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Current implementations of hybrid life cycle assessment (LCA) mostly do not fully exploit valuable information from multi‐regional input–output databases by aggregating regional supply chains to the lower geographical resolution of process LCA databases. We propose a method for sampling the various individual regions within the aggregated regional scope of LCA processes. This sampling maximizes the information content of hybrid LCA footprint results by preserving the regional variance, and it allows for regional price distributions from BACI/UN‐COMTRADE international trade statistics to be used to simultaneously improve the accuracy of the hybrid model. This work makes the previously hidden regional and price variance explicit and analyzes uncertainty of the hybrid carbon (global warming potential 100, GWP100) and land use footprints arising from these variances, both separately and in combination. We find that the median process footprint intensity increases by 7−3+18%$7^{+18}_{-3}\%$ for the GWP100 due to hybridization, and 90−23+143%$90^{+143}_{-23}\%$ for the land use footprint. Results show that the magnitude of the footprint uncertainty strongly depends on the product sector of the LCA process and environmental impact considered. In a case study of Swiss household consumption, we find truncation error estimates of 8.4−2.7+9.2%$8.4^{+9.2}_{-2.7}\%$ for the GWP100 and 36−14+64%$36^{+64}_{-14}\%$ for the land use footprint. Our results highlight the importance of regionalization of process LCA databases, as it has the potential to significantly improve both the precision and accuracy of derived hybrid LCA models. This article met the requirements for a gold/gold JIE data openness badge described at http://jie.click/badges. [ABSTRACT FROM AUTHOR]

Purpose: There is a growing concern about the resilience and sustainability of horticultural production in the United Kingdom (UK) as a result of high energy costs and insufficient local labour, causing over-reliance on imports. In this study, we present an integrated environmental and economic assessment of organic peri-urban horticulture using primary data from a farm in Sheffield. Methods: This study includes a farm-to-gate hybrid life cycle assessment (LCA) using the ReCIPE (H) approach for the functional unit of 1-kg tomatoes produced in an unheated polytunnel without supplementary lighting, and 1 kg of field-grown courgettes. All analyses were conducted in SimaPro software using environmental data from the ecoinvent database. Results were compared with those from a systematic literature review of similar studies. Results: We found that the production of organic tomatoes and courgettes resulted in a global warming potential (GWP) of 0.61 kg CO2-eq and 0.11 kg CO2-eq respectively using a process-based LCA approach. Using a hybrid LCA approach, however, yielded a GWP of 3.53 kg CO2-eq and 1.70 kg CO2-eq for the production of organic tomatoes and courgettes respectively. An additional scenario included farmgate-to-warehouse transportation for both domestic and imported produce from Spain, but found that the GWP of tomatoes in the case study was 1.87 times higher than those from Spain. Economic analysis showed that the marginal increase in the prices of tomatoes and courgettes from the case study farm was 4.6 and 5.15 times less than the market prices. Conclusion: We conclude that the studied production system is both economically and environmentally sustainable as compared to the existing scenario. Other potential benefits of peri-urban organic horticulture include employment, mental health, community cohesion, which remain to be explored in a future qualitative study. The present study is novel as it appears to be the first application of hybrid LCA to UK horticulture. The findings are highly topical given the recent horticultural supply constraints in the UK. [ABSTRACT FROM AUTHOR]

Abstract The construction industry contributes around 18% of greenhouse gas emissions, 40% of depletion of natural resources, and 25% of wastes globally. To reduce these impacts, construction industries can adopt low-carbon alternatives for construction materials and waste minimisation strategies, including the recycling of construction and demolition waste. However, a comprehensive understanding of the full life cycle carbon profile of low-carbon and recyclable construction materials is required to accurately assess the efficacy of decarbonisation strategies in the built environment. Despite recent progress in hybrid life cycle assessment (hybrid LCA) methods, some weaknesses remain with respect to the inherent uncertainty relating to price variations and aggregated sectors that are unable to provide detailed waste-specific information in hybrid LCA. Furthermore, attributional, hybrid LCA for a functional unit does not reflect the actual, economy-wide physical flows of materials in a real economy. In this study, a mixed-unit hybrid LCA approach based on a combination of process life cycle inventory, input–output, and material flow data is used to model the economy-wide potential use of recycled construction materials in Australia. A comparison between methods of life cycle emissions of geopolymer concrete revealed that the mixed-unit hybrid LCA approach produced a more accurate and Australian-specific result. The usefulness of the proposed mixed-unit IO model is demonstrated through quantifying the cradle-to-gate embodied emissions of recycled construction materials and by-products utilised in concrete and steel sectors in Australia. The results yield a 1% reduction when recycled concrete aggregate completely replaces natural aggregate in both ordinary Portland cement and geopolymer concrete. Greenhouse gas emissions reduction of 30% is quantified for geopolymer concrete using recycled concrete aggregate compared with ordinary Portland cement concrete utilising natural aggregate and 43% is estimated for electric arc furnace route using iron and steel scrap compared with basic oxygen furnace route. The method merges physical and monetary units of industrial systems related to low-carbon alternatives and recycled construction materials to enable the calculations of embodied carbon with improved accuracy. The results of this study can help inform decarbonisation strategies in the built environment sector.

In this study a tiered hybrid life cycle assessment (LCA) multi‐objective optimization model is developed and applied to determine the optimal choice of new biorefinery technologies in Germany. Thereby, several aspects can be explicitly addressed, including a regionally differentiated accountability of sustainable feedstock availability, identification of environmental impacts along global value chains, and identification of trade‐offs between different sustainability goals. The model is applied to assess the optimal choice between two lignocellulosic biorefinery concepts. Two optimization objectives are taken into account: maximizing the investor's profit and minimizing global impacts on climate change related to a specified demand for products. In terms of environmental impacts, the model also takes into account the comparison of new biorefineries with current available technologies producing the specified final demand. The results of the case study show that the biorefinery concept including the ethylene production is more beneficial in terms of reducing climate impacts, while on the other hand the biorefinery including the ethanol production is more cost‐effective. Depending on the decision‐maker's preference on weighting the two objectives, different capacities of biorefineries and optimal locations in Germany are identified. Furthermore, regions in Germany providing the necessary biomass feedstock can be identified on a county level. Finally, we argue that the extension of LCA by multi‐objective optimization is well suited guiding the way toward well‐informed decision‐making in the field of technological choices. [ABSTRACT FROM AUTHOR]

Abstract The objectives of this paper are 1) to estimate emissions in managing a sewer pipeline project from a life cycle perspective; and 2) to develop methods that can be used to assist engineers and stakeholders in the estimation especially when data are limited. The motivation is to provide an approach that can be used readily in practice to evaluate emissions in managing a sewer pipeline or a general infrastructure system by using available data. The life cycle assessment tool is applied over the pipe material manufacturing, installation, and maintenance phases. In the material manufacturing and installation phase, this research routinely tends to collect and evaluate detailed inventories data. The results show that the manufacturing phase contributes the most emissions. Material transportation in the installation also generates great amounts which are highly impacted by the transportation distance of vehicles. Emissions from activities such as equipment use and architecture and engineering services are not negligible which need to be considered in practice. In the maintenance phase, the study develops methods to estimate emissions based on the Markov chains model. The developed methods make it possible to estimate emissions within a given duration conventionally and at a 'steady state' phase once a strategy is applied. The study also presents a method to conduct the model sensitivity analysis using simulating results from Matlab tools. The analysis shows that the model has decent robustness. In addition, the methodology proposed may be applied to estimate emissions in other infrastructure management as well. Highlights • Methods to estimate environmental emissions in managing sewer pipeline projects are proposed. • A detailed inventory was developed to estimate emissions in the pipeline installation phase. • A stochastic method was presented to estimate emissions in the maintenance phase. • A sensitivity analysis was proposed to evaluate the model sensitivity. [ABSTRACT FROM AUTHOR]

As Yang and Heijungs (Int J Life Cycle Assess 10.1007/s11367-018-1532-y, 2018) bring forward, there is indeed a need for "more realistic modeling of the economy" in LCA. However, what I discuss in this letter is that this does not imply that research should be "moving from completing system boundaries to more realistic modeling" or that "hybrid LCA with further linear sophistication is a step forward in the wrong direction", as Yang and Heijungs (2018) state. Five arguments are brought forward as to why not: (1) completing system boundaries is a fundamental aspect of LCA; (2) the approach that leads to a higher accuracy in LCA will in practice remain relative and case dependent; (3) the general argument of hybrid LCA is not that every economic activity is in theory connected; (4) hybrid LCA is applied for more reasons than just completing system boundaries; and (5) hybrid LCA is more a step forward in a pragmatic data-driven direction, which is not a wrong direction. Finally, I propose that a more broad empirical study is needed to pinpoint which type of adaptation might most probably lead to higher accuracy, keeping in mind that this still will never be completely generalizable. [ABSTRACT FROM AUTHOR]

Waste management is becoming a crucial issue in modern society owing to rapid urbanization and the increasing generation of municipal solid waste (MSW). This paper evaluates the carbon footprint of the waste management sector to identify direct and indirect carbon emissions, waste recycling carbon emission using a hybrid life cycle assessment and input-output analysis. China and Japan was selected as case study areas to highlight the effects of different industries on waste management. The results show that the life cycle carbon footprints for waste treatment are 59.01 million tons in China and 7.01 million tons in Japan. The gap between these footprints is caused by the different waste management systems and treatment processes used in the two countries. For indirect carbon footprints, China’s material carbon footprint and depreciation carbon footprint are much higher than those of Japan, whereas the purchased electricity and heat carbon footprint in China is half that of Japan. China and Japan have similar direct energy consumption carbon footprints. However, CO2 emissions from MSW treatment processes in China (46.46 million tons) is significantly higher than that in Japan (2.72 million tons). The corresponding effects of waste recycling on CO2 emission reductions are considerable, up to 181.37 million tons for China and 96.76 million tons for Japan. Besides, measures were further proposed for optimizing waste management systems in the two countries. In addition, it is argued that the advanced experience that developed countries have in waste management issues can provide scientific support for waste treatment in developing countries such as China. [ABSTRACT FROM AUTHOR]

Low-carbon transition in the non-electric energy sector, which includes transport and heating energy, is necessary for achieving the 2 °C target. Meanwhile, as non-electric energy accounts for over 60% of total water consumption in the energy supply sector, it is vital to understand future water trends in the context of decarbonization. However, few studies have focused on life-cycle water impacts for non-electric energy; besides, applying conventional LCA methodology to assess non-electric energy has limitations. In this paper, a Multi-Regional Hybrid Life-Cycle Assessment (MRHLCA) model is built to assess total CO 2 emissions and water consumption of 6 non-electric energy technologies – transport energy from biofuel and gasoline, heat supply from natural gas, biogas, coal, and residual biomass, within 7 major emitting economies. We find that a shift to natural gas and residual biomass heating can help economies reduce 14–65% CO 2 and save more than 21% water. However, developed and developing economies should take differentiated technical strategies. Then we apply scenarios from IMAGE model to demonstrate that if economies take cost-effective 2 °C pathways, the water conservation synergy for the whole energy supply sector, including electricity, can also be achieved. [ABSTRACT FROM AUTHOR]

Normalisation is an optional step in Life Cycle Assessment (LCA), often used in decision making since it helps interpreting the results of LCA studies with regard to some reference information. The applicable ISO standard recommends considering different reference systems to guarantee the robustness of the normalisation step, and so the availability of different normalisation datasets becomes of high relevance. Life Cycle Impact Assessment (LCIA) methods provide normalisation factors (NFs) for global and regional areas, but no NFs are proposed for smaller areas such as local or subnational scales. The aim of this paper is to evaluate the feasibility of using territorial LCA approach to determine subnational NFs. Normalisation datasets for both Galician (NW Spain) production and consumption activities have been calculated considering a life cycle perspective. In addition to this, the normalisation datasets calculated for Galicia have been used to evaluate two food products produced and/or consumed in the region as case studies. Then, the normalised results have been compared to those obtained using different reference systems (Europe and the World), calculated following the same methodology (ReCiPe). A qualitative uncertainty analysis of the NFs has been carried out, and the usefulness of territorial LCA to determine them has been discussed. It was concluded that territorial LCA is a promising way to determine NFs but that some improvements could be made, which have also been pointed out here. [ABSTRACT FROM AUTHOR]

China’s rapid urbanization along with the development of the modern economy is certain to result in a long-standing and substantial energy demand in the entire society. Therefore, industrialization in building construction is a vital strategy for alleviating adverse environmental burdens and accelerating urbanization with the current construction practice. An integrated method was employed to evaluate the life cycle energy performance of prefabricated buildings, using the process-based hybrid life cycle assessment and scenario-based energy simulation as the underlying methods. Results revealed the less obvious energy reduction potential of prefabricated buildings during the embodied phase. During the building operation phase, the scenario and comparative analyses from a life-cycle perspective indicate that prefabrication generates environmental gains by providing enhanced thermal performance. A regional level policy analysis reveals the backwards status quo of the precast construction in Northern and Western China. Given the significance of using prefabrication in building energy conservation, it is quite urgent and necessary to establish a mature construction market with highly evolved industrialization in these “backward” regions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electric arc furnace slag can improve the performance of rutting and abrasion resistance in slurry surfacing. • Electric arc furnace slag can reduce the carbon footprint in the slurry surfacing mixture. • Aggregate packing degree and asphalt-aggregate bonding value plays important role in the slurry surfacing mixture design. • Electric arc furnace slag can become a potential source for aggregate replacement in slurry surfacing. Incorporating Electric Arc Furnace Slag (EAFS) into construction materials such as hot-mix asphalt and Portland cement concrete has shown increasing wear and polishing resistance while reducing solid waste and mitigating the carbon footprint of construction engineering. Pavement surface treatment is one of the most used pavement preservation approaches. The slurry surfacing (SS) technique provides the most hot-mix asphalt-like surface texture among the surface treatment techniques. This study aimed to investigate the feasibility of using EAFS for SS by incorporating various amounts of EAFS and then analyzing the treatment's performance and the resulting carbon footprint reduction. Performance tests of SS, including the wet track abrasion test and loaded wheel test, were performed to evaluate SS's abrasion and deformation resistance. Aggregate packing degree and bonding strength based on the surface charge were also considered to understand the mechanism affecting the performance. The corresponding reduction in carbon footprint is then analyzed using the tiered hybrid life cycle assessment method to understand further the benefits of using EAFS in SS. The results revealed that mixtures incorporating EAFS could be carefully designed to perform better by increasing the packing degree and bonding strength. Also, adding EAFS into SS increased abrasion resistance by up to 18.2%, rutting resistance by up to 72.8%, and reduced the carbon footprint by up to 39.6%. [ABSTRACT FROM AUTHOR]

Concrete is the second most used material after water and the production of cement is responsible for 5–8% of global carbon dioxide emissions. The development of low-carbon concretes is pursued worldwide to help the construction industry make its contribution to decarbonising the built environment and achieving carbon reduction targets agreed under the Paris Climate Agreement. However, there is uncertainty around the actual amount of greenhouse gas emissions that can be avoided by employing alternative types of concrete. This study quantifies the carbon footprint intensities of Australian cement and concrete production, including ordinary Portland cement, standard ordinary Portland cement concrete, blended cement-based concrete and geopolymer concrete production. For the first time, an input-output based hybrid life-cycle assessment method is used for these products. The main goal of this paper is therefore to make a methodological comparison between process-based and hybrid life cycle assessment using the Australian cement and concrete production as a case study. A comparison with published results from process-based life-cycle inventories as well as a decomposition of results into product categories is provided. The hybrid life cycle assessment resulted in higher greenhouse gas emissions for ordinary Portland cement and all types of concrete due to the methodology incorporating an economy-wide system boundary, which includes the emissions from upstream processes. For geopolymer concrete in particular, the results were also dependent on the method applied for allocating greenhouse gas emissions from fly ash and slag. The findings from this study are likely to inform the development of strategies and policies aimed at greenhouse gas reduction in the cement and concrete industries. [ABSTRACT FROM AUTHOR]

Purpose: Hybrid life cycle assessment (LCA) with a complete system boundary is recognized as an advanced approach widely applied in comparative analysis with the goal of product promotion. Here, I evaluate the theoretical foundation, or assumptions, of hybrid LCA in this application and discuss alternative models. The goal of this article is partly to call attention to the restrictive assumptions involved in the models used in LCA and to instigate further research and effort to improve these models. Methods: As with process-based LCA, hybrid LCA is a type of linear model when it is used to estimate changes. It relies on several restrictive assumptions such as fixed input/output coefficients and unlimited supply of inputs. Besides, hybrid LCA further rests on the assumption of economy-wide effect, i.e., a change of any magnitude in the output of any product would affect the entire economy. This may be another restrictive assumption, and to what extent it is reasonable depends on an array of factors, including the product being studied, its role in the economy, the magnitude of change, and the structure of the economy. Results and discussion: Because of the restrictive assumptions, hybrid LCA may not necessarily yield adequate results for product promotion. This, however, does not mean that it entirely falls short, but that the assumptions need to be scrutinized and determined if they reasonably reflect the reality. If so, the results yielded by hybrid LCA may be adequate. But if not, the results fall short, and further research is needed. Conclusions: For comparative analysis with the goal of product promotion, understanding how increases in the output of the product being studied would affect the economy is crucial. And this should form the basis of decision making. Alternative models to consider for large-scale changes include computable general equilibrium models and rectangular choice of technology models, recognizing their limitations and assumptions as well. Alternatively, one may use simpler models such as process-based inventory but build scenarios to study how the impact of product promotion may ripple through the economy. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this study is to identify which processes contribute most to fuel COe emissions, energy use, and employment generation when driving a typical Brazilian flex fuel vehicle (FFV) model with bagasse-derived ethanol. A hybrid life cycle assessment (LCA) is used to report the associated impacts and a structural path analysis (SPA) is utilized to identify, quantify, and rank the highest carbon emissions, energy use, and employment generation input paths in the supply chain of bagasse-derived ethanol. Additionally, this study explores the integrated hybrid LCA approach as a tool to explain the economic impacts of bagasse-derived ethanol. Methods: Hybrid LCA links process-based and input-output-based analyses into a consistent mathematical framework, thereby allowing the incorporation of economic factors into an environmental intervention matrix. The functional unit used in this study is a travel of 500 km with hydrated bagasse-derived ethanol in a Brazilian average FFV 1.0. Results and discussion: The total COe emission is 55.4 kg, with 40 % of the emissions from lime and enzyme production and the sugarcane production for bagasse (agricultural phase). The sulfuric acid, lime, and the agricultural phase are identified as the most intensive energy consumers, representing approximately 50 % of the total energy used. From the economic perspective, commerce and services, ethanol industrial, and agricultural phase generate the greatest number of jobs in this bagasse-derived ethanol life cycle. Conclusions: The focus has shifted from first-generation biofuels to more advanced technologies. The results illustrate the importance of a complete life cycle vision for assessing the sustainability of a biofuel. Agricultural biomass production is identified as relevant in all environmental and economic impact categories assessed here. Integrated hybrid LCA was used as an analytical tool capable of assessing the product's sustainability performance, based on the fact that its mathematical framework allows the incorporation of economic and environmental coefficients into a single intervention matrix using a combined database. [ABSTRACT FROM AUTHOR]

Small-scale bio-energy projects have been launched in rural areas of China and are considered as alternatives to fossil-fuel energy. However, energetic and environmental evaluation of these projects has rarely been carried out, though it is necessary for their long-term development. A village-level biomass gasification project provides an example. A hybrid life-cycle assessment (LCA) of its total nonrenewable energy (NE) cost and associated greenhouse gas (GHG) emissions is presented in this paper. The results show that the total energy cost for one joule of biomass gas output from the project is 2.93 J, of which 0.89 J is from nonrenewable energy, and the related GHG emission cost is 1.17 × 10−4 g CO2-eq over its designed life cycle of 20 years. To provide equivalent effective calorific value for cooking work, the utilization of one joule of biomass gas will lead to more life cycle NE cost by 0.07 J and more GHG emissions by 8.92 × 10−5 g CO2-eq compared to natural gas taking into consideration of the difference in combustion efficiency and calorific value. The small-scale bio-energy project has fallen into dilemma, i.e., struggling for survival, and for a more successful future development of village-level gasification projects, much effort is needed to tide over the plight of its development, such as high cost and low efficiency caused by decentralized construction, technical shortcomings and low utilization rate of by-products.

What could be the reduction in greenhouse gas emissions if the conventional way of maintaining roads is changed? Emissions of greenhouse gases must be reduced if global warming is to be avoided, and urgent political and technological decisions should be taken. However, there is a lock-in in built infrastructures that is limiting the rate at which emissions can be reduced. Self-healing asphalt is a new type of technology that will reduce the need for fossil fuels over the lifetime of a road pavement, at the same time as prolonging the road lifespan. In this study we have assessed the benefits of using self-healing asphalt as an alternative material for road pavements employing a hybrid input–output-assisted Life-Cycle Assessment, as only by determining the plausible scenarios of future emissions will policy makers identify pathways that might achieve climate change mitigation goals. We have concluded that self-healing roads could prevent a considerable amount of emissions and costs over the global road network: 16% lower emissions and 32% lower costs compared to a conventional road over the lifecycle.

Assessing the environmental impacts of electricity generation is fundamental for designing a low-carbon future for our societies. The amount of data collected for that purpose has significantly increased over the past decade due to the emergence of various methods, such as life cycle assessment and input-output analysis. We present here a comparison of environmental assessment methods for geothermal plants, based on physical and/or monetary data. Results show that some hybrid (mass-monetary) inventories yield results that vary significantly between impact categories. However, for the particular geothermal system investigated, direct emissions of geothermal fluids dominate the few impact categories to which they contribute. [ABSTRACT FROM AUTHOR]

Decision concerning manufacturing process design and management, under sustainable constraints, are difficult to draw when taking into account variability of process conditions. Life-cycle analysis and exergetic analysis are even more jointly adopted to improve the accuracy of resource use efficiency – the so-called hybrid approach – even though these are based on the assumption of constant operating conditions. The paper discussed a new idea to take into account variability in hybrid exergetic LCA due to contingent conditions, by proposing an exergetic control-chart (ExCC) scheme to formalise the variable conditions. The idea behind the ExCC approach is that manufacturing sustainability analysis may change its outcomes when taking into account this ‘dynamic’ point of view. The control-charting scheme here proposed provides a mean to formalise explicitly the effects of variability in time, under the real operating conditions. The main advantage of the approach is to allow a more complete view of the process and to drive hints for improvements or innovations of processes. A real industrial case here presented of an Italian SME explains the potentialities of the idea as well as the limits of the current hybrid approaches available. [ABSTRACT FROM AUTHOR]

Recently it has been estimated that one third of biodiversity threats are driven by consumer demand from outside the country in which the threat occurs. This occurs when the production of export goods exerts pressure on vulnerable populations. While population biologists have in cases been able to establish links between species threats and the causative industry(s), little has been done to trace this biodiversity footprint from the directly implicated industry out to final consumers, a step that would open a wider variety of policy responses. Here we investigate the suitability of multi-region input–output (MRIO) analysis for tracing out links between particular species threats, directly implicated industries, and the countries and consumer goods sectors ultimately driving these industries. Environmentally extended MRIO models are understood to provide reliable results at a macroeconomic level but uncertainty increases as the models are used to investigate individual sectors, companies, and products. In this study we examine several case studies (nickel mining in New Caledonia, coltan from the Democratic Republic of Congo, cut flowers from Kenya, and forestry in Papua New Guinea) in order to understand how and when MRIO techniques can be useful for studying biodiversity implicated supply chains. The study was conducted using the Eora global input–output database that documents >5 billion global supply chains. Calculating the biodiversity footprint at this level of detail, between specific threats, supply chains, and consumer goods, has not been done before. These case studies provide interesting insights in their own right and also serve to highlight the strengths and weaknesses of using input–output analysis techniques to calculate detailed biodiversity footprints. We conclude that MRIO analysis, while no panacea, can be useful for outlining supply chains and identifying which consumption sectors and trade and transformation steps can be subjected to closer analysis in order to enable remedial action. [ABSTRACT FROM AUTHOR]

This paper proposes a method for the calculation and evaluation of C02 emissions resulting from the implementation of a large-scale infrastructure. The method is based on a Hybrid Life-Cycle Assessment, which considers the teiri- torial and geographical characteristics in the calculation of energy consumption and associated emissions. It identifies four macro phases of the construction process (excavation, production and application of building materials, operability of tunnels and construction sites), each of which is broken down into specific sub-activities. The method is tested on the Brenner base tunnel, for which emissions equal to 2.28 m of C02 are estimated. The majority of them (85%) derives from the production of concrete and steel, while the other phases contribute to a more limited extent. The results are useful in the process of optimisation of the implementation processes, providing guidance on factors to consider in order to reduce C02 emissions. In addition, the method can serve to decision makers for an assessment of transport policies that is more attentive to environmental issues. [ABSTRACT FROM AUTHOR]

This study presents comparative life cycle assessments (LCAs) and levelised cost (LC) analyses of desalination supply systems, integrated with a spatial–temporal model at three geographical scales: a centralised scenario and two alternative decentralised scenarios . For the centralised scenario we focused on a proposed 320,000 m 3 /day SWRO desalination plant to support future urban expansion in the northern corridor of Perth, Western Australia. The alternative, decentralised scenarios each integrate several medium sized plants into the same geographical water demand area as the centralised scenario and also produce 320,000 m 3 /day in total. Results indicate that environmental impacts would be ~ 20% lower and LC 7% to 18% lower for the decentralised scenarios than for the centralised scenario . Contribution analysis revealed that, for the centralised scenario , although economies of scale resulted in lower environmental impacts from the desalination plant construction and operation phases, these savings were outweighed by the environmental impacts associated with the construction and operation of the water transfer mains required to connect the large plant to the network. Perth water stakeholders and policy makers can use our results to inform development decisions, and the proposed LCA method can be implemented in other metropolitan areas for desalination planning. [ABSTRACT FROM AUTHOR]

One of the most important challenges facing our society is the efficient and economic use of energy, and with it the corresponding need to reduce greenhouse gas (GHG) emissions. Due to growing concerns over global warming and climate change in recent years, warm mix asphalt (WMA) has become an important new research topic in the field of pavement materials, as it offers a potential solution for the reduction of energy consumption and GHG emissions during the production and placement of asphalt mixtures. While many studies have been conducted to demonstrate that the mechanical properties of such mixtures are not significantly affected, many questions and concerns regarding the environmental benefits they offer have yet to be addressed. In this study, a comprehensive hybrid life cycle assessment of WMA production was carried out to accurately evaluate and quantify the potential benefits of WMA technology by assessing the environmental impacts of its production associated with energy consumption and GHG emissions. The results of this study show that, for the WMA mixtures considered here, when the upstream supply chain related to the production of the materials composing such mixtures is taken into account, WMA technology is able to significantly save energy and reduce GHG emissions when compared to the control mixtures. However, it must be noted that in some cases, the manufacturing temperature at the asphalt plant must be reduced before the benefits of reduced emissions and fuel usage can be obtained. The results of a detailed production layer decomposition indicate that the fuel, mining and construction sectors are the main contributors to the environmental impacts of manufacturing the WMA mixtures studied. [ABSTRACT FROM AUTHOR]

Purpose: Data centres are high-energy consumers, and historical assessment of their environmental impact has focused largely on energy consumption. Widely adopted assessment methods consider either single issues or do not comprehensively assess links between issues. One exception is the CLEER Model, which compares life cycle energy and greenhouse gas (GHG) emissions of Cloud-based and present-day services. However, there remains the need to verify components for inclusion in a data centre life cycle assessment (LCA), assess quality and quantity of secondary data, benchmark an existing data centre LCA, assess non-Cloud-based services for multiple impacts, and establish facility areas that are sensitive to change. Methods: A hybrid approach, combining process-based and economic input output (EIO) data, was used to perform the screening LCA of an existing UK data centre. The study includes the definition of the goal and scope, modelling assumptions, a life cycle inventory, results and interpretation and a sensitivity check. Results and discussion: The dominance of the information technology (IT) operational phase to the overall impact and the severity of the impact on human health are concluded. Due to the use of free cooling, the IT-embodied impact is greater than the combined mechanical and electrical operational impact. Electricity production dominates the total life cycle impact; however, the second most significant impact derives from the disposal of metal refining waste products during the manufacture of IT components and electricity distribution networks. The release of carcinogens is one of the largest contributors to the whole life cycle impact and is almost equal in value between the embodied and operational phases. Finally, a sensitivity check found that a Swedish facility optimised for operational energy efficiency with a 1.25-year server refresh resulted in an embodied impact almost double the operational. Conclusions: It was concluded that current LCI data, software packages and project data allow for a sufficiently accurate data centre LCA model. The results support the need to broaden environmental impact reduction to beyond operational energy consumption for cooling and that building environmental assessment methods (BEAMs) should consider more embodied impacts. It is concluded also that three parameters are sensitive to design changes that influence the overall impact: operational energy for the IT equipment, cooling and power delivery; the energy mix; and the amount of IT equipment across the facility's lifetime. The results present a clear need to monitor life cycle impact, develop further tools to compare different design/operation options and functional units, improve data and develop an LCA-based BEAM. [ABSTRACT FROM AUTHOR]

Life cycle assessment is a multidisciplinary framework usually deployed to appraise the sustainability of various product or service supply-chains. Over recent decades, its use in the agri-food sector has risen sharply, and alongside this, a wide range of methodological advances have been generated. Spatial-life cycle assessment, defined in the current document as the interpretation of life cycle assessment results within a geographical nature, has not gone unexplored entirely, yet its rise as a sub-method of life cycle assessment has been rather slow relative to other avenues of research (e.g., including the nutritional sciences within life cycle assessment). With this relative methodological stagnation as a motivating factor, our paper combines a process-based model, the Catchment Systems Model, with various life cycle impact assessments (ReCiPe, Centre for Environmental Studies and Environmental Product Declaration) to propose a simple, yet effective, approach for visualising the technically feasible efficacy of various on-farm intervention strategies. As water quality was the primary focus of this study, interventions reducing acidification and eutrophication potentials of both arable and livestock farm types in the Southeast of England were considered. The study site is an area with a marked range of agricultural practices in terms of intensity. All impacts to acidification potential and eutrophication potential are reported using a functional unit of 1 ha. Percentage changes relative to baseline farm types, i.e., those without any interventions, arising from various mitigation strategies, are mapped using geographical information systems. This approach demonstrates visually how a spatially-orientated life cycle assessment could provide regional-specific information for farmers and policymakers to guide the restoration of certain waterbodies. A combination of multiple mitigation strategies was found to generate the greatest reductions in pollutant losses to water, but in terms of individual interventions, optimising farm-based machinery (acidification potential) and fertiliser application strategies (eutrophication potential) were found to have notable benefits. [Display omitted] • A novel yet data intensive spatial-life cycle assessment framework is proposed. • Farm types with and without agri-environmental interventions are assessed. • Eutrophication and acidification potentials are calculated for each farm type. • Optimising machinery usage reduces water impacts through decreased sediment loss. • Spatial-life cycle assessment is an effective tool for visualising environmental impact. [ABSTRACT FROM AUTHOR]

Life cycle impacts have been evaluated to compare and assess six tertiary treatment alternatives for secondary treated municipal wastewater for reuse in thermo-electric power plant cooling systems. Impacts during construction and operation of tertiary treatment processes using databases and characterization tools embedded in the process-based life cycle assessment (LCA) software, Simapro v7.3, and the Carnegie Mellon economic input-output LCA (EIO-LCA) 2002 model were estimated. Infrastructure cost estimates from life cycle cost analysis were used as inputs to the EIO-LCA model. Inputs to the process-based analysis included chemical doses added during and after tertiary treatment, approximate transport distance of chemicals from producer to treatment site, and energy generation to operate major equipment during treatment. Impacts considered included global warming potential (in kg CO2 eq.), acidification (in kg SO2 eq.), eutrophication (in kg N eq.) and ecotoxicity (in kg 2,4-D eq.)-estimated using TRACI model characterization factors. The environmental impacts analysis showed that manufacture of chemicals for tertiary treatment and conditioning, and electric power generation were the main processes that contribute to environmental impacts. Thus, alternatives with no or less tertiary treatment are recommended from an environmental impact perspective for reuse of secondary treated wastewater in cooling systems. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 178-187, 2015 [ABSTRACT FROM AUTHOR]

Remediation operations may have a wide range of environmental, social and economic impacts not only within the physical boundary of a contaminated site and over the operational period, but also across geophysical boundaries and beyond project life cycle. Life cycle assessment (LCA) has been increasingly used by both researchers and industrial practitioners in the ongoing green and sustainable remediation movement. This paper proposes a new hybrid-LCA method. In comparison with most remediation LCA studies in literature, the proposed approach offers several advantages by: 1) expanding the system boundary and reduces truncation errors; 2) incorporating consequential benefits (i.e. tertiary impact) of remediation; and 3) covering social and economic impact in addition to environmental impact. The hybrid LCA method is built on the 123 sector input–output analytical table and environmental account for the UK. The model was augmented with additional socioeconomic data (e.g. employment, occupational health and safety) to measure social and economic impact indicators. A sediment remediation project at the London Olympic Park site was examined using this method. The hybrid LCA was found to capture an additional 32% of secondary impact in soil washing, and 8% of secondary impact in landfilling. The tertiary impact was found to be over twice the primary plus secondary impact in soil washing, and nearly 80% of the primary plus secondary impact in landfilling. The quantitative social and economic impact assessment results also provided useful information for holistic decision making, balancing project costs with social and economic benefits. [ABSTRACT FROM AUTHOR]

We investigate the economic and employment consequences of introducing a new sugarcane-based biofuel industry into Australia. We model the new biofuel industry on the production recipe of the existing large-scale gasoalcohol and alcohol sectors in the Brazilian economy. To this end we utilise a hybrid IO-LCA (input–output life cycle assessment) approach, which involves inserting data on new processes and/or sectors into an existing IO table. In particular, we develop and test an analytical and a numerical approach for re-balancing an IO table augmented with rows and columns representing large new biofuel industries. We quantify changes in economic output and employment in the Australian economy. We conclude that a future biofuel industry will be employment-positive for Australia. [ABSTRACT FROM AUTHOR]

Purpose: Hazard-resistant materials for homes promise environmental benefits, such as avoided waste and materials for repairs, which can be overlooked by scoping in life-cycle assessment (LCA) approaches. Our motivation for pursuing this research was to see how incorporating these avoided losses in the LCA could impact choices between hazard-resistant and traditional materials. Methods: Two choices common in home construction were analyzed using an LCA process that incorporates catastrophe modeling to consider avoided losses made possible with hazard-resistant materials. These findings were compared to those based on a similar LCA that did not consider these avoided losses. The choices considered were standard windows vs. windows with impact-resistant glass and standard windows with no opening protection vs. standard windows with impact-resistant storm panels. Results and discussion: For the window comparisons, the standard products were environmentally preferable when avoided losses from storm events were not considered in the LCA. However, when avoided losses were considered, the hazard-resistant products were environmentally preferable. Considering avoided losses in LCAs, as illustrated by the window choices, can change which product appears to be the environmentally preferable option. Further, as home service life increases, the environmental net benefit of the hazard-resistant product increases. Conclusions: Our results show the value of an LCA approach which allows more complete scopings of comparisons between hazard-resistant materials and their traditional counterparts. This approach will help translate the impacts of hazard-resistant products into the more familiar language used to talk about 'green' products, enabling more informed decisions by product manufacturers, those who develop building certification systems and codes, researchers, and other building industry stakeholders. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to contribute to an improved understanding of the environmental implications of offshore power grid and wind power development pathways. To achieve this aim, we present two assessments. First, we investigate the impacts of a North Sea power grid enabling enhanced trade and integration of offshore wind power. Second, we assess the benefit of the North Sea grid and wind power through a comparison of scenarios for power generation in affected countries. Methods: The grid scenario explored in the first assessment is the most ambitious scenario of the Windspeed project and is the result of cost minimization analysis using a transmission-expansion-planning model. We develop a hybrid life cycle inventory for array cables; high voltage, direct current (HVDC) links; and substations. The functional unit is 1 kWh of electricity transmitted. The second assessment compares two different energy scenarios of Windspeed for the North Sea and surrounding countries. Here, we utilize a life cycle inventory for offshore grid components together with an inventory for a catalog of power generation technologies from Ecoinvent and couple these inventories with grid configurations and electricity mixes determined by the optimization procedure in Windspeed. Results and discussion: Developing, operating, and dismantling the grid cause emissions of 2.5 g CO-Eq per kWh electricity transmission or 36 Mt CO-Eq in total. HVDC cables are the major cause of environmental damage, causing, for example, half of total climate change effects. The next most important contributors are substations and array cabling used in offshore wind parks. Toxicity and eutrophication effects stem largely from leakages from disposed copper and iron mine tailings and overburden. Results from the comparison of two scenarios demonstrate a substantial environmental benefit from the North Sea grid extension and the associated wind power development compared with an alternative generation of electricity from fossil fuels. Offshore grid and wind power, however, entail an increased use of metals and, hence, a higher metal depletion indicator. Conclusions: We present the first life cycle assessment of a large offshore power grid, using the results of an energy planning model as input. HVDC links are the major cause of environmental damage. There are differences across impact categories with respect to which components or types of activities that are responsible for damage. The North Sea grid and wind power are environmentally beneficial by an array of criteria if displacing fossil fuels, but cause substantial metal use. [ABSTRACT FROM AUTHOR]

Purpose: Life cycle assessment (LCA) of chemicals is usually developed using a process-based approach. In this paper, we develop a tiered hybrid LCA of water treatment chemicals combining the specificity of process data with the holistic nature of input-output analysis (IOA). We compare these results with process and input-output models for the most commonly used chemicals in the Australian water industry to identify the direct and indirect environmental impacts associated with the manufacturing of these materials. Methods: We have improved a previous Australian hybrid LCA model by updating the environmental indicators and expanding the number of included industry sectors of the economy. We also present an alternative way to estimate the expenditure vectors to the service sectors of the economy when financial data are not available. Process-based, input-output and hybrid results were calculated for caustic soda, sodium hypochlorite, ferric chloride, aluminium sulphate, fluorosilicic acid, calcium oxide and chlorine gas. The functional unit is the same for each chemical: the production of 1 tonne in the year 2008. Results and discussion: We have provided results for seven impact categories: global warming potential; primary energy; water use; marine, freshwater and terrestrial ecotoxicity potentials and human toxicity potential. Results are compared with previous IOA and hybrid studies. A sensitivity analysis of the results to assumed wholesale prices is included. We also present insights regarding how hybrid modelling helps to overcome the limitations of using IO- or process-based modelling individually. Conclusions and recommendations: The advantages of using hybrid modelling have been demonstrated for water treatment chemicals by expanding the boundaries of process-based modelling and also by reducing the sensitivity of IOA to fluctuations in prices of raw materials used for the production of these industrial commodities. The development of robust hybrid life cycle inventory databases is paramount if hybrid modelling is to become a standard practice in attributional LCA. [ABSTRACT FROM AUTHOR]

Abstract: Given the rising expectations for the substitution of fossil energy with renewable energy as one of the solutions to cope with climate change, the carbon emission reduction potential of possible solutions should be evaluated in a holistic and systematic way. In this paper, a systematic account of carbon emission reduction potential was conducted for a typical household biogas system with a digester volume of 8 m3, using a hybrid life-cycle assessment method. Using a 20 year operation scenario, the total life cycle CO2 emission of this family-size biogas utilization system is 2.60 tons, i.e., 0.02 kg CO2/MJ, of which 98.46% is attributed to indirect emissions from building materials and labor inputs. Considering the carbon emission savings due to energy and fertilizer substitution, the annual CO2 emission reduction potential is 1.25 tons for the biogas system that is under consideration. Consequently, such rural household biogas systems should be operated for at least 1.78 years to achieve a positive reduction benefit, i.e., cumulative CO2 emission savings could offset the life-cycle-related CO2 emissions. The results also indicate that long-term, stable running and maintenance are key points to maximize the benefits of household biogas as an effective approach for carbon emission abatement in the rural areas of China. [Copyright &y& Elsevier]

Small-scale bio-energy projects have been launched in rural areas of China and are considered as alternatives to fossil-fuel energy. However, energetic and environmental evaluation of these projects has rarely been carried out, though it is necessary for their long-term development. A village-level biomass gasification project provides an example. A hybrid life-cycle assessment (LCA) of its total nonrenewable energy (NE) cost and associated greenhouse gas (GHG) emissions is presented in this paper. The results show that the total energy cost for one joule of biomass gas output from the project is 2.93 J, of which 0.89 J is from nonrenewable energy, and the related GHG emission cost is 1.17 × 10-4 g CO2-eq over its designed life cycle of 20 years. To provide equivalent effective calorific value for cooking work, the utilization of one joule of biomass gas will lead to more life cycle NE cost by 0.07 J and more GHG emissions by 8.92 × 10-5 g CO2-eq compared to natural gas taking into consideration of the difference in combustion efficiency and calorific value. The small-scale bio-energy project has fallen into dilemma, i.e., struggling for survival, and for a more successful future development of village-level gasification projects, much effort is needed to tide over the plight of its development, such as high cost and low efficiency caused by decentralized construction, technical shortcomings and low utilization rate of by-products. [ABSTRACT FROM AUTHOR]

Purpose: In LCA, the intrinsic dependence of productions to human labour (HL) activities is usually neglected, without providing any clear arguments. HL is not considered to be related to and affected by, changes to the functional unit, although this is evidently not the case. This research aims at investigating the relationship between HL and LCA and at developing an operational framework to assess the life cycle environmental impact of HL in LCA. Materials and methods: System boundaries and functional unit (euro/working-hour) of HL were defined. Statistical datasets of household expenditures (HEs) allowed differentiating among human consumption behaviours and the definition of three HL types, based on different work skills: HL-1 (qualified worker), HL-2 (technician), and HL-3 (manual worker). The HEs framework of Luxembourg was used because of data availability and was then extended to other EU-27 countries. A comparative LCIA of the HLs types was carried out using an environmentally extended input-output model (EU-27). Afterwards, ten agri-food and industrial LCAs case studies were modified for hybrid LCAs, adding HL input to LCIs and using the ReCiPe midpoint method for LCIA. Results and discussion: The LCIA comparison of HLs shows that HL-1 generates environmental impacts that are always greater than HL-2 and HL-3, e.g. 1 h of HL-1, which involves workers with the highest consumption of goods and services, does generate 0.52 kg CO-eq, whereas HL-2 and HL-3 generate 0.46 and 0.41 kg CO-eq, respectively. The impact of average HL is higher in EU countries with the highest HEs budgets, e.g. the average HL impact in Luxembourg is 28% to 79% higher than the corresponding HL impact in other EU-27 countries. Within the case studies, the HL significantly contributes to the total impact for several categories (e.g. fossil and ozone depletion up to 16% and 20%, respectively). Despite these important results, some limitations due to data and models used are investigated to suggest further methodological improvements. Conclusions: The integration of HL inputs to product LCIs can improve accuracy of the entire life cycle analysis, since no product would exist without direct and/or indirect HL. This leads considering humans at the same level of technological/economic activities that cause environmental damage, with humans being perceived as leading actors and explicitly responsible for the impacts. What remains an open question is how to account for non-physical information, such as knowledge/education/culture, which distinguish humans from machinery and are essential items for our future sustainable development. [ABSTRACT FROM AUTHOR]

Purpose: The cities merit special attention in global warming since they produce up to 80% of the global greenhouse gas emissions. Even though this has been widely acknowledged, only few papers exist that have studied cities holistically from a demand, i.e., consumption, perspective. The study presents a detailed analysis of the carbon footprint of two metropolitan cities from a consumption perspective. With the analysis of consumer carbon footprints (carbon consumption), the distribution of emissions in the key source categories is presented and compared. Materials and methods: The study utilizes Finnish consumer survey data by cities, regional emission data for key processes, and general emission data to produce a hybrid LCA model for a holistic assessment of city-level greenhouse gas emissions from the consumption perspective. Results and discussion: The study results showed the carbon consumption to be 13.2 t CO2e per person in Helsinki with a 17,400 € annual consumption expenditure and 10.3 t CO2e per person in Porvoo with a 15,900 € annual consumption expenditure, respectively. The dominant carbon sources for metropolitan living are heat and electricity, building and property, private driving, and services. Within the cities, some significant differences were found. The carbon emissions from energy consumption are 4.5 t CO2e for an average consumer in Helsinki, whereas an average consumer in Porvoo only causes 2.0 t CO2e due to the cleaner energy production in Porvoo. On the other hand, private driving causes 2.0 t CO2e in Porvoo, but only 1.3 t in Helsinki. The overall trip generation in Helsinki is only half of that in Porvoo, and also, the usage of public transport is at a substantially higher level in Helsinki. The current results contradict interestingly some earlier studies in finding that the theoretical carbon-reducing influence of city density is overridden with other factors, such as the type of energy production, energy efficiency of the housing stock, and increased use of services. In our study, Helsinki represents a metropolitan area with a denser structure and a more efficient public transport system, but still consuming around 25% more carbon emissions than the other city in the metropolitan area, Porvoo. The sensitivity analysis showed that even with the normalization of the key parameters between the two cities, the main finding still holds. Conclusions: The evaluation of the carbon footprint of cities from the consumption perspective, instead of a more traditional production perspective, seems to offer an interesting new insight into the carbon footprints of the cities. It identifies similar key sources of carbon as production-oriented studies but further emphasizes the significance of the utilized services in the carbon footprint evaluations. In the future, the carbon footprint of services, especially in the service-intensive economies and cities that tend to outsource their manufacturing and carbon emissions, should be further examined since they cause an ever increasing proportion of the carbon consumption of consumers. [ABSTRACT FROM AUTHOR]

In this study, we conducted a hybrid life-cycle assessment (LCA) to evaluate reductions in CO2 emissions by food waste biogasification of household food wastes in Japan. Two alternative scenarios were examined. In one alternative (Ref), all combustible municipal solid wastes (MSWs), including food waste, are incinerated. In the other (Bio), food waste is biogasified, while the other combustible wastes are incinerated. An inventory analysis of energy and material flow in the MSW management system was conducted. Subsequently, the inventory data were summarized into an input-output format, and a make-use input-output framework was applied. Furthermore, a production equilibrium model was established using a matrix representing the input- output relationship of energy and materials among the processes and sectors. Several levels of power generation efficiency from incineration were applied as a sensitivity analysis. The hybrid LCA indicated that the difference between the Bio and Ref scenarios, from the perspective of CO2 emissions, is relatively small. However, a 13-14% reduction of CO2 emissions of the total waste management sector in Japan may be achieved by improving the efficiency of power generation from incineration from 10% to 25%. [ABSTRACT FROM AUTHOR]

Background and theory Life cycle assessment (LCA) and life cycle inventory (LCI) practice needs to engage with the debate on water use in agriculture and industry. In the case of the red meat sector, some of the methodologies proposed or in use cannot easily inform the debate because either the results are not denominated in units that are meaningful to the public or the results do not reflect environmental outcomes. This study aims to solve these problems by classifying water use LCI data in the Australian red meat sector in a manner consistent with contemporary definitions of sustainability. We intend to quantify water that is removed from the course it would take in the absence of production or degraded in quality by the production system. Materials and methods The water used by three red meat supply systems in southern Australia was estimated using hybrid LCA. Detailed process data incorporating actual growth rates and productivity achieved in two calendar years were complemented by an input-output analysis of goods and services purchased by the properties. Detailed hydrological modelling using a standard agricultural software package was carried out using actual weather data. Results The model results demonstrated that the major hydrological flows in the system are rainfall and evapotranspiration. Transferred water flows and funds represent small components of the total water inputs to the agricultural enterprise, and the proportion of water degraded is also small relative to the water returned pure to the atmosphere. The results of this study indicate that water used to produce red meat in southern Australia is 18-540 L/kg HSCW, depending on the system, reference year and whether we focus on source or discharge characteristics. Interpretation Two key factors cause the considerable differences between the water use data presented by different authors: the treatment of rain and the feed production process. Including rain and evapotranspiration in LCI data used in simple environmental discussions is the main cause of disagreement between authors and is questionable from an environmental impact perspective because in the case of some native pastoral systems, these flows may not have changed substantially since the arrival of Europeans. Regarding the second factor, most of the grain and fodder crops used in the three red meat supply chains we studied in Australia are produced by dryland cropping. In other locations where surface water supplies are more readily available, such as the USA, irrigation of cattle fodder is more common. So whereas the treatment of rain is a methodological issue relevant to all studies relating water use to the production of red meat, the availability of irrigation water can be characterised as a fundamental difference between the infrastructure of red meat production systems in different locations. Conclusions Our results are consistent with other published work when the methodological diversity of their work and the approaches we have used are taken into account.We show that for media claims that tens or hundreds of thousands of litres of water are used in the production of red meat to be true, analysts have to ignore the environmental consequences of water use. Such results may nevertheless be interesting if the purpose of their calculations is to focus on calorific or financial gain rather than environmental optimisation. Recommendations and perspectives Our approach can be applied to other agricultural systems. We would not suggest that our results can be used as industry averages. In particular, we have not examined primary data for northern Australian beef production systems, where the majority of Australia's export beef is produced. [ABSTRACT FROM AUTHOR]

Background, aim, and scope One barrier to the further implementation of LCA as a quantitative decision-support tool is the uncertainty created by the diversity of available analytical approaches. This paper compares conventional (`process analysis') and alternative (`input-output analysis') approaches to LCA, and presents a hybrid LCA model for Australia that overcomes the methodological limitations of process and input-output analysis and enables a comparison between the results achieved using each method. A case study from the water industry illustrates this comparison. Materials and methods We have developed a tiered hybrid model for calculating the life cycle impacts of a system. In so doing, we have developed a novel way of overcoming a key methodological issue associated with this method: avoiding double counting. We calculate `system incompleteness factors' and use these to delete the lower-order burdens in the input-output inventory according to the depth of production taken into account in the process inventory. We apply this method to a case study of Sydney Water Corporation. The functional unit is the provision of water and sewerage services to residential, industrial, and commercial customers in the city of Sydney in the year 2 002/03. Results and discussion We analysed the case study using three methods: process analysis, input-output analysis, and hybrid analysis. In each case, we obtained results for eight impact categories: water use; primary energy use; global warming potential; carcinogenic and non-carcinogenic human toxicity potentials; and terrestrial, marine and freshwater ecotoxicity potentials. Although the process analysis has a relatively shallow investigative depth, it shows good system coverage (i.e. a small truncation error) for most indicators. The truncation errors for all of the indicators except marine aquatic ecotoxicity potential compare favourably with predicted truncation errors for the relevant industry sector. This suggests that the truncation error of a particular process analysis cannot be accurately predicted using generic system completeness curves, and implies that the truncation error of a typical process analysis may be less severe than is commonly generalised by the proponents of input-output analysis. Conclusions The case study supports the largely theoretical claims in the literature about the relative merits and drawbacks of process and input-output analysis. Each method has the potential to highlight different aspects of the system. By estimating the truncation error of the process analysis independently of the relationship between the results obtained using the other methods, our hybrid model enhances the ability to investigate the differences between results and thus adds considerable value to such a study. Recommendations and perspectives Input-output LCA has become more popular as computational tools have become more accessible. We directly compare input-output, process and hybrid LCA and recommend that, from an environmental analysis perspective, it would be beneficial to consider the three methodologies in parallel. We highlight the potential for misinterpretation of differences between methods that rely on different reporting frameworks, and recommend that LCA method and practice continue to emphasise the role of careful interpretation. [ABSTRACT FROM AUTHOR]

Background, aim, and scope As the sustainability improvement becomes an essential business task of industry, a number of companies are adopting IT-based environmental information systems (EIS). Life cycle assessment (LCA), a tool to improve environmental friendliness of a product, can also be systemized as a part of the EIS. This paper presents a case of an environmental information system which is integrated with online LCA tool to produce sets of hybrid life cycle inventory and examine its usefulness in the field application of the environmental management. Main features Samsung SDI Ltd., the producer of display panels, has launched an EIS called Sustainability Management Initiative System (SMIS). The system comprised modules of functions such as environmental management system (EMS), green procurement (GP), customer relation (e-VOC), eco-design, and LCA. The LCA module adopted the hybrid LCA methodology in the sense that it combines process LCA for the site processes and input-output (IO) LCA for upstream processes to produce cradle-to-gate LCA results. LCA results from the module are compared with results of other LCA studies made by the application of different methodologies. The advantages and application of the LCA system are also discussed in light of the electronics industry. Results and discussion LCA can play a vital role in sustainability management by finding environmental burden of products in their life cycle. It is especially true in the case of the electronics industry, since the electronic products have some critical public concerns in the use and end-of-life phase. SMIS shows a method for hybrid LCA through online data communication with EMS and GP module. The integration of IT-based hybrid LCA in environmental information system was set to begin in January 2006. The advantage of the comparing and regular monitoring of the LCA value is that it improves the system completeness and increases the reliability of LCA. By comparing the hybrid LCA and process LCA in the cradle-to-gate stage, the gap between both methods of the 42-in, standard definition plasma display panel (PDP) ranges from 1% (acidification impact category) to -282% (abiotic resource depletion impact category), with an average gap of 68.63%. The gaps of the impact categories of acidification (AP), eutrophication (EP), and global warming (GWP) are relatively low (less than 10%). In the result of the comparative analysis, the strength of correlation of three impact categories (AP, EP, GWP) shows that it is reliable to use the hybrid LCA when assessing the environmental impacts of the PDP module. Hybrid LCA has its own risk on data accuracy. However, the risk is affordable when it comes to the comparative LCA among different models of similar product line of a company. In the results of 2 years of monitoring of 42-in. … [ABSTRACT FROM AUTHOR]

Abstract: In a recent paper in this journal, Suh [Suh, S., 2004. Functions, commodities and environmental impacts in an ecological-economic model. Ecological Economics 40 (4), 451-467.] presented a model combining life cycle assessment (LCA) with input–output analysis (IOA); termed “integrated hybrid LCA”. In this paper, we discuss various issues relating to the use of the integrated hybrid LCA approach. In particular, the interpretation of the downstream feedback term, C d, is discussed with particular focus on practical implementation. In this paper, two interpretations of C d are suggested depending on the particular LCA data used. If the LCA data is designed for a demand on the functional unit only, then it is argued that the C d term is negligible in many applications. If the LCA data is compatible with an arbitrary demand, then it is argued that in many cases the consistent use of the C d term implies data requirements that may not be justified by the potential gains. [Copyright &y& Elsevier]

The Life Cycle Assessment (LCA) method is widely used to assess the environmental impacts generated during the entire life cycles of products. The traditional process-based LCA (P-LCA), however, has some weaknesses. One of them is incompleteness resulting from the omission of environmental loads on the higher upstream orders of product system. This problem is called "truncation error." There are some relatively new initiatives to combine the conventional P-LCA with the economic Input Output Analysis (IOA) in one general approach defined as a hybrid LCA. It allows solving different problems, even those which seemed to be unsolvable until now. [ABSTRACT FROM AUTHOR]

Hybrid life-cycle assessment employing input–output analysis has advantages over conventional methods. In the inventory phase of a hybrid assessment, the data collection and the boundary selection can be tailored by using structural path analysis. This technique was applied to recent Australian data in order to determine environmentally important input paths in terms of energy consumption, land disturbance, water use, and emissions of greenhouse gases, NOx, and SO2, for all Australian industry sectors. Due to the complexity of inter-industrial transactions, up to third-order paths can be top-ranking. The identification of such paths is considerably more labour-intensive in conventional life-cycle assessments. [Copyright &y& Elsevier]

Life cycle assessments (LCAs) are used to evaluate the environmental impacts attributable to products and processes. For construction projects, LCAs can be used to assess the pollution associated with the manufacture of building materials for the construction process. Despite the reliability of traditional LCA data, many upstream processes are excluded, which adversely affects overall reliability. Input-output analysis is systemically complete, but is subject to inherent errors when applied to the LCA of specific products. Analysis of an input-output LCA model provides a basis for more informed decision making regarding processes which can be ignored during the collection of traditional LCA data. This paper proposes a hybrid LCA method for construction in which national input-output data fill those `gaps' not accounted for by traditional LCA data. Regardless of the level of detail at which data are collected, LCAs can now be performed at similar overall levels of framework completeness. [ABSTRACT FROM AUTHOR]

• Life cycle assessment of a new nuclear power plant in Europe. • Three methods used: process-based, input-output, and hybrid life cycle assessment. • Results range from 8 to 64 gCO 2 e/kWh e. • Averages for the three methods are 16.97, 24.89 and 27.63 gCO 2 e/kWh e. • Results are higher than generally accepted figures for nuclear energy. Nuclear energy contributes ~10% of the global electricity generation and different views exist on its carbon-intensity and sustainability. Context is crucial to determine the sustainability of new nuclear power generators, making the existence of a global answer to the unresolved question unlikely. This study aims to establish the life-cycle greenhouse gas emissions associated with nuclear energy in Europe given ongoing construction of nuclear generators. Due to the high uncertainty and complexity that characterise construction and operation of nuclear generators, we adopt a multi-method, scenario-based approach. The three methods used are: process-based, input-output, and hybrid life cycle assessment. Scenarios account for different total energy outputs over the life cycle of the nuclear generator, different end of life options, and different sectoral allocations of costs in the input-output calculus. Results for the process-based, input-output, and hybrid methods range between 16.55–17.69, 18.82–35.15, and 24.61–32.74 gCO 2 e/kWh, respectively. These are either well above or at the upper end of the range of possibilities (5 to 22 gCO 2 e/kWh) stated in a report for the UK's Committee on Climate Change, and significantly higher than the median value of 12 gCO 2 e/kWh presented by the Intergovernmental Panel on Climate Change. They are also higher than the values acknowledged by the nuclear industry. Given the severe potential lock-in effects of today's energy choices for future generations, this research questions the role of nuclear energy to meet the UN Sustainable Development Goals and calls for further scrutiny on its sustainability and environmental viability. [ABSTRACT FROM AUTHOR]