Cumulative Energy Demand Research Articles

Environmental Sustainability Assessment of Cold Storage Panel Production

Today's ever-increasing environmental sustainability concerns have led to a major shift in construction sites and industrial sectors. In this context, the choice of construction materials for important structures such as cold storages plays an important role in terms of both environmental impacts and energy efficiency. The aim of this study is to evaluate the environmental loads of cold storage panels with thicknesses of 80 mm, 100 mm, 120 mm, 150 mm, 180 mm and 200 mm. In order to reveal the production inputs that cause these loads, the environmental effects were examined specifically for the 100 mm thick cold storage panel. Environmental impacts were analyzed using the Life Cycle Assessment (LCA) method in accordance with the ISO 14040/44 methodology as a system boundary "cradle to gate". This study focused on three different environmental impact categories of cold storage panels produced in Türkiye: global warming potential (GWP), cumulative energy demand (CED) and water footprint. In the evaluation of environmental impacts, production inventory information obtained from the panel manufacturer was used. For analyses, Simapro v. 8.5 LCA software was used. Analysis results show that the use of galvanized sheet metal in cold storage panel production is a hot spot in terms of global warming effect. It has been determined that the largest share in the water footprint belongs to polyurethane used as insulation material. Additionally, according to the CED, non-renewable fossil and non-renewable nuclear were determined to be the most affected categories, and the use of galvanized sheet metal and polyurethane were determined to be the most important hot spots in terms of non-renewable and renewable resources. To help improve the environmental performance of the cold storage panel, it is recommended to use bio-based and less environmentally impactful raw materials in production and to measure their environmental impact on a life cycle basis from cradle to grave.

Environmental sustainability, energy efficiency and uncertainty analysis of agricultural residue-based bioethanol production: A comprehensive life cycle assessment study

Bioethanol produced from agro-residue provides a sustainable alternative to fossil fuels, mitigating pollution, reducing waste, and promoting a circular economy. However, challenges arise in sustainable sourcing, resource conflicts, water quality concerns, and managing environmental footprints to maximize agro-residue-based bioethanol benefits. The environmental impacts, net energy ratio (NER), net energy value, water footprint, and uncertainties associated with bioethanol production from agro-residues are analyzed in this study. The analysis followed a cradle-to-gate approach using 1 L of bioethanol produced as a functional unit (FU), allowing for a direct comparison of the environmental performance of the different feedstocks. The result shows that rice straw-based bioethanol exhibited higher environmental impacts, particularly in terms of ecotoxicity, ionizing radiation, human toxicity, and ozone layer depletion, except for greenhouse gas emission, which is lowest for corn stover (0.37 kg CO2 eq. per FU) and highest for cassava straw (1.1 kg CO2 eq. per FU). Furthermore, the Cumulative Energy Demand analysis highlighted a significant reliance on fossil fuels from agricultural biomass throughout the bioethanol production process. The energy balance analysis shows that the agricultural residues are feasible for bioethanol production with NER of 1.20, 3.10, and 3.28 for rice straw, corn stover, and cassava straw, respectively. To enhance the accuracy and reliability of the LCA results, Monte Carlo simulation was employed to account for uncertainty and variability in the data. This methodology provides a better understanding of the impacts of bioethanol production, with a focus on sustainability and advancements in reducing our reliance on fossil fuels.

Cradle-to-gate analyses of biochar produced from agricultural crop residues by vacuum pyrolysis

Abstract Agricultural waste, if not managed efficiently, can pose significant environmental threats. Biochar production, a cost-effective solution, offers a potential to significantly reduce carbon dioxide emissions and thereby combat climate change. However, the environmental impact of this process is not uniform and varies depending on the agricultural residue used. These impacts, spanning the entire lifecycle from cultivation to disposal, underscore the necessity of a thorough assessment before biochar can be widely adopted for practical applications. This study employs a cradle-to-gate approach to evaluate the life cycle assessment (LCAs) of producing biochar from various agro-residues, such as rice husk, sugarcane bagasse (SB), and corn cob (CC). The LCA was conducted using SimaPro software, version 9.5.0.1, and the ReCiPe impact assessment method. The results indicate that CC cultivation has the highest impact across most categories, while rice husks exhibit higher water consumption (2.8 × 103 m3). Using diesel, electricity, and fertilizers significantly contributes to global warming potential (GWP). SB shows the most negligible impact during biomass cultivation. However, pyrolysis processes exhibit high implications on various indicators. Applying biochar to soil for carbon sequestration and improvement can reduce GWP. Sensitivity analysis demonstrates a notable reduction in GWP and cumulative energy demand, approximately 10%–24% and 4–11 MWh, respectively. Paddy cultivation and rice husk biochar production have a lesser environmental impact. Changing energy sources during biomass growth and biochar production significantly influences environmental factors.

Carbon and Energy Footprinting across Archetypes for U.S. Maple Syrup Production.

The production of maple syrup from sap requires extensive processing, which has traditionally led to significant energy inputs and greenhouse gas (GHG) emissions per gallon produced. Technology advancements, e.g., vacuum tubing sap collection systems, reverse osmosis (RO), and electric evaporators have changed the way syrup is produced, resulting in widespread variability in processing equipment and sugar-making operational decisions. This paper evaluates these complex operations through a cradle-to-retail gate carbon footprinting model and by capturing variability in a series of producer archetypes. By isolating energy and emissions impacts, we find that implementing RO has the largest reduction effect on energy (54-77%) and emissions (57-82%), depending on both production size and evaporator fuel (wood, fuel-oil, or electricity). Results also demonstrate the effect of production scale on cumulative energy demand (CED) and emissions per gallon of syrup, with small producers ranging from 333-1,425 MJ/gal and 27-118 kg CO2e/gal (61-90% biogenic on-site) for wood-fired operations and 18-65 kg CO2e/gal for oil-fired operations. Large producers ranged from 90-131 MJ and 3.5-7 kg CO2e/gal (electricity to oil-fired operations). Producers of all scales with the highest rates of electrification in their operations have the lowest GHG emissions and energy use per gallon of syrup produced.

Environmental benefits of valorising food waste into bio-based polyols for the production of polyurethane rigid foams

Under the global pursuit of sustainable development, waste streams are being recognised as renewable feedstocks to produce value-added products. Given this, food waste (FW) was explored to synthesise bio-based polyols to further develop polyurethane rigid foams (PURF). However, relevant environmental aspects are yet to be examined to support this biorefinery scheme as a green and sustainable solution. In this work, we examined the environmental performance associated with the production of PURF using polyols derived from a FW biorefinery scheme by life cycle assessment (LCA). Analysis was first conducted at the polyol level. Different allocation and offset options were examined to configure the LCA model. Based on mass allocation, compared with fossil-based production, the production of FW-derived polyols achieved reductions of 24.30 % and 34.19 % in global warming potential (GWP) and cumulative energy demand (CED), respectively. At the midpoint level, FW-derived polyols had reduced impacts on human carcinogenic toxicity, freshwater eutrophication, and fossil resource scarcity but caused additional burdens on freshwater and marine ecotoxicity. Key environmental hotspots at this level included diethylene glycol, ion exchange resin (epoxidation catalyst), and hydrogen peroxide. The lipid content in FW also played a significant role. It was demonstrated that reducing the use of enzymes for FW hydrolysis to a cost-effective level remarkably mitigated the overall impacts of FW-derived polyol production. At the next level, we examined the production of FW-derived PURF using the obtained polyols. When 70 % of the polyols were replaced with bio-based products, the resultant PURF production achieved a GWP and CED of 5.67 kg CO2eq and 110.66 MJ/kg, respectively. In general, FW-derived PURF leads to environmental benefits compared to fossil-based ones. However, isocyanate used for foam formulation was the dominant contributor, causing almost two-thirds of the total impacts. The flame retardant also caused considerable impacts. Through the systematic examination of FW-derived polyols and PURF, this study demonstrated that FW-derived PURF could benefit the sustainable development of FW biorefineries and bio-based plastic industries, while the identified environmental hotspots need to be further studied and replaced with greener substitutes. AcronymsUnlabelled TableCEDCumulative energy demandDEGDiethylene glycolDALYDisability-adjusted life yearsFWFood wasteGWPGlobal warming potentialLCALife cycle assessmentLCILife cycle inventoryMDIMethylene diphenyl diisocyanateNIPUNon-isocyanate polyurethanespMDIPolymeric 4,4′-methylene diphenyl isocyanatePURFPolyurethane rigid foamsPUsPolyurethanesTPhPTriphenyl phosphateTCPPTris(1-chloro-2-propyl) phosphate

Life Cycle Assessment of Blended Cement Product: A Case Study

Abstract Large-scale cement production has led to serious environmental issues since the process is energy and resource intensive. Moreover, the cement industry is one of the sources of anthropogenic CO2 emissions. As a matter of fact, in the Philippines, the CO2 emission increased by 88.23% in over a decade. Hence, this research conducted a life cycle assessment of blended cement products in a cement manufacturing facility in Bulacan, Philippines from cradle to gate. The research utilized functional units of one metric ton of clinker, and one metric ton of blended cement. For the life cycle assessment (LCA), SimaPro 9.3.0.3 software was employed, and the impact assessment was conducted using the IPCC 2021 Global Warming Potential (GWP) at a 100-year timeframe and the Cumulative Energy Demand Method. Results of the research showed that the baseline carbon footprint and cumulative energy demand for the clinker are 995 kg CO2-eqv and 4.74 x 103 MJ, respectively. Also, the baseline carbon footprint and cumulative energy demand for the blended cement are 760 kg CO2-eqv and 4.13 x 103 MJ, respectively. Further, the evaluation of the carbon footprint of clinker, and blended cement in this research is comparable with the results from similar studies, with slight variation on certain instances. The energy utilization in the production of clinker, and blended cement in this research is significantly lower than the result of other studies

Life cycle assessment and energy return of investment of nutritionally-enhanced snacks supplemented with Spanish quinoa

The trend in the consumption of unconventional, more nutritious foods is leading to the globalization and decentralization of their production, giving rise to the adaptation and innovation of traditional products to make them healthier and more sustainable. This article focuses on quinoa and aims to estimate the environmental impacts of its production adapted to the Spanish conditions and of potential derived snacks enriched with this pseudo cereal by applying conventional and nutritional life cycle assessment (LCA) methodologies. Besides, an exhaustive study of the energy flows by measuring the cumulative energy demand and the calculation of the energy return of investment (EROI) is carried out to assess the most impactful aspect of the processing industries. The application of cradle to gate LCA revealed that polluting emissions of Spanish quinoa are rather similar to those of the Andean grain, with an impact on climate change of 1.03 kg CO2 eq./kg. However, high resource footprints were obtained, for instance a water deprivation potential of 60 m3/kg due to the scarcity in this country. Besides, the consideration of a nutrient profile model as functional unit led to the conclusion that quinoa-based snacks are generally more environmentally sustainable than their conventional counterparts in terms of climate change, resources consumption or water degradation. EROI scores were relatively low for all options, with only between 1.77 and 4.35 % of the energy invested returned, which evidences the unsustainable agricultural practices and low efficiency of processing units. Based on this research, producers can reorient production systems in support of nature, and consumers are able to guide their choices towards improved eating patterns.

Comparative Life Cycle Assessment of Bacterial and Thermochemical Retting of Hemp.

The processes of hemp bast fiber retting, forming, and drying offer the opportunity for value-added products such as natural fiber-reinforced composites. A new process for the retting of raw bast fibers through enzyme-triggered self-cultured bacterial retting was developed in the lab-scale setup. This study focused on comparing the energy consumption and environmental impacts of this bacterial retting process with the thermochemical retting process currently widely used to obtain lignocellulosic fibers for composites. The gate-to-gate life cycle assessment (LCA) models of the two retting processes were constructed to run a comparison analysis using the TRACI (the tool for the reduction and assessment of chemical and other environmental impacts) method for environmental impacts and the cumulative energy demand (CED) method for energy consumptions. This work has demonstrated the advantages of the bacterial retting method from an environmental standpoint. The result of our research shows about a 24% gate-to-gate reduction in CED for bacterial retting and 20-25% lower environmental impacts relating to global warming, smog formation, acidification, carcinogenics, non-carcinogenics, respiratory effects, ecotoxicity, and fossil fuel depletion when compared to that of thermochemical retting.

Designing with building-integrated photovoltaics (BIPV): A pathway to decarbonize residential buildings

The ambitious targets set for greenhouse gas emissions and energy efficiency by 2050 demand a critical increase of building renovation rates. This challenge is shared by most Western nations, including Europe and Switzerland, where the current annual renovation rate stands at a mere 0.6 %. In this context, designing renovation strategies using building integrated photovoltaic (BIPV) components as a new building material is one of the most promising ways to achieve decarbonization of the building stock in an economical and environmentally efficient manner. To this end, building design teams are key, especially in promoting BIPV-based projects to their clients and taking this approach into account from the initial design phase where pivotal decisions with significant impact are made. This article illustrates the potential impact of specific choices in renovation processes on the overall building performance, considering a Life-Cycle Analysis/Cost (LCA/LCC) and multi-criteria analysis. It uses a 1970's residential building as case study, examining different refurbishment scenarios. Findings reveal that scenarios integrating BIPV can significantly enhance energy savings, achieving up to 122 % in energy efficiency gains, and can meet the 2050 targets for cumulative energy demand (CED) and global warming potential (GWP). Additionally, the most effective BIPV scenarios demonstrate economic viability with a payback period of 14–18 years and internal rates of return (IRR) between 5.3 % and 5.9 %. These results underscore the economic and environmental benefits of BIPV in building renovations and advocate for its broader adoption to achieve national and international climate goals.

Sustainable waste management: a comprehensive life cycle assessment of bioethanol production from agricultural and municipal waste.

Biofuels have emerged as a promising and eco-friendly alternative to conventional fossil fuels. Biofuel sourced from rice straw (RS) and municipal solid waste (MSW), which are abundant residues from agricultural and municipal activities, present a sustainable solution to address waste management challenges. Utilizing life cycle assessment, this study quantifies the environmental advantages by assessing the reduction in greenhouse gas emissions, energy consumption, and other environmental impacts linked with employing these waste materials for biofuel production. Employing a cradle-to-gate approach as the system boundary for bioethanol production, with the functional unit set as per liter of bioethanol produced, the analysis reveals that the global warming potential (GWP) for ethanol from MSW is 4.4 kg CO2 eq., whereas for RS, it is 2.1 kg CO2 eq. per functional unit. The total environmental impacts were primarily due to enzymatic hydrolysis and electricity consumption for ethanol production from MSW and RS. Despite advancements, fossil fuel consumption remains a potential energy source for biofuel production. The cumulative energy demand stands at 18.6 MJ for RS and 71.5 MJ for MSW per functional unit, underscoring the potential to significantly reduce overall impacts by transitioning to a more environmentally sustainable energy source. The uncertainty analysis acknowledges the inherent uncertainties associated with data, assumptions, and methodologies, highlighting the crucial need for ongoing research and updates to enhance the accuracy of future assessments. This analysis forms the foundation for well-informed decision-making, providing valuable insights for policymakers, industry stakeholders, and consumers.

Life cycle assessment of culture media with alternative compositions for cultured meat production

PurposeCultured meat is produced by cultivating animal cells in a bioreactor in a culture medium that provides nutrients and growth factors. Among other animal sera, fetal bovine serum (FBS) has traditionally been the most common used in the culture medium of mammalian cell cultures, i.e., 10% FBS medium that contains 10% FBS and 90% DMEM/F12 (v/v). As the aim of cultured meat is to replace livestock production, animal component-free culture media needs to be developed. MethodsWe analyzed the environmental impact of replacing the 10% FBS culture medium with serum substitutes, i.e., growth factors, Essential 8™, protein hydrolysates from egg-white, eggshell membrane, poultry residues, pork plasma, and pea concentrate, and Tri-basal 2.0 + ITS medium that contains fibroblast growth factor (FGF-2), fetuin, bovine serum albumin (BSA), and insulin transferrin selenium (ITS). Life cycle assessment with a cradle-to-gate approach was used to quantify global warming potential, freshwater and marine eutrophication, terrestrial acidification, land use, water consumption, fossil resource scarcity, particulate matter formation, cumulative energy demand, and ozone formation of preparing 1-L culture medium. Sensitivity analysis was conducted to examine the impact changes under various production conditions including variations in the impact allocation strategy, production location, and energy sourcing.Results and discussionThe 2% FBS medium (2% FBS, 96% DMEM/F12, and 2% growth factors (v/v)) reduced all environmental impacts where marine eutrophication had the highest reduction (77%), while land use was the least affected with a reduction of 6%. The Tri-basal 2.0 + ITS and protein hydrolysates media reduced most of the analyzed environmental impacts. Protein hydrolysates from egg-white had the lowest environmental impacts reducing 81% global warming potential, 28% water consumption, 59% fossil scarcity, 87% eutrophying emissions, 91% terrestrial acidification, 82% particulate matter, and 70% ozone formation, compared to FBS-containing medium. Land use and energy demand were reduced the most by 17 and 37%, respectively, when the 10% FBS medium was replaced with the Tri-basal 2.0 + ITS medium.ConclusionsChanging the input of FBS in culture media from 10 to 2% (v/v) reduced all studied environmental impacts. Further reductions were achieved when FBS was totally replaced by basal media DMEM/F12, Essential 8™, protein hydrolysates, and recombinant growth factors. Land use was the least reduced, as it was driven by starch extraction to produce glucose for the DMEM/F12 basal medium. Culture medium with protein hydrolysates from egg-white achieved the highest impact reductions compared with the FBS-containing medium.

Assessment of climate change impact and resource-use efficiency of lettuce production in vertical farming and greenhouse production in Finland: a case study

PurposeOur aim in this study was to examine lettuce production in vertical farming or in conventional greenhouse production in Northern European conditions from the perspective of climate change impact and environmental sustainability. Further, the goal was to identify practices and choices that could mitigate adverse effects and increase resource-use efficiency, allowing the development of more sustainable production systems.MethodsThis article provides new information of the environmental impacts of lettuce production in greenhouses and vertical farming in Finland, compared using the life cycle assessment (LCA) methodology. The impact categories used were climate change impact, cumulative energy demand, resource use of fossil energy sources, resource use of minerals and metals, land use, and water scarcity. The system boundaries covered the production chains from cradle to farmgate, including inputs in production, as well as direct emissions caused by fertiliser use and the onsite composting of organic waste. The environmental impacts of the two production systems with different energy scenarios were assessed: (1) a greenhouse either with average or renewable energy; and (2) vertical farming either with average or renewable energy and with or without waste heat recovery. The data for vertical farming were based on one Finnish production site and supplementary data for the construction materials. The greenhouse data were based on a previous LCA investigation of average Finnish lettuce production.ResultsThe climate change and all other impact categories were lowest for lettuce produced in vertical farming with renewable energy and waste heat recovery. The climate change impact was largest for lettuce produced in greenhouse with average energy use. For energy use and energy resource use, the impacts of vertical farming were lower than greenhouse production, but for mineral and metal use and water scarcity, the impact of vertical farming was higher for average energy use without heat recovery. Direct land and irrigation water use on the production sites in Finnish circumstances represented only a small share of total land-use and water-use impacts on both production methods.ConclusionPaying attention to the energy source and heat recovery, the environmental sustainability can be advanced in both vertical and greenhouse production systems.

Cumulative energy demand and environmental impact analysis in the manufacture of recycled fiber reinforced composites panels for use in truck bodies

ABSTRACT The reuse of fiber-reinforced composite materials has become increasingly important with the tremendous waste produced by aerospace, wind turbine blades, and automobile components. Recycling fiber-reinforced composites from parts at their end-of-life provides the benefit of reinforcing strength and integrity. The life cycle assessment (LCA) method has been widely used to examine the embodied energy (EE) and the environmental impact of the manufacturing process. Two different types of composite panels made via hand layup and compression molding are considered for a comparative LCA investigation using SimaPro software. Some panels are made with a mixture of 50% virgin glass fiber (GF) and 50% polyester resin. Others are produced with a mixture of 25% virgin GF, 25% shredded recyclates from wind turbine blade, and 50% of polyester resin. Panels from the recyclates termed Recycled Glass Fiber Reinforced Polyester (rGFRP) had 2.44% lower EE as compared to their counterparts vGFRP. Ozone depletion proved to be the greatest impact on the environment as regard to the manufacturing of rGFRP (4.38E–6 kg CFC-11eq). rGFRP panels manufacture generated 3.8% less greenhouse gas emissions than the vGFRP. LCA analysis suggests that the manufacture of panels for truck body/floor using recyclates from shredded wind turbine blades involves less energy use and has less environmental impact.

Comparing life cycle environmental impacts of food access and consumption pre- and during COVID 19 in New York State's Capital Region

The COVID-19 pandemic has significantly influenced household food shopping, food consumption, and food waste generation. However, the dietary environmental impacts for different income groups during COVID-19 remain unknown. To analyze dietary environmental impacts for various income groups, a process-based life cycle assessment (LCA) was conducted based on two electronic food access surveys implemented in the New York State's Capital Region during the COVID-19 pandemic and public and proprietary databases. We found that life cycle global warming potential, cumulative energy demand, acidification potential, and water resource depletion of per capital food consumption in the studied area tended to be lower during COVID-19 than pre-COVID-19. In contrast, life cycle eutrophication during COVID-19 was slightly higher than pre-COVID-19. The environmental impacts occurring at the food production stage were higher than those at the local transportation and waste disposal stages. The lowest income group had the lowest dietary environmental impacts due to their lowest food consumption of all the food categories. The second-highest income group had the highest dietary environmental impacts, since they consumed the most red meat which has a high impact intensity. This is the first study to our knowledge to investigate the differences in dietary environmental impacts among income groups during COVID-19.

Machine‐learning‐based demand forecasting against food waste: Life cycle environmental impacts and benefits of a bakery case study

AbstractRapid advancements in artificial intelligence (AI) are driving transformative changes in many areas, with significant environmental implications. Yet, environmental assessments for specific applications are scarce. This study presents an in‐depth life cycle assessment of “Foodforecast,” a machine learning (ML) cloud service designed to reduce food waste in bakeries by optimizing sales forecasting. It covers four impact categories: global warming, abiotic resource depletion, cumulative energy demand, and freshwater eutrophication. The assessment includes both the direct environmental impacts of the ML model and the underlying system hardware, as well as the indirect benefits of avoided bakery returns compared to traditional ordering methods, using real‐world case study data. In 2022, “Foodforecast” led to an average 30% reduction in bakery returns, primarily bread and rolls, according to sales reports. The associated environmental benefits significantly outweighed the system's direct impacts by one to three orders of magnitude across impact categories and return utilization scenarios. The study identifies support activities such as service maintenance during deployment as major direct impact factors, surpassing those from cloud compute for ML operations. Data processing and inference dominate the latter, while the much‐discussed ML training plays a minor role. The environmental consequences of AI are complex and dual sided. This case study demonstrates that AI might provide environmental benefits in certain contexts, yet results are constrained by methodological challenges and data uncertainties. There remains a need for further holistic LCAs across different ML applications to inform decision‐making processes and ultimately guide the responsible use of AI.

Analyzing sustainability in bread production: a life cycle assessment approach to energy, exergy and environmental footprint.

Bread production is a pivotal component of global nutrition. However, its extensive production imposes significant strain on resources and energy, resulting in substantial environmental consequences. This study focuses on a multidimensional assessment of the environmental sustainability of the bread life cycle as a case study in Iran. By integrating four life cycle assessment (LCA) methods, this research demonstrates a comprehensive analysis of environmental effects, energy consumption, and exergy demand in bread production. It also identifies the hotspot stages and inputs within the bread production chain. Eventually, it proposes strategies for mitigating the environmental impacts in line with sustainable development goals. Data collection involved questionnaires by face-to-face interviews. The LCA evaluation was conducted using SimaPro software. Sustainability analysis was assessed using four different methods: CML, ReCiPe, cumulative energy demand (CED), and cumulative exergy demand (CExD) method, from cradle to bakery gate. The CML method results indicate that the highest environmental impacts are associated with marine aquatic ecotoxicity (157.04 to 193.36 kg 1,4-DB eq), fossil fuel depletion (11.05 to 12.73 MJ), eutrophication (4.20 × 10-3 to 4.70 × 10-3 kg PO4-3eq), acidification (8.09 × 10-3 to 9.16 × 10-3 kg SO2 eq), and global warming (0.61 to 0.69 kg CO2 eq). The ReCiPe method highlights wheat production stages and gas consumption as the most significant contributors to damage in terms of human health, ecosystems, and resource consumption indicators. The CED method reveals that fossil energy accounts for over 97% of the energy consumed during the bread life cycle. Energy consumption per kilogram of bread ranges from 12.07 to 13.93 MJ. The CExD method for producing 1 kg of traditional bread falls between 32.25 and 35.88 MJ. More than 60% of this value is attributed to renewable resources of water used in irrigation during the wheat farming stage, while over 35% is linked to non-renewable fossil resources, primarily due to the consumption of natural gas in bakery operations. To assess the potential decrease in environmental emissions, a sensitivity analysis was performed, considering the effects of substituting natural gas with biogas and grid electricity with photovoltaic electricity in the bakery. Then, three improved scenarios were developed, each demonstrating effective reductions in environmental impacts, with the most remarkable decreases observed in marine aquatic ecotoxicity (55%) and fossil fuel depletion (44%). Overall, the findings demonstrate that Sangak bread production exhibits a more environmentally friendly profile than other types of bread. These results can guide decision-makers in the bread production industry towards implementing sustainable practices that prioritize resource efficiency and environmental conservation. Also, stakeholders can develop strategies to reduce the environmental impacts and work towards a more sustainable future.

Assessing the environmental impact of construction waste management in northern Thailand: An approach to estimate greenhouse gas emissions and cumulative energy demand

Over the past century, the world has grappled with the looming challenge of climate change, with the construction sector emerging as a significant greenhouse gas emitter. This research aims to estimate greenhouse gas (GHG) emissions, cumulative energy demand (CED), and associated disposal costs by applying life cycle assessment (LCA) principles to the disposal of construction materials in northern Thailand. The study employs LCA as the analytical method, focusing on the disposal of concrete, steel, and wood waste from residential construction projects. The life cycle inventory analysis investigates waste management practices, including on-site landfilling, recycling, and transportation with an average distance of 30 km. The findings reveal that concrete waste is the primary contributor, with transportation playing a pivotal role. In the conventional case, total GHG emissions reach 38.624 kgCO2eq/m2, with CED at 12.991 MJ/m2 and disposal costs totaling 420.97 THB/m2. Three waste management scenarios are explored: Scenario 1 (50% on-site landfilling, 50% reuse/recycling), Scenario 2 (75% on-site landfilling, 25% transportation landfill), and Scenario 3 (100% on-site concrete landfilling, 100% steel reuse/recycling, 100% wood waste landfilling). Scenario 3 shows a significant 20.3% reduction in GHG emissions, a 90.5% decrease in CED, and a disposal cost reduction of 20.9% compared to the conventional case. This study underscores the importance of strategic waste management decisions, highlighting the potential of sustainable practices to foster an eco-friendly construction sector. Its findings offer valuable insights and recommendations, advocating for refined strategies like prioritizing recycling, optimizing transportation, and minimizing incineration to effectively reduce emissions and promote environmental responsibility in construction.

How will manufacturing capacity additions in China and North America affect the carbon footprint of silicon photovoltaics?

Global annual PV installation is expected to increase from 150 GW in 2021 to 820 GW in 2030 to reach net zero emissions by 2050. Electricity production from PV generates almost zero carbon emissions, but the emissions from the manufacturing phase are nonnegligible. While most installed PV modules in the US are imported from China, manufacturers are expanding the manufacturing capacity in North America to reduce reliance on Chinese PV modules. Although it has been commonly perceived that the North American modules would have a lower environmental footprint than Chinese ones, the effect of capacity expansions and regional impact considering where each component is produced has yet to be fully understood. This study aims to compare the carbon footprint and cumulative energy demand of PERC modules manufactured in China and North America based on the expected 2024 manufacturing capacity additions. We develop PV manufacturing scenarios to perform life cycle assessment (LCA) for the first time considering the regional manufacturing capacity, partnerships between suppliers and manufacturers, and regional electricity grids, while previous PV LCA studies evaluated the national average production. The carbon footprint of China's PERC modules for monofacial and bifacial designs, when using the national average grid, is 517 and 412 kg CO2eq/kWp, respectively. In comparison, the GWP of modules produced in North America is 22.0–22.2 % lower than in China, a difference attributed to the lower carbon footprint of electricity grids. When considering where each component is made, the GWP increases by 1.5 % in China compared to the national average. This difference arises because most of China's solar manufacturing facilities are in regions with higher carbon intensity grids than the national average. Solar manufacturers can reduce the carbon footprint of their products by changing manufacturing locations or increasing the share of renewable sources for manufacturing. We find that both China- and North America-made PERC modules meet the Electronic Product Environmental Assessment Tool (EPEAT) low carbon solar criteria (630 kg CO2eq/kWp). However, to meet the ultra-low carbon solar criteria (400 kg CO2eq/kWp), a significant share, approximately 60 % for China and 15 % for North America, of the total electricity supply must be sourced from renewable energy in addition to the existing grid. This study identifies the significant impact of manufacturing locations on the overall carbon footprint of PV modules. It is important to consider production locations by stage and the regional electricity supply when developing the carbon assessment methodology of PV modules. Otherwise, manufacturers may take advantage of assessing carbon footprint using the country's average grid while producing products in dirty grid regions.

Advanced membrane photobioreactors in algal CO2 biofixation and valuable biomass production: Integrative life cycle assessment and sustainability analysis

This paper presents and discusses the life cycle assessment (LCA) of CO2 capture and of microalgae biomass production in an advanced membrane photobioreactor (mPBR) system for climate change mitigation and the generation of renewable energy carriers. The study aims to evaluate environment-relevant aspects and propose alternative solutions for optimization of the environmental sustainability of the biologically based technology. The mPBR biotechnology, composed by an adsorption column, coupled with a reactor with a self-forming dynamic membrane (SFDM) module inside, was used for the experimental activities. Four principal operational steps (cultivation, harvesting, cleaning and drying) at three different scenarios were investigated and evaluated in terms of energy demand and environmental impacts amongst the boundary conditions based on the “cradle-to-gate” model. The ReCiPe 2016 and the Cumulative Energy Demand (CED) methodologies were applied for the assessment. In addition, a sensitivity analysis has been conducted.The results showed that across the operational phases, algae cultivation and drying are the most phases that lead to greater environment-relevant aspects. Analysing different scenarios, the use of wastewater as a source of nutrients for algae (Chlorella vulgaris species), with respect to the use of synthetic nutrients with the same biomass productivity, resulted to be the most feasible and attractive alternative in terms of environmental impact. Finally, the sensitivity analysis highlighted how the environmental performance can be significantly improved by enhancing the productivity and the harvesting rate.The study provides important information to the different actors involved in the biotechnologies sectors, to be able to build and/or evaluate different production options with a holistic and proactive approach, in order to optimize the technologies with a view to maximize its environmental sustainability.

Towards circularity in aquaculture systems: Environmental impact of Hermetia illucens meal inclusion in diets for rainbow trout reared in aquaponics

In advancing towards more sustainable aquaculture, the inclusion of insect meals in aquafeeds has significant potential to increase circularity and reduce environmental impacts, especially in aquaponics. Nevertheless, there is a lack of information regarding the environmental performance of these innovative feeding and management solutions. This study assessed the environmental impact associated with the dietary inclusion of Hermetia illucens (HI) meal (0%, 6% and 12%) in diets for rainbow trout (Oncorhynchus mykiss) reared in a low-tech aquaponic system characterised by nine independent experimental units (6.06 kg/m3 of fish and 14 strawberry plants per unit). A cradle-to-gate attributional life cycle assessment model was used to consider the impacts related to the whole aquaponic system (AQ-FISH) and those only related to the production and use of the aquafeed (AQ-FEED). The impact categories were 100-year global warming (kg CO2-eq) – with (GWP_LUC) and without (GWP) the emissions associated with land-use change (LUC), acidification (AP, g SO2-eq) and eutrophication (EP, g PO4-eq) potentials, cumulative energy demand (CED, MJ), land occupation (LO, m2/y) and water scarcity (WS, m3-eq). The functional unit was a 1 kg live weight increase of rainbow trout. Data originated from a previous 76-d fish performance trial. Data regarding HI meal were derived from an interview with the manufacturer. An economic method was used to partition the impacts between HI meal, HI fat and the frass (exhausted substrate). The effect of the HI meal inclusion level on the AQ-FISH and AQ-FEED impact values was tested using one-way analysis of variance.A 1 kg live weight increase of rainbow trout reared in the aquaponic system (AQ-FISH) produced 15.6 kg CO2-eq (GWP), 18.3 kg CO2-eq (GWP_LUC), 67 SO2-eq and 55 g PO4-eq and used 354 MJ, 3.5 m2/y and 311 m3-eq. The dietary inclusion of HI meal did not affect the AQ-FISH results, except for CED (+2%–5%). When considering the impact resulting from feed production (AQ-FEED), the inclusion of HI meal did not affect GWP_LUC, AP, EP and LO, but it negatively affected GWP (+13%–26%) and CED (+34%–68%). Results from AQ-FISH and AQ-FEED scenarios showed low sensitivity to the methodological choices. Overall, our findings suggest that general improvements to reduce the environmental impact associated with rainbow trout production in aquaponics should be concurrently directed towards both the system setting and management, as well as towards the HI meal production process, with a particular emphasis on enhancing energy efficiency. To minimise potential trade-offs, especially from an environmental perspective, future studies should prioritise the investigation of energy use and greenhouse gas emission associated with feed production. This requires a thorough evaluation of all changes in the diet formulation resulting from the inclusion of a new ingredient.