The insight implemented in the work is functional in drafting suggestions for manufacturers and customers to reduce the environmental burdens of the examined product.

Comparative environmental assessment of coated ferritic steels suited to steam turbines of coal-fired supercritical and ultra-supercritical power plants

Coated ferritic steels are the most common materials used for steam turbines construction in coal-fired power plants operating at supercritical and ultra-supercritical conditions of pressure and temperature because of their corrosion and oxidation resistance. However, the environmental implications associated to the steel-coating system have not been fully investigated to choose the best option in terms of sustainability.This work presents three types of ferritic steels as well as three coatings with its corresponding deposition technique, normally used in these environments. The designated materials are P91, P92 and VM12 ferritic steels, while the selected protective coatings are Ni50Cr applied by High-Velocity Oxi Fuel Spray (HVOF), CrN/NbN applied by High Power Impulse Magnetron Sputtering (HiPIMS) and slurry aluminide applied by painting and diffusion heat treatment. Taking these data as a starting point, comparative Life Cycle Assessments (LCA) and economic analysis are performed.This work aims to contribute to better understanding of environmental damages as well as the importance of considering the technical and environmental assessment in the steel-coating selection. The results obtained indicated that the P92 ferritic steel coated with slurry aluminide had the best performance. On the other hand, CrN/NbN coating showed the greater impacts in all the categories studied.

EcoPrintAnalyzer: Assessing Sustainability in Material Extrusion Additive Manufacturing for Informed Decision-Making

Sustainability is fundamental in the field of additive manufacturing (AM) for improving eco-consciousness and driving evolution toward environmentally responsible production methods. Compared to traditional manufacturing processes, AM technologies can be more resource-efficient and offer innovative solutions for creating eco-friendly processes and products. Nevertheless, there is significant potential for improvement in additive manufacturing sustainability. The key factors driving this improvement include design optimization and increased awareness. Designers and engineers can create designs that optimize material efficiency and reduce support structures. Raising awareness and educating stakeholders about the environmental benefits of AM can promote responsible choices throughout the industrial process. The development of a tool to assess the environmental impact of AM processes could be a significant contribution to advancing sustainability in the AM field. The EcoPrintAnalyzer, introduced as a complementary plugin for UltiMaker Cura, offers data on the equivalent carbon dioxide footprint and energy consumption in material extrusion additive manufacturing. This tool facilitates informed decision-making regarding materials, designs, and settings, enabling users to optimize their AM processes for reduced waste and enhanced energy efficiency. Beyond aiding decision-making, the EcoPrintAnalyzer fosters environmental consciousness and encourages the adoption of sustainable practices within the AM ecosystem. The efficacy of the tool is demonstrated through the 3DBenchy model case study, showcasing its intuitive interface and seamless integration within the AM process workflow for immediate and comparative environmental impact assessments across different process configurations.

Comparative environmental impact assessment of activated carbon electrodes for supercapacitors

Comparative environmental impact assessment of activated carbon electrodes for supercapacitors

Comparative Environmental Impact Assessment of Fuel Cell Electric Vehicles and Internal Combustion Engine Vehicles in Bangladesh

Comparative Environmental Impact Assessment of Fuel Cell Electric Vehicles and Internal Combustion Engine Vehicles in Bangladesh

Comparative environmental assessment of zeolites synthesized from chemicals and natural minerals

Life cycle assessment and green metrics were used to comparatively assess the synthesis of zeolites from natural minerals and chemicals in which the former exhibits a better balance between efficiency and environmental impacts than the latter.

Ballasted or ballastless for a railway infrastructure? A comparative environmental impact assessment of two solutions

In the railways sector environmental concerns are growing, and many state-owned holding companies are investigating which is the best superstructure solution from the environmental point of view. In this regards, in the last years some companies have proposed ballastless systems, to reduce the replacement and maintenance activities and increase the reliability of the solution. Nevertheless, some environmental discussion emerged, even bearing in mind of different reference service lives.This study aims at comparing from an environmental point of view a ballasted and ballastless solutions using Life Cycle Assessment, by considering a declared unit of 1 km of railways infrastructure located in Italy. Results show the ballastless system has, on the contrary of previous studies, the lower environmental impact, due to its extended shelf life (90years) and low maintenance activities if compared with a ballasted one. Considering the same timeframe, the ballastless system has about halved impact on climate change (3.33E+06 kg CO2eq) compared to the ballasted one (1.75E+06 kg CO2eq). A sensitivity analysis has been carried out to consider possible variations in reference service life, transports and interval of rails substitution.

Comparative Life Cycle Environmental Impact Assessment of Fruit and Vegetable Waste Valorization by Anaerobic Digestion as an Alternative in a Mediterranean Market

Landfilling and incineration are the most widely used methods for the management and treatment of fruit and vegetable waste (FVW) in Mediterranean markets, despite their potential environmental impact. A comparative life cycle assessment was conducted in this study to evaluate the environmental improvements from replacing the current landfill disposal method for FVW management and treatment in the wholesale market of Amman (Jordan) with an integrated anaerobic digestion process followed by composting. The proposed FVW treatment scenario is the best treatment option for all the assessed impact categories under the system expansion approach. Significant reductions in global warming and terrestrial ecotoxicity impacts categories would be achieved, reaching up to 322% and 352%, respectively, when compared to the current treatment scenario. Furthermore, the higher production of electrical energy (413%), as well as the production of co-products that would avoid the production of 100 kg/d of inorganic fertilizers, would contribute to such a low value of avoided impacts.

A study on comparative environmental impact assessment of thermochemical cycles and steam methane reforming processes for hydrogen production processes

Alternative energy sources are extensively studied to meet the increasing energy demand. To address rising energy demand, hydrogen generation through environmentally friendly sources are explored, and new technologies are now needed badly. Hydrogen can be generated using fossil fuels, nuclear energy and renewable energy. Most of the hydrogen is still produced using fossil-based fuels, which increases the amount of greenhouse gases. This study examines the life-cycle impact of three alternative hydrogen-generating processes. The solar-based hybrid sulfur (HyS) thermochemical cycle, the nuclear-based HyS thermochemical cycle, and steam methane reforming (SMR) are all considered, and the environmental consequences of the SMR and thermochemical facilities are evaluated. The CML-IA impact categories are used to analyze environmental impacts. The SimaPro 9.2, a modeling software package developed for the detailed descriptions and simulations of complex products, services and processes, is used to perform the life cycle impact assessment (LCIA). This study aims to determine the best environmentally friendly option for hydrogen production by analyzing and comparing its environmental implications. Different impact categories namely global warming potential (GWP), human toxicity potential (HTP), ozone layer depletion (ODP), abiotic depletion factor (ADF), and acidification potential (AP), are examined based on the CML-IA impact classifications. The results show that the solar-based HyS cycle options yield the lowest global warming potential, abiotic depletion, acidification potential, ozone layer depletion, and human toxicity potential values were 1.04 kg CO2 eq/kg H2, 0.013 kg Sb eq/kg H2, 0.0027 kg SO2 eq/kg H2, 0.0007 kg CFC-11 eq/kg H2, and 0.27 kg 1,4-DB-eq/kg H2, respectively. The environmental impact results further show that the solar-powered hydrogen generation is a promising approach for cleaner hydrogen generation.

Environmental impact assessment of green ammonia-powered very large tanker ship for decarbonized future shipping operations

Maritime transport has been critical for the world economy and trade for centuries. Greenhouse gases and their environmental impacts are significant contributors to global warming and climate change and have compelled authorities to take substantial steps toward decarbonizing the energy system. Since then, the International Maritime Organization, policymakers, classification societies, shipping companies, and related stakeholders have been increasingly concerned about the environmental impacts of carbon-based fuels. Green ammonia as an energy vector is considered one of the top contenders for future energy systems. However, gaps remain in the literature regarding environmental impact assessment and usage. This study assessed the environmental impacts and performance of a newly built green ammonia-powered, very large oil and chemical tanker designed for the Atlantic Ocean route from Rotterdam to New York Port. This life cycle assessment study considers a tanker's entire transport life cycle from its manufacturing process to the production, material transportation, energy required for manufacturing, operation, maintenance, disassembly, scrap processing, and using green ammonia as a marine fuel. Performed an environmental impact assessment using IPCC, Environmental footprint, and ReCiPe midpoint Hierarchist (H) methodologies for five broad impact groups: Eutrophication, ozone, Climate change, Human and Ecotoxicity, and analyzed green ammonia process impacts. This study performed a comparative environmental performance assessment of HFO, LNG, blue ammonia, and green ammonia using impact categories such as GWP 100 and GTP 100. Green ammonia exhibited the most substantial negative percentage difference values (higher than −90%) per tonne-kilometer, indicating a lower environmental impact than all fuels in both categories. Adequately managing the ammonia-powered marine energy system would be indispensable for reducing environmental footprints and successfully lowering carbon, nitrogen oxide, and ammonia-based emissions.

Geospatial environmental techno-economic assessment of pretreatment technologies for bioethanol production

Second-generation biofuels, starting from lignocellulosic biomass, are considered as a renewable alternative for fossil fuels with lower environmental impact and potentially higher supply and energy security. The economic and environmental performance of second-generation bioethanol production from corn stover in the European Union (EU) is studied, starting in Belgium as base case. A comparative environmental techno-economic assessment has been conducted, with process simulations in Aspen Plus and corn stover availability data in thirteen EU countries to calculate minimum ethanol selling prices (MESP) and Greenhouse gas emissions (GHGe). In this analysis, the emphasis is on the comparison of different pretreatment technologies, namely (i) dilute acid, (ii) alkaline, (iii) steam explosion and (iv) liquid hot water. Dilute acid showed the best economic and environmental performance for the base case scenario. Within the EU, Hungary and Romania presented the lowest MESP for the steam explosion model at 0.39 and 0.43 EUR/L respectively. Poland showed the lowest GHGe, at 0.46 kg CO2eq/L for the alkaline model, mainly due to the avoided product allocation on electricity and its high carbon intensity in the electricity generation sector. The second lowest GHGe were obtained in France for the dilute acid model and are attributed to its low agricultural emissions intensity. This study identifies a location-dependence of the economic and environmental performance of pretreatment technologies, which can be extrapolated from the EU to other large regions around the world and should be taken into consideration by decision-makers.

Comparative life cycle environmental assessment of recycled aggregates concrete blocks using accelerated carbonation curing and traditional methods

Accelerated carbonization curing has been a technically feasible alternative to the conventional curing method in the production of recycled aggregate concrete blocks (RACB). However, the environmental impacts of the curing scenarios on production have not yet been studied. Therefore, the paper evaluated the environmental feasibility of curing methods to produce RACB based on the LCA framework. The system boundary from the cradle to the door was selected to compare the overall influence of accelerated carbonation curing methods (pressurized carbonation curing, wet carbonation curing) and traditional curing methods (standard curing, autoclave curing) on the environmental impact. CO2 absorption was calculated by the Kim and Chae carbonation model combined with experimental carbonation depth. Environmental emission calculated from the inventory database was distributed to ten midpoint indicators and three endpoint indicators by the CML 2016 baseline and ReCiPe endpoint method. The distribution of contributions to the environmental impacts of the four production stages (raw material processing stage, raw material transportation stage, block manufacture stage, and block curing stage) was subdivided to facilitate decision-making and improve the management of the block plant. A sensitivity analysis ultimately complements the effect of curing time on the environmental sustainability of RACB production. The results showed that the traditional curing method had a more significant environmental impact, while accelerated carbonization curing had a relatively lower environmental impact. Compared with standard curing, the GWP value of pressurized and wet carbonization curing decreased by 33.3% and 52.8%, respectively. The 1 m3 RACB showed the lowest GWP value of 254.7 kg CO2-eq under wet carbonization curing and the highest GWP value of 539.5 kg CO2-eq under standard curing. The CO2 absorption capacity of −73.0 kg CO2-eq and −99.3 kg CO2-eq was demonstrated by pressurized and wet carbonization curing, respectively. The ranking from all midpoint and endpoint indicators is standard curing > autoclaved curing > pressurized carbonization curing > wet carbonization curing. Contribution analysis based on midpoint indicators showed that the raw material handling stage has the highest percentage contribution. Cement is still the most significant contributor to the environmental impact, followed by significant energy consumption, while water consumption hardly negatively impacts the environment. The results of sensitivity analysis indicate that accelerated carbonation curing (especially wet carbonation curing) is less relevant to the variation of curing time, while conventional curing methods are strongly influenced by curing time.

Comparative environmental impact assessment of additive-subtractive manufacturing processes for Inconel 625: A life cycle analysis

This paper presents a life cycle assessment (LCA) approach to compare the environmental impacts of additive-subtractive manufacturing processes for Inconel 625. The LCA follows a cradle-to-gate methodology and employs the Eco-chain Mobius Software, in accordance with ISO 14044 standards. The chosen LCA model enables industries to develop sustainable production techniques by evaluating 18 environmental variables' potential effects on human health, ecosystems, and resource availability. The LCA adopts the midpoint(H) approach from ReCiPe 2016 to comprehensively assess the environmental impacts. In the first case study, a plate is created using the Wire Arc Additive Manufacturing (WAAM) method, followed by post-processing through drilling in both wet and dry environments. The dry condition results in a remarkable 24.23% reduction in environmental impact when the LCA is applied to the entire process, making it the most sustainable choice. In the second case study, a hollow cylinder is manufactured using the WAAM technique, and post-processing is conducted using turning processes under cryogenic, dry, and electrostatic minimum quantity lubrication (EMQL) conditions. The dry environment yields a 16.4% lower impact on the environment, establishing it as the most sustainable choice. Overall, the results from both case studies demonstrate that utilizing WAAM technology in a dry environment leads to the most sustainable manufacturing procedure for Inconel 625. This comparative analysis provides valuable insights to support the development of environmentally friendly production techniques in the manufacturing industry.

Economic optimization and comparative environmental assessment of natural gas combined cycle power plants with CO2 capture

Economic optimization and comparative environmental assessment of natural gas combined cycle power plants with CO2 capture

Comparative Exergy and Environmental Assessment of the Residual Biomass Gasification Routes for Hydrogen and Ammonia Production.

The need to reduce the dependency of chemicals on fossil fuels has recently motivated the adoption of renewable energies in those sectors. In addition, due to a growing population, the treatment and disposition of residual biomass from agricultural processes, such as sugar cane and orange bagasse, or even from human waste, such as sewage sludge, will be a challenge for the next generation. These residual biomasses can be an attractive alternative for the production of environmentally friendly fuels and make the economy more circular and efficient. However, these raw materials have been hitherto widely used as fuel for boilers or disposed of in sanitary landfills, losing their capacity to generate other by-products in addition to contributing to the emissions of gases that promote global warming. For this reason, this work analyzes and optimizes the biomass-based routes of biochemical production (namely, hydrogen and ammonia) using the gasification of residual biomasses. Moreover, the capture of biogenic CO2 aims to reduce the environmental burden, leading to negative emissions in the overall energy system. In this context, the chemical plants were designed, modeled, and simulated using Aspen plus™ software. The energy integration and optimization were performed using the OSMOSE Lua Platform. The exergy destruction, exergy efficiency, and general balance of the CO2 emissions were evaluated. As a result, the irreversibility generated by the gasification unit has a relevant influence on the exergy efficiency of the entire plant. On the other hand, an overall negative emission balance of -5.95 kgCO2/kgH2 in the hydrogen production route and -1.615 kgCO2/kgNH3 in the ammonia production route can be achieved, thus removing from the atmosphere 0.901 tCO2/tbiomass and 1.096 tCO2/tbiomass, respectively.

Comparative Environmental Impact Assessment of Copper-Based Nanopesticides and Conventional Pesticides

Comparative Environmental Impact Assessment of Copper-Based Nanopesticides and Conventional Pesticides

Comparative environmental assessment of low and high CaO fly ash in mass concrete mixtures for enhanced sustainability: Impact of fly ash type and transportation

The effect of fly ash type on the sustainability of concrete mixtures has yet to be quantified. This study aims to assess the environmental impacts of low calcium oxide (CaO) and high CaO fly ash in mass concrete mixtures from Thailand. The study analyzed 27 concrete mixtures with varying percentages of fly ash as a cement replacement (0%, 25%, and 50%) for 30 MPa, 35 MPa, and 40 MPa compressive strengths at specified design ages of 28 and 56 days. Sources of fly ash have been located between 190 km and 600 km away from batching plants. The environmental impacts were assessed using SimaPro 9.3 software. The global warming potential of concrete is reduced by 22–30.6% and 44–51.4% when fly ash, regardless of type, is used at 25% and 50%, respectively, in comparison with pure cement concrete. High CaO fly ash has more environmental benefits than low CaO fly ash when utilized as a cement substitute. The reduction in environmental burden was most significant for the midpoint categories of mineral resource scarcity (10.2%), global warming potential (8.8%), and water consumption (8.2%) for the 40 MPa, 56-day design with 50% fly ash replacement. The longer design age (56 days) for fly ash concrete showed better environmental performance. However, long-distance transport significantly affects ionizing radiation and ecotoxicity indicators for terrestrial, marine, and freshwater environments. Furthermore, the results show that a high cement replacement level (50%) may not always have a reduced environmental impact on mass concrete when considering long-distance transportation. The critical distance calculated based on ecotoxicity indicators was shorter than those calculated using global warming potential. The results of this study can provide insights for developing policies to increase concrete sustainability using different types of fly ash.

Development of a new photoelectrochemical system for clean hydrogen production and a comparative environmental impact assessment with other production methods

Hydrogen is recognized as a critical substance for diversifying the global energy supply, providing new economic opportunities and realizing a carbon-free energy sector. In the current study, a life cycle assessment is conducted on a photoelectrochemical hydrogen production process of a newly developed photoelectrochemical reactor. With a photoactive electrode area of 870 cm2, the hydrogen production rate of the reactor is 47.1 μg/s while operating with the energy and exergy efficiencies of 6.3% and 6.31%, respectively. For a Faradaic efficiency of 96%, the produced current density is evaluated as 3.15 mA/cm2. A comprehensive study is conducted for a cradle-to-gate life cycle assessment of the proposed hydrogen photoelectrochemical production system. The life cycle assessment results of the proposed photoelectrochemical system are further evaluated within a comparative analysis by considering a total of four key hydrogen generation processes, namely steam-methane reforming, photovoltaics-based and wind electricity-driven proton exchange membrane water electrolysis and the current photoelectrochemical system and studying five environmental impact categories. The global warming potential of hydrogen production via the proposed photoelectrochemical cell is evaluated as 1.052 kg CO2 equivalent per kg of produced hydrogen. In the normalized comparative life cycle assessment results, the PEC-based hydrogen production is found to be the most nature-friendly option among the considered pathways.

Comparative energy, exergy, economic, and environmental (4E) analysis and optimization of two high-temperature Kalina cycles integrated with thermoelectric generators for waste heat recovery from a diesel engine

High-temperature Kalina cycles are among the efficient approaches to recovering waste heat. However, high-temperature Kalina cycles are characterized by complex layouts, lower efficiency, and higher cost. This work aims at conducting a comparative thermodynamic, economic, and environmental assessment of two different configurations of the high-temperature Kalina cycle. Thermoelectric generators, as the simple and developing heat recovery modules for electricity generation, have been embedded in the condensers of the simple High-temperature Kalina cycle, thereby proposing the enhanced thermal performance of the Kalina cycles. A parametric optimization approach was adopted to optimize the net power output and the location of pinch points of condensers. The results indicate that thermoelectric generators can improve the total power capacity of High-temperature Kalina cycles by about 0.29–0.82 kW. Meanwhile, the economic feasibility of this integration has also been investigated. The first enhanced Kalina cycle has energy and exergy efficiencies of 32 % and 63.23 %, respectively. As an economic parameter, the net present values of these cycles are 84.56, 84.77, 86.63, and 86.84 k$ for standard Kalina cycle configuration 1, enhanced Kalina cycle configuration 1, standard Kalina cycle configuration 2, and enhanced Kalina cycle configuration 2, respectively. In addition, the environmental assessment reveals that 15.55, 15.85, 15.54, and 15.84 lit/hr diesel fuel would be saved by operating the waste heat recovery cycles, respectively. Finally, a parametric study has been carried out to study the influences of variations of different parameters on the performance criteria of all four cycles.