A modeling framework to evaluate sustainability of building construction based on LCSA

Purpose

Life cycle sustainability assessment (LCSA) is a method that combines three life cycle techniques, viz. environmental life cycle assessment (LCA), life cycle costing (LCC), and social life cycle assessment (S-LCA). This study is intended to develop a LCSA framework and a case study of LCSA for building construction projects.

Methods

A LCSA framework is proposed to combine the three life cycle techniques. In the modeling phases, three life cycle models are used in the LCSA framework, namely the environmental model of construction (EMoC), cost model of construction (CMoC), and social-impact model of construction (SMoC). A residential building project is applied to the proposed LCSA framework from “cradle to the end of construction” processes to unveil the limitations and future research needs of the LCSA framework.

Results and discussion

It is found that material extraction and manufacturing account for over 90 % to the environmental impacts while they contribute to 61 % to the construction cost. In terms of social impacts, on-site construction performs better than material extraction and manufacturing, and on-site construction has larger contributions to the positive social impacts. The model outcomes are validated through interviews with local experts in Hong Kong. The result indicates that the performance of the models is generally satisfactory.

Conclusions

The case study has confirmed that LCSA is feasible. Being one of the first applications of LCSA on building construction, this study fulfills the current research gap and paves the way for future development of LCSA.

     

Using life cycle sustainability assessment to trade off sourcing strategies for humanitarian relief items

Purpose

While interest in supply chain sustainability has risen over the past few years in academic and business worlds, very little research has been conducted on sustainability in humanitarian supply chains, specifically. This study aims to contribute to the development of the field by conducting a life cycle sustainability analysis (LCSA) of sourcing scenarios for a core relief item in a humanitarian supply chain.

Methods

This paper is structured according to the LCSA framework developed by Guinée et al. (Environ Sci Technol 45(1):90–96, 2011). The relief item analyzed is a kitchen set supplied by a UN agency. Environmental, social, and economic impacts of two sourcing scenarios for a kitchen set are mapped: one international and one local. Sources of data include interviews, company records, and online databases. Results are analyzed using the ReCiPe method to assess environmental impact and the United Nations Environmental Programme (UNEP)/Society of Environmental Toxicology and Chemistry (SETAC) guidelines to assess social impact.

Results and discussion

We show how LCSA can be used to map the sustainability of two sourcing scenarios for kitchen sets in a humanitarian supply chain along triple bottom line dimensions. We report findings on sourcing scenarios for distribution to two refugee camps in Kenya: one from a supplier in India and one from a supplier in Kenya. We use an environmental life cycle analysis (LCA), a social LCA, and a life cycle costing (LCC) to analyze differences and similarities. We find that local sourcing is preferred over international sourcing on two out of the three sustainability dimensions—environmental and social impacts. Humanitarian organizations may further use this paper as a guideline to develop their own sustainability assessments of supply chain scenarios.

Conclusions

The results of our study provide a fresh, sustainability-focused perspective on the debate over international vs. local procurement. This paper is the first to apply LCSA to a humanitarian context. It also addresses a void in the sourcing literature by determining the sustainability impacts of different sourcing strategies. The study evaluates only two sourcing options and also uses a limited number of data sources.

     

Geopolitical-related supply risk assessment as a complement to environmental impact assessment: the case of electric vehicles

Purpose

Introducing a geopolitical-related supply risk (GeoPolRisk) into the life cycle sustainability assessment (LCSA) framework adds a criticality aspect to the current life cycle assessment (LCA) framework to more meaningfully address direct impacts on Natural Resource AoP. The weakness of resource indicators in LCA has been the topic of discussion within the life cycle community for some time. This paper presents a case study on how to proceed towards the integration of resource criticality assessment into LCA under the LCSA. The paper aims at highlighting the significance of introducing the GeoPolRisk indicator to complement and extend the established environmental LCA impact categories.

Methods

A newly developed GeoPolRisk indicator proposed by Gemechu et al., J Ind Ecol (2015) was applied to metals used in the life cycle of an electric vehicle, and the results are compared with an attributional LCA of the same resources. The inventory data is based on the publication by Hawkins et al., J Ind Ecol 17:53–64 (2013), which provides a current, transparent, and detailed life cycle inventory data of a European representative first-generation battery small electric vehicle.

Results and discussion

From the 14 investigated metals, copper, aluminum, and steel are the most dominant elements that pose high environmental impacts. On the other hand, magnesium and neodymium show relatively higher supply risk when geopolitical elements are considered. While, the environmental indicator results all tend to point the same hotspots which arise from the substantial use of resources in the electric vehicle’s life cycle, the GeoPolRisk highlights that there are important elements present in very small amounts but crucial to the overall LCSA. It provides a complementary sustainability dimension that can be added to conventional LCA as an important extension within LCSA.

Conclusions

Resource challenges in a short-term time perspective can be better addressed by including social and geopolitical factors in addition to the conventional indicators which are based on their geological availability. This is more significant for modern technologies such as electronic devices in which critical resources contribute to important components. The case study advances the use of the GeoPolRisk assessment method but does still face certain limitations that need further elaboration; however, directions for future research are promising.

     

Integrated environmental and economic assessment of current and future fuel cell vehicles

Purpose

Light-duty vehicles contribute considerably to global greenhouse gas emissions. Fuel cell vehicles (FCVs) may play a key role in mitigating these emissions without facing the same limitations in range and refueling time as battery electric vehicles (BEVs). In this study, we assess the environmental impacts and costs of a polymer electrolyte membrane fuel cell system (FCS) for use in light-duty FCVs and integrate these results into a comparative evaluation between FCVs, BEVs, and internal combustion engine vehicles (ICEVs).

Methods

We conduct a detailed life cycle assessment (LCA) and cost assessment for the current state of the technology and two future scenarios for technological development. We compile a detailed and consistent inventory for the FCS by systematically disassembling and integrating information found in cost studies. For the vehicle-level comparison, we use models to ensure that vehicle size, performance, and fuel consumption are unbiased between vehicle types and consistent with the scenarios for technological development.

Results and discussion

Our results show that FCVs can decrease life cycle greenhouse gas emissions by 50 % compared to gasoline ICEVs if hydrogen is produced from renewable electricity, thus exhibiting similar emission levels as BEVs that are charged with the same electricity mix. If hydrogen is produced by natural gas reforming, FCVs are found to offer no greenhouse gas reductions, along with higher impacts in several other environmental impact categories. A major contributor to these impacts is the FCS, in particular the platinum in the catalyst and the carbon fiber in the hydrogen tank. The large amount of carbon fiber used in the tank was also the reason why we found that FCVs may not become fully cost competitive with ICEVs or BEVs, even when substantial technological development and mass production of all components is assumed.

Conclusions

We conclude that FCVs only lead to lower greenhouse gas emissions than ICEVs if their fuel is sourced from renewable energy, as is the case with BEVs. FCVs are an attractive alternative to ICEVs in terms of vehicle performance criteria such as range and refueling time. However, the technological challenges associated with reducing other environmental impacts and costs of FCVs seem to be as large, if not larger, than those associated with the capacity and costs of batteries for BEVs—even when not taking into account the efforts required to build a hydrogen infrastructure network for road transportation.

     

A new hybrid method for reducing the gap between WTW and LCA in the carbon footprint assessment of electric vehicles

Purpose

The well-to-wheel (WTW) methodology is widely used for policy support in road transport. It can be seen as a simplified life cycle assessment (LCA) that focuses on the energy consumption and CO₂ emissions only for the fuel being consumed, ignoring other stages of a vehicle’s life cycle. WTW results are therefore different from LCA results. In order to close this gap, the authors propose a hybrid WTW+LCA methodology useful to assess the greenhouse gas (GHG) profiles of road vehicles.

Methods

The proposed method (hybrid WTW+LCA) keeps the main hypotheses of the WTW methodology, but integrates them with LCA data restricted to the global warming potential (GWP) occurring during the manufacturing of the battery pack. WTW data are used for the GHG intensity of the EU electric mix, after a consistency check with the main life cycle impact (LCI) sources available in literature.

Results and discussion

A numerical example is provided, comparing GHG emissions due to the use of a battery electric vehicle (BEV) with emissions from an internal combustion engine vehicle. This comparison is done both according to the WTW approach (namely the JEC WTW version 4) and the proposed hybrid WTW+LCA method. The GHG savings due to the use of BEVs calculated with the WTW-4 range between 44 and 56 %, while according to the hybrid method the savings are lower (31–46 %). This difference is due to the GWP which arises as a result of the manufacturing of the battery pack for the electric vehicles.

Conclusions

The WTW methodology used in policy support to quantify energy content and GHG emissions of fuels and powertrains can produce results closer to the LCA methodology by adopting a hybrid WTW+LCA approach. While evaluating GHG savings due to the use of BEVs, it is important that this method considers the GWP due to the manufacturing of the battery pack.

     

Integrating triple bottom line input–output analysis into life cycle sustainability assessment framework: the case for US buildings

Purpose

With the increasing concerns related to integration of social and economic dimensions of the sustainability into life cycle assessment (LCA), traditional LCA approach has been transformed into a new concept, which is called as life cycle sustainability assessment (LCSA). This study aims to contribute the existing LCSA framework by integrating several social and economic indicators to demonstrate the usefulness of input–output modeling on quantifying sustainability impacts. Additionally, inclusion of all indirect supply chain-related impacts provides an economy-wide analysis and a macro-level LCSA. Current research also aims to identify and outline economic, social, and environmental impacts, termed as triple bottom line (TBL), of the US residential and commercial buildings encompassing building construction, operation, and disposal phases.

Methods

To achieve this goal, TBL economic input–output based hybrid LCA model is utilized for assessing building sustainability of the US residential and commercial buildings. Residential buildings include single and multi-family structures, while medical buildings, hospitals, special care buildings, office buildings, including financial buildings, multi-merchandise shopping, beverage and food establishments, warehouses, and other commercial structures are classified as commercial buildings according to the US Department of Commerce. In this analysis, 16 macro-level sustainability assessment indicators were chosen and divided into three main categories, namely environmental, social, and economic indicators.

Results and discussion

Analysis results revealed that construction phase, electricity use, and commuting played a crucial role in much of the sustainability impact categories. The electricity use was the most dominant component of the environmental impacts with more than 50 % of greenhouse gas emissions and energy consumption through all life cycle stages of the US buildings. In addition, construction phase has the largest share in income category with 60 % of the total income generated through residential building’s life cycle. Residential buildings have higher shares in all of the sustainability impact categories due to their relatively higher economic activity and different supply chain characteristics.

Conclusions

This paper is an important attempt toward integrating the TBL perspective into LCSA framework. Policymakers can benefit from such approach and quantify macro-level environmental, economic, and social impacts of their policy implications simultaneously. Another important outcome of this study is that focusing only environmental impacts may misguide decision-makers and compromise social and economic benefits while trying to reduce environmental impacts. Hence, instead of focusing on environmental impacts only, this study filled the gap about analyzing sustainability impacts of buildings from a holistic perspective.     

A selection of safeguard subjects and state indicators for sustainability assessments

Purpose

The purpose of this work is to identify and select safeguard subjects and state indicators that are suitable for sustainability assessment in product and production development, using an interpretation of the Brundtland definition of sustainable development. The purpose is also to investigate how indicators selected in this way differ from other selections in the literature.

Methods

We use a top-down approach, which starts with reviewing the Brundtland definition of sustainability and identifying the corresponding human basic needs to be satisfied. For each basic need, we identify relevant satisfiers, and for each satisfier, a number of safeguard subjects. The safeguard subjects represent critical resources for making satisfiers available. For each safeguard subject, a number of state indicators (=endpoint category indicators) are selected that are relevant for describing impacts from product life cycles on the safeguard subject.

Results and discussion

Ecosystem services, access to water, and abiotic resources are identified as environmental safeguard subjects. Technology for transports, environment, textiles, housing, food, information, and energy, together with income, are identified as economical safeguard subjects. Human health, land availability, peace, social security, continuity, knowledge, jobs/occupation, and culture are identified as social safeguard subjects. In comparison with the other selections of safeguard subjects in literature, our safeguard subjects are structured differently and delimited in scope, but there are also many similarities. The best agreement is on environmental issues, but we classify human health as a social issue. For social issues, we identify fewer safeguard subjects and state indicators than recommendations from UNEP/SETAC. For economic issues, we diverse from current LCC and approach UNECE measures of sustainability.

Conclusions

Identification and selection of safeguard subjects and state indicators benefit from a clear definition of sustainability, needs to be satisfied, and satisfiers. The interpretation of the sustainability concept has a large influence on which safeguard subjects that are included and which indicators that are needed to describe their state. Capacity building is an important sustainability indicator, which should be developed further for use in life cycle sustainability assessment. The top-down approach offers a good arena for a further research and discussions on how to structure and focus LCSA. Our results shall be seen as one example of which safeguard subject that may be identified with the top-down approach presented here.

     

Budget constraint and the valuation of environmental impacts in Thailand

Purpose

This study aims to develop a valuation scheme for environmental impacts in Thailand. This would assist in integrating environmental concerns into economic assessment tools such as cost-benefit analysis (CBA), system of environmental-economic accounting (SEEA), etc., which could be used in policymaking.

Methods

The damage categories considered are human health and ecosystem quality. The value of a quality-adjusted life year (QALY) measuring damage to human health is estimated using the budget constraint approach. The value of a biodiversity-adjusted hectare year (BAHY) measuring damage to ecosystems is calculated relatively to the value of a QALY.

Results and discussion

Potential economic production per capita, which is considered as the willingness to pay (WTP) for a QALY, is in the range 458,000–566,000 Thai baht (THB) (equivalent to 14,000–18,000 USD where 1 USD ≈ 32 THB). The value of a BAHY, which is expressed in terms of the value of a QALY, is in the range 7900–9800 THB (or around 250–300 USD), based on the exchange rate between the protection targets for ecosystems and human well-being. These results are tested by applying to the monetization of potential environmental burdens from producing several biofuels and petroleum-based fuels in Thailand; the environmental externalities account for about 20–40 % of the retail price.

Conclusions

The results can benefit policymakers in terms of decision-making on environmental management. Besides, the pathways to derive the monetary value of environmental impacts could be useful for other countries.

     

Vehicle lightweighting through the use of molybdenum-bearing advanced high-strength steels (AHSS)

Purpose

The past two decades have seen growing pressure on vehicle manufacturers to reduce the environmental impact of their vehicles. One effective way to improve fuel efficiency and lower tailpipe emissions is to use advanced high-strength steels (AHSS) that offer equal strength and crash resistance at lower mass. The present study assesses the life cycle environmental impacts of two steel grades considered for the B-pillar in the Ford Fusion: A press-hardened boron steel design as used in the previous model of the vehicle and a hydroformed component made from a mix of the molybdenum-bearing dual phase steels DP800 and DP1000.

Methods

Information related to the component masses and grades was provided by Ford. Process models for the steelmaking process, finishing, forming, vehicle use and end of life were created in the GaBi LCA software tool. Sensitivity analyses were conducted on the impact of the hydroforming process for the new component, for which only proxy data were available and on the mix of DP800 and DP1000 in the B-pillar. Results have been presented for the environmental impact categories deemed most relevant to vehicle use.

Results and discussion

The life cycle assessment showed that the new DP800/DP1000 B-pillar design has a lower impact for the environmental impact categories assessed. Overall, the global warming potential (GWP) of the new DP800/DP1000 design was 29 % lower than the boron steel design over the full life cycle of the vehicle. The use phase was found to be the major source of environmental impacts, accounting for 93 % of the life cycle GWP impact. The 4 kg weight saving accounts for the majority of the difference in impacts between the two B-pillar designs. Impacts from manufacturing were also lower for the new design for all of the impact categories assessed despite the higher alloy content of the steel. A sensitivity analysis of the hydroforming process showed that even if impacts from forming were 100 % greater than for press hardening, the GWP from production of the new B-pillar design would still be lower than the boron steel version.

Conclusions and recommendations

The molybdenum-bearing DP1000/DP800 B-pillar was found to have lower life cycle and production impacts than the previous boron steel design. The assessment indicates that significant improvements in the environmental impacts associated with the body structure of vehicles could be made through the increased use of AHSS in vehicles without compromising crash performance.

     

LCA applied to nano scale zero valent iron synthesis

Purpose

Application of zero valent iron nanoparticles is an innovative technology for ground water treatment and soil remediation. There are several methods to synthesise nano scale zero valent iron (nZVI), namely through bottom-up methods which consists on chemical reactions using strong reducing agents. In this work, the environmental impacts and costs were determined for two methods, namely the traditional one that uses sodium borohydride and the green method that uses extracts obtained from natural products.

Methods

The consideration of environment and economic aspects in the earlier stages of the synthesis processes and in the development of new materials is of great importance since it can help to decide if alternative methods are promising and should be further developed aiming more sustainable processes. In this work, life cycle assessment (LCA) was used as an ecodesign strategy evaluating environmental performance of the two synthesis methods, identifying critical stages of the synthesis processes of nZVI. An economic evaluation and a sensitivity analysis considering a different scenario for electricity production were also performed.

Results and discussion

The results obtained in this study showed that the green synthesis method presents lower environmental impacts than the traditional one, roughly 50% lower in the first scenario. In the second scenario, environmental impact of green synthesis corresponds to 38% of the environmental impact of traditional synthesis. In the green method, the critical stage is the extraction process which is closely related to the electricity production. In the traditional method, the reactant use is the critical stage that is related to the production of sodium borohydride. The economic evaluation indicated that the traditional synthesis method is much more expensive than the green synthesis (roughly eight times higher).

Conclusions

From the results obtained, it is possible to conclude that the green synthesis method presents lower environmental impacts in both scenarios and lower costs than the traditional synthesis.

     

The importance of using life cycle assessment in policy support to determine the sustainability of fishing fleets: a case study for the small-scale <Emphasis Type="Italic">xeito</Emphasis> fishery in Galicia,Spain

Purpose

Drift net fishing activities have undergone a thorough revision at a European Union level, since authorities argue that several loopholes still exist in the legislation that allow small-scale fisheries to use these gears. High incidental catches, or the lack of selectivity, are some of the primary scientific criteria behind this discussion. This new framework is of particular interest in the region of Galicia (NW Spain) due to the social importance of small-scale fishing vessels using drift nets. In fact, over 400 vessels have a licence to capture European pilchard (Sardina pilchardus) with a fishing gear called xeito, which is a small-scale drift net.

Methods

The main goal of this article is to provide stakeholders in the fishing sector with environmentally relevant results regarding the life cycle impacts linked to fishing practices performed by small-scale vessels using the xeito gear to target European pilchard. We hypothesize that environmental impacts computed with LCA will provide additional insights to the sustainability of the pilchard small-scale fishery in NW Spain, adding a series of criteria that may be useful for policy-makers to determine the consequences of forbidding this type of drift netting in the future.

Results and discussion

Results show that environmental impacts across impact categories and operational activities do not differ much from that of other similar fishing fleets examined in recent years, with fuel for propulsion being the main environmental burden in most impact categories. When conducting a statistical analysis, no significant difference in energy use was identified between this small-scale fleet and purse seiners targeting pilchard in Galicia. Moreover, the results obtained demonstrate, in line with previous studies, that European pilchard is still an energy-efficient source of animal protein option as compared to demersal fish alternatives, crustaceans, or livestock.

Conclusions

The results do not indicate that European pilchard landed with small-scale drift nets generates higher environmental life cycle impacts than pilchard landed by purse seiners in NW Spain. However, longer time frames for the analysis should be performed to attain results with lower uncertainty.

     

Environmental impacts of the rental business model compared to the conventional business model: a Korean case of water purifier for home use

Purpose

This paper compares environmental impacts of the rental business model with the conventional model of manufacturing and selling. The case study examines a home use-water purifier by defining scenarios for operation and maintenance of the conventional and rental business models. Another purpose is to explore the potential improvement for the environmental performance of the rental business model in terms of the resource consumption and climate change.

Methods

The functional unit was supplying hot/cold drinking water for 15 years between 1998 and 2013. Primary data were from a Korean company that manufactures and servicizes water purifier; secondary data were from the Korean national LCI database, literatures, and interviews. Scenarios associated with all life cycle stages of a water purifier including operation and maintenance were based on current sales and rental market. Impact assessments were conducted according to the International Organization for Standardization’s 14044, and impact categories considered were global warming and abiotic resource depletion. The key issues and improvement potential of the rental business model were determined with the impact categories of global warming and abiotic resource depletion.

Results and discussion

This study indicates that the rental business model is more environmentally friendly than the conventional model in the impact on global warming while the conventional model shows lower abiotic resource depletion. Product operation was the most significant contributor to the selected environmental impacts for both conventional and rental models. Product maintenance was the second major contributor for the rental business model in terms of abiotic resource depletion. For the conventional model, however, production was a more significant contributor to the selected environmental impacts. The rental model showed approximately 32~37% improvements in the selected environmental impacts by focusing on the environmental education or information to consumers.

Conclusions

This quantitative life cycle assessment can be a tool for service business providers to understand the life cycle environmental impacts of Korean water purifier and explore potential improvement opportunities for sustainability. The lower life cycle impacts of the water purifier-rental business model can be attributed to the following: the preparation of instruction or environmental education regarding the consumer’s turning off behavior when the product is not in use, thus lower energy consumption during the use stage and shorter distance traveled for maintenance.

     

Application of LCSA to used cooking oil waste management

Purpose

Used cooking oil (UCO) is a domestic waste generated as the result of cooking and frying food with vegetable oil. The purpose of this study is to compare the sustainability of three domestic UCO collection systems: through schools (SCH), door-to-door (DTD), and through urban collection centres (UCC), to determine which systems should be promoted for the collection of UCO in cities in Mediterranean countries.

Methods

The present paper uses the recent life cycle sustainability assessment (LCSA) methodology. LCSA is the combination of life cycle assessment (LCA), life cycle costing, and social life cycle assessment (S-LCA).

Results and discussion

Of the three UCO collection systems compared, the results show that UCC presents the best values for sustainability assessment, followed by DTD and finally SCH system, although there are no substantial differences between DTD and SCH. UCC has the best environmental and economic performance but not for social component. DTD and SCH present suitable values for social performance but not for the environmental and economic components.

Conclusions

The environmental component improves when the collection points are near to citizens’ homes. Depending on the vehicle used in the collection process, the management costs and efficiency can improve. UCO collection systems that carry out different kind of waste (such as UCC) are more sustainable than those that collect only one type of waste. Regarding the methodology used in this paper, the sustainability assessment proposed is suitable for use in decision making to analyse processes, products or services, even so in social assessment an approach is needed to quantify the indicators. Defining units for sustainability quantification is a difficult task because not all social indicators are quantifiable and comparable; some need to be adapted, raising the subjectivity of the analysis. Research into S-LCA and LCSA is recent; more research is needed in order to improve the methodology.     

Lightweighting in light commercial vehicles: cradle-to-grave life cycle assessment of a safety-relevant component

Purpose

Currently, the reduction of weight in automotive is a very important topic in order to lower the air pollution. In this context, the purpose of the present paper was to analyze a real case study through a comparison of the environmental sustainability between a conventional steel crossbeam for light commercial vehicles and an innovative lightweight aluminum one.

Methods

For both scenarios, a cradle-to-grave life cycle assessment methodology and a sensitivity analysis has been used through the study of the following phases: mineral extraction, component manufacturing, use on vehicle, and end of life. In particular, many primary data and a complete vehicle model simulation with three different European driving cycles have been used in order to reach the highest possible level of accuracy during the analysis.

Results and discussion

Regarding the manufacturing phase, the aluminum component’s production gave the highest impact because of the high energy required in the mineral reduction. Anyway, this stage of the analysis had a low effect on the entire LCA, because the benefit of weight reduction during vehicle use showed a strongly higher contribution. The urban driving cycle had the most relevant impact, as a consequence of the frequent start and stop operations and the longest time with engine at idle speed, while the extra-urban cycle is the less demanding due to its higher average speed and no start and stop.

Conclusions

In conclusion, the present research demonstrated the environmental importance of the lightweight for an actual case study in the commercial vehicles field.

     

Comparative life cycle assessment and life cycle costing of lodging in the Himalaya

Purpose

The main aim of the study is to assess the environmental and economic impacts of the lodging sector located in the Himalayan region of Nepal, from a life cycle perspective. The assessment should support decision making in technology and material selection for minimal environmental and economic burden in future construction projects.

Methods

The study consists of the life cycle assessment and life cycle costing of lodging in three building types: traditional, semi-modern and modern. The life cycle stages under analysis include raw material acquisition, manufacturing, construction, use, maintenance and material replacement. The study includes a sensitivity analysis focusing on the lifespan of buildings, occupancy rate and discount and inflation rates. The functional unit was formulated as the ‘Lodging of one additional guest per night’, and the time horizon is 50 years of building lifespan. Both primary and secondary data were used in the life cycle inventory.

Results and discussion

The modern building has the highest global warming potential (kg CO_2-eq) as well as higher costs over 50 years of building lifespan. The results show that the use stage is responsible for the largest share of environmental impacts and costs, which are related to energy use for different household activities. The use of commercial materials in the modern building, which have to be transported mostly from the capital in the buildings, makes the higher GWP in the construction and replacement stages. Furthermore, a breakdown of the building components shows that the roof and wall of the building are the largest contributors to the production-related environmental impact.

Conclusions

The findings suggest that the main improvement opportunities in the lodging sector lie in the reduction of impacts on the use stage and in the choice of materials for wall and roof.

     

Road transport: new life cycle inventories for fossil-fuelled passenger cars and non-exhaust emissions in ecoinvent v3

Purpose

The paper presents new and updated datasets for the operation of fossil-fuelled passenger cars. These are intended to be used either as background processes or in the comparative assessment of transport options. Central goals were to achieve a high level of consistency, transparency and flexibility for a representative range of current vehicle sizes, emission standards and fuel types, and to make a clear definition between exhaust and non-exhaust emissions. The latter is an important contribution to studies focusing on hybrid and electric vehicles.

Methods

The datasets are the direct development of those available in ecoinvent v2 and are largely based on updated versions of the same sources. The datasets address petrol, diesel and natural gas vehicle fuels. The number of datasets was increased to cover small, medium and large vehicles. Other data sources were used in order to fill data gaps and to balance inconsistencies, particularly for the natural gas vehicles. Parameterisation was incorporated via the ecoeditor tool. This allows the datasets to be adapted for use as foreground processes and also increases transparency. An important method used was to observe the trends in fuel consumption and emissions across all sizes and emission standards simultaneously so that consistency would be achieved across the whole range of vehicles. Non-exhaust emissions were made dependent on vehicle weight and thereby independent of vehicle type.

Results and discussion

Some significant changes in individual emission factors between the v2 and v3 datasets was shown. This can be explained by a combination of corrections, updates based on more recent versions of the data sources, and attempts to make the datasets consistent to each other. This has also meant that the non-exhaust emissions are readily definable in terms of brake, tyre and road wear as a factor of vehicle weight, with the intention that this data can be applied to passenger vehicles of all technologies.

Conclusions

Fuel consumption, emission factors and infrastructure demand have been improved, extended and updated for petrol, diesel and natural gas vehicles adhering to the Euro 3, 4 and 5 emissions standards. Using the ecoeditor tool, significant parameterisation was included which has made the datasets far more flexible, consistent and transparent. The clear definition of non-exhaust emissions means that these can easily be applied to studies on hybrid and electric vehicles.

     

Multi-actor multi-criteria sustainability assessment framework for energy and industrial systems in life cycle perspective under uncertainties. Part 1: weighting method

Purpose

Life cycle sustainability assessment is meaningful for the decision-makers/stakeholders to select the most sustainable option among multiple alternatives; however, there are usually various severe uncertainty problems in sustainability-oriented decision-making, i.e., the vagueness and ambiguity that existed in human judgments and the lack of information. This study aims at developing a novel life cycle multi-criteria sustainability assessment method for helping the decision-makers/stakeholders to determine the sustainability level of the industrial and energy systems. In part 1, an improved interval analytic hierarchy process (AHP) which allows multiple decision-makers/stakeholders to participate in the decision-making was developed to determine the weights of the criteria which were used in life cycle sustainability assessment.

Methods

It is usually difficult for the decision-makers/stakeholders to use the numbers from 1 to 9 and their reciprocals for determining the comparison matrix when using the traditional AHP method for weight calculation, because human judgments usually involve various uncertainties. In order to the overcome this weak point of the traditional AHP, an improved AHP, so-called interval AHP, in which, multiple decision-makers/stakeholders are allowed to participate in the decision-making and allowed to use interval numbers instead of crisp numbers to establish the comparison matrix for determining the weights of the criteria for life cycle sustainability assessment, has been developed.

Results and discussion

The proposed method was used to determine the weights of the four aspects for life cycle sustainability assessment including economic, safety, social, and environmental aspects. Five representative stakeholders were invited to participate in the decision-making. After Monte Carlo simulation, the final weights of the four aspects have been determined with the proposed interval AHP.

Conclusions and perspectives

An interval AHP method was developed for determining the weights of the criteria for life cycle sustainability assessment; the decision-makers are allowed to use interval numbers to establish the comparison matrix for weight calculation. The weighting coefficients determined by Monte Carlo method can accurately reflect the preferences and willingness of multi-actor comparing with the traditional AHP method. This paper merely presents a novel method to calculate the weights of the criteria for life cycle sustainability assessment, but the method for determining the sustainability performance has been presented in part 2.

     

Environmental trade-offs across cascading lithium-ion battery life cycles

Purpose

The purpose of this study was to analyze the environmental trade-offs of cascading reuse of electric vehicle (EV) lithium-ion batteries (LIBs) in stationary energy storage at automotive end-of-life.

Methods

Two systems were jointly analyzed to address the consideration of stakeholder groups corresponding to both first (EV) and second life (stationary energy storage) battery applications. The environmental feasibility criterion was defined by an equivalent-functionality lead-acid (PbA) battery. A critical methodological challenge addressed was the allocation of environmental impacts associated with producing LIBs across the EV and stationary use systems. The model also tested sensitivity to parameters such as the fraction of battery cells viable for reuse, service life of refurbished cells, and PbA battery efficiency.

Results and discussion

From the perspective of EV applications, cascading reuse of an LIB in stationary energy storage can reduce net cumulative energy demand and global warming potential by 15 % under conservative estimates and by as much as 70 % in ideal refurbishment and reuse conditions. When post-EV LIB cells were compared directly to a new PbA system for stationary energy storage, the reused cells generally had lower environmental impacts, except in scenarios where very few of the initial battery cells and modules could be reused and where reliability was low (e.g., life span of 1 year or less) in the secondary application.

Conclusions

These findings demonstrate that EV LIB reuse in stationary application has the potential for dual benefit—both from the perspective of offsetting initial manufacturing impacts by extending battery life span as well as avoiding production and use of a less-efficient PbA system. It is concluded that reuse decisions and diversion of EV LIBs toward suitable stationary applications can be based on life cycle centric studies. However, technical feasibility of these systems must still be evaluated, particularly with respect to the ability to rapidly analyze the reliability of EV LIB cells, modules, or packs for refurbishment and reuse in secondary applications.

     

Well-to-wheel GHG emissions and mitigation potential from light-duty vehicles in Macau

Purpose

The rapid growth of vehicle sales and usage has highlighted the need for greenhouse gas (GHG) emission reduction in Macau, a special administrative region (SAR) of China. As the most primary vehicle type, light-duty vehicles (LDV, including light-duty gasoline vehicles (LDGVs) and light-duty diesel vehicles (LDDVs)) play a key role in promoting the GHG reduction and development of green transportation system in Macau.

Methods

This study, on the basis of real-world tested and statistical data, firstly performed a streamlined life-cycle assessment (SLCA) on LDVs, to evaluate the potential GHG emissions and reduction through shifting to hybrid electric vehicles (HEVs) and electric vehicles (EVs).

Results and discussion

The results show that the mean GHG emissions from the LDGVs, LDDVs, and HEVs per 100 km were 25.16, 20.30, and 15.00 kg CO₂ eq, respectively. Under the current electricity mix in Macau, EVs with the emissions of 12.39 kg CO₂ eq/100 km can achieve a significant GHG emission reduction of LDVs in Macau. The total GHG emissions from LDVs increased from 124.99 to 247.82 thousand metric tons over the periods 2001–2014, with a 5.42% annual growth rate. A scenario analysis indicated that the development of HEVs and EVs—especially EVs—has the potential to control the GHG emissions from LDVs. Under the electricity mix of natural gas (NG) and solar energy (SE), the GHG emissions from EVs would drop by about 22 and 28%, respectively, by 2030.

Conclusions

This study develops a useful approach to evaluate the potential GHG emissions and its reduction strategies in Macau. All the obtained results could be useful for decision makers, providing robust support for drawing up an appropriate plan for improving green transportation systems in Macau.

     

Addressing positive impacts in social LCA—discussing current and new approaches exemplified by the case of vehicle fuels

Purpose

This paper seeks ways to address positive social impacts in social life cycle assessment (SLCA) and attempts to answer two questions: How can the SLCA methodology be improved in order to systematically identify all potential positive impacts in the supply chain? How can positive impacts be taken into consideration along with negative impacts in SLCA? In order for SLCA to be an attractive tool, it needs to provide users with the possibility to include positive impacts, not as variables stipulating lack of negative impacts but rather as fulfilment of positive potentials.

Methods

By scrutinising the social impacts addressed in the SLCA UNEP/SETAC Guidelines today and reviewing approaches for positive impacts in other research fields, a developed approach to capture and aggregate positive social impacts in SLCA is proposed. To exemplify the application, the case of vehicle fuels is used to investigate the possibilities of addressing positive impacts in SLCA. This includes a literature review on potential positive social impacts linked to vehicle fuels.

Results and discussion

The subcategories in the SLCA Guidelines are proposed to be divided into positive and negative impacts and complemented with some additional positive impacts. Related indicators are proposed. A draft approach for assessing positive impacts is developed where the proposed indicators are categorised in four different levels, from low to very high potential positive impact. The possibility to aggregate positive social impacts is discussed. Besides multi-criteria decision analysis (MCDA), few useful ideas for aggregating positive impacts in SLCA were found in the literature that mostly focused on surveys and monetarisation. Positive social impacts linked to vehicle fuels (fossil fuels and biofuels) are identified, and the proposed approach is schematically applied to vehicle fuels.

Conclusions

The SLCA methodology may be refined in order to better identify and assess positive impacts, and approaches developed for capturing and aggregating such impacts are proposed. Challenges of aggregating positive and negative social impacts still remain. The knowledge on social impacts from vehicle fuels could be improved by applying the proposed approach. However, the approach needs more development to be practically applicable.