Modelling the economic and environmental performance of engineering products: a materials selection case study

Purpose

Life cycle assessment (LCA) studies allow understanding all relevant processes and environmental impacts involved in the life cycle of products. However, in order to fully assess their sustainability, these studies should be complemented by economic (LCC) and societal analyses. In this context, the present work aims at assessing all costs (internal and external) and the environmental performance associated to the full life cycle of specific engineering products. These products are lighting columns for roadway illumination made with three different materials: a glass fibre reinforced polymer composite, steel and aluminium.

Methods

The LCA/LCC integrated methodology used was based in a ??cradle-to-grave?? assessment which considers the raw materials production, manufacture, on-site installation, use and maintenance, dismantlement and end-of-life (EoL) of the lighting columns. The fossil fuels environmental impact category was selected as the key environmental impact indicator to perform the integrated environmental and cost analysis.

Results

The potential total costs obtained for the full life cycle of the lighting columns demonstrated that the one made in steel performs globally worse than those made in composite or aluminium. Although the three systems present very similar internal costs, the steel column has higher external costs in the use phase that contribute for its higher total cost. This column has very high costs associated to safety features, since it constitutes a significant risk to the life of individuals. The raw material and column production stages are the main contributors for the total internal life cycle costs. The EoL treatment is a revenue source in all systems because it generates energy (in the case of the composite incineration) or materials (in the case of metal recycling). The composite and aluminium lighting columns present similar ??cradle-to-grave?? life cycle total cost. However, until the dismantlement phase, the aluminium column presents the highest environmental impact, whereas in the EoL treatment phase this scenario is reversed. The ??cradle-to-grave?? life cycle potential total cost and the environmental impact (fossil fuels) indicator of the steel lighting column are higher than those of the other columns.

Conclusions

Even though the uncertainties in the LCC are larger if external costs are included, their consideration when modelling the economic performance of engineering products increases the probability of developing a more sustainable solution from a societal perspective.     

基于生命周期方法的生活垃圾资源化利用系统生态效率分析

我国生活垃圾产量大但处理能力不足,产生多种环境危害,对其资源化利用能够缓解环境压力并回收资源。为探讨生活垃圾资源化利用策略,综合生命周期评价与生命周期成本分析方法,建立生态效率模型。以天津市为例,分析和比较焚烧发电、卫生填埋-填埋气发电、与堆肥+卫生填埋3种典型生活垃圾资源化利用情景的生态效率。结果表明,堆肥+卫生填埋情景具有潜在最优生态效率;全球变暖对总环境影响贡献最大,而投资成本对经济影响贡献最大。考虑天津市生活垃圾管理现状,建议鼓励发展生活垃圾干湿组分分离及厨余垃圾堆肥的资源化利用策略。     

Integrating life cycle assessment (LCA) and life cycle costing (LCC) in the early phases of aircraft structural design: an elevator case study

Purpose

The main objective of this paper is to develop a model that will combine economic and environmental assessment tools to support the composite material selection of aircraft structures in the early phases of design and application of the tool for an aircraft elevator.

Methods

An integrated life cycle cost (LCC) and life cycle assessment (LCA) methodology was used as part of the sustainable design approach for the laminate stacking sequence design. The model considered is the aircraft structure made of carbon fiber reinforce plastic prepreg and processed via hand layup-autoclave process which is the preferred method for the aircraft industry. The model was applied to a cargo aircraft elevator case study by comparing six different laminate configurations and two different carbon fiber prepreg materials across aircraft’s entire life cycle.

Results and discussion

The results show, in line with other studies using different methodologies (e.g., life cycle engineering, or LCE), that the combination of LCA with LCC is a worthwhile approach for comparing the different laminate configurations in terms of cost and environmental impact to support composite laminate stacking design by providing the best trade-off between cost and environment. Elevator LCC reduces 19% by changing the material type and applying different ply orientations. Elevator LCA score reduces 53% by selecting the optimum instead of best technical solution that minimizes the displacement. Improving the structural performance does not always lead to an increase in the cost.

     

Life-Cycle based methods for sustainable product development

Sustainability-a term originating from silviculture, which was adopted by UNEP as the main political goal for the future development of humankind-is also the ultimate aim of product development. It comprises three components: environment, economy and social aspects which have to be properly assessed and balanced if a new product is to be designed or an existing one is to be improved. The responsibility of the researchers involved in the assessment is to provide appropriate and reliable instruments. For the environmental part there is already an internationally standardized tool: Life Cycle Assessment (LCA). Life Cycle Costing (LCC) is the logical counterpart of LCA for the economic assessment. LCC surpasses the purely economic cost calculation by taking into account hidden costs and potentially external costs over the life cycle of the product. It is a very important point that different life-cycle based methods (including Social Life Cycle Assessment) for sustainablity assessment use the same system boundaries.     

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.     

Input-Output Analysis of Waste Management

A new scheme of hybrid life-cycle assessment (LCA) termed the waste input-output (WIO) model is presented that ex-plicitly takes into account the interdependence between the flow of goods and waste. The WIO model has two distin-guishing features. First, it expands the Leontief environmental input-output (EIO) model with respect to waste flows. It turns out that the EIO model is a special case of the WIO model in which there is a strict one-to-one correspondence between waste types and treatment methods. By relaxing this condition, the WIO model provides a general framework for LCA of waste management. Second, the WIO model takes into account the "dynamics of waste treatment", which refers to the fact that the input-output relationships of waste treatment are significantly affected by the level and composition of waste feedstock, by incorporating an engineering process model of waste treatment. Because waste treatment is expected to accept whatever waste is generated by industry and households, a proper consideration of this feature is vital for LCA of waste management. We estimated a WIO table for Japan and applied it to evaluating effects of alternative waste management poli-cies with regard to regional concentration of incineration and the sorting of waste with regard to flammability. We found that concentrating treatment in a small number of large incin-erators combined with an increased degree of sorting could decrease both landfill consumption and the emission of carbon dioxide.     

Electrical and electronic components in the automotive sector: Economic and environmental assessment

Background Aims and Scope Automotive electrical and electronic systems (EES) comprise an area that has grown steadily in importance in the past decade and will continue to gain relevance in the foreseeable future. For this reason, the SEES project (Sustainable Electrical & Electronic System for the Automotive Sector) aims to contribute to cost-effective and eco-efficient EES components. Scenarios for the recovery of automotive EES are defined by taking into consideration the required improvements in EES design and the development and implementation of new technologies. The research project SEES is funded by the European Commission (Contract no. TST3-CT-2003-506075) within the Sixth Framework Programme, priority 6.2 (see 〈www.sees-project.net〉 for more information). This paper presents the findings of an assessment of the environmental and economic improvements for automotive EES from a system perspective, taking into account all life cycle steps. Methods Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) case studies have been employed within the SEES project to define optimum design and end-of-life scenarios. These case studies have been applied to two selected EES components: an engine wire harness and a smart junction box, both manufactured by LEAR and assembled in an existing Ford car model. The component design has a significant impact on the product system and its processes, including its use and end-of-life (EOL) phase. For each of the analysed components, two potential design alternatives have been compared with the original design, based on designers’ recommendations from the status quo scenario results. These include the use of alternative wiring systems with a reduced copper content (flat flexible cable), lead-free solder alloys and new fixation mechanisms to facilitate disassembly. The overall EOL scenario determines the technologies of processes that must be modelled within the EOL phase of a product system. The analysed end-of-life scenarios include: status quo car recycling and two alternatives: 1. disassembly for specific EES component recycling; 2. advanced post-shredder recycling of shredding residues. The influences of the different design and EOL treatment scenarios on the LCA and LCC results have been analysed. Results The most dominant life cycle phases for the LCA results are manufacturing (including raw material extraction and manufacturing of materials and components) and the use-phase. Similarly, manufacturing was the predominant phase during the LCC study. Disassembly costs were shown to be significant during the EOL phase. Among the analysed design alternatives, the highest environmental improvement potential were gained from the use of alternative wiring systems with reduced weight and copper content, but with slightly increased life cycle costs. Smaller differences of the results were determined for the different end-of-life scenarios. Discussion The results of the EOL scenario depend on the component in question. The influence of variations in process data, model choices, e.g. which LCIA model was used for calculating the Human Toxicity Potential (HTP), which inventory data for copper production was used and other variables have been assessed in the sensitivity analysis. The sensitivity analysis demonstrates a strong dependency of results for HTP on the selected model. The presented results are based on a public report of the SEES project. The study has undergone a critical review by an external expert according to ISO 14040, § 7.3.2. Conclusions The environmental impacts during the life cycle of the analysed products are generally most strongly influenced by material production and the use phase of the products. In comparison, improvements during the EOL phase have only a very limited potential to reduce environmental impacts. The studied design changes displayed clear environmental advantages for (lighter) flat, flexible cables. Whereas, the lead-free solder design alternatives showed a slight increase in some environmental impact categories. The application of these design changes has been limited in some cases by technical issues. Recommendations and Perspectives Focussing only on end-of-life improvements cannot be recommended for automotive EES products. A life-cycle perspective should be utilised for assessing improvements in individual life cycle stages of a product. The presented results will be an input for Eco-design guidelines for automotive EES, to be developed at a later stage within the SEES project. ESS-Submission Editor: Dr. Lester Lave (II01@andrew.cmu.edu)     

Life cycle environmental and economic assessment of industrial symbiosis networks: a review of the past decade of models and computational methods through a multi-level analysis lens

Purpose

Industrial symbiosis network (ISN) facilitation tools seek to holistically evaluate the environmental and economic performance of ISNs through life cycle assessment (LCA) and life cycle costing (LCC). ISNs have many stakeholders with diverse interests in the LCA and LCC results thus requiring multi-level analysis. The objective of this review was to examine the state-of-the-art methodologies used in LCAs and LCCs of ISNs and understand how multi-level analysis can be conducted.

Methods

The systematic literature review methodology was applied to develop a corpus of peer-reviewed LCA and LCC studies of ISNs published between 2010 and 2019 without any geographic boundary. Abstracts were reviewed to shortlist studies that conducted an LCA or LCC of an ISN with numerical results. LCA and LCC methodologies used in the shortlisted studies were collected and categorized. Each methodology was examined to understand how the foreground and background systems are represented, how waste-to-resource exchanges are analyzed, and how the results can be computed at the network, entity, and flow levels.

Results and discussion

The review yielded 42 LCA studies and 11 LCC studies of ISNs that used eight different methodologies. Process-based LCA was used in 71% of the LCA studies, whereas tiered hybrid LCA was used in 14% of the studies. Waste-to-resource exchanges in ISN scenarios were represented either through process analysis or as a black box. Fewer LCC studies that evaluate the economic performance of ISNs exist compared with LCA studies. Economic studies often evaluated financial feasibility, net present value, profitability, or payback period of specific waste-to-resource exchanges or the network overall.

Conclusions

The insights derived from this review chart future areas of research in multi-level modeling and analysis of the life cycle environmental and economic performance of ISNs. To improve the model construction and analysis process, research should be explored in developing a methodology for constructing a single model that represents multiple entities linked together by waste-to-resource exchanges and can provide LCA and LCC results for different stakeholder perspectives. The lack of LCC studies of ISNs merits the need for more research in this area at both the network and entity levels to quantify potential economic trade-offs between stakeholders. Developing a methodology for unified LCA and LCC modeling and analysis of ISNs can help ISN facilitation tool developers conduct simultaneous life cycle environmental and economic analysis of the potential symbiosis connections identified and how they contribute to the overall network.

     

A Supply‐Use Approach to Waste Input‐Output Analysis

In this article, we extend Namakura and Kondo's waste input‐output (WIO) framework by incorporating a supply‐use formalism, resulting in waste supply‐use tables (WSUTs). We present the theoretical underpinnings of the WSUT and, in particular, the transition from Nakamura and Kondo's WIO form to the new WSUT form. Further, we offer a mathematical proof of the equivalence of WIO and WSUT multipliers. We illustrate the workings of the WSUT calculus using economic and waste data for the Australian economy in 2008–2009.     

Life cycle assessment of desktop PCs in Macau

Purpose

With the tremendous growth in the worldwide electronic information and telecommunication industries, there continues to be an increasing awareness of the environmental impacts related to the accelerating mass production, electricity use, and waste management of electrical and electronic products (e-products). Although Macau is a small region with a total land area of about 29.5 km² and a population of 557,000 in 2011, there are two personal computers (PCs) for every household in Macau.

Methods

This paper aims to describe the application of life cycle assessment (LCA) to investigate the environmental performance of PCs in Macau. An assessment of the PC (focusing on the desktop PC) was carried out using a detailed modular LCA based on the international standards of the ISO 14040 series. The LCA was constructed using SimaPro software version 7.2 and expressed with both the Eco-indicator'99 method and the Centrum voor Milieuwetenschappen method. Life cycle inventory information was compiled by Ecoinvent 2.2 databases, combined with literature and field investigations of the actual situations.

Results and discussion

The established LCA study showed that the manufacturing and the use of such devices are of the highest environmental importance. In the manufacturing stage, the desktop contributes the most to the total environmental impacts (44.89 Pt), followed by the LCD screens (about 27.53 Pt), while the CRT screen, keyboard, and mouse are of minor importance. During the use phase, the environmental impact is due entirely to the consumption of electricity generated by coal, oil, natural gas, and hydropower. The electricity generated by coal is by far the most important, accounting for about 66 % of the total environmental impact, followed by oil and gas. Within the EoL treatment phase, using incineration, there will be little environmental impact. When adopting recycling technology in the EoL phase, apparent environmental benefits will be generated due mainly to avoiding emissions to water (arsenic ions and cadmium ions) and to air (SO₂) in the primary production phase. For the competing technologies of CRT and LCD screens, the environmental impacts are different in different phases, but the total impacts over their entire life cycle are similar.

Conclusions

Results from a life cycle assessment can be used to compare the relative environmental impacts of competing technologies; it can also help designers and managers to focus efforts toward making environmental improvements to a particular technology.     

Life cycle thinking in small and medium enterprises: the results of research on the implementation of life cycle tools in Polish SMEs—Part 3: LCC-related aspects

Purpose

This article is the third of a series of articles presenting the results of research on the implementation of life cycle management tools in small- and medium-sized companies in Poland. The purpose of the three-part series of articles is to present the results of research on the implementation of life cycle tools in Polish small and medium enterprises (SMEs). This work is part of a project financed by the Polish Agency for Enterprise Development (PAED) which began in February 2011. It was carried out by the Wielkopolska Quality Institute—a business environment institution associated with the Polish Centre for LCA (PCLCA). The main practical objective of the project was to support SMEs in their business development, e.g. by expanding their horizons beyond the sphere of their operation and identifying new areas for the improvement and promotion of the products and services on offer. The specific objective of the analysis involving the assessment of life-cycle costs of products and services was an attempt to answer the question to determine whether the assessment carried out in accordance with the life-cycle cost (LCC) methodology is a good tool for cost management in this type of business. Part 3 describes the results of studies on the assessment of the implementation of LCC in SMEs conducted in 50 companies involved in the project.

Methods

In order to assess the effectiveness of the project and the effectiveness of the implementation of LCA and LCC, a survey was conducted of small- and medium-sized businesses where the implementation works had been fully completed. In total, 50 organisations agreed to participate in the LCC survey (while 46 in the LCA—part 2 paper), which was 71 % of all the companies where the LCA and LCC studies had been carried out within the project. The survey was conducted using individual in-depth interviews. Questions to the representatives of the companies referred both to aspects of their operating in the market (characteristics of a company, its market share, management systems, environmental policy, suppliers, clients) and the implementation of their environmental service (assessment of its effectiveness, motivation, difficulties in its implementation), as well as opinions on the potential applications of LCA in their current operations.

Results and discussion

The experience and observations of LCC experts resulting from their cooperation with the analysed organisations are largely supported by the results of the survey. The overall impression gained from the project is that the small- and medium-sized enterprises considered have a problem with accepting and understanding the life-cycle perspective, and show limited interest in taking liability for environmental and cost aspects beyond the mandatory legal standards and boundaries of their business operations. Nevertheless, the LCC analyses aroused much bigger interest among the companies than the environmental due to the fact that the cost aspects in companies undergoing normal development are seen as an important source of information about the structure of the costs generated with respect to the products or services provided. It is important to note that a very important factor encouraging businesses to join the studies was the fact that they were cost-free. Moreover, the planned introduction of a new product onto the market was the argument that often influenced the decision to implement the LCC. The survey has shown that companies rarely perform cost analyses including all stages of the life cycle of a product or service. Although the awareness of the importance of conducting economic researches for the entire life cycle of a product or service is great, it turned out to be problematic to unambiguously define the practical use of such an analysis, at least at the present stage of development of the companies surveyed.

Conclusions

The results obtained in the survey indicate that in the case of simple products, with a short life cycle, complex cost analyses may seem less useful. For more complex products or services, with long periods of use, high reliability required, and high operating costs, the analyses presented are useful tools that increase the economic efficiency of the projects implemented. It appears that from the point of view of polish SMEs, the usefulness of an LCA is seen mainly from the angle of opportunities for cost reduction (preferably in business) and increased sales (marketing). A good solution would be to conduct relatively simple, but integrated LCA/LCC analyses in SMEs so that the companies would clearly see the economic effects of the proposed environmental improvements.     

Life cycle assessment of construction materials: the influence of assumptions in end-of-life modelling

Purpose

The nature of end-of-life (EoL) processes is highly uncertain for constructions built today. This uncertainty is often neglected in life cycle assessments (LCAs) of construction materials. This paper tests how EoL assumptions influence LCA comparisons of two alternative roof construction elements: glue-laminated wooden beams and steel frames. The assumptions tested include the type of technology and the use of attributional or consequential modelling approaches.

Methods

The study covers impact categories often considered in the construction industry: total and non-renewable primary energy demand, water depletion, global warming, eutrophication and photo-chemical oxidant creation. The following elements of the EoL processes are tested: energy source used in demolition, fuel type used for transportation to the disposal site, means of disposal and method for handling allocation problems of the EoL modelling. Two assumptions regarding technology development are tested: no development from today’s technologies and that today’s low-impact technologies have become representative for the average future technologies. For allocating environmental impacts of the waste handling to by-products (heat or recycled material), an attributional cut-off approach is compared with a consequential substitution approach. A scenario excluding all EoL processes is also considered.

Results and discussion

In all comparable scenarios, glulam beams have clear environmental benefits compared to steel frames, except for in a scenario in which steel frames are recycled and today’s average steel production is substituted, in which impacts are similar. The choice of methodological approach (attributional, consequential or fully disregarding EoL processes) does not seem to influence the relative performance of the compared construction elements. In absolute terms, four factors are shown to be critical for the results: whether EoL phases are considered at all, whether recycling or incineration is assumed in the disposal of glulam beams, whether a consequential or attributional approach is used in modelling the disposal processes and whether today’s average technology or a low-impact technology is assumed for the substituted technology.

Conclusions

The results suggest that EoL assumptions can be highly important for LCA comparisons of construction materials, particularly in absolute terms. Therefore, we recommend that EoL uncertainties are taken into consideration in any LCA of long-lived products. For the studied product type, LCA practitioners should particularly consider EoL assumptions regarding the means of disposal, the expected technology development of disposal processes and any substituted technology and the choice between attributional and consequential approaches.     

An integrated environmental and cost assessment method based on LCA and LCC for automobile interior and exterior trim design scheme optimization

Purpose

This paper provided an integrated method to evaluate environmental impact and life cycle cost (LCC) of various alternative design schemes in the early design and development stages of complex mechanical product; an optimization method of product design schemes based on life cycle assessment (LCA) and LCC is proposed as a supporting design tool to achieve optimal integration of environmental impact and cost of the design.

Methods

The applied research methods include product level deconstruction model, LCA/LCC integrated analysis model, and the product design scheme optimization method. In the life cycle environmental assessment, GaBi software and CML2001 evaluation method are used to evaluate product environmental impact. In terms of product design configuration scheme optimization, the TOPSIS method is used to optimize the design schemes generated. Taking the internal and external trim of automobile as an example, the specific implementation process of the method is illustrated.

Results and discussion

The case study indicates that, when comprehensively considering the environmental impact and cost, the composite indices of the optimal and worst schemes are 0.8667 and 0.3001, respectively; their costs are ¥164.87 and ¥179.68, respectively; and the eco points of environmental impact are 14.74 and 39.78, respectively. The cost of the two schemes are not much different, but the environmental impact of the optimal scheme is only 37.1% of the worst scheme’s; When cost is the only factor to be considered, the lowest cost design scheme is about 36.7% of the maximum scheme’s cost, and the environmental impact of the lowest cost design scheme is about 1.6 times of the maximum cost scheme’s. When environmental impact is the only factor to be considered, the least environmental impact of design scheme accounts about 31.7% of the largest; the cost of design scheme with the least environmental impact accounts for about 58.1% of the largest one’s. Integrating LCA and LCC, scientific suggestions can be provided from several perspectives.

Conclusions

By considering the environmental impact and LCC, this paper proposes a method of product design scheme optimization as a supporting design tool which could evaluate the design options of the product and identify the preferred option in the early stage of product design. It is helpful to realize the sustainability of the product. In order to improve the applicability of this method, the weighting factors of environmental impact and cost could be adjusted according to the requirements of energy saving and emission reduction of different enterprises.

     

The Effect of Life Cycle Cost Information on Consumer Investment Decisions Regarding Eco-Innovation

Life cycle cost (LCC) computations are a well-established instrument for the evaluation of intertemporal choices in organizations, but they have not been widely adopted by private consumers yet. Consumer investment decisions for products and services with higher initial costs and lower operating costs are potentially subject to numerous cognitive biases, such as present-biased preferences or framing effects. This article suggests a classification for categorizing different cost profiles for eco-innovation and a conceptual model for the influence of LCC information on consumer decisions regarding eco-innovation. It derives hypotheses on the decision-making process for eco-innovation from a theoretical perspective. To verify the hypotheses, the publication reviews empirical studies evaluating the effects of LCC information on consumer investment decisions. It can be concluded that rather than finding ways to make customers pay more for environmentally sound products, the marketing challenge for eco-innovation should be reconceptualized as one of lowering customers' perceived initial cost and increasing awareness of LCC. Most existing studies report a positive effect of LCC information on the purchase likelihood of eco-innovations. Disclosing LCC information provides an important base for long-term thinking on the individual, corporate, and policy levels.     

Uncertainty Quantification in Life Cycle Assessments: Interindividual Variability and Sensitivity Analysis in LCA of Air‐Conditioning Systems

The life cycle environmental profile of energy‐consuming products, such as air conditioning, is dominated by the products’ use phase. Different user behavior patterns can therefore yield large differences in the results of a cradle‐to‐grave assessment. Although this variation and uncertainty is increasingly recognized, it remains often poorly characterized in life cycle assessment (LCA) studies. Today, pervasive sensing presents the opportunity to collect rich data sets and improve profiling of use‐phase parameters, in turn facilitating quantification and reduction of this uncertainty in LCA. This study examined the case of energy use in building cooling systems, focusing on global warming potential (GWP) as the impact category. In Singapore, building cooling systems or air conditioning consumes up to 37% of national electricity demand. Lack of consideration of variation in use‐phase interaction leads to the oversized designs, wasted energy, and therefore reducible GWP. Using a high‐resolution data set derived from sensor observations, energy use and behavior patterns of single‐office occupants were characterized by probabilistic distributions. The interindividual variability and use‐phase variables were propagated in a stochastic model for the life cycle of air‐conditioning systems and simulated by way of Monte Carlo analysis. Analysis of the generated uncertainties identified plausible reductions in global warming impact through modifying user interaction. Designers concerned about the environmental profile of their products or systems need better representation of the underlying variability in use‐phase data to evaluate the impact. This study suggests that data can be reliably provided and incorporated into the life cycle by proliferation of pervasive sensing, which can only continue to benefit future LCA.     

Eco-efficiency

Goal, Scope and Background The eco-efficiency analysis and portfolio is a powerful decision support tool for various strategic and marketing issues. Since its original academic development, the approach has been refined during the last decade and applied to a multitude of projects. BASF, as possibly the most prominent company using and developing this tool, has applied the eco-efficiency approach to more than 300 projects in the last 7 years. One of the greatest difficulties is to cover both dimensions of eco-efficiency (costs or value added and environmental impact) in a comparable manner. This is particularly a challenge for the eco-efficiency analyses of products. Methods In this publication, an important approach and field of application dealing with product decisions based on the combination of Life Cycle Cost (LCC) and Life Cycle Assessment (LCA) is described in detail. Special emphasis is put on the quantitative assessment of the relation of costs and environmental impacts. In conventional LCA an assessment of environmental impact categories is often made by normalization with inhabitant equivalents. This is necessary to be able to compare the different environmental impact categories, because of each different unit. For the proposed eco-efficiency analysis, the costs of products or processes are also normalized with adapted gross domestic product figures. Results and Discussion The ratio between normalized environmental impact categories and normalized costs (R_E,C) is used for the graphical presentation of the results in an eco-efficiency portfolio. For the interpretation of the results of an eco-efficiency analysis, it is important to distinguish ratios R_E,C which are higher than one from ratios lower than one. In the first case, the environmental impact is higher than the cost impact, while the inverse is true in the second case. This is very important for defining which kind of improvement is needed and defining strategic management decisions. The paper shows a statistical evaluation of the R_E,C factor based on the results of different eco-efficiency analyses made by BASF. For industries based on large material flows (e.g. chemicals, steel, metals, agriculture), the R_E,C factor is typically higher than one. Conclusions and Recommendations This contribution shows that LCC and LCA may be combined in a way that they mirror the concept of eco-efficiency. LCAs that do not consider LCC may be of very limited use for company management. For that very reason, corporations should install a data management system that ensures equal information on both sides of the eco-efficiency coin.     

Consumption-as-usual instead of ceteris paribus assumption for demand

Background, aims, and scope  

Life cycle assessment (LCA) according to ISO 14040 standard (ISO-LCA) is applied to assess the environmental impact per functional unit of new or modified products. However, new or modified products can also induce demand changes—so-called rebound effects. If overall environmental impact is of interest, there is a need to assess the potential magnitude of such rebound effects and to allow recommendations on how to mitigate these effects. To do so, this study proposes to complement the constant demand assumption (implicitly assumed by the ISO-LCA), commonly known as the ceteris paribus assumption, with a consumption-as-usual assumption allowing a systematic stepwise inclusion of rebound effects.     

Is LCC relevant in a sustainability assessment?

In a recent letter to the editor, Jørgensen et al. questioned that life cycle costing (LCC) is relevant in life cycle-based sustainability assessment (LCSA). They hold the opinion that environmental and social aspects are sufficient. We argue that sustainability has three dimensions: environment, economy, and social aspects in accordance with the well-accepted “three pillar interpretation” of sustainability, although this is not verbally stated in the Brundtland report (WCED 1987). An analysis of the historical development of the term “sustainability” shows that the economic and social component have been present from the beginning and conclude that LCSA of product systems can be approximated by LCSA = (environmental) LCA + (environmental) LCC + S-LCA where S-LCA stands for social LCA. The “environmental” LCC is fully compatible with life cycle assessment (LCA), the internationally standardized (ISO 14040 + 14044) method for environmental product assessment. For LCC, a SETAC “Code of Practice” is now available and guidelines for S-LCA have been published by UNEP/SETAC. First examples for the use of these guidelines have been published. An important practical argument for using LCC from the customers’ point of view is that environmentally preferable products often have higher purchasing costs, whereas the LCC may be much lower (examples: energy saving light bulbs, low energy houses, and cars). Also, since LCC allows an assessment for different actor perspectives, the producers may try to keep the total costs from their perspective below those of a conventional product: otherwise, it will not succeed at the market, unless highly subsidized. Those are practical aspects whichfinally decide about success or failure of “sustainable” products. Whether or not an analysis using all three aspects is necessary will depend on the exact question. However, if real money flows are important in sustainability analysis of product systems, inclusion of LCC is advisable.     

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.