Recent developments in Life Cycle Assessment

Environmental Performance of Innovative Ground-Source Heat Pumps with PCM Energy Storage

Space conditioning is responsible for the majority of carbon dioxide emission and fossil fuel consumption during a building’s life cycle. The exploitation of renewable energy sources, together with efficiency enhancement, is the most promising solution. An innovative layout for ground-source heat pumps, featuring upstream thermal energy storage (uTES), was already proposed and proved to be as effective as conventional systems while requiring lower impact geothermal installations thanks to its ability to decouple ground and heat-pump energy fluxes. This work presents further improvements to the layout, obtained using more compact and efficient thermal energy storage containing phase-change materials (PCMs). The switch from sensible- to latent-heat storage has the twofold benefit of dramatically reducing the volume of storage (by a factor of approximately 10) and increasing the coefficient of performance of the heat pump. During the daily cycle, the PCMs are continuously melted/solidified, however, the average storage temperature remains approximately constant, allowing the heat pump to operate closer to its maximum efficiency. A life cycle assessment (LCA) was performed to study the environmental benefits of introducing PCM-uTES during the entire life cycle of the system in a comparative approach.

Environmental Footprints of High-Speed Railway Construction in China: A Case Study of the Beijing-Tianjin Line

The environmental footprints of China’s high-speed railway (HSR) have attracted much attention nationally and internationally. Although there is some research focusing on CO₂ emissions, a comprehensive environmental impacts assessment of HSR construction is still lacking. In this study, the emissions of the Beijing–Tianjin intercity HSR line was calculated using a hybrid input–output life cycle assessment method to quantify the environmental impacts of HSR throughout its construction. The environmental footprints during the construction stage were analyzed in terms of different subsystems and sectors. The results showed that bridges contribute the largest environmental footprints at approximately 60%, followed by rail and electric multiple unit (EMU) systems. The top three sectors that contribute to pollutant emissions are the metal smelting and rolling industry, transport equipment manufacturing, and non-metallic mineral production. CO₂ and NO_x are the major pollutants directly emitted by site equipment operation. More chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), and petroleum are emitted in EMU production than in rail construction, while NH₃-N is emitted more in rails instead. Cd, Pb, As, and Hg are the significant pollutants in the metal smelting and rolling industry, whereas Cr, Cu, and Zn are the main heavy metal emissions in the transport equipment manufacturing sector. Heavy metals are the main types of environmental footprints in bridges, stations, and electric systems. Water pollutants are the main environmental impacts for rail and EMU systems, and the emissions of air pollutants are significant in subgrades. The production efficiency of upstream materials, desulfurization and denitration in fossil combustion, and the length of the bridge construction should be considered for an HSR under construction, in order to become environmentally friendly and sustainable.

Assessment of the Environmental Impact of a Car Tire throughout Its Lifecycle Using the LCA Method

There are numerous threats to the natural environment that pose a significant risk both to the environment and to human health, including car tires. Thus, there is a need to determine the impact of the life cycle of car tires on the environment, starting with the processes of raw materials acquisition, production, and ending with end-of-life management. Therefore, the authors of this study chose to do research on passenger car tires (size: P205/55/R16). As part of the research, the life cycle assessment (LCA) of traditional car tires was performed with the use of the Eco-indicator 99, cumulative energy demand (CED), and Intergovernmental Panel on Climate Change (IPCC) methods. The level of negative effects was determined for the life cycle of a tire and its particular stages: Production, use, and end of life. The negative impact on the atmosphere, soil, and water, as well as on human health, the environment, and natural resources was also investigated. The results show that the most energy-absorbing stage of a car tire life cycle is the use stage. It was found that the most harmful impact involves the depletion of natural resources and emissions into the atmosphere. Recycling car tires reduces their negative environmental impact during all their life cycle stages.

Life Cycle Assessment of Bitcoin Mining

This study estimates the environmental impact of mining Bitcoin, the most well-known blockchain-based cryptocurrency, and contributes to the discussion on the technology's supposedly large energy consumption and carbon footprint. The lack of a robust methodological framework and of accurate data on key factors determining Bitcoin's impact have so far been the main obstacles in such an assessment. This study applied the well-established Life Cycle Assessment methodology to an in-depth analysis of drivers of past and future environmental impacts of the Bitcoin mining network. It was found that, in 2018, the Bitcoin network consumed 31.29 TWh with a carbon footprint of 17.29 MtCO₂-eq, an estimate that is in the lower end of the range of results from previous studies. The main drivers of such impact were found to be the geographical distribution of miners and the efficiency of the mining equipment. In contrast to previous studies, it was found that the service life, production, and end-of-life of such equipment had only a minor contribution to the total impact, and that while the overall hashrate is expected to increase, the energy consumption and environmental footprint per TH mined is expected to decrease.

The environmental impacts and the carbon intensity of geothermal energy: A case study on the Hellisheiði plant

Geothermal energy, alongside other low-carbon and renewable energies, is set to play a key role in decarbonising the power generation industry to meet the Paris Agreement goal. Thus far the majority of Life Cycle Assessment (LCA) studies focused on enhanced geothermal plants. However, conventional geothermal plants that harness hydrothermal reservoirs dominate the production of electricity from geothermal energy worldwide. This article focuses on Hellisheiði, a combined heat and power double flash geothermal plant located in Iceland, with an installed capacity of 303.3 MW of electricity and 133 MW of hot water. The study has a twofold goal: (i) identify hot spots in the life cycle and, where possible, suggest improvements, and (ii) understand the potential of geothermal energy to decarbonise the power generation industry. First, a detailed LCA study has been performed on Hellisheiði, with cradle-to-grave system boundaries and detailed site-specific data obtained from the literature. The analysis identifies consumption of diesel for drilling and use of steel for wells casing and construction of the power plant as the main hot spots. Second, carbon intensities of electricity production for various possible configurations of the Hellisheiði power plant (including single flash, and power-only production) have been compared with those of other geothermal plants and other energy sources. Different allocation procedures have been used to allocate impacts between electricity and hot water where necessary, and Monte Carlo simulations have been used to estimate uncertainties of Hellisheiði's carbon intensities. The comparison shows that the carbon intensity of Hellisheiði is in the range of 15-24 g CO₂-eq./kWh, which is similar to those of binary cycle geothermal plants, solar (photovoltaic) and hydropower, lower than other geothermal technologies and fossil-based technologies, and higher than nuclear and onshore wind.

A Scientometric Review of Resource Recycling Industry

With rapid economic development and urbanization, a large number of primary resources are consumed and accumulate in society as recyclable resource, which causes great pressure on the environment. The development of the resource recycling industry (RRI) can reduce environmental impacts and achieve sustainable development and green growth. Scholars are paying more attention to the resource recycling industry (RRI), and the related literature continues to increase. There are over 7041 publications covering RRI in the Web of Science database from 1996 to 2018. This paper analyzes the time distribution characteristics of the literature and the status of the scientific research cooperation network using the visualization analysis software CiteSpace. The number of documents increased from 94 in 1996 to a peak of 963 in 2018. There is no relatively stable core author group. The number of papers published by “Chinese Acad Sci” ranks first among all research institutions. Document co-citation analysis and burst detection are adopted to assess the status and emerging trends in the RRI research domain. A publication by M.C. Monte on waste management is the most cited paper. Additionally, “green and sustainable and technology” and “science and technology—other topics” are the latest emerging subject categories in RRI research. Furthermore, “e-waste”, “reverse logistics” and “lean manufacturing” are emerging research trends for RRI, and “carbon emissions”, “policy”, “demolition waste”, “supply chain management” and “compressive strength” have become hot topics. These findings may provide inspiration for scholars to search for new research directions and ideas.

Handling uncertainties inherited in life cycle inventory and life cycle impact assessment method for improved life cycle assessment of wastewater sludge treatment

Life cycle assessment (LCA) has been used to evaluate environmental impacts of products or processes including wastewater treatment. Uncertainty has not received adequate attention in LCA studies. Uncertainty inherited in LCA steps such as the life cycle inventory (LCI) or the life cycle impact assessment (LCIA) method use is unavoidable, but it affects LCA outcomes and associated decision-making. The objective of this paper was to show the impact of uncertainty from LCI and LCIA method on LCA outcomes by using a case study base approach on wastewater sludge treatment processes. A qualitative analysis included setting criteria about what data to be included in LCI, characterization of data, differentiating between major and minor contributors in LCI modeling, evaluation of data quality indicators, setting achievable alternative scenarios, and selecting proper LCIA method were used, in addition to quantitative analysis included assigning most appropriate values for data gaps and proper distribution, and conducting probabilistic analysis to evaluate overall uncertainty. This research used a full-scale wastewater treatment plant in Missouri, USA for case study in which multiple hearth incineration (MHI) is the existing process, while fluid bed incineration (FBI) and anaerobic digestion (AD) were proposed as the alternatives. Using ReCipe method, the study revealed that variation in LCA results of MHI is 63.4% for a single end-point score of 57.9 mPt. On the two alternative processes, it is 54.6% probable that FBI would have more environmental impact than AD. The case study showed that the proposed steps were able to address issues of data uncertainty. Due to differences in characterization, normalization, and weighting factors, different LCIA methods may point out different conclusions and need to be addressed in evaluation.

Knowledge Mapping of Carbon Footprint Research in a LCA Perspective: A Visual Analysis Using CiteSpace

Carbon emissions are inevitably linked to lifestyle and consumption behaviours, and the concept of “carbon footprinting” is now well-recognised beyond academia. Life cycle assessment (LCA) is one of the primary tools for assessing carbon footprints. The aim of this paper is to present a systematic review of literatures focusing on carbon footprint calculated with life cycle assessment. We used CiteSpace software to draw the knowledge map of related research to identify and trace the knowledge base and frontier terminology. It was found that the LCA application in respects of carbon footprint studies was completed mainly for the following aspect: beef production and dairy industry, seafood and fishery, nutrition, urban structure and energy use. The CiteSpace analysis showed the development path of the above aspects, for example, beef production and dairy industry has been a long-term topic in this kind of research, while the topic of nutrition appeared in recent years. There was also a cluster of literature discussing footprint evaluation tools, such as comparing LCA with input–output analysis. The CiteSpace analysis indicated that earlier methodological literature still plays an important role in recent research. Moreover, through the analysis of burst keywords, it was found that agriculture productions (dairy, meat, fish, crop) as well as global climate issues (greenhouse gases emission, global warming potential) have always been the areas of concern, which matches the result of co-citation analysis. Building materials (low-carbon building, natural buildings, sustainable buildings) and soil issues (soil carbon sequestration, soil organic carbon) are the topics of recent concern, which could arouse the attention of follower-up researchers.

Life cycle costing of energy recovery from solid recovered fuel produced in MBT plants in Italy

The Environmental Life Cycle Costing (LCC) methodology was applied to assess the costs of the processing in Italy of municipal Residual Waste (RW) in Mechanical-Biological Treatment (MBT) plants aimed at the production of Solid Recovered Fuels (SRFs), delivered to dedicated waste-to-energy (WTE) plants or to co-combustion. Two different functional units were defined to consider two different perspectives: 1 tonne of residual waste in input of the MBT plant, and 1 MWh of exergy produced by the energy valorisation of the streams delivered by the MBT plant. Four strategies were analysed that differ for the type of MBT (single stream or separated streams) and the destiny of the SRF (dedicated WTE plant or cement kiln). The results appear to strongly recommend the treatment of the RW in a single stream MBT plant and the production of a SRF with characteristics suitable to meet the technological, economic and environmental needs for co-combustion, substituting fossil fuels.

Sustainable Seafood and Vegetable Production: Aquaponics as a Potential Opportunity in Urban Areas

Global population growth will increase pressures on current food systems in order to supply adequate protein and produce to the increasingly urban world population. The environmental impact of food production is a critical area of study as it influences water and air quality, ecosystem functions, and energy consumption. Aquaponics (in which seafood and vegetables are grown in a closed-loop system) has the potential to reduce the environmental impact of food production. A review of the current environmental and economic considerations is provided in order to identify current research gaps. Research gaps exist with respect to 1) diversity of aquatic and plant species studied; 2) inconsistent bounds, scope, and lifetime across studies; 3) diverse allocation of the environmental and economic impacts to the coproducts; 4) scale of systems considered; 5) transportation of produced food; and 6) presence of heavy metals, pests, and pathogens with human health implications. These aspects require increased attention to close the existing gaps prior to widescale deployment of these systems for increased sustainable food production toward satisficing human needs. Integr Environ Assess Manag 2019;00:1-12. © 2019 SETAC.

A Scale-up of Energy-Cycle Analysis on Processing Non-Woven Flax/PLA Tape and Triaxial Glass Fibre Fabric for Composites

In the drive towards a sustainable bio-economy, a growing interest exists in the development of composite materials using renewable natural resources. This paper explores the life cycle assessment of processing of Flax fibre reinforced polylactic acid (PLA), with a comparison of glass fibre triaxial fabric in the production process. The use of hydrocarbon fossil resources and synthetic fibres, such as glass and carbon, have caused severe environmental impacts in their entire life cycles. Whereas, Flax/PLA is one of the cornerstones for the sustainable economic growth of natural fibre composites. In this study, the manufacturing processes for the production of Flax/PLA tape and triaxial glass fibre were evaluated through a gate-to-gate life cycle assessment (LCA). The assessment was based on an input-output model to estimate energy demand and environmental impacts. The quality of the natural hybrid composite produced and cost-effectiveness of their LCA was dependent on their roving processing speeds and temperature applied to both the Flax/PLA tape and triaxial glass fabrics during processing. The optimum processing condition was found to be at a maximum of 4 m/min at a constant temperature of 170 °C. In contrast, the optimum for normal triaxial glass fibre production was at a slower speed of 1 m/min using a roving glass fibre laminating machine. The results showed that when the Flax and PLA were combined to produce new composite material in the form of a flax/PLA tape, energy consumption was 0.25 MJ/kg, which is lower than the 0.8 MJ/kg used for glass fibre fabric process. Flax/PLA tape and glass fibre fabric composites have a carbon footprint equivalent to 0.036 kg CO2 and 0.11 kg CO2, respectively, under the same manufacturing conditions. These are within the technical requirements in the composites industry. The manufacturing process adopted to transform Flax/PLA into a similar tape composite was considerably quicker than that of woven glass fibre fabric for composite tape. This work elucidated the relationship of the energy consumptions of the two materials processes by using a standard LCA analytical methodology. The outcomes supported an alternative option for replacement of some conventional composite materials for the automotive industry. Most importantly, the natural fibre composite production is shown to result in an economic benefit and reduced environmental impact.

Life Cycle Assessment of LNG Fueled Vessel in Domestic Services

This research was focused on a comparative analysis of using LNG as a marine fuel with a conventional marine gas oil (MGO) from an environmental point of view. A case study was performed using a 50K bulk carrier engaged in domestic services in South Korea. Considering the energy exporting market for South Korea, the fuel supply chain was designed with the two largest suppliers: Middle East (LNG-Qatar/MGO-Saudi Arabia) and U.S. The life cycle of each fuel type was categorized into three stages: Well-to-Tank (WtT), Tank-to-Wake (TtW), and Well-to-Wake (WtW). With the process modelling, the environmental impact of each stage was analyzed based on the five environmental impact categorizes: Global Warming Potential (GWP), Acidification Potential (AP), Photochemical Potential (POCP), Eutrophication Potential (EP) and Particulate Matter (PM). Analysis results reveal that emission levels for the LNG cases are significantly lower than the MGO cases in all potential impact categories. Particularly, Case 1 (LNG import to Korea from Qatar) is identified as the best option as producing the lowest emission levels per 1.0 × 107 MJ of fuel consumption: 977 tonnages of CO2 equivalent (for GWP), 1.76 tonnages of SO2 equivalent (for AP), 1.18 tonnages of N equivalent (for EP), 4.28 tonnages of NMVOC equivalent (for POCP) and 26 kg of PM 2.5 equivalent (for PM). On the other hand, the results also point out that the selection of the fuel supply routes could be an important factor contributing to emission levels since longer distances for freight transportation result in more emissions. It is worth noting that the life cycle assessment can offer us better understanding of holistic emission levels contributed by marine fuels from the cradle to the grave, which are highly believed to remedy the shortcomings of current marine emission indicators.

Aligning sustainability assessment with responsible research and innovation: Towards a framework for Constructive Sustainability Assessment

Emerging technologies are increasingly promoted on the promise of tackling the grand challenge of sustainability. A range of assessment and governance approaches seek to evaluate these claims, but these tend to be applied disparately and lack widespread operationalisation. They also face specific challenges, such as high levels of uncertainty, when it comes to emerging technologies. Building and reflecting on both theory and practice, this article develops a framework for Constructive Sustainability Assessment (CSA) that enables the application of sustainability assessments to emerging technologies as part of a broader deliberative approach. In order to achieve this, we discuss and critique current approaches to analytical sustainability assessment and review deliberative social science governance frameworks. We then develop the conceptual basis of CSA - blending life-cycle thinking with principles of responsible research and innovation. This results in four design principles - transdisciplinarity, opening-up, exploring uncertainty and anticipation - that can be followed when applying sustainability assessments to emerging technologies. Finally, we discuss the practical implementation of the framework through a three-step process to (a) formulate the sustainability assessment in collaboration with stakeholders, (b) evaluate potential sustainability implications using methods such as anticipatory life-cycle assessment and (c) interpret and explore the results as part of a deliberative process. Through this, CSA facilitates a much-needed transdisciplinary response to enable the governance of emerging technologies towards sustainability. The framework will be of interest to scientists, engineers, and policy-makers working with emerging technologies that have sustainability as an explicit or implicit motivator.

The Life-Cycle Environmental Impact of Recycling of Restaurant Food Waste in Lanzhou, China

The recycling of restaurant food waste can bring environmental benefits and improve food safety for urban residents. We here assessed the entire life cycle of the anaerobic digestion–aerobic composting technique of restaurant food waste recycling using Lanzhou as a case study. We used the CML2001 method provided with the Gabi software and compared the results to those produced using the traditional treatment techniques (landfill and incineration). This work includes a sensitivity analysis of the results. It is here concluded that the anaerobic digestion–aerobic composting technique had the smallest environmental impact of the methods here examined. The life cycle of anaerobic digestion–aerobic composting primarily consumes water, clay, coal, crude oil, and natural gas. The pre-processing phase consumes the most resources, and anaerobic digestion showed the greatest environmental impact. Specific environmental impacts in order from the highest to lowest potential to exacerbate global warming were found to be photochemical ozone production, acidification, eutrophication, marine aquatic ecotoxicity, human toxicity, freshwater aquatic ecotoxicity, and terrestrial ecotoxicity. The main factors associated with different environmental impacts and the environmental impacts themselves were found to differ across different phases. Some environmental impacts were shown to be sensitive to electricity, and the eutrophication potential and photochemical ozone creation potential showed the least sensitivity to all variables. To reduce the environmental impact of the anaerobic digestion–aerobic composting treatment technique, the energy structure and consumption of electricity, water, and diesel need to be optimized.

Bio-Based Production Systems: Why Environmental Assessment Needs to Include Supporting Systems

The transition to a bio-based economy is expected to deliver substantial environmental and economic benefits. However, bio-based production systems still come with significant environmental challenges, and there is a need for assessment methods that are adapted for the specific characteristics of these systems. In this review, we investigated how the environmental aspects of bio-based production systems differ from those of non-renewable systems, what requirements these differences impose when assessing their sustainability, and to what extent mainstream assessment methods fulfil these requirements. One unique characteristic of bio-based production is the need to maintain the regenerative capacity of the system. The necessary conditions for maintaining regenerative capacity are often provided through direct or indirect interactions between the production system and surrounding “supporting” systems. Thus, in the environmental assessment, impact categories affected in both the primary production system and the supporting systems need to be included, and impact models tailored to the specific context of the study should be used. Development in this direction requires efforts to broaden the system boundaries of conventional environmental assessments, to increase the level of spatial and temporal differentiation, and to improve our understanding of how local uniqueness and temporal dynamics affect the performance of the investigated system.

Environmental Assessment of an Urban Vertical Hydroponic Farming System in Sweden

With an expanding population and changing dynamics in global food markets, it is important to find solutions for more resilient food production methods closer to urban environments. Recently, vertical farming systems have emerged as a potential solution for urban farming. However, although there is an increasing body of literature reviewing the potential of urban and vertical farming systems, only a limited number of studies have reviewed the sustainability of these systems. The aim of this article was to understand the environmental impacts of vertical hydroponic farming in urban environments applied to a case study vertical hydroponic farm in Stockholm, Sweden. This was carried out by evaluating environmental performance using a life cycle perspective to assess the environmental impacts and comparing to potential scenarios for improvement options. The results suggest that important aspects for the vertical hydroponic system include the growing medium, pots, electricity demand, the transportation of raw materials and product deliveries. By replacing plastic pots with paper pots, large reductions in GHG emissions, acidification impacts, and abiotic resource depletion are possible. Replacing conventional gardening soil as the growing medium with coir also leads to large environmental impact reductions. However, in order to further reduce the impacts from the system, more resource-efficient steps will be needed to improve impacts from electricity demand, and there is potential to develop more symbiotic exchanges to employ urban wastes and by-products.

Environmental assessment of intake alternatives for seawater reverse osmosis in the Arabian Gulf

The study carried out an environmental assessment for two seawater reverse osmosis (RO) plants located within the Arabian Gulf considering subsurface intake alternatives and differing energy source options. The study used life cycle assessment to quantify the environmental impacts for open intake pretreatment vs. subsurface intake pretreatments of two plants with operating capacities of approximately 175,000 m³/d and 275,000 m³/d respectively. For both RO plants, electricity and chemical inputs were considered. Significant energy reductions of 30% were observed with subsurface intakes for extraction and pretreatment, resulting in a plant-wide energy saving of 6%. Open intake pretreatment had higher environmental impacts compared to subsurface intake across all impact categories, although in some impact categories significant differences existed between the two similar plants due to differences in chemicals used. The study further established that the renewable PV power generation resulted in the lowest global warming potential (GWP); however, a significant trade-off occurs with this energy source since it had the highest impact relative to both ozone and abiotic depletion potentials and was also worse than natural gas for both marine and human toxicity potentials. The GWP reductions achievable using a subsurface intake for the larger of the two plants is equivalent to 58,000 tons of CO₂ per year, or more than 12,000 cars, making subsurface intakes a worthy alternative to conventional open intake systems in the Arabian Gulf region. Marine aquatic eco-toxicity potential was identified as the most significant normalized environmental impact, which should be best managed through using natural gas as an energy source.

Review of Methodological Choices in LCA-Based Textile and Apparel Rating Tools: Key Issues and Recommendations Relating to Assessment of Fabrics Made From Natural Fibre Types

Life cycle assessment (LCA) is a key tool for determining environmental impacts for textiles and apparel and is the basis for the publicly available Higg Material Sustainability Index (MSI) developed by the Sustainable Apparel Coalition (SAC). This paper reviews and evaluates the Higg MSI with respect to rating of fabrics made from natural fibre types, with the aim of providing a constructive analysis of methodological issues identified by comparison with the International Standards and LCA guidelines. The major issues identified by the review were: (1) lack of sufficient guidance for comparative analysis and public disclosure; (2) incomplete system boundaries and the choice of functional unit; (3) the choice of attributional LCA methods and variable methods applied for handling multi-functionality; (4) use of generalised data and small datasets, without reported sensitivity or uncertainty; (5) exclusion of important impact categories, choice of LCIA methods and lack of coverage of non-LCA assessed issues; and (6) the choice of the weighting and normalisation approach. This review found that the provision of, and adherence to the appropriate standards and best practice in LCA would rectify most of these issues. To achieve the laudable aims of the Higg MSI, further development and refinement is needed to ensure robust information is provided to improve the sustainability of textiles.

Methodological Approaches to End-Of-Life Modelling in Life Cycle Assessments of Lithium-Ion Batteries

This study presents a review of how the end-of-life (EOL) stage is modelled in life cycle assessment (LCA) studies of lithium-ion batteries (LIBs). Twenty-five peer-reviewed journal and conference papers that consider the whole LIB life cycle and describe their EOL modelling approach sufficiently were analyzed. The studies were categorized based on two archetypal EOL modelling approaches in LCA: The cutoff (no material recovery, possibly secondary material input) and EOL recycling (material recovery, only primary material input) approaches. It was found that 19 of the studies followed the EOL recycling approach and 6 the cutoff approach. In addition, almost a third of the studies deviated from the expected setup of the two methods by including both material recovery and secondary material input. Such hybrid approaches may lead to double counting of recycling benefits by both including secondary input (as in the cutoff approach) and substituting primary materials (as in the EOL recycling approach). If the archetypal EOL modelling approaches are not followed, it is imperative that the modelling choices are well-documented and motivated to avoid double counting that leads to over- or underestimations of the environmental impacts of LIBs. Also, 21 studies model hydrometallurgical treatment, and 17 completely omit waste collection.

Global Warming Potential of Biomass-to-Ethanol: Review and Sensitivity Analysis through a Case Study

In Europe, ethanol is blended with gasoline fuel in 5 or 10% volume (E5 or E10). In USA the blend is 15% in volume (E15) and there are also pumps that provide E85. In Brazil, the conventional gasoline is E27 and there are pumps that offer E100, due to the growing market of flex fuel vehicles. Bioethanol production is usually by means of biological conversion of several biomass feedstocks (first generation sugar cane in Brazil, corn in the USA, sugar beet in Europe, or second-generation bagasse of sugarcane or lignocellulosic materials from crop wastes). The environmental sustainability of the bioethanol is usually measured by the global warming potential metric (GWP in CO2eq), 100 years time horizon. Reviewed values could range from 0.31 to 5.55 gCO2eq/LETOH. A biomass-to-ethanol industrial scenario was used to evaluate the impact of methodological choices on CO2eq: conventional versus dynamic Life Cycle Assessment; different impact assessment methods (TRACI, IPCC, ILCD, IMPACT, EDIP, and CML); electricity mix of the geographical region/country for different factory locations; differences in CO2eq factor for CH4 and N2O due to updates in Intergovernmental Panel on Climate Change (IPCC) reports (5 reports so far), different factory operational lifetimes and future improved productivities. Results showed that the electricity mix (factory location) and land use are the factors that have the greatest effect (up to 800% deviation). The use of the CO2 equivalency factors stated in different IPCC reports has the least influence (less than 3%). The consideration of the biogenic emissions (uptake at agricultural stage and release at the fermentation stage) and different allocation methods is also influential, and each can make values vary by 250%.

Human health benefit and burden of the schizophrenia health care pathway in Belgium: paliperidone palmitate long-acting injections

Background

Environmental impact assessments of pharmaceuticals typically consider only a part of the pharmaceutical supply chain, e.g. tablet formulation. While the environmental impact can be expressed in environmental Human Health burden due to resource use and emissions, the Human Health benefit of the pharmaceutical treatment of patients is currently not simultaneously taken into account. The study aims include a cradle-to-grave assessment of all Human Health impacts of the production, administration and disposal of two antipsychotics for the treatment of schizophrenia. This is complemented with the environmental impact of health care providers such as hospitals. The aim is to holistically quantify to what extent the environmental Human Health burden compares to the Human Health benefit associated with the treatment.

Methods

We applied an overall framework which included Life Cycle Assessment to model the environmental Human Health impacts of the pharmaceutical supply chain, administration and disposal of the drug and health care providers. To model the patient benefit, this was complemented with a Markov model with a 1-year time horizon. Three patient groups were modeled: medicine coverage of paliperidone palmitate for either one month (PP1M) or three months (PP3M) at a time, and compared to Treatment Interruption (TI) as a control group. Outcomes were quantified using Years of Life Lost (YLL), Years Lived with Disability (YLD) and Disability-Adjusted Life Years (DALY).

Results

The main environmental impacts were visits to the psychiatrist and psychiatric hospitals. The pharmaceutical supply chain had a limited impact. For 1000 patients for 1 year, PP1M and PP3M respectively avoided 0.38 and 0.49 environmental DALYs compared to TI. PP1M and PP3M further avoided 45.60 and 57.87 YLL and 23.31 and 29.91 YLD compared to TI. The main outcome was the sum of environmental DALYs, YLL and YLD, in which PP1M and PP3M respectively avoided 69.29 and 88.26 DALYs. Alternative analysis of Quality-Adjusted Life Years confirmed the results.

Conclusions

The overall environmental burden was lower for PP1M and PP3M treatment than Treatment Interruption because patients are kept more stable, which reduces the environmental burden due to hospitals. Moreover, the Human Health burden was outweighed by the Human Health benefit.

Electronic supplementary material

The online version of this article (10.1186/s12913-019-4247-2) contains supplementary material, which is available to authorized users.

Towards optimal trade-offs between material and energy recovery for green waste

Green waste is a type of biomass consisting mainly of grass, leaves and fresh prunings originating from gardens and parks. It can be used as feedstock for composting, or for energy recovery. The EU Waste Directive 2008/98/EC advocates composting to prevent waste. This directive allows green waste to be used for (renewable) energy valorization only if a better overall environmental outcome can be demonstrated. In this paper, we propose an assessment procedure based on examining the Pareto front of optimal trade-off combinations for maximizing composting and energy recovery of green waste while minimizing environmental impact and minimizing particulate matter emission. The Pareto optimal front is determined by solving a multi-objective optimization problem using the ε-constraint method. Previous research on green waste valorization using Life Cycle Analysis (LCA) shows that either energy recovery or composting is the preferred option depending on how environmental impact is assessed. In contrast to the full assignment to one of these recovery methods produced by LCA, we demonstrate, using the case of green waste valorization in the Netherlands and Belgium, that the proposed assessment procedure provides optimal solutions in a range between full allocation to compost or energy recovery. The proposed methodology supports the selection of optimal solutions taking the decision makers' preference into account that allows complying with Directives that have opposite goals on green waste valorization. Finally, computational results show that the assessment of the "better environmental outcome" requested by the EU waste Directive 2008/98/EC is influenced by the life cycle impact categories and the policy makers preferences with respect to the valorization options taken into account. Since the EU waste Directive 2008/98/EC does not specify how to execute the outcome assessment of valorization alternatives, this can lead to ambiguity.

The Third Wave of LCA as the “Decade of Consolidation”

Several authors have pointed out the importance of systems thinking, and have considered both environmental and social aspects (holistic perspective) of sustainability assessment in the past. Sustainability assessment tools which integrate different aspects (e.g., environmental/social aspects) in order to identify negative impacts have already been developed. Common tools used to assess environmental, social, or economic impacts include the life cycle assessment (LCA), social life cycle assessment (S-LCA), life cycle costing (LCC) and life cycle sustainability assessment (LCSA) approaches. The goal of the present study was to investigate how and to what extent the three dimensions of sustainability (environmental, social, economic; holistic sustainability perspective) have been integrated into the field of LCA. A topic modeling method was applied to examine whether the emphasis placed on integrating environmental, social, and economic aspects in sustainability assessment has resulted in a more comprehensive application of the LCA approach. The results show that topics related to energy and infrastructure are currently prevailing, and that topics related to methods have been decreasing since 1997. A minor discussion of social aspects and a lack of discussion on economic aspects were identified in the present study. These results do not support the predicted “decade of life cycle sustainability assessment.” Consequently, a new period of LCA extension and application is predicted, namely, the third wave of LCA as the “decade of consolidation.” During this period, the LCA framework will be enhanced to reduce existing practical and methodological difficulties and integrate environmental and social aspects in a sustainability assessment to support global sustainable development.

Life cycle assessment as decision support tool for environmental management in hospitals: A literature review

BACKGROUND

Life cycle assessment (LCA) is an environmental accounting tool aimed at determining environmental impacts of products, processes, or organizational activities over the entire life cycle. Although this technique already provides decision-makers in other sectors with valuable information, its application in the health care setting has not yet been examined.

PURPOSE

The aim of this study was to provide a comprehensive overview of scientific research on the application of LCA in hospitals and its contribution to management decision-making.

METHOD

We perform a systematic literature review by searching a range of databases with synonyms of "LCA" in combination with the term "hospital" in order to identify peer-reviewed studies. The final sample of 43 studies were then subjected to a content analysis.

RESULTS

We categorize existing research and show that single and multi-indicator LCA approaches are used to examine several products and processes in hospitals. The various approaches are favored by different scientific communities. Whereas researchers from environmental sciences perform complex multi-indicator LCA studies, researchers from health care sciences focus on footprints. The studies compare alternatives and identify environmental impacts and harmful hotspots.

PRACTICE IMPLICATIONS

LCA results can support health care managers' traditional decision-making by providing environmental information. With this additional information regarding the environmental impacts of products and processes, managers can implement organizational changes to improve their environmental performance. Furthermore, they can influence upstream and downstream activities. However, we recommend more transdisciplinary cooperation for LCA studies and to place more focus on actionable recommendations when publishing the results.

Life Cycle Assessment of waste disposal from olive oil production: Anaerobic digestion and conventional disposal on soil

Extra virgin olive-oil (EVO) production is an important economic activity for several countries, especially in the Mediterranean area such as Spain, Italy, Greece and Tunisia. The two major by-products from olive oil production, solid-liquid Olive Pomace (OP) and the Olive Mill Waste Waters (OMWW), are still mainly disposed on soil, in spite of the existence of legislation which already limits this practice. The present study compares the environmental impacts associated with two different scenarios for the management of waste from olive oil production through a comparative Life Cycle Assessment (LCA). The two alternative scenarios are: (I) Anaerobic Digestion and (II) Disposal on soil. The analysis was performed through SimaPro software and the assessment of the impact categories was based on International Life Cycle Data and Cumulative Energy Demand methods. Both the scenarios are mostly related to the cultivation and harvesting phase and are highly dependent on the irrigation practice and related energy demand. Results from the present study clearly show that the waste disposal on soil causes the worst environmental performance of all the impact categories considered here. Important environmental benefits have been identified when anaerobic digestion is chosen as the final treatment. It was consequently demonstrated that anaerobic digestion should be a feasible alternative for olive mills, to produce biogas from common olive oil residues, reducing the environmental burden and adding value to the olive oil production chain.

Evaluating the Environmental Performance of Solar Energy Systems Through a Combined Life Cycle Assessment and Cost Analysis

The paper presents a holistic evaluation of the energy and environmental profile of two renewable energy technologies: Photovoltaics (thin-film and crystalline) and solar thermal collectors (flat plate and vacuum tube). The selected renewable systems exhibit size scalability (i.e., photovoltaics can vary from small to large scale applications) and can easily fit to residential applications (i.e., solar thermal systems). Various technical variations were considered for each of the studied technologies. The environmental implications were assessed through detailed life cycle assessment (LCA), implemented from raw material extraction through manufacture, use, and end of life of the selected energy systems. The methodological order followed comprises two steps: i. LCA and uncertainty analysis (conducted via SimaPro), and ii. techno-economic assessment (conducted via RETScreen). All studied technologies exhibit environmental impacts during their production phase and through their operation they manage to mitigate significant amounts of emitted greenhouse gases due to the avoided use of fossil fuels. The life cycle carbon footprint was calculated for the studied solar systems and was compared to other energy production technologies (either renewables or fossil-fuel based) and the results fall within the range defined by the global literature. The study showed that the implementation of photovoltaics and solar thermal projects in areas with high average insolation (i.e., Crete, Southern Greece) can be financially viable even in the case of low feed-in-tariffs. The results of the combined evaluation provide insight on choosing the most appropriate technologies from multiple perspectives, including financial and environmental.

Bringing value to the chemical industry from capture, storage and use of CO2: A dynamic LCA of formic acid production

Low carbon options for the chemical industry include switching from fossil to renewable energy, adopting new low-carbon production processes, along with retrofitting current plants with carbon capture for ulterior use (CCU technologies) or storage (CCS). In this paper, we combine a dynamic Life Cycle Assessment (d-LCA) with economic analysis to explore a potential transition to low-carbon manufacture of formic acid. We propose new methods to enable early technical, environmental and economic assessment of formic acid manufacture by electrochemical reduction of CO₂ (CCU), and compare this production route to the conventional synthesis pathways and to storing CO₂ in geological storage (CCS). Both CCU and CCS reduce carbon emissions in particular scenarios, although the uncertainty in results suggests that further research and scale-up validation are needed to clarify the relative emission reduction compared to conventional process pathways. There are trade-offs between resource security, cost and emissions between CCU and CCS systems. As expected, the CCS technology yields greater reductions in CO₂ emissions than the CCU scenarios and the conventional processes. However, compared to CCS systems, CCU has better economic potential and lower fossil consumption, especially when powered by renewable electricity. The integration of renewable energy in the chemical industry has an important climate mitigation role, especially for processes with high electrical and thermal energy demands.

Greenhouse Gas Emissions from Landfills: A Review and Bibliometric Analysis

The landfill is an important method of disposal of municipal solid waste. In particular, the landfill is especially vital in many developing countries, with it being the main biodegradable waste disposal method due to its simple management and ability for mass manipulation. Landfills have recently been shown to be an important source of greenhouse gas (GHG) emissions by researchers in different countries. However, few reviews have been conducted within the related fields, which means that there is still a lack of comprehensive understanding related to relevant study achievements. In this study, a bibliometric analysis of articles published from 1999 to 2018 on landfill GHG emissions was presented to assess the current trends, using the Web of Science (WOS) database. The most productive countries/territories, authors and journals were analyzed. Moreover, the overall research structure was characterized based on co-cited references, emerging keywords and reference citations by means of bibliometric analysis. Due to the increasing amount of attention being paid to the GHG emissions and their mitigation methods, this study provided comprehensive bibliometric information on GHG emissions from landfills over the past two decades and highlighted the importance of the development and dissemination of updated knowledge frameworks.

Towards a low CO2 emission building material employing bacterial metabolism (2/2): Prospects for global warming potential reduction in the concrete industry

The production of concrete is one of the most significant contributors to global greenhouse gas emissions. This work focuses on bio-cementation-based products and their potential to reduce global warming potential (GWP). In particular, we address a proposed bio-cementation method employing bacterial metabolism in a two-step process of limestone dissolution and recrystallisation (BioZEment). A scenario-based techno-economic analysis (TEA) is combined with a life cycle assessment (LCA), a market model and a literature review of consumers' willingness to pay, to compute the expected reduction of global GWP. Based on the LCA, the GWP of 1 ton of BioZEment is found to be 70-83% lower than conventional concrete. In the TEA, three scenarios are investigated: brick, precast and onsite production. The results indicate that brick production may be the easiest way to implement the products, but that due to high cost, the impact on global GWP will be marginal. For precast production the expected 10% higher material cost of BioZEment only produces a marginal increase in total cost. Thus, precast production has the potential to reduce global GWP from concrete production by 0-20%. Significant technological hurdles remain before BioZEment-based products can be used in onsite construction scenarios, but in this scenario, the potential GWP reduction ranges from 1 to 26%. While the potential to reduce global GWP is substantial, significant efforts need to be made both in regard to public acceptance and production methods for this potential to be unlocked.

Life Cycle Impact of Titanium Dioxide Nanoparticle Synthesis through Physical, Chemical, and Biological Routes

The sustainable manufacturing of nanoparticles (NPs) has become critical to reduce life cycle energy use and the associated environmental impact. With the ever-growing production volume, titanium dioxide (TiO₂) NPs have been produced through various synthesis routes with differing input materials and reactions, which result in differential reactivity, crystallinity, surface areas, and size distributions. In this study, life cycle assessment is used to analyze and compare the environmental impact of TiO₂ NPs produced via seven routes covering physical, chemical, and biological syntheses. The synthesis routes are chosen to represent mainstream NP manufacturing and future trends. Mass-, surface area-, and photocatalytic reactivity-based functional units are selected to evaluate the environmental impact and reflect the corresponding changes. The results show that impact associated with the upstream production of different precursors are dominant for the chemical route. Compared to the chemical route, the physical route requires substantial quantities of supporting gas and high-energy inputs to maintain high temperature; therefore, a higher environmental burden is generated. A high environmental burden is also modeled for the biological route due to the required bacterial culture media. This present study aims to identify the most efficient synthesis route for TiO₂ NP production, lower the potential environmental impact, and improve green synthesis and sustainability.

Uncertainty Implications of Hybrid Approach in LCA: Precision versus Accuracy

The hybrid approach in Life Cycle Assessment (LCA) that uses both input-output and process data has been discussed in the context of mitigating truncation error and burdens of data collection. However, the implication of introducing input-output data on the overall uncertainty of an LCA result has been debated. In this study, we selected an existing process LCA, performed a Monte Carlo simulation after hybridizing each truncated flow at a time, and analyzed the dispersion and position of the distribution in the results. The results showed that hybridization effectively moved the mean of the life cycle greenhouse gas (GHG) emissions 38% higher while maintaining the standard deviation within the 0.62-0.78 range (relative standard deviation, 3-4%). We identified key activities contributing to the overall uncertainty and simulated the potential effect of collecting higher quality supplier-specific data for those activities on the overall uncertainty. The results showed that replacing as few as 10 of the largest uncertainty contributors with high precision supplier-specific data substantially narrowed the distribution. Our results suggest that hybridizing truncated inputs improves accuracy of LCA results without compromising their precision, and prioritizing supplier-specific data collection can further enhance precision in a cost-effective manner.

Toward Sustainable Chemical Engineering: The Role of Process Systems Engineering

Products from chemical engineering are essential for human well-being, but they also contribute to the degradation of ecosystem goods and services that are essential for sustaining all human activities. To contribute to sustainability, chemical engineering needs to address this paradox by developing chemical products and processes that meet the needs of present and future generations. Unintended harm of chemical engineering has usually appeared outside the discipline's traditional system boundary due to shifting of impacts across space, time, flows, or disciplines, and exceeding nature's capacity to supply goods and services. Being a subdiscipline of chemical engineering, process systems engineering (PSE) is best suited for ensuring that chemical engineering makes net positive contributions to sustainable development. This article reviews the role of PSE in the quest toward a sustainable chemical engineering. It focuses on advances in metrics, process design, product design, and process dynamics and control toward sustainability. Efforts toward contributing to this quest have already expanded the boundary of PSE to consider economic, environmental, and societal aspects of processes, products, and their life cycles. Future efforts need to account for the role of ecosystems in supporting industrial activities, and the effects of human behavior and markets on the environmental impacts of chemical products. Close interaction is needed between the reductionism of chemical engineering science and the holism of process systems engineering, along with a shift in the engineering paradigm from wanting to dominate nature to learning from it and respecting its limits.

Energy Analysis, and Carbon and Water Footprint for Environmentally Friendly Farming Practices in Agroecosystems and Agroforestry

Agriculture accounts for 5% of the entire energy used worldwide. Most of it is not in a renewable form, so it can be linked to greenhouse gas emissions. According to the Paris Agreement, on climate change, one of its major targets is the reduction of greenhouse gas emissions. Therefore, the agricultural production process must drastically change. Currently, the sustainable use of water is critical for any agricultural development. Agricultural production effects water quality and sufficiency, as well as, freshwater wetlands. Energy balance, carbon, and water footprint are crucial for sustainable agricultural production. Agroforestry systems are important in reducing high inputs of non-renewable energy and greenhouse gas emissions, along with better water use, leading to the most minimal influence on climate change. Energy analysis, carbon, and water footprint can be applied to agroforestry systems’ production. An outline could be applied by adopting a modified—for agricultural production—life cycle assessment methodology to assess energy use, greenhouse gas emissions, and water consumption in agroforestry ecosystems.

Comparative Life Cycle Assessment of HTC Concepts Valorizing Sewage Sludge for Energetic and Agricultural Use

In many countries, sewage sludge is directly used for energy and agricultural purposes after dewatering or digestion and dewatering. In recent years, there has been a growing interest in additional upstream hydrothermal carbonization (HTC), which could lead to higher yields in the energetic and agricultural use. Twelve energetic and agricultural valorization concepts of sewage sludge are defined and assessed for Germany to investigate whether the integration of HTC will have a positive effect on the greenhouse gas (GHG) emissions. The study shows that the higher expenses within the HTC process cannot be compensated by additional energy production and agricultural yields. However, the optimization of the HTC process chain through integrated sewage sludge digestion and process water recirculation leads to significant reductions in GHG emissions of the HTC concepts. Subsequently, nearly the same results can be achieved when compared to the direct energetic use of sewage sludge; in the agricultural valorization, the optimized HTC concept would be even the best concept if the direct use of sewage sludge will no longer be permitted in Germany from 2029/2032. Nevertheless, the agricultural valorization concepts are not generally advantageous when compared to the energetic valorization concepts, as it is shown for two concepts.

Techno-Economic and Life Cycle Impacts Analysis of Direct Methanation of Glycerol to Bio-Synthetic Natural Gas at a Biodiesel Refinery

An economic and environmental feasibility study were carried out on the thermochemical conversion of glycerol to medium methane content biological synthetic natural gas (bio-SNG). A plant that processed 497 kg·h−1 of glycerol to bio-SNG was modelled as an on-site addition to a soybean biodiesel plant based in Missouri (USA) that produced 30 million litres of soybean biodiesel per year. Assuming the glycerol contained only 80 wt% free glycerol, the bio-SNG could substitute up to 24% of the natural gas at the soybean biodiesel plant. The discounted cash flow analysis showed it was possible to generate positive NPVs and achieve internal rates of return within the hurdle rate (12%) for biomass gasification technologies. From the environmental analysis it was found that the bio-SNG could reduce global warming potential by 28% when compared to conventional natural gas in the USA and translates to roughly 7% reduction in biodiesel natural gas emissions, if the maximum 24% of natural gas were to be substituted by bio-SNG. The work highlights the potential to divert waste glycerol to an onsite energy vector at soybean biodiesel plants with minimal change to the main biodiesel production process and potential reductions to soybean biodiesel global warming potential.

Global warming potential and total material requirement in metal production: Identification of changes in environmental impact through metal substitution

In view of the increasing demand for metal use, it is of significant importance to evaluate the environmental impact of metal production. The global warming potential (GWP) in the process of metal production has often been focused upon as a major indicator for evaluating the burden on the environment. Moreover, the environmental impact and mineral exploitation arising from metal ore mining activities, which generate unavoidable mine wastes and have an impact on the ecological biodiversity, cannot be ignored. The major factors for determining the intensity of resource exploitation being the ore grades and strip ratio, the existing indicators for land use employed in the life cycle assessment (LCA) may not fully cover the criteria of the impact of metal mining on the environmental system. Therefore, this study employs the method of total material requirement (TMR) assessment, involving not only the direct and indirect material inputs but also the hidden flows, which are particularly associated with mine wastes. Firstly, the methodology of computing the TMR in the process of metal production is developed. Next, the relation between the GWP and TMR for 58 metals is assessed and finally, the environmental impact through metal substitutes is evaluated from the perspectives of the GWP and TMR. This analysis could identify some of the aspects overlooked in the previous environmental criteria that were concentrating on greenhouse gas emissions and global warming. The developed algorithm may be useful in identifying appropriate metal substitutes, considering the environmental impact.

Life cycle assessment of construction and demolition waste management in a large area of São Paulo State, Brazil

The study evaluated the environmental performance of the construction and demolition waste (C&DW) management in the area of PCJ Watershed, located in the São Paulo State, Brazil, by means of an attributional Life Cycle Assessment. The entire C&DW management under the responsibility of the municipal government was considered. The potential environmental impacts were assessed by using two specific life cycle impact assessment methodologies, CML baseline (v3.03) and Impact 2002+ (v2.12). The results obtained by both methodologies highlighted the importance of the avoided impacts from recovered materials, mainly those related to steel, glass and plastics recycling. In particular, the CML baseline indicated "Human Toxicity" as the most important category, mainly due to the avoided impacts from steel recycling and the generated impacts from transportation in all the C&DW management stages. The Impact 2002+ highlighted instead the role of the categories of "Respiratory Inorganics" and "Global Warming", in accordance with the results related again to steel recycling and transportation but also to landfilling of solid residues. The study considered some alternative scenarios of the mineral fraction management, which quantified the expected advantages of increasing C&DW recycling and improving the quality of recycled aggregates.

Assessing the Environmental Potential of Collaborative Consumption: Peer-to-Peer Product Sharing in Hammarby Sjöstad, Sweden

Collaborative consumption—through sharing services—has been promoted as an important step in transforming current consumption patterns toward more sustainable practices. Whilst there are high expectations for sharing services, there are few studies on the potential environmental benefits and impacts of sharing services. This study aims to analyze the potential environmental impacts of a peer-to-peer (P2P) product sharing platform and potential integration with a package drop-off/pick-up service in the urban district of Hammarby Sjöstad, Stockholm, Sweden. A life cycle approach is adopted, taking into account product lifetime and use, the potential replacement of conventional products and services, impacts from digital infrastructure and their impacts on the environment. The results indicate that there is significant potential for these sharing services to reduce environmental impacts associated with production and consumption; primarily through avoiding production and reducing the production impacts of new product purchases. The results also illustrate potential synergies to integrate with the package drop-off/pick up service; where the impacts from shared products are further reduced by reducing transportation impacts through improved logistics. However, the results are dependent upon, and sensitive to, a number of methodological choices and assumptions; highlighting the need for greater knowledge on the use environmental assessments of sharing services.

Integrating Dynamic Material Flow Analysis and Computable General Equilibrium Models for Both Mass and Monetary Balances in Prospective Modeling: A Case for the Chinese Building Sector

Integrated Assessment Models based on Computable General Equilibrium (IAM/CGE) and dynamic Material Flow Analysis (dynamic MFA) are two most widely used prospective model families to assess large-scale and long-term socioeconomic metabolism (SEM) and inform sustainable SEM transition. The latter approach could complement the former by a more explicit understanding of service provision, in-use stocks, and material cycles in a mass balanced framework. In this paper, we demonstrated this by integrating the dynamic MFA and CGE model approaches for the Chinese building sector from 2012 to 2030. Our results revealed the impacts of building stock dynamics on sectoral and economy-wide CO₂ emissions: lower service saturation levels and later saturation time of building stock development could free up investment on buildings and accumulatively save up to 25.4 Gt in embodied CO₂ emissions of the building construction sector, representing a 2.7-fold of 2012 countrywide CO₂ emissions. However, the save-ups are partly compensated by an increase of embodied CO₂ emissions in the other sectors due to economy-wide rebound effect (ca. 18.8 Gt or about 74%). The integrated model we developed could help ensure both mass and monetary balances, explore rebound effects in prospective modeling, and thus better understand the economy-wide consequences of infrastructure development.

Does the use of pre-calculated uncertainty values change the conclusions of comparative life cycle assessments? - An empirical analysis

In life cycle assessment (LCA), performing Monte Carlo simulation (MCS) using fully dependent sampling typically involves repeated inversion of a technology matrix for a sufficiently large number of times. As the dimension of technology matrices for life cycle inventory (LCI) databases grows, MCS using fully dependent sampling is becoming a computational challenge. In our previous work, we pre-calculated the distribution functions of the entire LCI flows in the ecoinvent ver. 3.1 database to help reduce the computation time of running fully dependent sampling by individual LCA practitioners. However, it remains as a question whether the additional errors due to the use of pre-calculated uncertainty values are large enough to alter the conclusion of a comparative study, and, if so, what is the odds of such cases. In this study, we empirically tested the probability of altering the conclusion of a comparative LCA due to the use of pre-calculated uncertainty values. We sampled 10,000 random pairs of elementary flows of ecoinvent LCIs (a_i and b_i) and ran MCSs (1) using pre-calculated uncertainty values and (2) using fully dependent sampling. We analyzed the distribution of the differences between a_i and b_i (i.e., a_i−b_i) of each run, and quantified the probability of reversing (e.g., a_i > b_i became a_i < b_i) or moderating the conclusion (e.g., a_i > b_i became a_i ≈ b_i). In order to better replicate the situation under a comparative LCA setting, we also sampled 10,000 random pairs of elementary flows from the processes that produce electricity, and repeated the same procedure. The results show that no LCIs derived using pre-calculated uncertainty values constitute large enough differences from those using fully dependent sampling to reverse the conclusion. However, in 5.3% of the cases, the conclusion from one approach is moderated under the other approach or vice versa. When elementary flow pairs are sampled only from the electricity-producing processes, the probability of moderating the conclusions increases to 10.5%, while that of reversing the conclusions remains nil. As the number of unit processes in LCI databases increases, running full MCSs in a PC-environment will continue to be a challenge, which may lead some LCA practitioners to avoid uncertainty analysis altogether. Our results indicate that pre-calculated distributions for LCIs can be used as a proxy for comparative LCA studies in the absence of adequate computational resources for full MCS. Depending on the goal and scope of the study, LCA practitioners should consider using pre-calculated distributions if the benefits of doing so outweighs the associated risks of altering the conclusion.

Temporalis, a generic method and tool for dynamic Life Cycle Assessment

The limitations of the static nature of Life Cycle Assessment (LCA) are well known. To overcome the loss of temporal information due to the aggregation of flows in the Life Cycle Inventory (LCI), several dynamic LCA methodologies have been proposed. In this paper we present a new generic and operational methodology for dynamic LCA that allows for the introduction of temporal information in both in the inventory and the Life Cycle Impact Assessment (LCIA) phases. The method makes use of graph traversal and convolution to calculate the temporally differentiated inventory, and makes it possible to use several types of dynamic impact assessment. We describe our method and apply it to a cradle-to-grave dynamic LCA of a glued laminated timber (glulam) product. We also test the sensitivity of the global warming results to temporal explicit LCI data. There is a considerable difference in outcome between the static and dynamic approaches. We have implemented our framework in the free and open source software Temporalis that is fully operational and can be used with existing LCA databases.

Economic analysis and life cycle impact assessment of municipal solid waste (MSW) disposal: A case study of Mumbai, India

Municipal solid waste (MSW) management is a major concern in Indian cities. This work rigorously assesses the relative costs and the environmental and health benefits of alternative MSW management methods. Management of MSW over the next 20 years for the city of Greater Mumbai was considered. A generic model was developed to determine the costs for (i) dumping on open ground, (ii) sanitary landfill without leachate treatment, (iii) landfilling with leachate treatment and (iv) regional composting and landfilling. LandGEM was used to quantify the gaseous emissions from landfill, while emissions from leachate and composting were taken from literature. The life cycle impact model of one tonne of MSW was developed using OpenLCA software and the International Reference Life Cycle Data System (ILCD) 2011 method was used for impact assessment. The cost of disposal of one tonne of waste was found to be INR344 (US$5.17), INR741 (US$11.13) and INR1367 (US$20.53), respectively, for the first three scenarios. As compared to open dumping, landfill gas flaring reduced the global warming potential by 32% and leachate treatment reduced freshwater ecotoxicity and total human toxicity marginally, by 20% and 60%, respectively. Composting-landfilling was the most preferred option, with a cost of INR531 tonne^-1 (US$7.97), leading to a reduction in global warming potential by 79% and a slight decrease in freshwater ecotoxicity by 64%. Further, emissions due to accidental fires were also quantified. The study provides valuable insights for the selection of MSW management options for large metropolitan cities in developing countries.

An attributional life cycle assessment for an Italian residential multifamily building

The study describes an attributional life cycle assessment carried out according to the ISO standards and focused on an Italian multifamily residential building. The aim was developing an exhaustive and reliable inventory of high-quality primary data, comparing the environmental impacts along the three stages of the building life cycle. The pre-use phase takes into account the production of all the construction materials, transportation, and on-site assembling. The use phase quantifies the resource consumptions for 50 years of the building utilization and ordinary maintenance. The end-of-life phase includes the building demolition and the management of generated wastes. The results quantify how the design criteria affect the environmental performances of the residential building along its life cycle. The role of the pre-use phase appears remarkable for global warming potential (GWP), due to the huge impacts of steel and concrete production processes. The use phase gives the largest contributions, which reach 77% and 84% of the total, for the categories of global warming and non-renewable energy. The end-of-life phase provides limited avoided impacts. A comparative analysis quantifies the improvements achievable with an alternative type of partitions and external walls. Acronyms: AC: air conditioning; C&DW: construction and demolition waste; CFL: compact fluorescent lamp; DHW: domestic hot water; EC: European Commission; EU: European Union; GDP: gross domestic product; GHG: greenhouse gases; GWP: global warming potential; LCA: life cycle assessment; LCI: life cycle inventory; LCIA: life cycle impact assessment; MFA: material flow analysis; NREP: non-renewable energy potential; RINP: respiratory inorganics potential; WFD: Waste Framework Directive.

Toward harmonizing ecotoxicity characterization in life cycle impact assessment

Ecosystem quality is an important area of protection in life cycle impact assessment (LCIA). Chemical pollution has adverse impacts on ecosystems on a global scale. To improve methods for assessing ecosystem impacts, the Life Cycle Initiative hosted by the United Nations Environment Programme established a task force to evaluate the state-of-the-science in modeling chemical exposure of organisms and the resulting ecotoxicological effects for use in LCIA. The outcome of the task force work will be global guidance and harmonization by recommending changes to the existing practice of exposure and effect modeling in ecotoxicity characterization. These changes will reflect the current science and ensure the stability of recommended practice. Recommendations must work within the needs of LCIA in terms of 1) operating on information from any inventory reporting chemical emissions with limited spatiotemporal information, 2) applying best estimates rather than conservative assumptions to ensure unbiased comparison with results for other impact categories, and 3) yielding results that are additive across substances and life cycle stages and that will allow a quantitative expression of damage to the exposed ecosystem. We describe the current framework and discuss research questions identified in a roadmap. Primary research questions relate to the approach toward ecotoxicological effect assessment, the need to clarify the method's scope and interpretation of its results, the need to consider additional environmental compartments and impact pathways, and the relevance of effect metrics other than the currently applied geometric mean of toxicity effect data across species. Because they often dominate ecotoxicity results in LCIA, we give metals a special focus, including consideration of their possible essentiality and changes in environmental bioavailability. We conclude with a summary of key questions along with preliminary recommendations to address them as well as open questions that require additional research efforts. Environ Toxicol Chem 2018;37:2955-2971. © 2018 SETAC.

Ecosystem Services in Life Cycle Assessment: A novel conceptual framework for soil

Ecosystem Services (ES) are the direct and indirect contributions of ecosystems to human well-being, which include provision of food and water, regulation of flood and erosion processes, soil formation and non-material benefits such as recreation. The integration of ES impact modeling in Life Cycle Assessment (LCA) still has limitations regarding the typology embodied and some conceptual errors in not actually evaluating the benefits provided by ES. In this context, soil is an important resource and provides a wide diversity of ES. Therefore, this article aims to: (i) Review the evolution of ES assessment in LCA and the current methods used to study the biophysical aspects of ES; (ii) Compare the ES cascade model and LCA environmental mechanism for land use impacts; and (iii) Improve and synthesize a new conceptual framework for soil-ES assessment in LCA studies. Results show that the cascade model provides a useful framework for operationalizing ES assessment and should integrate LCA. Thus, this study proposes a new conceptual framework for soil-ES including the main soil processes, functions, services, benefits and values. Each of these cascade model steps is aligned with LCA terminology in order to match the usual midpoint or endpoint levels of modeling. Future works should focus on new indicators to measure the supply of ES and their benefit to humans as well as indicators to their value.

Modeling and Simulation of Energy Systems: A Review

Energy is a key driver of the modern economy, therefore modeling and simulation of energy systems has received significant research attention. We review the major developments in this area and propose two ways to categorize the diverse contributions. The first categorization is according to the modeling approach, namely into computational, mathematical, and physical models. With this categorization, we highlight certain novel hybrid approaches that combine aspects of the different groups proposed. The second categorization is according to field namely Process Systems Engineering (PSE) and Energy Economics (EE). We use the following criteria to illustrate the differences: the nature of variables, theoretical underpinnings, level of technological aggregation, spatial and temporal scales, and model purposes. Traditionally, the Process Systems Engineering approach models the technological characteristics of the energy system endogenously. However, the energy system is situated in a broader economic context that includes several stakeholders both within the energy sector and in other economic sectors. Complex relationships and feedback effects exist between these stakeholders, which may have a significant impact on strategic, tactical, and operational decision-making. Leveraging the expertise built in the Energy Economics field on modeling these complexities may be valuable to process systems engineers. With this categorization, we present the interactions between the two fields, and make the case for combining the two approaches. We point out three application areas: (1) optimal design and operation of flexible processes using demand and price forecasts, (2) sustainability analysis and process design using hybrid methods, and (3) accounting for the feedback effects of breakthrough technologies. These three examples highlight the value of combining Process Systems Engineering and Energy Economics models to get a holistic picture of the energy system in a wider economic and policy context.