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.     

Stochastic decision modeling for sustainable pavement designs

Purpose

In the USA, several studies have been conducted to analyze the energy consumption and atmospheric emissions of Warm-mix Asphalt (WMA) pavements. However, the direct and indirect environmental, economic, and social impacts, termed as Triple-Bottom-Line (TBL), were not addressed sufficiently. Hence, the aim of this study is to develop TBL-oriented sustainability assessment model to evaluate the environmental and socio-economic impacts of pavements constructed with different types of WMA mixtures and compare them to a conventional Hot-mix Asphalt (HMA). The types of WMA technologies investigated in this research include Asphamin® WMA, Evotherm? WMA, and Sasobit® WMA.

Methods

To achieve this goal, supply and use tables published by the U.S. Bureau of Economic Analysis were merged with 16 macro-level sustainability metrics. A hybrid TBL-LCA model was built to evaluate the life-cycle sustainability performance of using WMA technologies in construction of asphalt pavements. The impacts on the sustainability were calculated in terms of socio-economic (import, income, gross operating surplus, government tax, work-related injuries, and employment) and environmental (water withdrawal, energy use, carbon footprint, hazardous waste generation, toxic releases into air, and land use). A stochastic compromise programming model was then developed for finding the optimal allocation of different pavement types for the U.S. highways.

Results and discussion

WMAs did not perform better in terms of environmental impacts compared to HMA. Asphamin® WMA was found to have the highest environmental and socio-economic impacts compared to other pavement types. Material extractions and processing phase had the highest contribution to all environmental impact indicators that shows the importance of cleaner production strategies for pavement materials. Based on stochastic compromised programming results, in a balanced weighting situation, Sasobit® WMA had the highest percentage of allocation (61 %); while only socio-economic aspects matter, Asphamin® WMA had the largest share (57 %) among the asphalt pavements. The optimization results also supported the significance of an increased WMA use in the U.S. highways.

Conclusions

This research complemented previous LCA studies by evaluating pavements not only from environmental emissions and energy consumption standpoint, but also from socio-economic perspectives. Multi-objective optimization results also provided important insights for decision makers when finding the optimum allocation of pavement alternatives based on different environmental and socio-economic priorities. Consequently, this study aimed to increase awareness of the inherent benefits of economic input–output analysis and multi-criteria decision making through application to emerging sustainable pavement practices.     

Comparative life cycle assessment and social life cycle assessment of used polyethylene terephthalate (PET) bottles in Mauritius

Purpose

Improper disposal of used polyethylene terephthalate (PET) bottles constitute an eyesore to the environmental landscape and is a threat to the flourishing tourism industry in Mauritius. It is therefore imperative to determine a suitable disposal method of used PET bottles which not only has the least environmental load but at the same time has minimum harmful impacts on peoples employed in waste disposal companies. In this respect, the present study investigated and compared the environmental and social impacts of four selected disposal alternatives of used PET bottles.

Methods

Environmental impacts of the four disposal alternatives, namely: 100 % landfilling, 75 % incineration with energy recovery and 25 % landfilling, 40 % flake production (partial recycling) and 60 % landfilling and 75 % flake production and 25 % landfilling, were determined using ISO standardized life cycle assessment (ISO 14040:2006) and with the support of SimaPro 7.1 software. Social life cycle assessments were performed based on the UNEP/SETAC Guidelines for Social Life Cycle Assessment of products. Three stakeholder categories (worker, society and local community) and eight sub-category indicators (child labour, fair salary, forced labour, health and safety, social benefit/social security, discrimination, contribution to economic development and community engagement) were identified to be relevant to the study. A new method for aggregating and analysing the social inventory data is proposed and used to draw conclusions.

Results and discussion

Environmental life cycle assessment results indicated that highest environmental impacts occurred when used PET bottles were disposed by 100 % landfilling while disposal by 75 % flake production and 25 % landfilling gave the least environmental load. Social life cycle assessment results indicated that least social impacts occurred with 75 % flake production and 25 % landfilling. Thus both E-LCA and S-LCA rated 75 % flake production and 25 % landfilling to be the best disposal option.

Conclusions

Two dimensions of sustainability (environmental and social) when investigated using the Life Cycle Management tool, favoured scenario 4 (75 %?% flake production and 25 % landfilling) which is a partial recycling disposal route. One hundred percent landfilling was found out to be the worst scenario. The next step will be to explore the third pillar of sustainability, economic, and devise a method to integrate the three dimensions with a view to determine the sustainable disposal option of used PET bottles in Mauritius.     

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.     

Integration of system dynamics approach toward deepening and broadening the life cycle sustainability assessment framework: a case for electric vehicles

Purpose

Quantitative life cycle sustainable assessment requires a complex and multidimensional understanding, which cannot be fully covered by the current portfolio of reductionist-oriented tools. Therefore, there is a dire need on a new generation of modeling tools and approaches that can quantitatively assess the economic, social, and environmental dimensions of sustainability in an integrated way. To this end, this research aims to present a practical and novel approach for (1) broadening the existing life cycle sustainability assessment (LCSA) framework by considering macrolevel environmental, economic, and social impacts (termed as the triple bottom line), simultaneously, (2) deepening the existing LCSA framework by capturing the complex dynamic relationships between social, environmental, and economic indicators through causal loop modeling, (3) understanding the dynamic complexity of transportation sustainability for the triple bottom line impacts of alternative vehicles, and finally (4) investigating the impacts of various vehicle-specific scenarios as a novel approach for selection of a macrolevel functional unit considering all of the complex interactions in the environmental, social, and economic aspects.

Methods

To alleviate these research objectives, we presented a novel methodology to quantify macrolevel social, economic, and environmental impacts of passenger vehicles from an integrated system analysis perspective. An integrated dynamic LCSA model is utilized to analyze the environmental, economic, and social life cycle impact as well as life cycle cost of alternative vehicles in the USA. System dynamics modeling is developed to simulate the US passenger transportation system and its interactions with economy, the environment, and society. Analysis covers manufacturing and operation phase impacts of internal combustion vehicles (ICVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). In total, seven macrolevel indicators are selected; global warming potential, particulate matter formation, photochemical oxidant formation, vehicle ownership cost, contribution to gross domestic product, employment generation, and human health impacts. Additionally, contribution of vehicle choices to global atmospheric temperature rise and public welfare is investigated.

Results and discussion

BEVs are found to be a better alternative for most of sustainability impact categories. While some of the benefits such as contribution to employment and GDP, CO₂ emission reduction potential of BEVs become greater toward 2050, other sustainability indicators including vehicle ownership cost and human health impacts of BEVs are higher than the other vehicle types on 2010s and 2020s. While the impact shares of manufacturing and operation phases are similar in the early years of 2010s, the contribution of manufacturing phase becomes higher as the vehicle performances increase toward 2050. Analysis results revealed that the US transportation sector, alone, cannot reduce the rapidly increasing atmospheric temperature and the negative impacts of the global climate change, even though the entire fleet is replaced with BEVs. Reducing the atmospheric climate change requires much more ambitious targets and international collaborative efforts. The use of different vehicle types has a small impact on public welfare, which is a function of income, education, and life expectancy indexes.

Conclusions

The authors strongly recommend that the dynamic complex and mutual interactions between sustainability indicators should be considered for the future LCSA framework. This approach will be critical to deepen the existing LCSA framework and to go beyond the current LCSA understanding, which provide a snapshot analysis with an isolated view of all pillars of sustainability. Overall, this research is a first empirical study and an important attempt toward developing integrated and dynamic LCSA framework for sustainable transportation research.

     

Economic modelling and indicators in life cycle sustainability assessment

Purpose

Sustainability assessment in life cycle assessment (LCA) addresses societal aspects of technologies or products to evaluate whether a technology/product helps to address important challenges faced by society or whether it causes problems to society or at least selected social groups. In this paper, we analyse how this has been, and can be addressed in the context of economic assessments. We discuss the need for systemic measures applicable in the macro-economic setting.

Methods

The modelling framework of life cycle costing (LCC) is analysed as a key component of the life cycle sustainability assessment (LCSA) framework. Supply chain analysis is applied to LCC in order to understand the relationships between societal concerns of value adding and the basic cost associated with a functional unit. Methods to link LCC as a foreground economic inventory to a background economy wide inventory such as an input–output table are shown. Other modelling frameworks designed to capture consequential effects in LCSA are discussed.

Results

LCC is a useful indicator in economic assessments, but it fails to capture the full dimension of economic sustainability. It has potential contradictions in system boundary to an environmental LCA, and includes normative judgements at the equivalent of the inventory level. Further, it has an inherent contradiction between user goals (minimisation of cost) and social goals (maximisation of value adding), and has no clear application in a consequential setting. LCC is focussed on the indicator of life cycle cost, to the exclusion of many relevant indicators that can be utilised in LCSA. As such, we propose the coverage of indicators in economic assessment to include the value adding to the economy by type of input, import dependency, indicators associated with the role of capital and labour, the innovation potential, linkages and the structural impact on economic sectors.

Conclusions

If the economic dimension of LCSA is to be equivalently addressed as the other pillars, formalisation of equivalent frameworks must be undertaken. Much can be advanced from other fields that could see LCSA to take a more central role in policy formation.     

An extended life cycle analysis of packaging systems for fruit and vegetable transport in Europe

Purpose

The year-round supply of fresh fruit and vegetables in Europe requires a complex logistics system. In this study, the most common European fruit and vegetable transport packaging systems, namely single-use wooden and cardboard boxes and re-useable plastic crates, are analyzed and compared considering environmental, economic, and social impacts.

Methods

The environmental, economic, and social potentials of the three transport packaging systems are examined and compared from a life cycle perspective using Life Cycle Assessment (LCA), Life Cycle Costing (LCC) and Life Cycle Working Environment (LCWE) methodologies. Relevant parameters influencing the results are analyzed in different scenarios, and their impacts are quantified. The underlying environmental analysis is an ISO 14040 and 14044 comparative Life Cycle Assessment that was critically reviewed by an independent expert panel.

Results and discussion

The results show that wooden boxes and plastic crates perform very similarly in the Global Warming Potential, Acidification Potential, and Photochemical Ozone Creation Potential categories; while plastic crates have a lower impact in the Eutrophication Potential and Abiotic Resource Depletion Potential categories. Cardboard boxes show the highest impacts in all assessed categories. The analysis of the life cycle costs show that the re-usable system is the most cost effective over its entire life cycle. For the production of a single crate, the plastic crates require the most human labor. The share of female employment for the cardboard boxes is the lowest. All three systems require a relatively large share of low-qualified employees. The plastic crate system shows a much lower lethal accident rate. The higher rate for the wooden and cardboard boxes arises mainly from wood logging. In addition, the sustainability consequences due to the influence of packaging in preventing food losses are discussed, and future research combining aspects both from food LCAs and transport packing/packaging LCAs is recommended.

Conclusions

For all three systems, optimization potentials regarding their environmental life cycle performance were identified. Wooden boxes (single use) and plastic crates (re-usable) show preferable environmental performance. The calibration of the system parameters, such as end-of-life treatment, showed environmental optimization potentials in all transport packaging systems. The assessment of the economic and the social dimensions in parallel is important in order to avoid trade-offs between the three sustainability dimensions. Merging economic and social aspects into a Life Cycle Assessment is becoming more and more important, and their integration into one model ensures a consistent modeling approach for a manageable effort.     

Progress in sustainability science: lessons learnt from current methodologies for sustainability assessment: Part 1

Purpose

Sustainability Science (SS) is considered an emerging discipline, applicative and solution-oriented whose aim is to handle environmental, social and economic issues in light of cultural, historic and institutional perspectives. The challenges of the discipline are not only related to better identifying the problems affecting sustainability but to the actual transition towards solutions adopting an integrated, comprehensive and participatory approach. This requires the definition of a common scientific paradigm in which integration and interaction amongst sectorial disciplines is of paramount relevance. In this context, life cycle thinking (LCT) and, in particular, life cycle-based methodologies and life cycle sustainability assessment (LCSA) may play a crucial role. The paper illustrates the main challenges posed to sustainability assessment methodologies and related methods in terms of ontology, epistemology and methodology of SS. The aims of the analysis are twofold: (1) to identify the main features of methodologies for sustainability assessment and (2) to present key aspects for the development of robust and comprehensive sustainability assessment.

Methods

The current debate on SS addressing ontological, epistemological and methodological aspects has been reviewed, leading to the proposal of a conceptual framework for SS. In addition, a meta-review of recent studies on sustainability assessment methodologies and methods, focusing those life cycle based, supports the discussion on the main challenges for a comprehensive and robust approach to sustainability assessment. Starting from the results of the meta-review, we identified specific features of sustainable development-oriented methods: firstly, highlighting key issues towards robust methods for SS and, secondly, capitalising on the findings of each review’s paper. For each issue, a recommendation towards a robust sustainability assessment method is given. Existing limitations of sectorial academic inquiries and proposal for better integration and mainstreaming of SS are the key points under discussion.

Discussion

In the reviewed papers, LCT and its basic principles are acknowledged as relevant for sustainability assessment. Nevertheless, LCT is not considered as a reference approach in which other methods could also find a place. This aspect has to be further explored, addressing the lack of multi-disciplinary exchange and putting the mainstreaming of LCT as a priority on the agenda of both life cycle assessment and sustainability assessment experts. Crucial issues for further developing sustainability assessment methodologies and methods have been identified and can be summarised as follows: holistic and system wide approaches, shift from multi- towards trans-disciplinarity; multi-scale (temporal and geographical) perspectives; and better involvement and participation of stakeholders.

Conclusions

Those are also the main challenges posed to LCSA in terms of progress of ontology, epistemology and methodology in line with the progress of SS. The life cycle-based methodologies should be broadened from comparing alternatives and avoiding negative impacts, to also proactively enhancing positive impacts, and towards the achievement of sustainability goals.     

Development of social sustainability assessment method and a comparative case study on assessing recycled construction materials

Purpose

Sustainability analysis should include the assessment of the environmental, social, and economic impacts throughout the life cycle of a product. However, the social sustainability performance assessment is seldom carried out during materials selection due to its complex nature and the lack of a social life cycle assessment tool. This study presents a single score-based social life cycle assessment methodology, namely social sustainability grading model, for assessing and comparing the social sustainability performance of construction materials using a case study on recycled and natural construction materials.

Methods

The proposed method is developed based on the methodological framework provided by the United Nations Environment Programme/Society of Environmental Toxicology and Chemistry guidelines published in 2009 and the methodological sheets published in 2013, the indicators and sustainability reporting guidelines provided by the Global Reporting Initiatives and ISO 26000 for social responsibility of products, and the indicators provided by the Hong Kong Business Environment Council Limited for construction sustainability. A twofold research approach is proposed in this model: the first one is the qualitative research based on expert interviews to identify, select, and prioritize the relevant subcategories and indicators, and the second one is the operational research based on the case-specific survey to collect the required data. A social sustainability index was proposed for the interpretation of the results effectively. A case study on construction materials was conducted to illustrate the implementation of the method using case-specific first-hand data.

Results and discussion

The major outcome of this study is the systematic development of a social sustainability assessment tool based on the established standards and guidelines. The case study showed that four subcategories are crucial social concerns for construction materials (i.e., health and safety issues of the materials, health and safety of workers, company’s commitment to sustainability, and company’s policies on energy and water consumption). Based on the sustainability index proposed, using recycled aggregates from locally generated waste materials scored higher (about 31–34%) social sustainability than using imported natural aggregates. In addition, recycled aggregates and natural aggregates achieved “sustainable” and “neutral” rating sustainability levels, respectively. However, several subcategories (e.g., health and safety, working hour, forced work, training and social benefits of workers, and quality of the materials and information disclosing to public) are still needed to improve the social sustainability performance of recycled aggregates.

Conclusions

An integrated social life cycle assessment method is presented in this study for assessing the social sustainability of construction materials. In addition, the reported case study in this paper is one of the first attempts for social sustainability assessment of recycled construction materials, and the method can be applied to other recycled materials/products for comparative analysis. However, several critical factors, such as integration in other life cycle methods and software, sensitivity analysis, and more case studies, are still needed for further improvement of the developed method.

     

Towards life cycle sustainability assessment: drawing on the NEEDS project’s total cost and multi-criteria decision analysis ranking methods

Purpose

In the European Union project New Energy Externalities Development for Sustainability (NEEDS), power generation technologies were ranked by means of two sustainability assessment approaches. The total costs approach, adding private and external costs, and a multi-criteria decision analysis (MCDA) were used, integrating social, economic and environmental criteria. Both approaches relied on environmental indicators based on life cycle assessment. This study aims to analyse the extent to which the development of life cycle sustainability assessment (LCSA) can draw on these ranking methods.

Methods

The approaches to rank technologies in the NEEDS project are reviewed in terms of similarities and differences in concept, quantification and scope. Identified issues are discussed and set into perspective for the development of a potential future LCSA framework.

Results and discussion

The NEEDS MCDA and total costs considerably overlap regarding issues covered, except for several social aspects. Beyond total costs being limited to private and external costs, most notable conceptual differences concern the coverage of pecuniary (i.e. price change-induced) external effects, and potential double-counting for instance of resource depletion or specific cost components. External costs take account of the specific utility changes of those affected, requiring a rather high level of spatial and temporal detail. This allows addressing intra- and inter-generational aspects. Differences between both ranking methods and current LCSA methods concern the way weighting is performed, the social aspects covered and the classification of indicators according to the three sustainability dimensions. The methods differ in the way waste, accidents or intended impacts are taken into account. An issue regarding the definition of truly comparable products has also been identified (e.g. power plants).

Conclusions

For the development of LCSA, the study suggests that taking a consequential approach allows assessing pecuniary effects and repercussions of adaptation measures, relevant for a sustainability context, and that developing a life cycle impact assessment for life cycle costing would provide valuable information. The study concludes with raising a few questions and providing some suggestions regarding the development of a consistent framework for LCSA: whether the analyses in LCSA shall be distinguished into the three dimensions of sustainable development at the inventory or the impact level also with the aim to avoid double-counting, whether or not LCSA will address exceptional events, whether or not benefits shall be accounted for and how to deal with methodological and value choices (e.g. through sensitivity analyses).     

Assessment of ecological sustainability of a building subjected to potential seismic events during its lifetime

Purpose

Sustainable development aims to enhance the quality of life by improving the social, economic and environmental conditions for present and future generations. A sustainable engineering decision-making strategy for design and assessment of construction works (i.e., civil engineering and buildings) should take into account considerations regarding the society, the economy and the environment. This study presents a novel approach for the life cycle assessment (LCA) of a case-study building subjected to seismic actions during its service life, accounting for structural reliability.

Methods

A methodology is presented that evaluates the time-dependent probability of exceeding a limit state considering the uncertainty in the representation of seismic action. By employing this methodology, the earthquake-induced damages are related to the environmental and social losses caused by the occurrence of the earthquake. A LCA of a case-study building accounting for the time-dependent seismic reliability is conducted using a damage-oriented LCA approach.

Results and discussion

The contributions of the different life cycle phases to the total environmental impact related to the building lifetime are in agreement with previous results in this field of study. However, the LCA results revealed significant risk-based contributions for the rehabilitation phase due to the induced damage resulting in seismic events. Particularly, the rehabilitation phase is expected to contribute to the total environmental impact with around the 25 % of the initial environmental impact load (related to the pre-use phase) as a consequence of seismic damage.

Conclusions and recommendations

The probability of occurrence of seismic events affects the LCA results for various life cycle phases of a building in terms of all the indicators adopted in the analysis. The time-dependent probability of collapse in a year can represent a benchmark indicator for human safety in the context of social sustainability for the building sector. The proposed approach can be implemented in a sustainable decision-making tool for design and assessment.     

A PCA-based method for construction of composite sustainability indicators

Purpose

Sustainable manufacturing is practiced globally as a comprehensive strategy for improving the sustainability performance of the manufacturing industry. While sustainability is characterized into such three dimensions as economic, environmental, and social, currently, there is no quantitative method yet to measure the so-called ??sustainability?? in the manufacturing industry. The objective of this research is to develop a comprehensive and effective quantitative method to measure the overall sustainability performance of manufacturing companies.

Methods

In this paper, an integrated methodology is presented for the development of composite sustainability indicators based on principal component analysis (PCA). In developing this integrated approach, both industry and academia surveys are conducted to identify what sustainability indicators are favored by the sustainable manufacturing community. A unique index is then generated to measure the overall sustainability performance of industrial practices. The methodology can be used for benchmarking the overall sustainability performance of various manufacturing companies.

Results

A case study is conducted on a total of 11 global electronic manufacturing companies. The overall sustainability performance of these companies are measured, benchmarked, and ranked. The results showed that PCA is an effective approach for constructing composite sustainability indicators across environmental, economic, and social dimensions.

Conclusions

From this research, it is found that industry and academia have different views on the sustainability measurement, evidenced by different weights put on the same indicator in industry and academia. The case study demonstrated that the methodology presented in this paper is an effective tool for comprehensive measurement of sustainability performance of manufacturing companies. Strengths and weaknesses of each company can be identified. Then, the recommended improvements can be suggested based on the study of each of the individual indicators.     

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.

     

Is there a place for culture in life cycle sustainability assessment?

Purpose

Cultures are increasingly recognised for their inherent value, yet, despite political and societal concern, culture is widely unrecognised in assessment techniques. Life cycle sustainability assessment (LCSA), a technique encompassing environmental, social and economic aspects, is growing in popularity. However, cultural values are rarely considered in LCSA. This paper reviews the meaning of culture; current efforts to include culture in environmental life cycle assessment (LCA), social LCA (S-LCA) and LCSA; and aspects to address when investigating integration of culture in LCA, S-LCA and LCSA.

Methods

A literature review was undertaken on definitions of culture, recognition of culture in policy and decision making, and how culture is incorporated into assessment techniques. The potential for integrating culture in LCSA was evaluated in terms of the potential benefits and challenges.

Results

Culture is often intangible and inaccessible, which may then lead to a lack of recognition in decision-making processes, or if it is recognised, then it is relegated as an afterthought. Explicitly including consideration of culture within LCSA will allow its representation alongside other sustainability aspects. The challenges of representing culture within LCSA include recognising when ‘culture’ should be distinguished from ‘social’; culture’s dynamic nature; the data collection process; and the diversity of cultures between stakeholders and at different scales from community through to nation. The potential benefits of representing culture within LCSA include greater resonance of LCSA results with stakeholders; a more comprehensive decision support tool which appropriately accounts for values; and an assessment technique which may help protect communities and their diversity of cultures.

Conclusions

Representing culture in LCSA is not straightforward and, to some extent, may be addressed through social indicators. However, developing LCSA to explicitly address cultural values has potential benefits. Future research should focus on opportunities for the development of (a) a culturally inclusive LCSA process and (b) additional cultural indicators and/or dimensions of existing LCSA indicators that represent cultural values.     

Integrating environmental and economic life cycle analysis in product development: a material selection case study

Purpose

Achieving sustainability by rethinking products, services and strategies is an enormous challenge currently laid upon the economic sector, in which materials selection plays a critical role. In this context, the present work describes an environmental and economic life cycle analysis of a structural product, comparing two possible material alternatives. The product chosen is a storage tank, presently manufactured in stainless steel (SST) or in a glass fibre reinforced polymer composite (CST). The overall goal of the study is to identify environmental and economic strong and weak points related to the life cycle of the two material alternatives. The consequential win–win or trade-off situations will be identified via a life cycle assessment/life cycle costing (LCA/LCC) integrated model.

Methods

The LCA/LCC integrated model used consists in applying the LCA methodology to the product system, incorporating, in parallel, its results into the LCC study, namely those of the life cycle inventory and the life cycle impact assessment.

Results and discussion

In both the SST and CST systems, the most significant life cycle phase is the raw materials production, in which the most significant environmental burdens correspond to the Fossil fuels and Respiratory inorganics categories. The LCA/LCC integrated analysis shows that the CST has globally a preferable environmental and economic profile, as its impacts are lower than those of the SST in all life cycle stages. Both the internal and external costs are lower, the former resulting mainly from the composite material being significantly less expensive than stainless steel. This therefore represents a full win–win situation. As a consequence, the study clearly indicates that using a thermoset composite material to manufacture storage tanks is environmentally and economically desirable. However, it was also evident that the environmental performance of the CST could be improved by altering its end-of-life stage.

Conclusions

The results of the present work provide enlightening insights into the synergies between the environmental and the economic performance of a structural product made with alternative materials. Furthermore, they provide conclusive evidence to support the integration of environmental and economic life cycle analysis in the product development processes of a manufacturing company or, in some cases, even in its procurement practices.     

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.

     

Environmental impact and cost assessment of incineration and ethanol production as municipal solid waste management strategies

Purpose

Municipal solid waste (MSW) can be handled with several traditional management strategies, including landfilling, incineration, and recycling. Ethanol production from MSW is a novel strategy that has been proposed and researched for practical use; however, MSW ethanol plants are not widely applied in practice. Thus, this study has been conducted to analyze and compare the environmental and economic performance of incineration and ethanol production as alternatives to landfilling MSW.

Methods

The ISO 14040 life cycle assessment framework is employed to conduct the environmental impact assessment of three different scenarios for the two MSW management strategies based on processing 1 ton of MSW as the functional unit. The first scenario models the process of incinerating MSW and recovering energy in the form of process heat; the second scenario also includes the process of incinerating MSW but yields in the recovery of energy in the form of electricity; and the third scenario models the process of converting MSW into ethanol. The economic impacts of each scenario are then assessed by performing benefit-to-cost ratio (BCR) and net present value (NPV) analyses.

Results and discussion

The results from the environmental impact assessment of each scenario reveal that scenario 2 has the highest benefits for resource availability while scenario 3 is shown to be the best alternative to avoid human health and ecosystems diversity impacts. Scenario 1 has the worst environmental performance with respect to each of these environmental endpoint indicators and has net environmental impacts. The results of the economic analysis indicate that the third scenario is the best option with respect to BCR and NPV, followed by scenarios 2 and 1, respectively. Furthermore, environmental and economic analysis results are shown to be sensitive to MSW composition.

Conclusions

It appears municipalities should prefer MSW incineration with electricity generation or MSW-to-ethanol conversion over MSW incineration with heat recovery as an alternative to landfilling. The contradiction between the environmental impact assessment results and economic analysis results demonstrates that the decision-making process is sensitive to a broad set of variables. Decisions for a specific MSW management system are subject to facility location and size, MSW composition, energy prices, and governmental policies.     

Fouling release coating application as an environmentally efficient retrofit: a case study of a ferry-type ship

Purpose and methods

The paper introduces a simple retrofit performed on a case study vessel, with the aim of assessing the retrofit’s potential environmental impacts via doing a life cycle assessment. Additionally, the case presented herein strives to evidence the applicability of life cycle assessment (LCA) appraisals within shipyard representatives or managers.

Results and discussion

The environmental results shown in this paper are related to cost calculations presented for the selected retrofit, underlining the potential environmental impacts from the retrofit, while appraising its economic performance.

Conclusions

The paper strives to evidence that significant savings with regard to fuel costs can be achieved by the application of this retrofit to ships with a similar operational profile, but more importantly, the improved operational efficiency and the emission reductions can be noteworthy. Lastly, the results summarised intend to offer an optimistic context towards the implementation of the retrofit at a larger scale, i.e. a section of the existing fleet.     

A hybrid life cycle assessment of water treatment chemicals: an Australian experience

Purpose

Life cycle assessment (LCA) of chemicals is usually developed using a process-based approach. In this paper, we develop a tiered hybrid LCA of water treatment chemicals combining the specificity of process data with the holistic nature of input–output analysis (IOA). We compare these results with process and input–output models for the most commonly used chemicals in the Australian water industry to identify the direct and indirect environmental impacts associated with the manufacturing of these materials.

Methods

We have improved a previous Australian hybrid LCA model by updating the environmental indicators and expanding the number of included industry sectors of the economy. We also present an alternative way to estimate the expenditure vectors to the service sectors of the economy when financial data are not available. Process-based, input–output and hybrid results were calculated for caustic soda, sodium hypochlorite, ferric chloride, aluminium sulphate, fluorosilicic acid, calcium oxide and chlorine gas. The functional unit is the same for each chemical: the production of 1 tonne in the year 2008.

Results and discussion

We have provided results for seven impact categories: global warming potential; primary energy; water use; marine, freshwater and terrestrial ecotoxicity potentials and human toxicity potential. Results are compared with previous IOA and hybrid studies. A sensitivity analysis of the results to assumed wholesale prices is included. We also present insights regarding how hybrid modelling helps to overcome the limitations of using IO- or process-based modelling individually.

Conclusions and recommendations

The advantages of using hybrid modelling have been demonstrated for water treatment chemicals by expanding the boundaries of process-based modelling and also by reducing the sensitivity of IOA to fluctuations in prices of raw materials used for the production of these industrial commodities. The development of robust hybrid life cycle inventory databases is paramount if hybrid modelling is to become a standard practice in attributional LCA.