In this work, an End-Of-Life (EOL) model is included in the Life Cycle Energy Optimisation (LCEO) methodology to account for the energy burdens and credits stemming from a vehicle’s EOL processing phase and balance them against the vehicle’s functional requirements and production and use phase energies. The substitution with a correction factor allocation method is used to model the contribution of recycling to the EOL phase’s energy. The methodology is illustrated through the optimisation of the design of a simplified vehicle sub-system. For the latter, multiple recycling scenarios with varying levels of assumed recycling induced material property degradation were built, and their impact on the vehicle sub-system’s optimal solutions was compared to that of scenarios based on landfilling and incineration with energy recovery. The results show that the inclusion of EOL modelling in the LCEO methodology can significantly alter material use patterns thereby effecting the life cycle energy of the optimal designs. Indeed, the vehicle sub-system’s optimal designs associated with the recycling scenarios are on average substantially heavier, and less life cycle energy demanding, than their landfilling or incineration with energy recovery-related counterparts.
In this work, an End-Of-Life (EOL) model is included in the Life Cycle Energy Optimisation (LCEO) methodology to account for the energy burdens and credits stemming from a vehicle's EOL processing phase and balance them against the vehicle's functional requirements and production and use phase energies. The substitution with a correction factor allocation method is used to model the contribution of recycling to the EOL phase's energy. The methodology is illustrated through the optimisation of the design of a simplified vehicle sub-system. For the latter, multiple recycling scenarios with varying levels of assumed recycling induced material property degradation were built, and their impact on the vehicle sub-system's optimal solutions was compared to that of scenarios based on landfilling and incineration with energy recovery. The results show that the vehicle sub-system's optimal designs are significantly dependent on the EOL scenario considered. In particular, the optimal designs associated with the recycling scenarios are on average substantially heavier, and less life cycle energy demanding, than their landfilling or incineration with energy recovery-related counterparts; thus, demonstrating how the inclusion of EOL modelling in the LCEO methodology can significantly alter material use patterns, thereby effecting the very mechanisms enabling the embodiment of the resulting life cycle energy optimal designs.
The present work describes a widening of the scope of the Life Cycle Energy Optimisation (LCEO) methodology with the addition of shape-related design variables. They describe the curvature of a vehicle which impacts its aerodynamic drag and therewith its operational energy demand. Aerodynamic drag is taken into account through the estimation of the drag coefficient of the vehicle body shape using computational fluid dynamics simulations. Subsequently, the aforementioned coefficient is used to calculate the operational energy demand associated with the vehicle. The methodology is applied to the design of the roof of a simplified 2D vehicle model which is both mechanically and geometrically constrained. The roof is modelled as a sandwich structure with its design variables consisting of the material compositions of the different layers, their thicknesses as well as the shape variables. The efficacy of the LCEO methodology is displayed through its ability to deal with the arising functional conflicts while simultaneously leveraging the design benefits of the underlying functional alignments. On average, the optimisation process resulted in 2.5 times lighter and 4.5 times less life cycle energy-intensive free shape designs. This redesign process has also underlined the necessity of defining an allocation strategy for the energy necessary to overcome drag within the context of vehicle sub-system redesign.
The Life Cycle Energy Optimisation (LCEO) methodology aims at finding a design solution that uses a minimum amount of cumulative energy demand over the different phases of the vehicle's life cycle, while complying with a set of functional constraints. This effectively balances trade-offs, and therewith avoids sub-optimal shifting between the energy demand for the cradle-to-production of materials, operation of the vehicle, and end-of-life phases. The present work describes the extension of the LCEO methodology to perform holistic product system optimisation. The constrained design of an automotive component and the design of a subset of the processes which are applied to it during its life cycle are simultaneously optimised to achieve a minimal product system life cycle energy. A subset of the processes of the end-of-life phase of a vehicle’s roof are modelled through a continuous formulation. The roof is modelled as a sandwich structure with its design variables being the material compositions and the thicknesses of the different layers. The results show the applicability of the LCEO methodology to product system design and the use of penalisation to ensure solution feasibility.
This paper explores how the systemic-level energy consumption of light-duty vehicles could be reduced through integrative design. To this end, the Life Cycle Energy Optimisation (LCEO) methodology is used to achieve the coupled optimal use of materials (including their circularity potential) and vehicle aerodynamic shape to reduce the overall Life Cycle Energy (LCE) footprint of light-duty vehicles, with the results being compared to the lightweight and aerodynamic alternatives. Initially, the methodology is functionally expanded to handle aerodynamic functional requirements through the definition of a novel allocation strategy for the aerodynamic energy, and a parametrised simple vehicle body model that ensures that the LCE knock-on effects of aerodynamically-motivated design decisions are fully accounted for. Subsequently, the methodology is used to perform the first, to the knowledge of the authors, aero-structural LCE-driven design optimisation of a vehicle subsystem, with the impact of the materials’ circularity potential being taken into account through various end-of-life (EOL) processing scenarios, including recycling. The results show that the environmental footprint of light-duty vehicles could significantly be reduced through integrative early-stage design. Specifically, it shows that a life cycle energy optimal vehicle's aerodynamic shape is significantly impacted by the vehicle's material composition and the latter's EOL characteristics — particularly recycling potential. Furthermore, LCE optimal vehicles have been found to be on average longer, heavier and more aerodynamic than their lightweight counterparts, as well as offering up to 20% energy savings per vehicle; while also being shorter and lighter than optimal aerodynamic configurations.
This study quantifies freshwater consumption throughout the life cycle of Brazilian exported yellow melons and assesses the resulting impact on freshwater availability. Results are used to identify improvement options. Moreover, the study explores the further impact of variations in irrigation volume, yield, and production location. The product system boundary encompasses production of seeds, seedlings, and melon plants; melon packing; disposal of solid farm waste; and farm input and melon transportation to European ports. The primary data in the study were collected from farmers in order to quantify freshwater consumption related to packing and to production of seeds, seedlings, and melons. Open-field melon irrigation was also estimated, considering the region's climate and soil characteristics. Estimated and current water consumptions were compared in order to identify impact reduction opportunities. Sensitivity analysis was used to evaluate variations in the impact because of changes in melon field irrigation, yield, and farm location. This study shows that the average impact on freshwater availability of 1 kg of exported Brazilian yellow melons is 135 l H2O-e, with a range from 17 to 224 l H2O-e depending on the growing season's production period. Irrigation during plant production accounts for 98 % of this impact. Current melon field water consumption in the Low Jaguaribe and A double dagger u region is at least 39 % higher than necessary, which affects the quality of fruits and yield. The impact of melon production in other world regions on freshwater availability may range from 0.3 l H2O-e/kg in Costa Rica to 466 l H2O-e/kg in the USA. The impact of temporary crops, such as melons, on water availability should be presented in ranges, instead of as an average, since regional consumptive water and water stress variations occur in different growing season periods. Current and estimated water consumption for irrigation may also be compared in order to identify opportunities to achieve optimization and reduce water availability impact.
This study is an original environmental assessment of the Brazilian cashew, a perennial tree cultivated in 30 tropical countries that yields four products: nuts, apples, gum and wood. While economic and agronomic data regarding cashew are available worldwide, the environmental issues related to the main production systems and products commercialized by Brazilian farms have not been discussed consistently. This environmental assessment is important to guide the efforts of researchers and farmers for improving the environmental performance of cashew cropping systems and products. Life cycle assessment is applied to assess the environmental impacts of cashew systems and products, considering multi-cropping systems, agriculture functions and allocation procedures. Two cashew cropping systems are compared: (i) a high-input system, or reference system, developed through 20 years of research, and (ii) a low input system, as defined by a sample of farms practicing multi-cropping systems. Aspects and impacts of these systems are reported via the following production stages: nursery, establishment, and low and full production. Two agriculture functions are adopted to analyze the cropping systems: land management (impacts per hectare) and financial (impact per US$ from total sales receipts). The impacts of cashew products are evaluated using the crop production function (per kilogram of product). The impacts of products are measured using both mass and economic allocation. This study shows that the low and full production stages account for the majority of impact in both cropping systems, but land transformation for the establishment of cashew orchards is the main contributor of climate change. The analysis of multiple agriculture function shows different results for the study of cashew production systems and products. Considering the land management function (impacts per hectare), the low-input system causes less significant environmental impact, when compared to the high-input system, in all categories but toxicity. When the financial function is analyzed (impacts per US$ from total sales receipts from one ha), the low-input system achieves better performance for only eutrophication and water depletion impact categories. The analysis of the crop production function (impacts per kilogram of product) shows that the choice of allocation procedure also affects the results when comparing the impact values of products from different cropping systems. If the choice is for mass allocation, products from the low-input system achieve better environmental performance, but if economic allocation is chosen, products from the high-input system perform equal or better than when produced in the low-input system. From the joint analysis of agriculture functions, the conclusion is that the best option to improve the environmental performance of the Brazilian cashew production is to adjust the high-input system with modifications regarding fertilization and pest management. From this case study, the benefits of considering multi-agriculture functions and accounting for all production stages in the study of perennial crops are highlighted. The importance of developing emission and characterization factors to reduce uncertainty when estimating pollutant loads and evaluating impacts of perennial crops cultivated in tropical regions is also discussed. This study advances the knowledge base on the environmental assessment of perennial crops in general, and on cashew crops specifically.
The carbon footprint of food has become important for producers worldwide as consumers and retail companies increasingly base their purchase decisions on carbon footprint labels. In this context, our objectives is to assess the carbon footprint (CF) of Brazilian yellow melon exported from the Low Jaguaribe and Acu region, including an uncertainty assessment, and to evaluate reduction potentials and improvement options. Exporting farms located in this region account for about 99 percent of Brazilian melon exports, mainly to the United Kingdom and the Netherlands. To determine the CF, we followed Life Cycle Assessment, according to ISO standards (14040 and 14044). The results are expressed in kg of CO2-eq/t of exported melon. The production system encompasses processes in the Low Jaguaribe and Acu region (such as seedling, plant production, packing, and disposal of solid wastes from farms), upstream processes (including the production and transportation of inputs, such as seeds, plastics, and fertilizers), and downstream processes (melon transport). The total yellow melon CF in the reference situation is 710 kg CO2-eq/t exported melon. However, scenario results indicate that this value can be reduced by 44 percent if melon fields are located in pre-existing agricultural areas, nitrogen fertilization is reduced, and no plastic field trays are used in melon production. GHG emissions from melon transport are relatively unimportant in the total CF. These results provide melon producers with an insight into the CF of their product, and options to reduce it.
Life cycle assessment (LCA) is a tool to assess potential environmental impacts throughout a product's life cycle, i.e., from natural resource acquisition, via production and use stage to waste management (including disposal and recycling). The term 'product' includes goods, technologies, and services. LCA is a comprehensive assessment that takes a product life cycle perspective, and covers a range of environmental impacts. These unique features of LCA facilitate avoiding problem shifting from one life cycle stage to another stage, or from one environmental impact to another impact. This article gives a short methodological overview.
Several renewable and (claimed) sustainable energy sources have been introduced into the market during the last century in an attempt to battle pollution from fossil fuels. Especially biomass energy technologies have been under debate for their sustainability. A new biomass energy technology was introduced in 2008: the plant-microbial fuel cell (P-MFC). In this system, electricity can be generated with living plants and thus bioelectricity and biomass production can be combined on the same surface. A green roof producing electricity with a P-MFC could be an interesting combination. P-MFC technology is nearing implementation in the market and therefore we assessed the environmental performance of the system with an early stage life cycle assessment (LCA). The environmental performance of the P-MFC is currently worse than that of conventional electricity production technologies. This is mainly due to the limited power output of the P-MFC and the materials presently used in the P-MFC. Granular activated carbon (anode material), gold wires (current collectors), and Teflon-coated copper wires (connecting anode and cathode) have the largest impact on environmental performance. Use of these materials needs to be reduced or avoided and alternatives need to be sought. Increasing power output and deriving co-products from the P-MFC will increase environmental performance of the P-MFC. At this stage it is too early to compare the P-MFC with other (renewable) energy technologies since the P-MFC is still under development.
Environmentally-friendly energy-efficient vehicles are an important contributor to meet future global transportation needs. To minimise the environmental impact of a vehicle throughout its entire life cycle, the life cycle energy optimisation (LCEO) methodology has been proposed. Using the proxy of life cycle energy, this methodology balances the energy consumption of vehicle production, operation and end-of-life scenarios. The overall aim is to design a vehicle where life cycle energy is at a minimum. While previous work only included vehicle production and operation, this paper aims at advancing the LCEO methodology by including an end-of-life phase. A simplified design study was conducted to illustrate how vehicle design changes when end-of-life treatment is included. Landfilling, incineration and recycling have been compared as end-of-life treatments, although the focus was put on recycling. The results reveal that the optimal design not only changes with the inclusion of an end-of-life phase but it changes with specific end-of-life treatment.
We qualitatively analysed how and why environmental improvement actions often lead to unintended environmental consequences. Different theories are integrated to delineate the underlying system structure causing this system behavior. Causal loop diagram technique is utilized to explore and visualize: how incremental improvements in material and energy efficiency can unintendedly cause consumption to increase; how this consumption rebound effect is linked to generation of waste and pollution; and how this can give rise to social and negative externalities, economic inequalities and other broad unintended consequences in our society. Consumption and incremental innovation are found to be the highest leverage points and reinforcing factors driving unintended environmental consequences in this complex system. The paper in addition explores two potential modes of behaviour dissimilar to those of unintended environmental consequences. These emerging modes of behaviour are product-service systems and environmental policy instruments. Their combination forms a prominent transition pathway from a production-consumption-dispose economy to a so-called circular economy.
Early environmental assessments provide important information for decision making processes in road construction projects. This report is about a comparative study among different Life Cycle Assessment (LCA) tools used in road construction. These are, KlimatKalkyl, LICCER and SimaPro. KlimatKalkyl was developed by a consultancy firm and used by Trafikverket, LICCER was developed by a collaboration of three universities and used in research studies and SimaPro is used by industry and academia for environmental studies. In this report the results are referring only to primary energy consumption in GJ/year and Global Warming Potential (GWP) in CO2-eq. kg/year.
The following report includes three cases studies based on different road projects. The results generated from each tool are compared in order to evaluate the tools and present the similarities and differences among them in quantitative and qualitative manner. Variations in the outputs regarding the impact in the environment mainly come from the different input formats and calculation processes that the tools have. Regarding the road type, the three models are generating different results for energy or CO2 emissions. In the qualitative comparison it is showed that the tools have different input formats and at some cases one has more input details against the other.
Use of life cycle assessment (LCA) in choice of road corridor could reduce environmental impacts of traffic and infrastructure. This paper explores how the LCA model LICCER, designed to compare life cycle climate impact and energy use of alternative road corridors, fulfills practitioners’ requirements concerning data availability and usefulness for decision-making. Results are based on a case study where the model was applied to a Swedish road reconstruction project and a workshop with potential users of the model. In the case study, the shorter construction alternatives had the lowest traffic related impacts and the highest infrastructure related impacts. Earthworks, soil stabilization, and pavement contributed most to infrastructure related impacts. For the stakeholders, the LICCER model was considered useful because it includes both traffic and infrastructure, includes default data that the user can replace by project specific data, identifies possible improvements, and presents results relative to a reference alternative. However, the model could be improved by including further nation specific default data, different traffic scenarios depending on the road corridor, more detailed traffic scenarios, and an uncertainty assessment of the model output. These findings may be useful in the development and improvement of LCA models and when evaluating the suitability of existing models for use in early planning.
The possibilities to influence environmental impacts during the road life cycle are greatest in early planning; however, the lack of project specific data makes it difficult to use life cycle assessment as decision-support. This paper examines how life cycle assessment can be used to support the choice of road corridor, considering the practical prerequisit of simplicity and usefulness of results for decision-making. The model LICCER was used to quantify life cycle impacts of road corridors in a construction project in Sweden. Availability of input data and usefulness of results was discussed with road authorities in Sweden, Norway, and Denmark. Traffic operation contributed most to life cycle impacts in all road corridors, thus the shortest construction alternative had the lowest life cycle impacts. However, the shortest alternative had the highest infrastructure related impacts due to large quantities of earthworks. Parameters that had the highest influence on results were those that affected the impacts of traffic, earthworks, and pavement. While workshop participants agreed that project specific data are scarce and uncertain in early planning, they also believed that planners can make satisfactory estimations and that the model output is useful to support the choice of road corridor. To balance simplicity and usefulness of results, data collection should focus on parameters that have high contribution to environmental impacts, that differentiate the road corridors, and are not proportional to the road length. To implement life cycle assessment in practice, models should preferably include nation specific data approved by the national road authority.
This paper introduces the IEA Annex 57 case study method, consisting of a format fordescribing individual case studies and an evaluation matrix covering all case studies. Samplecase studies are used to illustrate the method and the evaluation matrix through a firstpreliminary analysis. In compiling and evaluation existing, transparent case studies we havetaken a stakeholder perspective. By so doing it is intended to identify fordecision makers thekey issues affecting EE/EC in buildings. Analysis in this paper focuses on one of the six casestudy themes, building design strategies for EE/EC mitigation and references cases coveringe.g. material selection, building shape, construction stage strategies and strategies to handlethe trade-off between embodied and operational impacts in net-zero emission building design.
The dominance of operational energy and related greenhouse gas (GHG) emissions of most existing buildings is decreasing in new construction, when primary fossil energy of building operation decreases as result of the implementation of energy efficiency measures as well as a decarbonisation of national energy mixes. Stakeholders therefore have a growing interest in understanding the possibilities for reducing embodied impacts in buildings. In the LEA EBC project 'Annex 57' a broad call for case studies was launched with the aim to identify design strategies for reducing embodied energy and GHG emissions (EEG) from buildings. The aim of this paper is to identify and provide a collected and comprehensive overview of quantitative reduction potentials of the particular EEG reduction strategies which should be considered by the stakeholders engaged in, and with the capacity to influence the outcome of, individual building projects. This is done by a systematic analysis of the Annex 57 case study collection as well as additional scientific literature. While it should be noted that the actual EEG savings at building level illustrated in this collection of studies are only applicable to each specific case, importantly this multiple cross-case analysis has provided rigorous evidence of the considerable potential to reduce embodied impacts in the design and construction of new and refurbished buildings.
Energy use and greenhouse gas (GHG) emissions associated with life cycle stages of roadinfrastructure are currently rarely assessed during road infrastructure planning. This studyexamines the road infrastructure planning process, with emphasis on its use of EnvironmentalAssessments (EA), and identifies when and how Life Cycle Assessment (LCA) canbe integrated in the early planning stages for supporting decisions such as choice of roadcorridor. Road infrastructure planning processes are compared for four European countries(Sweden, Norway, Denmark, and the Netherlands).The results show that only Norway has a formalised way of using LCA during choiceof road corridor. Only the Netherlands has a requirement for using LCA in the laterprocurement stage. It is concluded that during the early stages of planning, LCA could beintegrated as part of an EA, as a separate process or as part of a Cost-Benefit Analysis.
Road infrastructure has effects on the environment throughout all of its life cycle phases: construction,maintenance, operation and end-of-life. It has been observed, however, that these life cycle impacts are notusually considered during early stages of road infrastructure planning (i.e. decisions on road corridor).The recently developed LICCER tool enables assessment of road corridor alternatives during early stages of roadinfrastructure planning. It includes input data for roads, bridges and tunnels. It also considers future emissionsfrom traffic. The life cycle impact categories covered are energy use and contribution to climate change.The developed tool is being tested in a case study. Construction of a specific road in Sweden was used todemonstrate how the model is able to show differences between road corridor alternatives. Sensitivity analysiswas applied to show the robustness of its results.
The road sector consumes large amounts of materials and energy and produces large quantities of greenhouse gas emissions, which can be reduced with correct information in the early planning stages of road project. An important aspect in the early planning stages is the choice between alternative road corridors that will determine the route distance and the subsequent need for different road infrastructure elements, such as bridges and tunnels. Together, these factors may heavily influence the life cycle environmental impacts of the road project. This paper presents a case study for two prospective road corridor alternatives for the Oslo fjord crossing in Norway and utilizes in a streamlined model based on life cycle assessment principles to quantify cumulative energy demand and greenhouse gas emissions for each route. This technique can be used to determine potential environmental impacts of road projects by overcoming several challenges in the early planning stages, such as the limited availability of detailed life cycle inventory data on the consumption of material and energy inputs, large uncertainty in the design and demand for road infrastructure elements, as well as in future traffic and future vehicle technologies. The results show the importance of assessing different life cycle activities, input materials, fuels and the critical components of such a system. For the Oslo fjord case, traffic during operation contributes about 94 % and 89 % of the annual CED and about 98 % and 92 % of the annual GHG emissions, for a tunnel and a bridge fjord crossing alternative respectively.
To enable the consideration of life cycle environmental impacts in the early stages of vehicle design, a methodology using the proxy of life cycle energy is proposed in this paper. The trade-offs in energy between vehicle production, operational performance and end-of-life are formulated as a mathematical problem, and simultaneously balanced with other transport-related functionalities, and may be optimised. The methodology is illustrated through an example design study, which is deliberately kept simple in order to emphasise the conceptual idea. The obtained optimisation results demonstrate that there is a unique driving-scenario-specific design solution, which meets functional requirements with a minimum life cycle energy cost. The results also suggest that a use-phase focussed design may result in a solution, which is sub-optimal from a life cycle point-of-view.
A methodology is presented in this paper, in which the trade-offs in energy between vehicle production, operational performance and end-of-life are formulated as a mathematical problem that may be optimised. This methodology enables the consideration of the life-cycle environmental impact, through the proxy of life-cycle energy, in the very first stages of transport vehicle design where it can be concurrently balanced with other functionalities. The methodology is illustrated through a sandwich panel design case study. The optimisation results for this case demonstrate that a design solution does exist, which meets functional requirements with a minimum life-cycle energy cost. They also highlight that a pure lightweight design may result in a solution, which is sub-optimal from a life cycle point-of-view.
This paper integrates two complementary life cycle assessment (LCA) studies with the aim to advice facility managers on the sustainable use of cups, either disposable or reusable. Study 1 compares three disposable cups, i.e., made from fossil-based polystyrene (PS), biobased and compostable plastic (polylactic acid; PLA) and paper lined with PLA (biopaper). Study 2 compares the disposable PS cup with reusable cups that are handwashed or dishwashed. Existing LCA studies show inconsistent and sometimes conflicting results, due to differences in used data and modeling choices. The comparison of disposable cups, study 1, deliberately applied multiple inventory data sets for relevant life cycle processes and multiple crediting principles for recycling. Included waste treatment options in study 1 were incineration, recycling, composting, and anaerobic digestion (last two not for the disposable PS cup). The PS cup is next compared with handwashed and dishwashed reusable cups (study 2). LCAs for the reusable cups use single data sets, and explore the influence of an increasing number of reuses. Cup LCA results were only compared within, and not across impact categories. All data relate to cups used with hot beverage vending machines in Dutch office settings. Impact results for each disposable cup show large and overlapping spreads. This prevents identifying a preferable disposable cup material, though still allows cautious preferences about waste treatment processes. Composting biocups is less good than other waste treatment processes. Average impact results for anaerobic digestion perform in almost all impact categories better than incineration for the PLA cup. Average impact results for recycling perform slightly better than incinerating for both biocups, but not for the PS cup. This comparison is affected, however, by the relatively large credits for avoided Dutch electricity production. Impact results for reusable cups do not perform better than disposable cups if both are used once. Impact results for the reusable cups contain large uncertainty due to widely varying user behavior. Overall results do not allow any preference for one of the disposable cups or for disposable versus reusable cups. All cups can be used for more than one consumption. This gives a considerable environmental gain for the second and third hot beverage consumption with all cups. Facility managers can encourage a second or third serving with the same cup by financial incentives, only putting on dishwashers around noon and after working time, and/or consumer awareness activities.
A life cycle assessment (LCA) was conducted for Ethiopian rose cultivation. The LCA covered the cradle-to-gate production of all inputs to Ethiopian rose cultivation up to, and including transport to the Ethiopian airport. Primary data were collected about materials and resources used as inputs to, and about the product outputs from 21 farms in 4 geographical regions (i.e. Holleta, Sebeta, Debre Ziet, and Ziway). The primary data were imported in, and analyzed with the SimaPro7.3 software. Data for the production of used inputs were taken from the EcoInvent®2.0 database. Emissions from input use on the farms were quantified based on estimates and emission factors from various studies and guidelines. The resulting life cycle inventory (LCI) table was next evaluated with the CML 2 baseline 2000. V2/world, 1990/characterization method to quantify the contribution of the rose cultivation chain to 10 environmental impact categories. The set of collected primary data was comprehensive and of high quality. The data point to an intensive use of fertilizers, pesticides, and greenhouse plastic. Production and use of these inputs also represent the major contributors in all environmental impact categories. The largest contribution comes from the production of the used fertilizers, specifically nitrogen-based fertilizers. The use of calcium nitrate dominates Abiotic Depletion (AD), Global Warming (GW), Human Toxicity (HT) and Marine Aquatic Ecotoxicity (MAET). It also makes a large contribution to Ozone Depletion (OD), Acidification (AD) and Fresh water Aquatic Ecotoxicity (FAET). Acidification (AC) and Eutrophication (EU) are dominated by the emission of fertilizers. The emissions from the use of pesticides, especially insecticides dominate Terrestrial Ecotoxicity (TE) and make a considerable contribution to Freshwater Aquatic Ecotoxicity (FAET) and Photochemical Oxidation (PhO). There is no visible contribution from the use of pesticides to the other toxicity categories. Production and use of greenhouse plastic are another important contributors, and just a bit less than the contribution of calcium nitrate to Abiotic Depletion (AD). The results of this study clearly indicate nutrient management and emissions from pesticide use, especially insecticides, as a focus point for environmental optimization of the rose cultivation sector in Ethiopia.
This chapter provides an overview of the environmental impacts of the supply chain for preserved seaweed. The supply chain includes the hatchery, marine infrastructure, deployment of juveniles and monitoring during cultivation (grow-out of seaweed), harvest, transport back to shore and preservation of the biomass. The chapter starts with a short overview of the life cycle assessment (LCA) methodology, and how it can be used to quantify the environmental impacts of seaweed supply chains. After a discussion of the overall environmental impacts of the preserved seaweed supply chain, the chapter focuses on specific life cycle stages: spore preparation and seeding of juvenile seaweed onto string in the hatchery, seaweed cultivation, harvesting preservation and storage of harvested seaweed. The chapter ends with a summary and discussion of future trends in the subject.
Seaweed cultivation and processing industries could contribute to sustainable blue growth and the European bioeconomy. This article contributes a case study evaluation of environmental sustainability of preserved brown seaweed Saccharina latissima by means of environmental life cycle assessment of a pilot facility in Sweden. The study accounts for nutrient bioremediation and carbon capture and includes two alternative hatchery processes, a 2-ha longline cultivation, and four alternative preservation methods (hang-drying outdoors, heated air-cabinet drying, ensiling, and freezing). The study found that as a result of carbon capture and nitrogen and phosphorus uptake (bioremediation) by seaweed, more CO2 and PO4 equivalents are (temporarily) absorbed than emitted by the supply chain. The extent of emissions is most affected by preservation methods undertaken. Impact profiles of the supply chain show that the greatest impact shares result from freezing and air-cabinet drying, both the two most energy-intensive processes, followed by the cultivation infrastructure, highlighting strategic optimization opportunities. Hatchery processes, harvesting, and the low-energy ensilage and hang-drying outdoors were found to have relatively small impact shares. These findings presage the environmentally friendliness of seaweed-based products by documenting their potential to mitigate eutrophication and climate change, even when taking a life cycle perspective.
Disposable cups can be made from conventional petro-plastics, bioplastics, or paperboard (coated with petro-plastics or bioplastics). This study compared ten life cycle assessment (LCA) studies of disposable cups with the aim to evaluate the robustness of their results. The selected studies have only one impact category in common, namely climate change with global warming potential (GWP) as its category indicator. Quantitative GWP results of the studies were closer examined. GWPs within and across each study show none of the cup materials to be consistently better than the others. Comparison of the absolute GWPs (after correction for the cup volume) also shows no consistent better or worse cup material. An evaluation of the methodological choices and the data sets used in the studies revealed their influence on the GWP. The differences in GWP can be attributed to a multitude of factors, i.e., cup material and weight, production processes, waste processes, allocation options, and data used. These factors basically represent different types of uncertainty. Sensitivity and scenario analyses provided only the influence of one factor at once. A systematic and simultaneous use of sensitivity and scenario analyses could, in a next research, result in more robust outcomes.
Many methods have been reported and used to include recycling in life cycle assessments (LCAs). This paper evaluates six widely used methods: three substitution methods (i.e. substitution based on equal quality, a correction factor, and alternative material), allocation based on the number of recycling loops, the recycled-content method, and the equal-share method. These six methods were first compared, with an assumed hypothetical 100% recycling rate, for an aluminium can and a disposable polystyrene (PS) cup. The substitution and recycled-content method were next applied with actual rates for recycling, incineration and landfilling for both product systems in selected countries. The six methods differ in their approaches to credit recycling. The three substitution methods stimulate the recyclability of the product and assign credits for the obtained recycled material. The choice to either apply a correction factor, or to account for alternative substituted material has a considerable influence on the LCA results, and is debatable. Nevertheless, we prefer incorporating quality reduction of the recycled material by either a correction factor or an alternative substituted material over simply ignoring quality loss. The allocation-on-number-of-recycling-loops method focusses on the life expectancy of material itself, rather than on a specific separate product. The recycled-content method stimulates the use of recycled material, i.e. credits the use of recycled material in products and ignores the recyclability of the products. The equal-share method is a compromise between the substitution methods and the recycled-content method. The results for the aluminium can follow the underlying philosophies of the methods. The results for the PS cup are additionally influenced by the correction factor or credits for the alternative material accounting for the drop in PS quality, the waste treatment management (recycling rate, incineration rate, landfilling rate), and the source of avoided electricity in case of waste incineration. The results for the PS cup, which are less dominated by production of virgin material than aluminium can, furthermore depend on the environmental impact categories. This stresses the importance to consider other impact categories besides the most commonly used global warming impact. The multitude of available methods complicates the choice of an appropriate method for the LCA practitioner. New guidelines keep appearing and industries also suggest their own preferred method. Unambiguous ISO guidelines, particularly related to sensitivity analysis, would be a great step forward in making more robust LCAs.
Life cycle assessment (LCA) is a standardized methodology, but LCAs of the same product often still lead to divers outcomes. This study purposely used multiple data sets and methodological choices in an LCA of a disposable PS cup to quantify how these variations propagate and lead to a spread in LCA-results. The results for the PS cup consistently show major contributions from PS production, cup manufacturing, incineration and recycling (and minor contributions from other processes). Notably differences in amounts and types of energy used and reported emissions caused variation in results. Energy related impact categories contain smaller spread than the toxicity categories. The spread in results might give less clear, but more certain results to decision makers.
Life Cycle Assessments (LCAs) of the same products often result in different, sometimes even contradictory outcomes. Reasons for these differences include using different data sets and deviating modelling choices. This paper purposely used different data sets and modelling choices to identify how these differences propagated in LCA results. Vehicle for this methodological exploration was an LCA case study of a typical polystyrene (PS) disposable cup. An initial LCA of PS cups was made using only one data set per process. Contribution and sensitivity analysis identified those processes with influential contribution to the overall environmental impact. Next additional data sets were acquired for all influential processes. The spread in impact results for each life cycle process was calculated after impact assessment for each individual inventory data set as to preserve the correlation between inventory data within each individual data set. The spread in impact results reflects uncertainty existing between different data sets for the same process and due to modelling choices. The influence on overall LCA results was quantified by systematically applying all combinations of data sets and modelling choices. Results from the different data sets and modelling choices systematically point to the same processes as main contributors to all impact categories (PS production, cup manufacturing, PS incineration and PS recycling). The spread in toxicity indicators exceeds the energy-related impact categories. Causes of spread are resources and energy used (type, amount, date and origin), reported emissions, and applied allocation procedures. Average LCA results show slight preference for recycling PS compared to incineration in most impact categories. Overlapping spread in results of the two waste treatments, however, does not support the preference for recycling. The approach in this paper showed how variation in data sets and modelling choices propagates in LCA outcomes. This is especially useful for generic LCAs as systematic use of multiple data sets and multiple modelling choices increases the insight in relative contributions of processes to, and uncertainty in the overall LCA. These results might be less easy to perceive, but they provide decision makers with more robust information.
This study used multiple data sets and modelling choices in an environmental life cycle assessment (LCA) to compare typical disposable beverage cups made from polystyrene (PS), polylactic acid (PLA; bioplastic) and paper lined with bioplastic (biopaper). Incineration and recycling were considered as waste processing options, and for the PLA and biopaper cup also composting and anaerobic digestion. Multiple data sets and modelling choices were systematically used to calculate average results and the spread in results for each disposable cup in eleven impact categories. The LCA results of all combinations of data sets and modelling choices consistently identify three processes that dominate the environmental impact: (1) production of the cup's basic material (PS, PLA, biopaper), (2) cup manufacturing, and (3) waste processing. The large spread in results for impact categories strongly overlaps among the cups, however, and therefore does not allow a preference for one type of cup material. Comparison of the individual waste treatment options suggests some cautious preferences. The average waste treatment results indicate that recycling is the preferred option for PLA cups, followed by anaerobic digestion and incineration. Recycling is slightly preferred over incineration for the biopaper cups. There is no preferred waste treatment option for the PS cups. Taking into account the spread in waste treatment results for all cups, however, none of these preferences for waste processing options can be justified. The only exception is composting, which is least preferred for both PIA and biopaper cups. Our study illustrates that using multiple data sets and modelling choices can lead to considerable spread in LCA results. This makes comparing products more complex, but the outcomes more robust
Seaweeds are presently explored as an alternative source to meet the future protein demand from a growing world population with an increasing welfare level. Present seaweed research largely focuses on agri-technical and economic aspects. This paper explores directions for optimizing the cultivation, harvesting, transport and drying of seaweed from an environmental point of view. An environmental life cycle assessment (LCA) and detailed sensitivity analysis was made for two different system designs. One system design is featuring one layer of cultivation strips (four longlines side by side) interspaced with access corridors. The other system design is featuring a doubling of cultivation strips by dual layers in the water column. Impact profiles and sensitivity analysis showed that the most important impacts came from drying the harvested seaweed, and from the production of the chromium steel chains and polypropylene rope in the infrastructure. This indicates that caution should be used when designing cultivation systems featuring such materials and processes. Furthermore, the high-density productivity of the dual layer system decreases absolute environmental impacts and so found to be a little more environmentally friendly from a life cycle perspective.