Life cycle assessment as a prospective tool for sustainable agriculture and food planning at a local level

Owing to the far-reaching environmental consequences of agriculture and food systems,such as their contribution to climate change,there is an urgent need to reduce their impact.International and national governments set sustainability targets and implement corresponding measures.Nevertheless,critics of the globalized system claim that a territorial administrative scale is better suited to address sustainability issues.Yet,at the subnational level,local authorities rarely apply a systemic environmental assessment to enhance their action plans.This paper employs a territorial life cycle assessment methodology to improve local environmental agri-food planning.The objective is to identify significant direct and indirect environmental hotspots,their origins,and formulate effective mitigation strategies.The methodology is applied to the administrative department of Finistere,a strategic agricultural region in North-Western France.Multiple environmental criteria including climate change,fossil resource scarcity,toxicity,and land use are modeled.The findings reveal that the primary environmental hotspots of the studied local food system arise from indirect sources,such as livestock feed or diesel consumption.Livestock reduction and organic farming conversion emerge as the most environmentally efficient strategies,resulting in a 25%decrease in the climate change indicator.However,the overall modeled impact reduction is insufficient following national objectives and remains limited for the land use indicator.These results highlight the innovative application of life cycle assessment led at a local level,offering insights for the further advancement of systematic and prospective local agri-food assessment.Additionally,they provide guidance for local authorities to enhance the sustainability of planning strategies.

Techno-Economic Analysis and Life Cycle Assessment for the Typical Intermediate Crude Refining Scheme in China

The integration of refinery and petrochemical units(IRPUs)has become an inevitable choice for the sustainable development of petrochemical industry.The utilization efficiency of petroleum resources could be improved obviously through IRPUs.However,integrating economic and environmental impacts into the model of IRPUs is still a grand challenge.Herein,a model called TEA-GHG-OPWM(Techno-Economic Analysis and GreenHouse Gases Oriented Plant-Wide Model)has been established on Aspen HYSYSTM platform to calculate the energy consumption,the technoeconomic performance,and the GHG emissions for two different kinds of schemes,viz,:VRHCU(Vacuum Residue Hydrocracking Unit)and VRDS-RFCC(Vacuum Residue Desulfurization and Residue Fluid Catalytic Cracking).Furthermore,a novel processing pathway named VGOHDT-HTMP-DC(Vacuum Gas Oil Hydrotreating,Hydrogenation and TMP coupling process and Delayed Coking)has also been developed to find methods to improve the economic performance based on a ten-million-CNY output value(TMYOV)and a reduced GHG emissions.Our results demonstrate that VRHCRU could consume more energy and emit more GHG(877.11 t of CO2 eq·TMYOV^-1·h^-1)than VRDS-RFCC(817.03 t of CO2 eq·TMYOV^-1·h^-1)and VGOHDT-HTMP-DC(721.96 t of CO2 eq·TMYOV^-1·h^-1),while obtaining a higher mass yield of petrochemicals.The VGOHDT-HTMP-DC process exhibits the lowest feedstock consumption,hydrogen consumption,energy consumption,and GHG emissions,indicating that VGOHDT-HTMP-DC has both well economic and environmentally friendly performance.

Environmental Analysis of Packaging for Soft Drinks Using the Life Cycle Assessment Methodology

The knowledge of a product＇s life cycle is the first step on the search of sustainable development. The life cycle assessment （LCA） is an important method because it allows an environment accounting, where the extraction of natural resources and energy of the nature are considered and the ＂returns＂ to the same one and allows in evaluating relative potential the environment impacts generated. The present work had as objective to make an analysis of material and energy flows of the life cycle of three types of packaging for soft drinks： glass bottles of 390 mL, aluminum cans of 350 mL, and bottles of PET of 2,000 mL. The study considered processes since the extraction of raw materials for production of the packaging until the stages of recycling, after the consumption of the soft drink. For the research, an inventory analysis followed the LCA methodology. The main critical points of generation of negative environmental impact during the life cycle of each packaging had been the identified and quantified data in this study. The consumption of natural resources like water and other raw materials and energy, the generation of atmospheric emissions, solid wastes and wastewaters had been the analyzed categories. The results showed that, in accordance with the scenes and defined variables, the most important conclusion was that the bottle of glass presented a less favorable scene to the environment in comparison with other packaging.

Life cycle environmental impact assessment of biochar-based bioenergy production and utilization in Northwestern Ontario,Canada

Biochar-based bioenergy production and sub- sequent land application of biochar can reduce greenhouse gas emissions by fixing atmospheric carbon into the soil for a long period of time. A thorough life cycle assessment of biochar-based bioenergy production and biochar land application in Northwestern Ontario is conducted using SimaPro Ver. 8.1. The results of energy consumption and potential environmental impact of biochar-based bioenergy production system are compared with those of conventional coal-based system. Results show that biocbar land application consumes 4847.61 MJ per tonne dry feedstock more energy than conventional system, but reduces the GHG emissions by 68.19 kg CO2e per tonne of dry feed- stock in its life cycle. Biochar land application improves ecosystem quality by 18 %, reduces climate change by 15 %, and resource use by 13 % but may adversely impact on human health by increasing disability adjusted life years by 1.7 % if biomass availability is low to medium. Replacing fossil fuel with woody biomass has a positiveimpact on the environment, as one tonne of dry biomass feedstock when converted to biochar reduces up to 38 kg CO2e with biochar land application despite using more energy. These results will help understand a comprehensive picture of the new interventions in forestry businesses, which are promoting biochar-based bioenergy production.

Development of a Disaggregated Hybrid Model for Life Cycle Assessment and De-manufacturing

The de-manufacturing stage is an overlooked component of most current LCA （life cycle assessment） methodologies. Most of the current LCA techniques do not fully account for the usage of the product and end of life aspects. This paper introduces a comprehensive methodology that takes strong consideration of the inventory costs of use and end of life of the functional unit by combining manufacturing and de-manufacturing into the centerpiece of the hybrid analysis. In order to obtain this goal, a new disaggregated model was developed by enhancing current LCA hybrid methods related to life cycle inventory compilations. The new methodology is also compared to existing methodologies.

Life Cycle Assessment and Life Cycle Cost of Waste Management—Plastic Cable Waste

The main driver for recycling cable wastes is the high value of the conducting metal, while the plastic with its lower value is often neglected. New improved cable plastic recycling routes can provide both economic and environmental incentive to cable producers for moving up the “cable plastic waste ladder”. Cradle-to-gate life cycle assessment, LCA, of the waste management of the cable scrap is suggested and explained as a method to analyze the pros and cons of different cable scrap recycling options at hand. Economic and environmental data about different recycling processes and other relevant processes and materials are given. Cable producers can use this data and method to assess the way they deal with the cable plastic waste today and compare it with available alternatives and thus illuminate the improvement potential of recycling cable plastic waste both in an environmental and in an economic sense. The methodology applied consists of: cradle-to-gate LCA for waste material to a recycled material (recyclate);quantifying the climate impact for each step on the waste ladder for the specific waste material;the use of economic and climate impact data in parallel;climate impact presented as a span to portray the insecurities related to which material the waste will replace;and possibilities for do-it-yourself calculations. Potentially, the methodology can be useful also for other waste materials in the future.

Prospective life cycle assessment of CO_(2)conversion by photocatalytic reaction

CO_(2)conversion is gradually seen as a better way for society to effectively use carbon sources and avoid climate crisis associated with fossil CO_(2)emissions.And the decision to deploy CO_(2)technology scale should be relied on its environmental impact.In this work,life cycle assessment model evaluates the environmental performance of CO_(2)conversion by photocatalytic reaction process with two different catalysts(NiAl-LDH and Co-ZIF-9).Six impact categories considered in this analysis,including climate change,acidification potential,depletion of abiotic resources,eutrophication potential,ozone layer depletion potential,and photochemical oxidation potential.Results indicated that CO_(2)conversion with Co-ZIF-9 photocatalyst has a better environmental impact than the NiAl-LDH photocatalyst route.Moreover,the Co-ZIF-9 catalyst scenario also has a lower total environmental burden than the conventional CO production route.Sensitivity analysis shows that recycle performance of the catalyst is highly sensitive to the production process in two scenarios.This study could provide a framework for robust decisions in CO_(2)conversion by photocatalytic reaction,which is useful for policymakers to decide the feasibility of industrialization.

Carbon emission analysis of a residential building in China through life cycle assessment

In this paper, a quantitative life cycle model for carbon emission accounting was developed based on the life cycle assessment （LCA） theory. A residential building in Sino-Singapore Tianjin Eco-city （Tianjin, China） was selected as a sample, which had been constructed according to the concept of green environmental protection and sustainable development. In the scenario of this research, material production, construction, use and maintenance, and demolition phases were assessed by building carbon emission models. Results show that use and maintenance phase and material production phase are the most significant contributors to the life cycle carbon emissions of a building. We also analyzed some factor influences in LCA, including the thickness of the insulating layer and the length of building service life. The analysis suggest that thicker insulating layer does not necessarily produce less carbon emissions in the light of LCA, and if service life of a building increases, its carbon emissions during the whole life cycle will rise as well but its unit carbon emission will decrease inversely. Some advices on controlling carbon emissions from buildings are also provided.

Carbon emissions from buildings based on a life cycle analysis:carbon reduction measures and effects of green building standards in China

Carbon emissions from buildings account for approximately half of China’s total social carbon emissions.Focusing only on the carbon emissions of building operation tends to neglect the carbon emissions of other related parts of the building sector,thus slowing down the progress of carbon peaking in the building sector.By applying life-cycle analysis to calculate carbon emissions throughout the building’s life cycle,the performance of carbon emissions at each stage of building materials,construction,operation and end-of-life demolition can be identified,so that carbon reduction strategies in building design can be selected..This paper constructed a method for calculating the carbon emissions of green buildings in whole-building life cycle,and conducted a summary analysis of the carbon emissions of 33 projects that were awarded green building certification.The study found that the Chinese Assessment Standard for Green Buildings has a significant effect on reducing the carbon emissions of buildings in whole-building life cycle.Compared with the current average operational carbon emissions of buildings in China,the carbon intensity of green public buildings is 41.43%lower under this standard and the carbon intensity of green residential buildings is 13.99%lower.A carbon correlation analysis of the provisions of the current Chinese Assessment Standard for Green Buildings was conducted,comparing the changes in the carbon intensity of buildings before and after the revision of the standards.The study concluded that the new version of the standards has a greater impact on public buildings than residential buildings,the requirement of carbon emission reduction in the production stage of building materials is strengthened in terms of carbon emission during the whole-building life cycle.This study addresses the current problem of unclear carbon emission reduction effect of green buildings.

Exergy Efficiency and Environmental Impact of Electricity of a 620 MW-Natural Gas Combined Cycle

In the first part of this investigation, a Natural Gas Combined Cycle (NGCC) producing 620 MW of electricity was simulated using the commercial software Aspen Hysys V9.0 and the Soave-Redlich-Kwong (SRK) equation of state. The aim of this second part is to use exergy-based analyses in order to calculate its exergy efficiency and evaluate its environmental impact under standard conditions. For the exergy efficiency, the performance index under investigation is the exergy destruction ratio (yD). The results of the study show that the combustor is the main contributor to the total exergy destruction of the power plant (yD = 24.35%) and has the lowest exergy efficiency of 75.65%. On the other hand, the Heat Recovery Steam Generator (HRSG) has the lowest contribution to the exergy destruction (yD = 5.63%) of the power plant and the highest exergy efficiency of 94.37%. For the overall power plant, the exergy efficiency is equal to 53.28%. For the environmental impact of the power plant, the relative difference of exergy-related environmental impacts (rb) is utilized as the performance index for each equipment of the plant and the environmental impact of a kWh of electricity (EIE) is used to represent the performance index of the overall power plant. In agreement with the exergy analysis, the results indicate that the combustor and the HRSG have respectively the highest (rb = 32.19%) and the lowest (rb = 5.96%) contribution to the environmental impact. The environmental impact of a kWh of electricity of the power plant is 34.26 mPts/kWh (exergy destruction only), and 34.42 mPts/kWh (both exergy destruction and exergy loss).

水力发电生命周期评价及碳足迹区域化分析

基于生命周期评价方法,对我国典型水电站水力发电生命周期碳足迹及其他环境影响进行了评估,并分析讨论了不同区域水力发电碳足迹的差异性及原因。结果显示,三峡水电站单位水电碳足迹(以CO_(2)当量计)为12.7 g/(kW·h),主要来源于运行阶段,造成其他环境影响的主要阶段为土建工程阶段,其次为机电设备制造阶段;我国不同省级行政区单位水电碳足迹差距较大,与全国平均值相差±20%以上的省级行政区有24个;各省级行政区运行阶段碳足迹占比为47.94%~96.82%,占比超过80%的省级行政区有19个。研究结果可以为我国及省级发电清单编制与电网结构调整提供数据支撑。

基于生命周期法的生鲜农产品冷链物流绿色度评价

随着国家节能减排政策的深入,生鲜冷链作为能耗较高的物流产业,其绿色性引起了人们的重视。文章基于生鲜农产品冷链物流的全生命周期分析其各阶段的绿色性,以各阶段碳排放量和资源利用率为指标建立绿色度评价体系,并以番茄为例,基于生命周期法的计算数值,采用熵权法进行权重计算,进而用灰色关联度法进行绿色度评价。评价结果表明,生鲜农产品运输过程的损耗是对绿色度影响最大的因素,其次是车辆的能源利用率和货物的实载率。另外,水路运输的碳排放量远低于公路运输,但受限于地理条件和运输时间。针对评价结果,给出了提高生鲜农产品冷链物流绿色度的建议,为减少碳排放量提供了改进方向。

Life cycle assessment of urban uses of biochar and case study in Uppsala,Sweden

Biochar is a material derived from biomass pyrolysis that is used in urban applications.The environmental impacts of new biochar products have however not been assessed.Here,the life cycle assessments of 5 biochar products(tree planting,green roofs,landscaping soil,charcrete,and biofilm carrier)were performed for 7 biochar supply-chains in 2 energy contexts.The biochar products were benchmarked against reference products and oxidative use of biochar for steel production.Biochar demand was then estimated,using dynamic material flow analysis,for a new city district in Uppsala,Sweden.In a decarbonised energy system and with high biochar stability,all biochar products showed better climate performance than the reference products,and most applications outperformed biomass use for decarbonising steel production.The climate benefits of using biochar ranged from−1.4 to−0.11 tonne CO_(2)-eq tonne−1 biochar in a decarbonised energy system.In other environmental impact categories,biochar products had either higher or lower impacts than the reference products,depending on biochar supply chain and material substituted,with trade-offs between sectors and impact categories.However,several use-phase effects of biochar were not included in the assessment due to knowledge limitations.In Uppsala’s new district,estimated biochar demand was around 1700 m^(3)year^(−1)during the 25 years of construction.By 2100,23%of this biochar accumulated in landfill,raising questions about end-of-life management of biochar-containing products.Overall,in a post-fossil economy,biochar can be a carbon dioxide removal technology with benefits,but biochar applications must be designed to maximise co-benefits.

水溶液体系构建超疏水木材及其环境影响

木材表面富含羟基,易吸水变形、腐烂以及机械强度下降。因此,采用湿化学法在水溶液体系中构建一种纳米气相二氧化硅和十六烷基三甲氧基硅烷的超疏水涂层。结果表明:该涂层能够在木材表面形成微纳米结构,有效减少水的渗透,提高木材的抗湿性能。与传统的有机溶剂相比,使用水作为溶剂,可以降低对环境的影响。通过对纳米气相二氧化硅和十六烷基三甲氧基硅烷的不同配比和改性量的研究,优化木材疏水改性方案。为了定量分析在水溶液体系时,制备的超疏水木材的环保性,采用生命周期评估的方法,通过收集制备流程中的能耗、物耗数据,与其他三种典型的超疏水木材制备方案进行对比分析,评估其环境友好性,并对各方案进行敏感度分析,得出影响其环境性能的主要因素。计算结果表明:含重金属元素的化学品和电力消耗是环境影响的主要因素。

基于生命周期的我国畜禽养殖业碳排放核算

针对我国畜禽养殖业目前碳排放核算方法学的研究相对缺乏,难以满足核算实践需求的问题,参考联合国政府间气候变化专门委员会(IPCC)国家温室气体清单指南以及生命周期评价(LCA)的相关核算方法,结合国内畜禽养殖业文献调研Meta分析数据和Ecoinvent数据库中相关数据,对排放因子等重新确定缺省值或者参考值,构建出从畜禽“饲养-清粪-存储-粪污处理”全生命周期的养殖业碳排放核算方法.结果表明,畜禽养殖业碳排放主要来源于粪污处理及能源消耗环节,对于反刍动物来说,饲喂环节肠道发酵产生的排放为最主要来源.通过误差传递方程分析该方法不确定性较低,该方法可实现对我国畜禽养殖业碳足迹进行科学的估算,并为减排技术的筛选及减排潜力评估进行理论支撑.

隧道工程建设碳排放特征与减碳潜力分析

为明晰隧道建设碳排放强度及贡献,指导隧道建设低碳转型,基于生命周期评价理论和排放因子法对公路隧道碳排放特征及不同情景下减碳潜力进行量化分析。研究结果表明:公路隧道建设碳排放强度平均值为3.437万t CO_(2)eq/km,材料生产、现场施工机械及场内材料转运碳排放贡献率分别为88.6%、9.2%和2.2%。碳排放来源主要集中于少数材料和机械,其中水泥、钢筋、冷轧带肋钢筋网、空气压缩机、自卸汽车、轴流式通风机、装载机需要进行重点管控。洞身开挖、洞身衬砌、仰拱、洞内路面碳排放强度较高需重点开展设计施工低碳优化,仰拱、洞身开挖碳排放强度与IV、V级围岩长度呈显著正相关。情景分析得到水泥低碳替代可减少1.83%~10.92%的材料生产碳排放,钢铁低碳替代可减少0.75%~5.99%的材料生产碳排放,电动化工程机械替代可减少3.48%~17.40%的场内运输碳排放和0.5%~2.53%的现场施工机械碳排放。

综合能源生产单元的全生命周期碳足迹评价与技术经济性评估

综合能源生产单元(integrated energy production unit,IEPU)通过耦合可再生能源制氢与火电碳捕集技术,制备易于储运的绿色燃料,在协调解决可再生能源消纳、碳利用及氢能储运等问题方面具有良好的应用前景。为定量评价IEPU的技术经济性与降碳潜力,该文通过构建IEPU工艺流程的仿真模型,模拟风电制氢、甲醇合成及压缩提纯等关键过程,建立多能流与物料流数据的全生命周期清单,进行碳足迹评价,并指出进一步碳减排的可行路径;通过对能量效率、电流密度等技术参数及风电价格、碳税等经济参数进行灵敏度分析,开展不同技术经济性背景下的经济性评估,探究IEPU的盈利条件。碳足迹评价表明,年产39万t绿色甲醇IEPU的全生命周期净碳减排量达5.88万t。技术经济性评估表明,在良好的技术经济性背景下,当风电售价降低至0.21元/(kW×h),基于IEPU生产的绿色甲醇成本可与传统甲醇生产工艺相当。

基于全生命周期评价的风光制氢综合系统容量配置优化研究

风光互补发电制氢是促进风光资源就地消纳、减少弃风弃光的重要技术途径。然而风光出力的波动性与系统设备复杂性也对风光制氢系统的容量优化配置决策提出了挑战。为此基于全生命周期评价方法,将平准化制氢成本、单位氢气碳排放强度与系统能量损失率作为优化目标,结合改进的NSGA-Ⅲ多目标优化算法,构建了年产2万t氢气的离网型风光制氢系统容量配置优化模型,并进一步分析了系统碳排放与经济性收益。研究结果表明,结合内蒙古某地区风光资源特征,经优化后系统平准化制氢成本为25.88元/kg,单位制氢碳排放量为0.59 kg/kg,同时全年风光利用率提升至91.09%,风光制氢系统的资源得到了高效利用。同时,结合全生命周期碳排放分析计算,系统碳排放总量为25.03万t,与典型煤制氢技术相比,单位制氢的碳减排量降低了97.05%。研究成果将为开展风光制氢综合利用提供了有益参考。

文献计量分析污水处理领域生命周期评价的研究热点趋势分析

生命周期评价(LCA)作为环境管理的重要工具,在污水处理领域得到广泛应用以全面评估处理效果。本研究运用文献计量学方法,通过Citespace和Vosviewer软件对Web of ScienceTM核心合集数据库中相关文献进行量化分析,涵盖1997年至2022年,期间共发布1 701篇论文,显示出年度递增趋势。中国为主要发文国,但相比之下平均引用率较低。Feijoo, Gumersindo团队发文最多,而Chong Mengnan团队发表的综述文章在该领域影响最大,引用次数达3 549次。该领域的研究热点聚焦于污水污泥处理与水处理的可持续性。未来研究将继续探讨如何通过LCA改进水处理工艺,优化能耗和环境效益。

基于混合生命周期评价的我国绿色航空器碳排放比较研究

为准确核算绿色航空器生命周期二氧化碳排放,并评估其减排效果,构建了将过程分析与投入产出分析相结合的混合生命周期评价模型,用于核算生物质能航空器、电动航空器以及氢能航空器的生命周期碳排放,并与传统航空器进行比较。结果发现,采用风电制氢驱动的航空器在全部绿色航空器中碳排放最低,仅为674.21 g/(t·km)。灰氢驱动的航空器碳排放最高,达到1 724.12 g/(t·km)。这说明燃料来源对航空器的“绿度”至关重要,若以化石能源制氢或发电驱动航空器,尽管运行过程不产生直接排放,但其排放却转移至上游产业链。总体上,绿色航空器减碳效果较好。与传统航空器相比,氢能航空器、生物燃料航空器和电动航空器可分别减少25%,20%和10%的二氧化碳排放。