Life Cycle Assessment Research Articles

Immobilization of Pb2+ and Cd2+ in water by sodium alginate magnet-biochar composite and LCA evaluation

Heavy metal pollution in water is one of the most pressing global environmental problems. In this research, two kinds of phosphorus-modified walnut shell biochar gel beads (P@WSBGB) and ferromagnetic gel beads (P@FWSBGB) were prepared by an environmentally friendly method to solve this problem. The maximum adsorption capacities for Pb2+ were 197 mg g−1 for P@WSBGB and 180 mg g−1 for P@FWSBGB, and for Cd2+, they were 125 mg g−1 and 108 mg g−1, respectively. Although Fe3O4 loading reduced adsorption capacity by approximately 10 %, life cycle assessment(LCA) showed that P@FWSBGB had a lower environmental impact than P@WSBGB when adsorbing the same amount of 1 mg of Pb2+. This indicates that a reasonable load of Fe3O4 can reduce the environmental impact. Conversely, when adsorbing Cd2+, the result was the opposite, demonstrating that unreasonable loading increased the environmental impact. To ensure that Fe3O4 loading did not lead to increased environmental impacts, we further analyzed the data to determine the optimal Fe3O4 loading level. The optimal Fe3O4 loading was determined to be 12.5 % for Pb2+ adsorption and <12.5 % for Cd2+. The main adsorption mechanism is that the -COOH and -OH groups on the surface of biochar form complexes with Pb2+ and Cd2+. Ion exchange, electrostatic attraction, co-precipitation of phosphate, and physical adsorption also contribute to the removal of Pb2+ and Cd2+. In summary, this research solved the challenge of difficult recycling of biochar powder and provides new insights for the synthesis and condition optimization of magnetic adsorbents.

Environmental impact assessment of alternative technologies for production of biofuels from spent coffee grounds

AbstractIn the strategy to combat climate change that has been caused by the world's overdependence on fossil fuels, current research is focusing on the decarbonisation of the energy sector through the production of renewable cleaner energy, such as biofuels. Spent coffee grounds (SCGs), the waste stream of the coffee brewing industry, are a potential feedstock for the production of valuable products, including biofuels. However, the environmental implications for the valorisation of this valuable waste need to be investigated. This study assesses the environmental impacts of six biomass‐to‐fuel processing technologies using SCGs as a feedstock, with the aim of identifying the most environmentally friendly technology. A cradle‐to‐gate life‐cycle assessment (LCA) was conducted on fast pyrolysis, fermentation, anaerobic digestion (AD), hydrothermal liquefaction (HTL), gasification, and biodiesel production. The mass and energy balances obtained from Aspen Plus simulations served as the life‐cycle inventory data. Using the ReCiPe 2016 midpoint (H) and Eco‐Indicator 99 as the assessment methods, potential environmental impacts were calculated in OpenLCA software. Electricity generation and carbon dioxide emissions were the biggest contributors of environmental impacts. For each category, the maximum result was set to 100% and the results of the other variants were displayed in relation to this result. AD, with the smallest total weighted score (160), was the most environmentally friendly biomass‐to‐fuel processing route, while HTL, with the biggest total weighted score (893), was the worst. A sensitivity analysis indicated that the environmental performance of biofuel production from SCGs was highly influenced by energy input flows and the source of energy generation.

Comparative Life Cycle Assessment and Life Cycle Cost Analysis of Bonded Nd-Fe-B Magnets: Virgin Production versus Recycling

Comparative Life Cycle Assessment and Life Cycle Cost Analysis of Bonded Nd-Fe-B Magnets: Virgin Production versus Recycling

Challenges and Issues of Life Cycle Assessment of Anaerobic Digestion of Organic Waste

Life Cycle Assessment (LCA) is a widely used tool to measure the environmental sustainability of products or processes. Integrating LCA into the assessment of waste diversion strategies recognizes that current waste diversion strategies are insufficient to stem the global impacts of waste effectively. The increased pressure to divert organic and inorganic materials to reduce landfills impacts and promotes the circular economy. Historically, waste diversion efforts in municipalities and industries focused on higher-profile inorganic wastes, such as plastics and other recyclables. However, organic waste is increasingly identified as a key waste fraction that must be effectively managed and regulated. This research surveys published LCAs from 2019 to 2023 focusing on the anaerobic digestion (AD) of organic waste. Notable conclusions include the lack of studies comparing AD with the latest treatment options such as co-gasification; the insufficient attention to the LCAs on biogas upgrading methods; and the monetization of LCA results using carbon credits. In addition, more than 50% of reviewed LCA studies concluded the results with a sensitivity analysis, which was not a common practice before 2019 in LCA studies on anaerobic digestion. This signifies the increasing need to understand uncertainty in the circumstances governing applying AD to wastes. Finally, neglecting the combined effect of several parameters in the sensitivity analysis might have reduced the accuracy of the sensitivity analyses in the reviewed LCAs. Overall, LCAs conducted on AD-related applications vary widely in terms of scope and consistency, implying that the outcomes may not be as applicable as intended. The identified challenges, issues, and other findings related to this research are expected to help standardize LCA procedures as applied to AD to promote greater comparability.

Process innovations and circular strategies for closing the water loop in a process industry

By implementing advanced wastewater treatment technologies coupled with digital tools, high-quality water is produced to be reused within the industry, enhancing process efficiency and closing loops. This paper investigates the impact of three innovation tools (process, circular and digital) in a Solvay chemical plant. Four technologies of the wastewater treatment plant “WAPEREUSE” were deployed, predicting their performance by process modelling and simulation in the PSM Tool. The environmental impact was assessed using Life Cycle Assessment and compared to the impact of the current industrial effluent discharge. The circularity level was assessed through three alternative closed-loop scenarios: (1) conventional treatment and discharge to sea (baseline), (2) conventional and advanced treatment by WAPEREUSE and discharge to sea, (3) conventional and advanced treatment by WAPEREUSE and industrial water reuse through cross-sectorial symbiotic network, where effluents are exchanged among the process industry, municipality and a water utility. Scenario 1 has the lowest pollutants’ removal efficiency with environmental footprint of 0.93 mPt/m3. WAPEREUSE technologies decreased COD by 98.3%, TOC by 91.4% and nitrates by 94.5%. Scenario 2 had environmental footprint of 1.12 mPt/m3. The cross-sectorial symbiotic network on the industrial value chain resulted in higher industrial circularity and sustainability level, avoiding effluents discharge. Scenario 3 is selected as the best option with 0.72 mPt per m3, reducing the environmental footprint by 21% and 36% compared to Scenarios 1 and 2, respectively.

Generic and site-specific social life cycle assessment of municipal wastewater treatment systems in Spain: challenges and limitations of the method when applied to resource recovery systems

Abstract Purpose This work aims to provide insights on the application of social life cycle assessment (S-LCA) in evaluating the social impacts associated with municipal wastewater treatment (WWT). The study assesses the social risks and social performance of two municipal WWT systems in Catalonia, Spain: a conventional wastewater treatment plant (WWTP) (Reference System) and a novel system that recovers water and other valuable resources (Novel System). Methods S-LCA was conducted at Generic and Site-Specific levels using 1 m3 of wastewater treatment as the functional unit (FU). The Generic assessment was conducted via the Product Social Impact Life Cycle Assessment (PSILCA) database, while the Site-Specific assessment employed the Subcategory Assessment Method (SAM) with four-level reference scales to assess the social performance of the WWTP operator and its first-tier suppliers. Furthermore, activity variables were calculated based on organizations’ shares in the total costs per FU, and the Novel System’s multifunctionality was solved through economic allocation. Results were aggregated by (i) assigning equal weights to organizations and (ii) factoring in organizations’ weights and the allocation factor, leading to results per FU. Results and discussion The Generic analysis results indicated that the Novel System entailed fewer social risks than the Reference System. Most social risks in both systems occurred in the subcategories “Access to material resources,” “Fair salary,” “Freedom of association and collective bargaining,” “Contribution to economic development,” and “Corruption.” In the Site-Specific assessment, the Novel System presented better social performance than the Reference System per 1 m3 of wastewater treatment. The latter’s performance per FU did not meet the basic requirement in four out of eleven subcategories, mainly due to the performance and weight of a chemical supplier. Allocation greatly benefitted the Novel System’s results per FU compared to the results obtained when equal weights were applied. Conclusions Activity variables were used to connect organizations’ conduct with particular WWT systems, and multifunctionality was solved. This approach allowed for obtaining results per FU at both assessment levels. However, social performance was also evaluated by calculating the average social performance of each system without considering activity variables and the FU, leading to different results. The social performance of the Novel System per FU was satisfactory across all subcategories but required improvement in four subcategories based on the average results. Given the limitations of using activity variables and allocation in S-LCA, further research is necessary to appropriately evaluate and compare the social effects of novel resource recovery systems.

Quality Assurance of Steel Slag Asphalt Mixtures for Sustainable Pavement Surface Courses

The present study investigates the use of electric arc furnace (EAF) steel slag, a by-product of the steel industry, in asphalt pavement surface courses instead of virgin aggregates (VAs). Therefore, a general performance evaluation of such mixtures compared to conventional mixtures is carried out through laboratory and in situ tests, while both mixtures are environmentally assessed using the life cycle assessment (LCA) tool. The results of the laboratory and in situ tests show that asphalt mixtures containing granulated EAF slag aggregates perform as well as mixtures containing only VA. In addition, the LCA results show that the use of EAF slag aggregates in the asphalt surface course has a lower environmental impact than the exclusive use of VA when it comes to the impact categories of acidification, climate change, marine and terrestrial eutrophication, energy consumption and photochemical pollution. In summary, these results show that replacing virgin aggregates with a proportion of EAF slag aggregate is a viable and sustainable method for road pavement construction.

Mild one-pot production of glycerol carbonate from CO2 with separation from ionic liquid catalyst

Carbon capture and utilization stands as way forward in the minimization of CO2 emissions. It complements the search for clean and effective energy, as it is challenging to achieve zero to negative CO2 net emissions. The glycerol carbonate product opens a new strategy based on a double-residue approach (glycerol and CO2) to contribute, together with ionic liquids (ILs), drafting a new one-pot concept (intensified three phase reactor) at mild conditions and using homogeneous catalysts. In this work, the catalytic activity of [P666,14][Br] in the cycloaddition of CO2 to glycidol has been demonstrated to be highly effective under mild conditions of 45 °C and 5 bar. In addition, liquid–liquid extraction approach is found to be an efficient separation strategy for carbonate product and IL catalyst. 1-Decanol (DOH) is selected as efficient extracting solvent, due to its almost complete immiscibility with glycerol carbonate, as well as the high distribution ratio of the IL catalyst in DOH rich phase. It implies an easy product separation and, simultaneously, an easy catalyst recovery. A preliminary kinetic validation of the three-phase reactor performance has been properly described, enabling the intensified concept. Finally, combining COSMO/Aspen simulation and life cycle assessment (LCA) methodologies, low energy consumption (avoiding heating) and low GWP scenarios for the CO2 conversion process have been concluded. This work enables a new concept together with concluding the path to developing this CCU technology in the search of zero to negative CO2 emissions to sustainably capture and convert CO2 into value-added products.

Carbon Footprint Assessment: Case Studies for Hemp-Based Eco-Concrete Masonry Blocks

In recent times, climate change has become more evident than ever, and measures to slow down its negative effects are imperative for the future of the world. The scientific and economic communities of countries around the world, under the force of international climate agreements, are identifying solutions to reduce greenhouse gas (GHG) emissions by establishing appropriate measures and developing new strategies. In the context of these objectives, the effort to identify eco-sustainable practices for the construction industry is growing significantly. Recently, much research has focused on solutions for producing green building materials, as well as applying circular economy principles to achieve a balance between anthropogenic emissions and absorptions by greenhouse gas absorbers. The relevant indicators of the level of achievement of these major objectives can be identified, already from the construction design phase, with the help of Life Cycle Assessment (LCA) analysis. This paper presents a series of environmental impact analyses for an eco-friendly solution of precast concrete masonry blocks. Ecological concrete is manufactured with aggregates from biological waste resulting from hemp crops. Impact assessments were performed with the SimaPro 9.5 software application. Research has shown that in the production chain, which includes the materials resulting from the recycling and reuse of hemp concrete blocks, the contribution to the effort to achieve neutrality in terms of global warming is significant. The Cradle-to-Cradle scenario revealed that the recycling of hemp concrete masonry blocks at the end of their use, for a functional unit of 0.5 m3, has a GHG emission of 33.5228 [kg CO2-eq] and CO2 uptakes can reach the negative value of −53.8397 [kg CO2-eq]. Thus, the balance of GHG emissions is negative, with values of approximately −20.3169 [kg CO2-eq]. The LCA analyses also reflect a decreased damage to human health, natural resources, and biodiversity when hemp concrete is used for masonry blocks.

Transforming the feeding regime towards low-input increases the environmental impact of organic milk production on a case study farm in central germany

Abstract Purpose Despite the direct effect of the feeding regime on the environmental impacts of dairy farming systems, its level of intensity, particularly in organic systems, has rarely been investigated. This study compares the environmental impact of a high-input feeding regime with a grassland-based, low-input feeding regime scenario within an organic milk production system conducted on Gladbacherhof, the research farm of Justus Liebig University Giessen, in Central Germany. Methods An integrated Life Cycle Assessment (LCA) analysis was performed from a cradle-to-farm gate perspective to quantify five environmental impacts, namely Global Warming (GW), Non-Renewable Energy Use (NREU), Land Use (LU), Terrestrial Acidification (TA), and Freshwater Eutrophication (FE). All agronomic data of the Gladbacherhof research farm, averaged over the years 2010–2017, were included. When not directly measured on the farm, ecoinvent data were included. Results and discussion Contrary to our hypothesis, the results suggest that a grassland-based low-input system has a higher environmental impact as compared to a high-input system for each of the five impact categories when using fat and protein-corrected milk (FPCM) as the functional unit. A 50% reduction in concentrates and exclusion of maize silage from the feed ration in the modelled low-input production system lead to a 20% drop in milk yield. To balance the energy content in low-input feeding ration, longer grazing period and higher amount of hay, alfalfa, and grass silage are required. This in turn results in higher emissions from enteric fermentation, manure management, and feed production and hence in higher environmental impact, particularly for GW, TA, and FE. Conclusions This study is one of the few that directly explores the environmental impact of feeding intensity in an organic milk production system. Nevertheless, there is a lack of research on consolidated emission factors for several greenhouse gas (GHG) sources in organic livestock and cropping systems to perform more robust carbon footprint calculations that comply with the Intergovernmental Panel on Climate Change (IPCC) Tier 3 GHG reporting guidelines. To generalize the results at the regional or national scale, direct comparisons with a larger number of organic farms representative of high-input and low-input intensities are still essential.

Carbon footprints of incineration, pyrolysis, and gasification for sewage sludge treatment

Thermal technologies have gained increasing attention in sludge management. This study applied life cycle assessment to assess the impacts to climate change of ten technological configurations (TCs) treating sludge with incineration, gasification, and pyrolysis. We used distributions of process parameters for quantifying the associated uncertainties and considered different energy exchanges. In a 55 %-fossil energy system, the TCs with various thermal processes showed impacts to climate change in a wide range of −2000 to 2000 kg CO2 eq/t total solid. A probabilistic comparison indicated that with a 10 %-fossil energy system, TCs with gasification and pyrolysis showed a > 95 % probability of performing better than TCs with incineration. Energy consumption and dewatering parameters contributed significantly to the uncertainty due to their large variation and sensitivity. This study emphasized the potential of optimizing key parameters and provided evidence from a climate change perspective for better technological selection and development in sludge management.

Evaluation and Application of Wellbore Stability of Deep Oil Wells in the Southern Margin of Junggar Basin

The stability of the oil well wellbore is a prerequisite for selecting the optimal completion method. In this paper, based on experimental testing and theoretical models of rock mechanics parameters in deep oil reservoirs, the in situ stress parameters of deep oil wells are accurately predicted. On this basis, a full life cycle assessment model for wellbore and perforation casing stability was established, and the effects of pressure depletion and changes in the production pressure differential on wellbore stability and casing stability were analyzed. The research results indicate that as the formation pressure decreases, the critical collapse pressure difference around the wellbore significantly decreases. The greater the production pressure difference, the more likely the wellbore is to become unstable. Under the original formation pressure coefficient, if there is no casing, the critical failure pressure difference of the wellbore wall is 55 MPa. After cementing and perforation, when the casing is uniformly stressed and the formation pressure drops to a coefficient of 0.83, the casing will not be damaged even when the wellbore is completely emptied. At this time, there is still a certain safety production pressure difference in the perforated formation. This study can effectively guide the optimization of well completion and safe development in deep oil reservoirs.

Life cycle assessment of common urban trees - The environmental performance of three Mediterranean cities

Given the increasing pressure from extreme events due to climate change, the planting of new trees has become a priority in the political agendas of cities. However, the rush to plant trees often fails to account for the reduced performance and lifespan of trees in heavily urbanized areas and the environmental impact of their production, maintenance, and eventual disposal. By means of the Life Cycle Analysis, this study aims to investigate the potential environmental benefit and impact of trees planted in three European cities located in Mediterranean areas (Perugia, Thessaloniki, and Cascais), that have adhered to the management guidelines of the LIFE Clivut project. The environmental performance of each tree is mainly affected by the tree management operations performed, by the climatic conditions, and by the tree performance in carbon dioxide (CO2) uptake and Particulate matter (PM) capture. The impact assessment obtained by ReCiPe 2016 Endpoint (H) methodology evidenced that the trees' beneficial effects widely overcome the impact of the operations carried out during the tree management. Broadleaved species showed an average environmental performance higher than conifers. The best results have been obtained by Tilia cordata Mill., Quercus ilex L., Populus spp. and Celtis australis L. in the case of broadleaved trees, and by Calocedrus decurrens (Torr.) Florin and Cedrus spp. for Conifers. The results of the Environmental Footprint (EF 3.1) method highlighted the urban trees' potentiality to mitigate Human Health problems and to improve Ecosystem Quality. Future studies may explore other management scenarios to optimize energy and materials use, reduce emissions, hence obtaining an increase of the environmental benefit for the urban areas.

Life cycle assessment (LCA) and economic analysis of two-stage anaerobic process of co-digesting palm oil mill effluent (POME) with concentrated latex wastewater (CLW) for biogas production

This study outlines the results of a process-based life cycle assessment (LCA) of the environmental performance of biogas production from co-digestion of palm oil mill effluent (POME) and concentrated latex wastewater (CLW) in the two-stage anaerobic digestion (AD) process. Biogas is utilized global across several sectors, including electricity generation, heating, and transportation. The Open LCA 2.0.2 software was used to evaluate the LCA at the midpoint level by using 18 different impact categories. This study reveals the three main contributions of the AD process, which were global warming (8.65 × 102 kg CO2eq), water consumption (5.32 m3), and land use change (3.39 × 102 m2 a crop eq), this result corresponded with the previous study in Malaysia that examined biogas production from the AD of POME In addition, alternative scenarios, in which a single substrate, have been established to quantify the impacts of potential improvements of biogas production to compare with base scenario of co-digestion. The results show that the environmental impacts of the base scenario released were lower than those of the single POME substrate of alternative scenario 1 in most impact categories. Furthermore, economic analysis is a crucial factor in the practical implementation of the AD process. Linking LCA with economic analysis offers a comprehensive perspective on sustainability, balancing environmental impacts with financial performance to optimize the potential of the AD co-digestion process. This is the first study to apply LCA and economic analysis to this specific co-digestion process in a two-stage AD system. The economic analysis of the two-stage AD of co-digesting POME and CLW was 1200 m3/d production of wastewater (70 % of POME and 30 % of CLW) based on the factories' data. The result indicates net present value, internal rate of return, and payback period of 515,813.94 USD, 9.13 %, and 8.87 years, respectively. This work proposed the potential approach for implementing the two-stage AD co-digestion of POME and CLW while concurrently producing valuable bioenergy carriers.

A life cycle assessment of CCU process to produce a nanocomposite from ethanol plant CO2 emission

The use of rubber septa for controlled release of semiochemicals has raised important discussions about their efficiency and environmental impact since they are composed of fossil raw material. The life cycle assessment (LCA) of the synthesis of a nanocomposite type calcium nanocarbonate/Kraft lignin (NC-CN-KL) obtained from CO2 capture aimed to quantify the environmental loads involved in the production process. The synthesis evaluated by the LCA was performed on a laboratory scale, since it is a synthetic route classified as technological readiness level 4 (TRL-4) and is in the study and development stage. The LCA was performed according to the principles of the ISO 14044/2006 series of standards, from 101.854 g of nanocomposite as a functional unit. The limitations of the study arose from its synthesis scale, absence of LCA data on the rubber septa and other nanocomposites. The results obtained in the LCA identified electricity and other energy generation processes as the largest contributors to environmental loads for all environmental impact categories studied and suggest that research should focus on these inputs when choosing the sources used in energy nanocomposite formulation processes. LCAs for this synthesis to obtain NC-CN-KL should be carried out on a pilot scale, and it is expected that this work will contribute to the formulation of the material and decision-making, especially regarding the choice of the energy matrix.

Methodological Challenges in Aligning EPDs with Whole Life Carbon Limits for Buildings: A B2B Approach

Abstract The environmental performance from the materials used in buildings is pivotal in reducing greenhouse gas (GHG) emissions from the building sector; buildings are in the top three of the world’s most significant contributors of GHG emissions and are responsible for one-fifth of the overall resource consumption. Alongside multiple countries enforcing legal GHG limits and requiring Life Cycle Assessment (LCA) for new buildings, the availability of product-level environmental data, known as Type III Environmental Product Declarations (EPDs) has increased exponentially. EPDs were originally used for Business-to-Business purposes but are now the main data source for building-level LCAs. However, this often comes with a large set of uncertainties, as EPDs are still evolving as a documentation approach, and not always readily applicable in the whole life cycle approach. There are a multitude of complex areas to engage into, this study focuses on how use-stage modules are documented in EPDs, and how varied approaches create further complexity and perils in relation to their use in LCA and regulations, in the sense of, potential leading to high uncertainties and wrongful interpretations. The study aims to address the methodological gaps associated with the use of EPDs as data inputs in legally binding LCA requirements particularly concerning modules B1-5, which constitute the embodied part of the use-stage. The findings reveal a significant margin of error if EPDs are not correctly implemented, underscoring the importance of the Business-to-Business documentation approach.

Exploring the relationship of building area and GHGe: a mitigation strategy?

Abstract Greenhouse gas emissions (GHGe) from new constructions must be reduced to address the climate change crisis. Life cycle assessment (LCA) is widely applied to document the environmental impacts of buildings, often reporting results by dividing the total emissions over the measured building area, such as the gross floor area. The appropriateness of this approach has been debated in the building LCA research community and the construction industry, with concerns about the potential consequence of designing larger buildings to reduce emissions over the buildings’ life cycle and if this entails easier compliance with limit values in regulations. With a large collection of 291 case studies divided into four weight categories, potential correlations between constructing larger areas and GHGe are explored by fitting linear models. The results show that theoretically, GHGe reported per area can be decreased due to increased building area. However, this requires significant increases in area, which realistically results in increased costs, resource use, and related environmental impacts, which is not feasible. Therefore, the findings do not support the notion that interpreting LCA results per square meter encourages the enlargement of buildings to reduce emissions over their life cycle. It should be noted that the study’s conclusions are drawn from the end results of individual LCAs. The potential decrease in GHGe by enlarging the building area during the design process is not possible to derive without involving stakeholders. Thus, this study underlines the need for future research to achieve a nuanced relationship between building size, design choices, and environmental impacts.

Life cycle assessment of photovoltaic panels including transportation and two end-of-life scenarios: Shaping a sustainable future for renewable energy

This research study addresses the growing environmental concerns associated with solar photovoltaic (PV) systems which is a pivotal component of renewable energy transition. The primary objective is to advance the comprehension of the environmental sustainability of solar PV technology, with a specific focus on the context of Mexico. This study applies a life cycle assessment (LCA) framework, employing an up-to-date methodology (ReCiPe 2016) and database (Ecoinvent 3.8) for midpoint and endpoint indicators in this problem by considering a specific focus on end-of-life and transportation scenarios which have been absent in the current state-of-the-art research. An LCA approach bridges the gap between midpoint and end-point indicators, bringing transparency to the environmental impact assessment. This research entails a cradle-to-grave LCA of a 1 kW crystalline silicon solar panel over a 25-year lifespan while adapting to ISO 14044 standards for LCA and encompassing both midpoint and end-point indicators, specifically including end-of-life and transportation scenario. Furthermore, a sensitivity analysis is conducted to evaluate the variations in environmental indicators considering the life-cycle data. It is reported that recycling processes can cause a substantial mitigating effect on environmental impacts across multiple categories, leading to reductions of up to 89 % in mineral resource scarcity. Notably, the cell processing phase emerges as the most environmentally impactful stage, accounting for 37 % of the total impact. This high impact is predominantly attributed to silver usage and heightened electricity consumption. The sensitivity analysis revealed that various performance indicators exhibited differing degrees of sensitivity to uncertainty in the design variables, highlighting the importance of careful consideration, particularly in addressing theimpact on theecosystem, when aiming to reduce environmental impacts in the life cycle of silicon solar panels. Our results have also indicated that transportation significantly impacts resource protection, accounting for 15 % of the total impacts in this category, with lesser yet notable contributions to ecosystems and human health. The implications of this work suggest a need for stringent policies to fabricate complete solar photovoltaic modules in Mexico to reduce the environmental burden caused by transportation. Additionally, the insights from this study offer a gateway for the Mexican government to reform current energy transition policies by including multiple recycling scenarios for solar photovoltaic systems, ultimately leading to sustainable growth in this market.

Reducing the embodied carbon using bio-based building materials: the biogenic carbon content of timber

Abstract In recent decades, several efforts have been made towards the reduction of operational energy and therefore carbon, thanks to the introduction of mandatory compliance in many national regulations, achieved by using specific certification tools. As operational carbon diminishes, the significance of embodied carbon - emissions released before the building and infrastructure begins to be used - will continue to increase as a portion of total emissions. Strategy for reducing embodied carbon include the use of building components derived from plants, which absorb atmospheric carbon during their growth through photosynthesis. Wood stands out among building materials, not only for its ability to store biogenic carbon but also for its lower emissions as per life-cycle assessments (LCA). The purpose of this paper is to conduct an LCA of a wooden building using a Whole-Building Life Cycle Assessment (WBLCA) software, and to explore three methodologies for assessing biogenic carbon in LCA. It follows the two primary calculation methods provided by the EN 15804 and ISO 21930 standards for LCA, along with an additional “dynamic approach”. Key procedural discrepancies between the explored methodologies arise, guiding designers to adopt varying strategies in minimising a building’s carbon footprint. This research aspires to underscore the shortcomings and advantages of prevalent methods.

Life cycle assessment and cost analysis of innovative agar extraction technologies from red seaweeds

Developing efficient and sustainable extraction technologies for valuable biocompounds from seaweed is crucial to overcome the limitations of conventional technologies. This study aims to compare three innovative technologies for agar extraction from two red seaweed species, G. sesquipedale and G. vermiculophylla: subcritical water extraction (performed at 125 °C, 2.5 atm, 1 min, and at 140 °C, 3.8 atm, 1 s), moderate electric fields (applied at 85 °C for 120 min and 95 °C for 180 min), and a combination of both methods. The comparison used life cycle assessment and life cycle costing methodologies, considering a gate-to-gate approach. The combined technology demonstrated the lowest energy consumption, with 67 MJ/kgagar for G. vermiculophylla and 100 MJ/kgagar for G. sesquipedale. A carbon footprint reduction of up to 94 % was obtained when compared to the control, with 15.9 kgCO2 eq. /kgagar for G. vermiculophylla and 20.4 kgCO2 eq. /kgagar for G. sesquipedale. Using photovoltaic panels as alternative energy further cut carbon emissions by 50 %. The cost analysis showed that the combined technology was the most cost-effective extraction method.