Generic Life Cycle Assessment Research Articles

Ecological Potential of Building Components in Multi-Storey Residential Construction: A Comparative Case Study between an Existing Concrete and a Timber Building in Austria

With the introduction of energy-efficient buildings, the importance of embodied energy in new buildings has become increasingly relevant to minimising the impact of climate change. This study compares two existing four-storey residential buildings: one building has a reinforced concrete (RC) structure and the other has a timber structure. The study’s aim is to find out which building components are responsible for the largest embodied impacts and whether there are differences between the two construction methods. The specificity of the wooden building is the combined use of solid and lightweight timber elements. The methodology consists of a general life cycle assessment (LCA) and a more detailed analysis of the product stage using the eco2soft software. The heating and cooling energy demand was calculated using the WUFI Plus software with recent regional climate data sets. The results show that for both types of construction in multi-storey buildings, it is not only the superstructure that needs to be considered, but also the floor structures, which have a major influence on the embodied impact. The timber building requires less energy to maintain the indoor climate within the set temperatures. As climate change has progressed rapidly in Austria in recent years, it is recommended that the standards for climate models be updated more quickly to allow realistic prediction of thermal comfort at the design stage.

Environmental life cycle assessment of recycling technologies for ternary lithium-ion batteries

To combat climate change, the transition to electrification has become a major trend in the transportation sector. However, the increasing growth in electric vehicles leads to a serious challenge to the waste management of retired power batteries. With the emergence of various recycling technologies, there is widespread concern about which ones are environmentally friendly. Consequently, a general life cycle assessment model is developed, which covers the whole process of production, using and recycling of ternary lithium-ion battery. China is taken as a case here, which is the largest electric vehicle market in the world. With the overall comparison of 5 different recycling technologies, the key links and main contributing factors to reduce the environmental impacts are further identified. Eventually, relevant decision-making supports for managing the end-of-life ternary lithium-ion power batteries are provided.

Circularity of water - good for conscience or the environment? A deeper look into the water footprint of factories.

Water plays an indispensable role in factories and is needed for a diversity of purposes. The circular use of water is an often-found approach nowadays which refers to the multiple internal recycling of water in factories before releasing it back to the environment. The intention behind that is clear and good – but the question is whether this is actually beneficial from an environmental perspective? This paper aims at providing a more detailed look into that important topic while analyzing efforts and benefits of water circularity. A generic life cycle assessment (LCA) model is presented and different industrial related scenarios serve as a base for deriving deeper and transferable insights into environmentally sustainable water management in factories. For the target objective water consumption, the recycling rate is of limited relevance as it only influences water use (withdrawal) but not the decisive evaporation rate. In a similar way, freshwater deprivation impacts resulting from water consumption (evaporation) depend on the location of the factory and the local scarcity – but not on recycling rates. Also for the global warming potential (GWP), the recycling rate is of limited relevance, as waste water treatment (WWT) is the decisive factor here. In cases in which the internal WWT causes more environmental efforts than municipal WWT and in which a relevant share of water is withdrawn from groundwater, an increasing recycling rate can reduce the depletion of groundwater resources – but causes higher carbon emissions. Depending on local scarcity and carbon intensity of electricity mixes, this can be justified but trade-offs need to be considered.

Plastic packaging substitution in industry: variability of LCA due to manufacturing countries

The raising environmental concerns related to fossil fuel-based plastic packaging resulted in policy efforts for reducing their use and introducing bio-based materials. However, the availability of bio-based material suppliers may be currently limited. At the industrial level, Life Cycle Assessment (LCA) can provide decision support to companies willing to substitute fossil fuel-based with bio-based plastic packaging. In this context, a detailed modelling of the plastic supply chain can markedly alter the LCA results and the consequent interpretation. The present work is based on preliminary results from the Italian project “Plastic New Deal”, which aims to support small enterprises on substituting fossil fuel-based plastic with other materials. The goal of this study is to investigate the variability of LCA results related to the substitution of fossil fuel-based low-density polyethylene (LDPE) with bio-based LDPE (bio-LDPE) and polylactic acid (PLA), used as film for packaging. A total of 11 scenarios was built, modelling the country of plastic manufacturing and type of feedstock. LCA results of bio-based plastics by country vary up to +165% and -95% with respect to the average, which is much higher than the one of fossil fuel-based LDPE across all the impact categories considered in the study. This is due to the additional variability in the cultivation and conversion processes, originated from different types of feedstocks. Uncertainties on End-of-Life (EoL) treatment processes of plastic packaging and on accounting for life cycle biogenic carbon dioxide exchanges might further alter the LCA results for the climate change total category. The present paper attempts to highlight potential issues associated to a generic LCA which does not sufficiently account for the company context, empowering the accuracy of LCA as decision support tool and opening a discussion on how to improve the reliability of practical LCA recommendations.

Assessing the embodied carbon footprint of IoT edge devices with a bottom-up life-cycle approach

In upcoming years, the number of Internet-of-Things (IoT) devices is expected to surge up to tens of billions of physical objects. However, while the IoT is often presented as a promising solution to tackle environmental challenges, the direct environmental impacts generated over the life cycle of the physical devices are usually overlooked. It is implicitly assumed that their environmental burden is negligible compared to the positive impacts they can generate. Yet, because IoT calls for a massive deployment of electronic devices in the environment, life-cycle assessment (LCA) is an essential tool to leverage in order to avoid further increasing the stress on our planet. Some general LCA methodologies for IoT already exist but quantitative results are still scarce. In this paper, we present a parametric framework based on hardware profiles to evaluate the cradle-to-gate carbon footprint of IoT edge devices. We exploit our framework in three ways. First, we apply it on four use cases to evaluate their respective production carbon footprint. Then, we show that the heterogeneity inherent to IoT edge devices must be considered as the production carbon footprint between simple and complex devices can vary by a factor of more than 150×. Finally, we estimate the absolute carbon footprint induced by the worldwide production of IoT edge devices through a macroscopic analysis over a 10-year period. Results range from 22 to 562 MtCO2-eq/year in 2027 depending on the deployment scenarios. However, the truncation error acknowledged for LCA bottom-up approaches usually lead to an undershoot of the environmental impacts. We compared the results of our use cases with the few reports available from Google and Apple, which suggest that our estimates could be revised upwards by a factor around 2× to compensate for the truncation error. Worst-case scenarios in 2027 would therefore reach more than 1000 MtCO2-eq/year. This truly stresses the necessity to consider environmental constraints when designing and deploying IoT edge devices.

A general Life Cycle Assessment framework for sustainable bleaching: A case study of peracetic acid bleaching of wood pulp

Bleaching is an important industrial operation that has significant environmental impacts. Many new bleaching technologies have been developed; nonetheless, it is challenging to quantify their potential environmental impacts due to the lack of quantitative information and robust analysis methods across different bleaching agents. This study addresses this gap by developing a general Life Cycle Assessment (LCA) framework that integrates LCA with manufacturing process simulations and lab-scale bleaching experiments. The framework was applied to a case study of Peracetic Acid (PAA), a promising bleaching agent, used in the Total Chlorine-Free (TCF) technology for wood pulp production, compared with the traditional Elemental Chlorine-Free (ECF) using chlorine dioxide. Different PAA synthetic pathways (i.e., using acetic acid or triacetin) and bleaching charges were explored using scenario analysis. Results showed that PAA-based TCF achieves a brightness similar to the conventional ECF technology with lower life-cycle impacts in categories such as global warming and eutrophication. From a process perspective, PAA-based TCF reduces the consumption of energy, water, pulping chemicals, completely avoids the use of chlorinated compounds, and provides enhanced process safety. The source of PAA significantly affects the life-cycle environmental impacts of pulp bleaching. Using PAA synthesized from triacetin rather than acetic acid leads to higher environmental impacts; however, such impacts can be mitigated by reducing excessive use of triacetin (direction for future optimization) or using bio-based glycerin in the production of the triacetin feedstock for PAA production. Although this case study focuses on PAA bleaching for wood pulp, the framework has the potential to be used for other/same bleaching agents in different industrial sectors.

Environmental impacts of cross-laminated timber production in Japan

Japan has promoted a policy to use lumber in various types of buildings since 2010. As cross-laminated timber (CLT) is one of the engineered timber products, an amount of CLT production has been increasing in Japan under this policy. The purpose of this study is to produce generic life cycle assessment data for CLT production in Japan and to propose measures for reducing environmental impacts of CLT production. The system boundary includes from material production to CLT production (cradle-to-gate). The operational data at three major Japanese companies are collected in the fiscal year of 2018. The evaluated environmental impact categories are climate change, ozone layer depletion, eutrophication, acidification, photochemical oxidant, land occupation, and land transformation. The results show that electricity used in wood laminae production had the largest impact to climate change and the roundwood production had the second largest. The sensitivity analysis clarified that the use of fossil fuels during the drying process greatly increased CLT’s environmental impacts. The policies to promote the introduction of biomass boilers for sawmills are appropriate for reducing environmental impacts. If CLT is used for more than 30 years, greenhouse gas reduction due to temporary carbon storage will be greater than that of the CLT production. It is also recommended to extend the life of buildings using CLT and/or to use CLT for a long time through the reuse of CLT panels to avoid releasing biogenic carbon to the atmosphere.

How to Obtain Accurate Environmental Impacts at Early Design Stages in BIM When Using Environmental Product Declaration. A Method to Support Decision-Making

The construction sector plays an important role in moving towards a low-carbon economy. Life cycle assessment (LCA) is considered one of the most effective methods of analytically evaluating environmental profiles and an efficient tool for calculating the environmental impacts in building design-oriented methodologies, such as building information modelling (BIM). At early design stages, generic LCA databases are used to conduct the life cycle inventory (LCI), while detailed stages require more detailed data, such as environmental product declarations (EPDs), namely documents that provide accurate results and precise analyses based on LCA. Limitations are recognized when using EPDs in BIM elements at different levels of development (LOD) in the design stages, especially related to the data consistency and system boundaries of the LCA. This paper presents a method of achieving accurate LCA results, that helps with decision-making and provides support in the selection of building products and materials. The method is validated by its application in the structural concrete of an office building located in Germany. The method defines a safety factor adopted for embodied impacts (“cradle-to-gate”), based on EPD results to predict the environmental impact of BIM elements at different LODs. The results obtained show that by integrating the method to conduct the LCA, the range of errors and possible inconsistencies in the LCA results can be reduced.

Environmental and Economic Water Management in Shale Gas Extraction

This paper introduces a comprehensive study of the Life Cycle Impact Assessment (LCIA) of water management in shale gas exploitation. First, we present a comprehensive study of wastewater treatment in the shale gas extraction, including the most common technologies for the pretreatment and three different desalination technologies of recent interest: Single and Multiple-Effect Evaporation with Mechanical Vapor Recompression and Membrane Distillation. The analysis has been carried out through a generic Life Cycle Assessment (LCA) and the ReCiPe metric (at midpoint and endpoint levels), considering a wide range of environmental impacts. The results show that among these technologies Multiple-Effect Evaporation with Mechanical Vapor Recompression (MEE-MVR) is the most suitable technology for the wastewater treatment in shale gas extraction, taking into account its reduced environmental impact, the high water recovery compared to other alternatives as well as the lower cost of this technology. We also use a comprehensive water management model that includes previous results that takes the form of a new Mixed-Integer Linear Programming (MILP) bi-criterion optimization model to address the profit maximization and the minimization Life Cycle Impact Assessment (LCIA), based on its results we discuss the main tradeoffs between optimal operation from the economic and environmental points of view.

Parametric life cycle assessment of a reusable brick veneer

A possible design strategy to improve the sustainability of building products is facilitating their future reuse. This strategy inspires some manufacturers to design innovative products, such as reusable façade products. Although these products might have a higher environmental impact for production, their reusability could lead to an environmental saving from a life cycle perspective. A possible method to evaluate their environmental performance is life cycle assessment (LCA). Nevertheless, LCA studies of reusable products are still rare. Furthermore, although the general LCA frameworks is fixed by ISO and CEN standards, some methodological choices must still be made by LCA practitioners. This paper first presents a method (as four methodological choices) for a parametric life cycle assessment of reusable building elements. Then, this method is applied to a comparative LCA of reusable and brick-and-mortar veneers. With proposed method, the reusable brick veneer is environmentally advantageous if it is reused at least once and if it is properly recycled at its end-of-life. The parametric method also indicates the relative influence of various parameters such as reuse rate, number of interventions, transport distances and waste treatment. The manufacturers can use this LCA study as a retrospective assessment to validate the relevance of design choices, but also as target-driven product management support to know hot-spots in the product’ life cycle management. This study will hopefully inspire other designers and manufacturers and accelerate the transition towards a sustainable built environment.

Assessing and managing sustainability in international perspective: corporate sustainability across cultures \u2013 towards a strategic framework implementation approach

IntroductionSustainability constitutes an essential element in corporate contexts by now. Corporate sustainability may be addressed differently, either selectively or integrated. The holistic approach opted for primarily focuses on conveying aspects of corporate sustainability across different socio-cultural contexts. In doing so, the full quadruple scope of sustainability dimensions is considered cornerstone of a well-chosen case-study design. Such particular reference prototypically exemplifies business models in highly volatile commodity markets. Continuously longing for optimization and rationalization due to creativity and productivity gains, the company is predominantly challenged by changing customer needs resulting from digitization as mega trend of the twenty-first century.Case descriptionAlluding to the business of stationery and professional office supplies, this case study aims at advocating the systematic proceeding of how to strengthen corporate sustainability through both embracing existing and evolving culture-bound approaches of sustainability vis-à-vis a framework implementation strategy and related guidelines for implementation at operational level. The essential quest is how to convey aspects of corporate sustainability across different socio-cultural contexts? Aiming at contributing to some kind of framework implementation strategy this implies reflecting upon assessing the status quo of corporate sustainability-related strategic approaches, activities and initiatives, means and instruments (sustainability performance); identifying universal and culture-bound drivers (sustainability opportunity); and deducing operational guidelines towards stakeholder awareness, selected strategic options, projects and best practices (sustainability commitment).Given the theoretical background of corporate sustainability and related contexts, impetus for operationalizing is created by triple means of:▪ Adopting an extended and generic life-cycle assessment (LCA) as core analytic framework and structuring element, corresponding with the value-chain-oriented approach of business segments,▪ Applying the multi-method paradigm of methodological triangulation, including stakeholder observation, expert interviews and company resources, and▪ Framing major characteristics as case study according to principles of qualitative content analysis.Discussion and evaluationAssuming that corporate sustainability may be conducive to foster innovation and evolution of products and services, the company’s sustainability performance, sustainability opportunity and sustainability commitment is systematically analysed in line with the generic life cycle. By covering supply chain, production, distribution/packaging, service/use, and end-of-life, the status quo of corporate sustainability-related strategic approaches is assessed first, followed by identifying universal and culture-bound drivers to corporate sustainability, and concluding operational guidelines in terms of stakeholder awareness, selected strategic options, projects and best practices. A resultant framework implementation strategy provides four strategic options of product stewardship, operational efficiency, innovative transformation, and adaptive responsiveness, and attributing them to cross-sectoral aspects of innovation, business-model evolution and socio-cultural contexts, first and foremost.Innovative value is added by systematically and holistically assessing corporate sustainability driven by grounded heuristics, multi-dimensional and culture-inclusive rationale, and implementation-focused impetus.ConclusionsIt can be concluded that adequately taking socio-cultural contexts into consideration may constitute a strategic and influential driving force to corporate sustainability, that strengthening cultural aspects of corporate sustainability may push the innovative capacity for business-model evolution; and that highlighting comparative advantages of sustainability-oriented manufacturing and branding favours the identification of business cases for sustainability.In a nutshell, corporate commitment to/for sustainability is essentially advised in challenging times of economic turbulence and rapid changes; it represents the window of opportunity to revisit assumptions and value propositions of long-lived business models.

Understanding the sustainability potential of part consolidation design supported by additive manufacturing

The environmental performance of additive manufacturing (AM) processes and the produced parts has gained increasing interest. Various assessment models have been developed based on the general life cycle assessment (LCA) framework, although different in goals and boundaries, the inputs for these models are always a single part (or a batch of same parts). In contrast, the present research provides a new perspective towards the selection of a more sustainable assembly design. A comparative LCA model is built to investigate the environmental performance difference of two design approaches: assembly design (AD) made via conventional manufacturing (CM) plus assembly operations and part consolidation (PC) made via AM plus machining. The effects of weight reduction, prolonged life expectancy, and improved functional performance (e.g. fuel efficiency) attainable in the PC routine and the advantages of replaceable subcomponents in the AD routine are studied in a throttle pedal assembly example throughout the lifespan of the vehicle. The results reveal that the PC routine can be more environmental friendly than the AD counterpart when the lifespan can be improved by over 200% or the weight savings are more than 30%. The role of functional performance improvement on affecting sustainability may depend on the part/vehicle ratio and vehicle types. This article extends the literature on sustainable assembly design and the proposed LCA model provides a way of identifying the profitable margins of PC in the early design stage.

Harmonized rules for future LCAs on pharmaceutical products and processes

The manufacturing of pharmaceuticals and their occurrence in the environment generated growing concerns of stakeholders. Life Cycle Assessment (LCA) is a suitable tool to identify potential environmental impacts within the whole pharmaceutical value chain. However, existing pharma-LCAs revealed several methodological shortcomings and challenges. To support the development of future LCAs in the sector, draft Product Category Rules (PCR) for pharmaceuticals for human use and their manufacturing processes are proposed. Existing LCA case studies were evaluated and compared based on the methodological requirements according to the ISO 14044 standard. In addition, PCRs from the pharmaceutical sector, generic LCA standards, and product-specific guidelines were reviewed. Subsequently, overlaps between and deviations from these sources were identified. It was determined whether methodological requirements can be adopted from existing standards and guidelines or whether additional rules or specifications for pharmaceutical products are needed. The overall PCR structure was established in alignment with ISO 14044, ISO TS 14027, and the Guidance for PCR development (GPCRD). For the definition of product groups, the third level of the Anatomic Therapeutic Chemical (ATC) classification system was determined as appropriate level of detail (granularity). The methodological requirements, e.g., the definition of goal and scope, inventory analysis, as well as the impact assessment, were set considering the intended application and the product system. However, the majority of these proposed methodological requirements go beyond current practice in existing pharma-LCAs (e.g., definition of an effect-based functional unit). Moreover, the need for specific rules depending on the active pharmaceutical ingredient (API), the galenic formulation, and regional aspects was described and discussed. This work tackles current methodological challenges of LCA application in the pharmaceutical sector by providing harmonized rules to guide future studies on pharmaceutical products and processes. However, modelling the use- and end of life phase as well as considering pharma-specific impacts were revealed as remaining challenges.

Ökobau.dat 3.0–Quo Vadis?

Life cycle assessment (LCA) is the standard method for the quantification of environmental impacts within the construction sector, relying on available generic LCA databases. New developments, such as the increased influence of the building construction for LCA and the forthcoming of building information modeling (BIM), implicate new requirements on multiscale levels of development and complexity for LCA construction databases. At the example of the German “Ökobau.dat”, one of the leading LCA construction databases, this publication discusses whether the database is able to meet these requirements. The analysis shows the strengths of the Ökobau.dat with regard to standardization conformity (EN 15804, ILCD), data provision in machine-readable XML format, and the provision of an application programming interface. Shortcomings include incorrect linking of building life cycle inventory data with environmental information, incorrect documentation of functional units, missing generic datasets, the modeling of energy use data or the lack of a uniform structuring, or material classification. The authors propose solutions such as the provision of appropriate functional units, the implementation of a top-down approach to investigate the completeness of data based on existing nomenclatures or the extension with an appropriate material classification. This would allow for future viability and adaptability of Ökobau.dat for digital LCA.

Life Cycle Assessment of Greenhouse Gas Emissions from Marine Fuels: A Case Study of Saudi Crude Oil versus Natural Gas in Different Global Regions

SummaryThe understanding of the greenhouse gas (GHG) emissions dimension in discussing the future of marine fuels makes it important to advance the current life cycle assessment (LCA) practice in this context. Previous LCA studies of marine fuels rely on general LCA models such as GREET and JEC well‐to‐wheels study. These models do not fully capture the various methane losses in the fuel supply chain. The primary goal of this LCA study is to compare the GHG emissions of heavy fuel oil and marine gas oil produced from Saudi crude oil to liquefied natural gas (LNG) in different global regions. A sensitivity analysis was performed to show how results may vary with non‐Saudi crudes. A secondary goal was to advance LCA of marine fuels by utilizing, for the first time, a set of bottom‐up engineering models that enable detailed analysis of specific oil and gas projects worldwide. The results show particular cases where LNG use in marine applications has a significant countereffect in terms of climate change compared to conventional marine fuels produced from a low‐carbon‐intensity crude oil. When the results are calculated based on a 20‐ versus 100‐year methane global warming potential, LNG appears noncompetitive for climate impact in marine applications.

From value-added tax to a damage and value-added tax partially based on life cycle assessment: principles and feasibility

PurposeThe purpose of this article is to examine the arguments in favor of a shift from value-added tax (VAT) or sales tax to a damage and value-added tax (DaVAT) partially based on the life cycle assessment (LCA) of goods and services. With this shift, goods and services that seriously harm the environment and human health will be priced up, those that impact them less will be priced down. The paper recalls the proposal made by De Camillis and Goralczyk (Int J Life Cycle Assess 18:263–272, 2013) to differentiate the VAT rate associated with products according to their environmental impacts over their life cycle. The paper suggests a new way to convert VAT into DaVAT, examines the operating principles of such a system, and considers its practical feasibility. The new policy tool based on LCA presented is intended to be applied to every country wishing to reform its consumption tax system in order to strive for a more sustainable future. Some aspects specific to countries having the same currency, notably the Euro zone, are also discussed.MethodsThe proposal of De Camillis and Goralczyk is discussed from the perspective of both environmental performance and compliance with LCA standards. To overcome the identified difficulties, a new way of adapting VAT (or consumption taxes in general) according to LCA is suggested. The proposal relies on three essential points: (i) apply VAT (or consumption taxes in general) to all goods and services and reduce its multiple rates to one single low rate (e.g., 3%) called uniform VAT (UVAT); (ii) add to UVAT a per-unit tax called global damage tax (GDT) calculated on the basis of environmental impacts assessed by means of specific or generic LCAs. In the case of potentially high-polluting products or industries, a specific LCA will be automatically imposed. The obligation to assess high-polluting activities already exists in many countries with, e.g., environmental impact studies, but the impacts are not necessarily evaluated by LCA; (iii) in order to reflect environmental, social, or ethical concerns specific to a country, another damage tax termed specific damage tax (SDT) is proposed that extends beyond LCA. DaVAT is the sum of UVAT, GDT, and SDT. DaVAT is conceived not as an additional burden but rather as a shift of taxation, as the rate of the old consumption taxes can decrease proportionally to the increase of GDT. DaVAT is also designed in such a way that the erosion of tax revenues, when pollutant would decline, is offset by the extension of the tax to all goods and services and by the possibility to gradually re-increase the UVAT rate when the number of highly polluting products decreases.Results and discussionThe proposal is examined first from a theoretical point of view by considering which principles should be used to comply with LCA standards and general requirements of (environmental) tax policies. Four general principles emerge: consistency in the choice of the functional unit and in the characterization, normalization and weighting methods, transparency of information about the environmental score of the product, evolution capacity of the levers of the tax and of the assessment methods, respect for national sovereignty concerning the setting of the tax price. The proposal is also examined from a practical point of view by asking how the DaVAT system would work in practice. The answer takes into account associated costs, risks of fraud, price changes, and acceptability of the proposal. The issue about price changes is addressed on the basis of a simulation drawn from six published LCA studies on different products.ConclusionsThe proposal to replace most of the VAT or sales tax with a unitary global damage tax based on LCA of goods and services seems to meet expectations not only in terms of theoretical consistency and practical feasibility but also from the perspective of income tax consolidation, environmental efficiency, and sustainable growth. The study concludes by pointing out the limits of an LCA-based tax and by suggesting a framework for a closer examination of the DaVAT system in order to verify that it would provide the intended incentives and to explore the modalities of its implementation.

복합재료 소형선박의 지속가능한 설계를 위한 전과정평가 사례 연구

In this study, application study of the life cycle assessment (LCA) is conducted on a composite small craft for sustainable design and production according to ISO 14040-14044 series. Procedure of general LCA is reconstituted to apply to composite small craft, and life cycle inventory (LCI) analysis is conducted on principal structures of composite small craft by developing a process flow diagram for boat building. Also, this study leads LCA results of structures and materials into the environmental impact category such as carbon footprint, water eutrophication, air acidification, and energy consumption. Especially, LCA results about production methodologies that are hand lay-up and vacuum infusion of glass fiber reinforced plastic are quantitatively compared and analyzed.

Understanding Life Cycle Thinking and its Practical Application to Agri-Food System

Global agri-food system will face great pressure to meet the continuing demands for food due to the increasing number of world population. The high demand requires an increase in food production and agricultural output, which, therefore, means more raw materials, water, energy, and other resources needed. Increasing the amount of these resources for agri-food system will harm the environment since carbon dioxide generated by the burning of fuel will then result in global warming and climate change. This paper discusses global issues related to sustainable agri-food system, such as climate change, sustainability, green products, food loss and food mileage relationships with emissions. It describes Life Cycle Thinking (LCT) philosophy and how LCT is operated into practical applications, using Spanish Agri-food system as an example, and challenges for Life Cycle Assessment (LCA) applications in supporting sustainable agri-food systems. Environmental impacts associated with agri-food system need to be reduced. The use of an LCA framework to determine the areas with the greatest impact and reduction strategies for agri-food operation is a viable strategy to reduce the environmental impacts in facing the increasing global demand. Nevertheless, the application of LCA in agri-food systems varies due to global, regional, and local differences in its practice. Thus, it makes it difficult for general LCAs to be conducted on agri-food system. Despite the increasing number of LCA studies in agri-food system, the literature on methodological aspects, and case studies, some challenges still need to be addressed to ensure that LCA provides significant results.

Identifying key process parameters for uncertainty propagation in environmental life cycle assessment for sewage sludge and food waste treatment

Life cycle assessment (LCA) results are often subject to uncertainty, which may lead to erroneous conclusions. This paper aims to tackle the parameter uncertainty involved in LCA. Hong Kong is selected as the reference city for the treatment of sewage sludge and food waste. A selection approach with sensitivity analysis is proposed to identify the key process parameters and Monte Carlo simulation is further conducted to propagate the uncertainty of the key process parameters identified. The results show that climate change is the major impact category among various impact categories that are generally considered in waste LCA studies. Scenarios 5 and 6, which consider anaerobic co-digestion (coAD) treatment, achieve the best performance in regard to the climate change impact. Scenario 6 which includes a combined cycle gas turbine system for biogas utilization has −6.75 × 104 kg avoided CO2e emissions and it is equal to 44% more avoided emissions compared to scenario 5 which applies a combined heat and power system. For the key process parameters identified, it is found that the electricity generation efficiencies in different waste treatment facilities, such as the incineration plant and the anaerobic digestion plant, have the greatest sensitivity to the result. Uncertainty propagation is then conducted to obtain the probability distribution functions in environmental performance of different scenarios. Scenario 6 has a 95% probability of achieving at least −5.32 × 104 kg avoided CO2e emissions, while the probability of scenario 5, which is the second best scenario, achieving the same avoid emissions is below 5%. It indicates a significant advantage of using combined cycle gas turbine over combined heat and power unit for biogas utilization in Hong Kong. The methodologies and results of this study provide comprehensive material that can be adapted for other areas planning sustainable sewage sludge and food waste treatment, as well as in tackling parameter uncertainty in general LCA studies.

Green-house gas mitigation capacity of a small scale rural biogas plant calculations for Bangladesh through a general life cycle assessment.

Calculations towards determining the greenhouse gas mitigation capacity of a small-scale biogas plant (3.2 m3 plant) using cow dung in Bangladesh are presented. A general life cycle assessment was used, evaluating key parameters (biogas, methane, construction materials and feedstock demands) to determine the net environmental impact. The global warming potential saving through the use of biogas as a cooking fuel is reduced from 0.40 kg CO2 equivalent to 0.064 kg CO2 equivalent per kilogram of dung. Biomethane used for cooking can contribute towards mitigation of global warming. Prior to utilisation of the global warming potential of methane (from 3.2 m3 biogas plant), the global warming potential is 13 t of carbon dioxide equivalent. This reduced to 2 t as a result of complete combustion of methane. The global warming potential saving of a bioenergy plant across a 20-year life cycle is 217 t of carbon dioxide equivalent, which is 11 t per year. The global warming potential of the resultant digestate is zero and from construction materials is less than 1% of total global warming potential. When the biogas is used as a fuel for cooking, the global warming potential will reduce by 83% compare with the traditional wood biomass cooking system. The total 80 MJ of energy that can be produced from a 3.2 m3 anaerobic digestion plant would replace 1.9 t of fuel wood or 632 kg of kerosene currently used annually in Bangladesh. The digestate can also be used as a nutrient rich fertiliser substituting more costly inorganic fertilisers, with no global warming potential impact.