Life Cycle Energy Assessment of Alternative Water Supply Systems (9 pp)

Goal, Scope and Background This paper discusses the merging of methodological aspects of two known methods into a hybrid on an application basis. Water shortages are imminent due to scarce supply and increasing demand in many parts of the world. In California, this is caused primarily by population growth. As readily available water is depleted, alternatives that may have larger energy and resource requirements and, therefore, environmental impacts must be considered. In order to develop a more environmentally responsible and sustainable water supply system, these environmental implications should be incorporated into planning decisions. Methods Comprehensive accounting for environmental effects requires life cycle assessment (LCA), a systematic account of resource use and environmental emissions caused by extracting raw materials, manufacturing, constructing, operating, maintaining, and decommissioning the water infrastructure. In this study, a hybrid LCA approach, combining elements of process-based and economic input-output-based LCA was used to compare three supply alternatives: importing, recycling, and desalinating water. For all three options, energy use and air emissions associated with energy generation, vehicle and equipment operation, and material production were quantified for life-cycle phases and water supply functions (supply, treatment, and distribution). The Water-Energy Sustainability Tool was developed to inform water planning decisions. It was used to evaluate the systems of a Northern and a Southern California water utility. Results and Discussion The results showed that for the two case study utilities desalination had 2–5 times larger energy demand and caused 2–18 times more emissions than importation or recycling, due primarily to the energy-intensity of the treatment process. The operation life-cycle phase created the most energy consumption with 56% to 90% for all sources and case studies. For each water source, a different life-cycle phase dominated energy consumption. For imported water, supply contributed 56% and 86% of the results for each case study; for desalination, treatment accounted for approximately 85%; for recycled water, distribution dominated with 61% and 74% of energy use. The study calculated external costs of air pollution from all three water supply systems. These costs are borne by society, but not paid by producers. The external costs were found to be 6% of desalinated water production costs for both case studies, 8% of imported water production costs in Southern California, and 1–2% for the recycled water systems and for the Northern California utility's imported water system. Conclusion Recycling water was found to be more energy intensive in Northern than in Southern California, but the results for imported water were similar. While the energy demand of water recycling was found to be larger than importation in Northern California, the two alternatives were competitive in Southern California. For all alternatives in both case studies, the energy consumed by system operation dominated the results, but maintenance was also found to be significant. Energy production was found to be the largest contributor in all water provision systems, followed by materials production. The assessment of external costs revealed that the environmental effects of energy and air emissions caused by infrastructure is measurable, and in some cases, significant relative to the economic cost of water. Recommendation and Perspective This paper advocates the necessity of LCA in water planning, and discusses the applicability of the described model to water utilities.     

Life Cycle Assessment of Kerosene Used in Aviation (8 pp)

Goal, Scope, and Background The main goal of the study is a comprehensive life cycle assessment of kerosene produced in a refinery located in Thessaloniki (Greece) and used in a commercial jet aircraft. Methods The Eco-Indicator 95 weighting method is used for the purpose of this study. The Eco-Indicator is a method of aggregation (or, as described in ISO draft 14042, 'weighting through categories') that leads to a single score. In the Eco-indicator method, the weighing factor (We) applied to an environmental impact index (greenhouse effect, ozone depletion, etc.) stems from the 'main' damage caused by this environmental impact. Results and Discussion The dominant source of greenhouse gas emissions is from kerosene combustion in aircraft turbines during air transportation, which contributes 99.5% of the total CO2 emissions. The extraction and refinery process of crude oil contribute by around 0.22% to the GWP. This is a logical outcome considering that these processes are very energy intensive. Transportation of crude oil and kerosene have little or no contribution to this impact category. The main source of CFC-11 equivalent emissions is refining of crude oil. These emissions derive from emissions that result from electricity production that is used during the operation of the refinery. NOx emissions contribute the most to the acidification followed by SO2 emissions. The main source is the use process in a commercial jet aircraft, which contributes approximately 96.04% to the total equivalent emissions. The refinery process of crude oil contributes by 2.11% mainly by producing SO2 emissions. This is due to the relative high content of sulphur in the input flows of these processes (crude oil) that results to the production of large amount of SO2. Transportation of crude oil by sea (0.76%) produces large amount of SO2 and NOx due to combustion of low quality liquid fuels (heavy fuel oil). High air emissions of NOx during kerosene combustion result in the high contribution of this subsystem to the eutrophication effect. Also, water emissions with high nitrous content during the refining and extraction of crude oil process have a big impact to the water eutrophication impact category. Conclusion The major environmental impact from the life cycle of kerosene is the acidification effect, followed by the greenhouse effect. The summer smog and eutrophication effect have much less severe effect. The main contributor is the combustion of kerosene to a commercial jet aircraft. Excluding the use phase, the refining process appears to be the most polluting process during kerosene's life cycle. This is due to the fact that the refining process is a very complicated energy intensive process that produces large amounts and variety of pollutant substances. Extraction and transportation of crude oil and kerosene equally contribute to the environmental impacts of the kerosene cycle, but at much lower level than the refining process. Recommendation and Perspective The study indicates a need for a more detailed analysis of the refining process which has a very high contribution to the total equivalent emissions of the acidification effect and to the total impact score of the system (excluding the combustion of kerosene). This is due to the relative high content of sulphur in the input flows of these processes (crude oil) that results to the production of large amount of SO2.     

From Life Cycle Assessment to Life Cycle Management

Life cycle assessment (LCA) is a widely accepted methodology to support decision‐making processes in which one compares alternatives, and that helps prevent shifting of environmental burdens along the value chain or among impact categories. According to regulation in the European Union (EU), the movement of waste needs to be reduced and, if unavoidable, the environmental gain from a specific waste treatment option requiring transport must be larger than the losses arising from transport. The EU explicitly recommends the use of LCA or life cycle thinking for the formulation of new waste management plans. In the last two revisions of the Industrial Waste Management Programme of Catalonia (PROGRIC), the use of a life cycle thinking approach to waste policy was mandated. In this article we explain the process developed to arrive at practical life cycle management (LCM) from what started as an LCA project. LCM principles we have labeled the “3/3” principle or the “good enough is best” principle were found to be essential to obtain simplified models that are easy to understand for legislators and industries, useful in waste management regulation, and, ultimately, feasible. In this article, we present the four models of options for the management of waste solvent to be addressed under Catalan industrial waste management regulation. All involved actors concluded that the models are sufficiently robust, are easy to apply, and accomplish the aim of limiting the transport of waste outside Catalonia, according to the principles of proximity and sufficiency.     

Life Cycle Assessment of Urban Wastewater Reclamation and Reuse Alternatives

Continuous population growth is causing increased water contamination. Uneven distribution of water resources and periodic droughts have forced governments to seek new water sources: reclaimed and desalinated water. Wastewater recovery is a tool for better management of the water resources that are diverted from the natural water cycle to the anthropic one. The main objective of this work is to assess the stages of operation of a Spanish Mediterranean wastewater treatment plant to identify the stages with the highest environmental impact, to establish the environmental loads associated with wastewater reuse, and to evaluate alternative final destinations for wastewater. Tertiary treatment does not represent a significant increment in the impact of the total treatment at the plant. The impact of reclaiming 1 cubic meter (m³) of wastewater represents 0.16 kilograms of carbon dioxide per cubic meter (kg CO₂/m³), compared to 0.83 kg CO₂/m³ associated with basic wastewater treatment (primary, secondary, and sludge treatment). From a comparison of the alternatives for wastewater final destination, we observe that replacing potable water means a freshwater savings of 1.1 m³, whereas replacing desalinated water means important energy savings, reflected in all of the indicators. To ensure the availability of potable water to all of the population—especially in areas where water is scarce—governments should promote reusing wastewater under safe conditions as much as possible.     

Life Cycle Assessment of Water Supply Plans in Mediterranean Spain

Life cycle assessment (LCA) was used to compare the current water supply planning in Mediterranean Spain, the so‐called AGUA Programme, with its predecessor, the Ebro river water transfer (ERWT). Whereas the ERWT was based on a single interbasin transfer, the AGUA Programme excludes new transfers and focuses instead on different types of resources, including seawater and brackish water desalination and wastewater reuse, among others. The study includes not only water supply but the whole anthropic cycle of water, from water abstraction to wastewater treatment. In addition to standard LCA impact categories, a specific impact category focusing on freshwater resources is included, which takes into account freshwater scarcity in the affected water catchments. In most impact categories the AGUA Programme obtains similar or even lower impact scores than ERWT. Concerning impacts on freshwater resources, the AGUA Programme obtains an impact score 49% lower than the ERWT. Although the current water planning appears to perform better in many impact categories than its predecessor, this study shows that water supply in Spanish Mediterranean regions is substantially increasing its energy intensity and that Mediterranean basins suffer a very high level of water stress due to increasing demand and limited resources.     

Distance-to-Target Weighting in Life Cycle Impact Assessment Based on Chinese Environmental Policy for the Period 1995-2005 (6 pp)

Background and Objective

. Values in the known weighting methods in Life Cycle Assessment are mostly founded by the societal systems of developed countries. What source of weights and which weighting methods are reliable for a big developing country like China? The purpose of this paper is to find a possible weighting method and available data that will work well for LCA practices conducted in China. Since government policies and decisions play a leading role in the process of environmental protection in developing countries, the weights derived from political statements may be a consensus by representatives of the public.

Methods

'Distance-to-political target' principle is used in this paper to derive weights of five problem-oriented impact categories. The critical policy targets are deduced from the environmental policies issued in the period of the Ninth Five-year (1996-2000) and the Tenth Five-year (2001-2005) Plan for the Development of National Economy and Society of China. Policy targets on two five-year periods are presented and analyzed. Weights are determined by the quotient between the reference levels and target levels of a certain impact category.

Results and Discussion

Since the Tenth Five-year Plan put forward the overall objective to reduce the level of regional pollution by 2005, the weights for AP, EP and POCP for 2000-2005 are more than 1. By comparison between the Ninth Five-year and Tenth Five-year period, the results show that the weights obtained in this paper effectively represent Chinese political environmental priorities in different periods. For the weights derived from China's political targets for the overall period 1995-2005, the rank order of relative importance is ODP>AP>POCP>EP>GWP. They are recommended to the potential users for the broader disparity among the five categories. By comparison with the weights presented by the widespread EDIP method, the result shows that there's a big difference in the relative importance of ozone depletion and global warming.

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In conclusion, the weighting factors and rank order of impact categories determined in this study represent the characteristics of the big developing country. The derived weighting set can be helpful to LCA practices of products within the industrial systems of China.

     

Life Cycle Assessment Software: Selection Can Impact Results

When software is used to facilitate life cycle assessments (LCAs), the implicit assumption is that the results obtained are not a function of the choice of software used. LCAs were done in both SimaPro and GaBi for simplified systems of creation and disposal of 1 kilogram each of four basic materials (aluminum, corrugated board, glass, and polyethylene terephthalate) to determine whether there were significant differences in the results. Data files and impact assessment methodologies (Impact 2002, ReCiPe, and TRACI 2) were ostensibly identical (although there were minor variations in the available ReCiPe version between the programs that were investigated). Differences in reported impacts of greater than 20% for at least one of the four materials were found for 9 of the 15 categories in Impact 2002+, 7 of the 18 categories in ReCiPe, and four of the nine categories in TRACI. In some cases, these differences resulted in changes in the relative rankings of the four materials. The causes of the differences for 14 combinations of materials and impact categories were examined by tracing the results back to the life cycle inventory data and the characterization factors in the life cycle impact assessment (LCIA) methods. In all cases examined, a difference in the characterization factors used by the two programs was the cause of the differing results. As a result, when these software programs are used to inform choices, the result can be different conclusions about relative environmental preference that are functions purely of the software implementation of LCIA methods, rather than of the underlying data.     

Life Cycle Assessment of Water Production Technologies - Part 1: Life Cycle Assessment of Different Commercial Desalination Technologies (MSF,MED, RO) (9 pp)

- Preamble. This series of two papers analyses and compares the environmental loads of different water production technologies in order to establish, in a global, rigorous and objective way, the less aggressive technology for the environment with the present state of the art of the technology. Further, it is also presented an estimation of the potential environmental loads that the considered technologies could provoke in future, taking into account the most suitable evolution of the technology. - Part 1 presents the assessment of most commercial desalination technologies which are spread worldwide: Reverse Osmosis, Multi Effect Desalination and Multi Stage Flash. Part 2 presents the comparative LCA analysis of a big hydraulic infrastructure, as is to be found in the Ebro River Water Transfer project, with respect to desalination. - DOI: http://dx.doi.org/10.1065/lca2004.09.179.1 - Intention, Goal and Background. In this paper, some relevant results of a research work are presented, the main aim of which consists of performing the environmental assessment of different water production technologies in order to establish, in a global, rigorous and objective way, the less aggressive technology for the environment of potable water supply to the end users. That is, the scope of this paper is mostly oriented to the comparative Life Cycle Assessment of different water production technologies instead of presenting new advancements in the LCA methodology. In Part 1, the environmental loads associated with the most widespread and important commercial desalination technologies all over the world - Reverse Osmosis (RO), Multi Effect Desalination (MED) and Multi Stage Flash (MSF) – are compared. The assessment technique is the Life Cycle Analysis (LCA), which includes the entire life cycle of each technology, encompassing: extraction and processing raw materials, manufacturing, transportation and distribution, operation and final waste disposal.- Methods and Main Features. The software SimaPro 5.0, developed by Dutch PRé Consultants, has been used as the analysis tool, because it is a well known, internationally accepted and validated tool. Different evaluation methods have been applied in the LCA evaluation: CML 2 baseline 2000, Eco-Points 97 and Eco-Indicator 99. Data used in the inventory analysis of this Part 1 come from: a) existing plants in operation; b) data bases implemented in the SimaPro 5.0 software -BUWAL 250, ETH-ESU 96, IDEMAT 2001. Different scenarios have been analyzed in both parts in order to estimate, not only the potential of reduction of the provoked environmental loads with the present state of the art of technology, but also the most likely future trend of technological evolution. In Part 1, different energy production models and the integration of desalination with other productive processes are studied, while the effect of the most likely technological evolution in the midterm, and the estimation of the environmental loads to the water transfer during drought periods are considered in Part 2. Results and Discussion The main contribution to the global environmental impact of desalination technologies comes from the operation, while the other phases, construction and disposal, are almost negligible when compared to it. Energy is very important in desalination, for this reason the environmental loads change a lot depending on the technology used for providing the energy used in the desalination process. Among the different analyzed technologies, RO is the least aggressive desalination technology (one order of magnitude lower than the thermal processes, MSF and MED) for the environment. When integrating thermal desalination with other productive processes taking advantage of the residual heat, the environmental loads of thermal desalination technologies is highly reduced, obtaining similar loads to that of RO. The environmental loads of desalination technologies are significantly reduced when an energy model based on renewable energies is used. Taking into account the technological evolution, which is experiencing the RO, a reduction of its environmental load by about 40% is to be expected in the mid-term. Conclusion The main conclusion of Part 1 is that, with the present state of the art of the technology, RO is clearly the desalination technology with a reduced environmental load (one order of magnitude lower than the thermal processes, MSF and MED). In the case of thermal desalination technologies, their environmental load can be highly reduced (about 1,000 times less) when integrated with other industrial processes. In the case of RO, the scores and the airborne emissions obtained from an electricity production model based on renewable energies are about 65-70 times lower than those obtained when the electricity production model is mainly based on fossil fuels. Recommendations and Outlook Although desalination technologies are energy intensive and provoke an important environmental load, they present a high potential in being reduced since: a) in the mid-term, it is to be expected that the different technologies could improve their efficiency significantly, b) the environmental loads would be highly reduced if the energy production models were not mainly based on fossil fuels and c) the energy consumption, particularly in the case of thermal desalination, can be drastically reduced when integrating desalination with other productive processes. The results presented in this paper indicate that a very interesting and promising field of research is available in order to reduce the environmental load of these vigorous and increasing desalination technologies.     

Extending the Life Cycle Methodology to Cover Impacts of Land Use Systems on the Water Balance (7 pp)

Goal, Scope and Background Whilst initially designed for industrial production systems, environmental life cycle assessment (LCA) has recently been increasingly applied to agriculture and forestry projects. Several authors suggested that the standard LCA methodology needs to be refined to cover the particularities of agri- and silvicultural production systems. Until now, water quantity received little attention in these methodological revisions, notwithstanding the well-known impact of agriculture and forestry on issues like water availability, drought and flood risk. This paper proposes an add-on to existing LCA methods in the form of an indicator set that integrates water quantity impacts of agri- and silvicultural production. Method First, system boundaries are discussed in order to identify the water flows between the production system and the environment. These flows are attributed to impact categories, linked to environmental burdens and to the areas of protection. Appropriate indicators are selected for each potential burden. Results and Discussion At the present, two input related impact categories deal with water quantity: Abiotic resource depletion and land use. The list of output related impact categories presented by Udo de Haes et al. (1999) does not include water quantity impacts like flood and drought risk. A new impact category “regional water balance” is introduced to cover these risks. Exceedance probabilities are used as indicators for these temporal variations in streamflow. Conclusion and Outlook The method presented in this paper can bring a life cycle assessment closer to real world concerns. The main drawback, however, is the increasing data requirement that might hinder the feasibility of the method. Future research should focus on this problem, for instance by applying a relatively simple numerical model that can calculate the indicator scores from more easily accessible data.     

Life Cycle Assessment of Water Production Technologies - Part 2: Reverse Osmosis Desalination versus the Ebro River Water Transfer (9 pp)

- Preamble. This series of two papers analyses and compares the environmental loads of different water production technologies in order to establish, in a global, rigorous and objective way, the less aggressive technology for the environment with the present state of the art of technology. Further, an estimation of the potential environmental loads that the considered technologies could provoke in future is also presented, taking into account the most suitable evolution of the technology. - Part 1 presents the assessment of most commercial desalination technologies which are spread worldwide: Reverse Osmosis, Multi Effect Desalination and Multi Stage Flash. Part 2 presents the comparative LCA analysis of a big hydraulic infrastructure, as is to be found in the Ebro River Water Transfer project, with respect to desalination. - Intention, Goal and Background. In this paper some relevant results of a research work are presented, the main aim of which consists of performing the environmental assessment of different water production technologies in order to establish, in a global, rigorous and objective way, the less aggressive technology for the environment for supplying potable water to the end users. The scope of this paper is mostly oriented to the comparative Life Cycle Assessment of different water production technologies instead of presenting new advancements in the LCA methodology. Based on the results obtained in Part 1 (LCA of most widespread commercial desalination technologies), the particular case of a big hydraulic project, which is the Ebro River Water Transfer (ERWT) considered in the Spanish National Hydrologic Plan, versus the production by desalination of the same amount of water to be diverted, is compared in Part 2. The assessment technique is the Life Cycle Analysis (LCA), which includes the entire life cycle of each technology, encompassing: extraction and processing raw materials, manufacturing, transportation and distribution, operation and final waste disposal. Methods and Main Features. The software SimaPro 5.0, developed by Dutch PRé Consultants, has been used as the analysis tool, because it is a well known, internationally accepted and validated tool. Different evaluation methods have been applied in the LCA evaluation: CML 2 baseline 2000, Eco-Points 97 and Eco-Indicator 99. Data used in the inventory analysis of this Part 2 come from: a) desalination: data obtained for existing plants in operation; b) ERWT: Project approved in the Spanish National Hydrologic Plan and its Environmental Impact Evaluation and; c) data bases implemented in the SimaPro software – BUWAL 250, ETH-ESU 96, IDEMAT 2001. Different scenarios have been analyzed in both parts in order to estimate not only the potential of reduction of the provoked environmental loads with the present state of the art of technology, but also the most likely future trend of technological evolution. In Part 1, different energy production models and the integration of desalination with other productive processes are studied, while the effect of the most likely technological evolution in the midterm, and the estimation of the environmental loads to the water transfer during drought periods are considered in Part 2. Results and Discussion As proven in Part 1, RO is a less aggressive desalination technology for the environment. Its aggression is one order of magnitude lower than that of the thermal processes, MSF and MED. The main contribution to the global environmental impact of RO comes from the operation, while the other phases, construction and disposal, are almost negligible when compared to it. In the case of the ERWT, the contribution of the operation phase is also the most important one, but the construction phase has an important contribution too. Its corresponding environmental load, with the present state of the art of technology, is slightly lower than that provoked by the RO desalination technology. However, the results obtained in the different scenarios analyzed show that the potential reduction of the environmental load in the case of the ERWT is significantly lower than that in the case of the RO. The effect of drought periods in the assessed environmental loads of the water transfer is not negligible, obtaining as a result an increasing environmental load per m3 of diverted water. Conclusion The environmental load associated with RO, with the present state of the art of technology, is slightly higher than that provoked by the ERWT. However, considering the actual trend of technological improvement of the RO and the present trend of energy production technology in the address of reducing the fossil fuels\ contribution in the electricity production, the environmental load associated with RO in the short mid-term would be likely to be lower than that corresponding to the ERWT. Recommendations and Outlook Although desalination technologies are energy intensive and provoke an important environmental load, as already explained in Part 1, they present a high potential of reducing it. In respect to ERWT, the results indicate, when the infrastructure of ERWT is completed (by 2010–2012), that the LCA of RO will be likely to be against the water transfer. With the present technological evolution of water production technologies and from the results obtained in this paper, it seems, from an environmental viewpoint, that big hydraulic projects should be considered the last option because they are rigid and long-term infrastructures (several decades and even centuries of operation) that provoke important environmental loads with only a small margin for reducing them.     

The Importance of Normalization References in Interpreting Life Cycle Assessment Results

A normalization step is widely exercised in life cycle assessment (LCA) studies in order to better understand the relative significance of impact category results. In the normalization stage, normalization references (NRs) are the characterized results of a reference system, typically a national or regional economy. Normalization is widely practiced in LCA‐based decision support and policy analysis (e.g., LCA cases in municipal solid waste treatment technologies, renewable energy technologies, and environmentally preferable purchasing programs, etc.). The compilation of NRs demands significant effort and time as well as an intimate knowledge of data availability and quality. Consequently only one set of published NRs is available for the United States, and has been adopted by various studies. In this study, the completeness of the previous NRs was evaluated and significant data gaps were identified. One of the reasons for the significant data gaps was that the toxic release inventory (TRI) data significantly underestimate the potential impact of toxic releases for some sectors. Also the previous NRs did not consider the soil emissions and nitrogen (N) and phosphorus (P) runoffs to water and chemical emissions to soils. Filling in these data gaps increased the magnitude of NRs for “human health cancer,” “human health noncancer,” “ecotoxicity,” and “eutrophication” significantly. Such significant changes can alter or even reverse the outcome of an LCA study. We applied the previous and updated NRs to conventional gasoline and corn ethanol LCAs. The results demonstrate that NRs play a decisive role in the interpretation of LCA results that use a normalization step.     

Methodological Aspects of Applying Life Cycle Assessment to Industrial Symbioses

In view of recent studies of the historical development and current status of industrial symbiosis (IS), life cycle assessment (LCA) is proposed as a general framework for quantifying the environmental performance of by‐product exchange. Recent guidelines for LCA (International Reference Life Cycle Data System [ILCD] guidelines) are applied to answer the main research questions in the IS literature reviewed. A typology of five main research questions is proposed: (1) analysis, (2) improvement, and (3) expansion of existing systems; (4) design of new eco‐industrial parks, and (5) restructuring of circular economies. The LCA guidelines were found useful in framing the question and choosing an appropriate reference case for comparison. The selection of a correct reference case reduces the risk of overestimating the benefits of by‐product exchange. In the analysis of existing systems, environmentally extended input‐output analysis (EEIOA) can be used to streamline the analysis and provide an industry average baseline for comparison. However, when large‐scale changes are applied to the system, more sophisticated tools are necessary for assessment of the consequences, from market analysis to general equilibrium modeling and future scenario work. Such a rigorous application of systems analysis was not found in the current IS literature, but would benefit the field substantially, especially when the environmental impact of large‐scale economic changes is analyzed.     

Application of Life Cycle Assessment for the Environmental Certificate of the Mercedes-Benz S-Class (7 pp)

Background, Aims and Scope Life cycle assessment (LCA) is used as a tool for design for environment (DfE) to improve the environmental performance of the Mercedes Car Group products. For the new S-Class model a brochure including an environmental certificate and comprehensive data for the product was published for the first time. The paper explains the use of LCA for these applications and presents exemplary results. Methods The environmental certificate brochure reports on processes, data and results based on the international standards for life cycle assessment (ISO 14040, ISO 14041, ISO 14042, ISO 14043), for environmental labels and declarations (ISO 14020, ISO 14021) and for the integration of environmental aspects into product design and development (ISO 14062), which are accepted by all stakeholders. Results and Discussion The compliance with these international standards and the correctness of the information contained in the certificate were reviewed and certified by independent experts. The global warming potential (GWP 100 years) of the new S-Class vehicle was reduced by 6%, the acidification potential by 2%, the eutrophication potential by 13% and the photochemical ozone creation potential by 9%. In addition, the use of parts made from renewable materials was increased by 73 percent to a total of 27 parts with a weight of about 43 kilograms. A total of 45 parts with a weight of 21.2 kilograms can be manufactured using a percentage of recycled plastics. Conclusion The application of LCA for DfE is fully integrated as a standard function in the vehicle development process. The DfE/LCA approach at the Mercedes Car Group was successful in improving the environmental performance of the new S-Class. It is shown that the objective of improving the environmental performance of the new S-Class model, compared to the previous one, was achieved. Recommendation and Outlook Vehicles are complex products with very complex interactions with the environment. Therefore, simple solutions, e.g. pure focus on fuel economy or light weighting or recycling or single material strategies, are bound to fail. It is a main task of DfE and LCA to take this fact into account and come up with more intelligent solutions. The application of LCAs for DfE and their integration as standard practice in the product development process is both the most demanding and the most rewarding. It requires a substantial effort to acquire the know-how, the data, the experience and the tools needed to generate meaningful results just in time. However, this is the way how LCA and DfE can add value – they have to be 'built' into the product.     

Implementing a Dynamic Life Cycle Assessment Methodology with a Case Study on Domestic Hot Water Production

This work contributes to the development of a dynamic life cycle assessment (DLCA) methodology by providing a methodological framework to link a dynamic system modeling method with a time‐dependent impact assessment method. This three‐step methodology starts by modeling systems where flows are described by temporal distributions. Then, a temporally differentiated life cycle inventory (TDLCI) is calculated to present the environmental exchanges through time. Finally, time‐dependent characterization factors are applied to the TDLCI to evaluate climate‐change impacts through time. The implementation of this new framework is illustrated by comparing systems producing domestic hot water (DHW) over an 80‐year period. Electricity is used to heat water in the first system, whereas the second system uses a combination of solar energy and gas to heat an equivalent amount of DHW at the same temperature. This comparison shows that using a different temporal precision (i.e., monthly vs. annual) to describe process flows can reverse conclusions regarding which case has the best environmental performance. Results also show that considering the timing of greenhouse gas (GHG) emissions reduces the absolute values of carbon footprint in the short‐term when compared with results from the static life cycle assessment. This pragmatic framework for the implementation of time in DLCA studies is proposed to help in the development of the methodology. It is not yet a fully operational scheme, and efforts are still required before DLCA can become state of practice.     

Entity Normalization in Life Cycle Assessment: Hybrid Schemes Applied to a Transportation Agency Case Study

Government agencies, companies, and other entities are using environmental assessments, like life cycle assessment (LCA), as an input to decision‐making processes. Communicating the esoteric results of an LCA to these decision makers can present challenges, and interpretation aids are commonly provided to increase understanding. One such method is normalizing results as a means of providing context for interpreting magnitudes of environmental impacts. Normalization is mostly carried out by relating the environmental impacts of a product (or process) under study to those of another product or a spatial reference area (e.g., the United States). This research is based on the idea that decision makers might also benefit from normalization that considers comparisons to their entity's (agency, company, organization, etc.) total impacts to provide additional meaning and aid in comprehension. Two hybrid normalization schemes have been developed, which include aspects of normalization to both spatially based and entity‐based impacts. These have been named entity‐overlaid and entity‐accentuated normalization, and the schemes allow for performance‐based planning or emphasizing environmental impact types that are most relevant to an entity's operational profile, respectively. A hypothetical case study is presented to demonstrate these schemes, which uses environmental data from a U.S. transportation agency as the basis for entity normalization factors. Results of this case study illustrate how entity‐related references may be developed, and how this additional information may enhance the presentation of LCA results using the hybrid normalization schemes.     

The Role of Washing Machines in Life Cycle Assessment Studies

A key requirement for those in industry and elsewhere who wish to reduce the environmental impact of a product is to develop priorities for action. Life cycle assessment (LCA) is increasingly used to identify such priorities but can be misleading. This article draws attention to two effects that can occur when the system boundary for a product LCA is not defined correctly. We illustrate the "washing machine effect" by showing that in separate life cycle studies of clothing, detergents, and washing machines, the use of energy is dominated by operation of the washing machine. All three studies prioritize the use phase for action, but in an aggregated study, double counting of the use-phase impact occurs. We demonstrate the "inverse washing machine effect" with an example related to energy used in transport. We show that some activities that are significant on a cumulative basis consistently fall outside the chosen system boundary for individual products. A consequence is that when LCA studies are used for prioritization, they are in danger of overemphasizing the use-phase impacts and overlooking the impacts from indirect activities. These effects, which are broadly understood by LCA developers, appear not to be understood properly by those who use LCA to direct priorities for action. Therefore, practitioners should be wary of using LCA for prioritizing action, and LCA guidance documents should reflect this caution.     

Life Cycle Inventories of Transport Services: Background Data for Freight Transport (10 pp)

Background, Goal and Scope The ecoinvent database is a reference work for life cycle inventory data covering the areas of energy, building materials, metals, chemicals, paper and cardboard, forestry, agriculture, detergents, transport services and waste treatment. Generic inventories are available for freight and passenger transport including air, rail, road, and water transport. The goal of freight transport modelling is to provide background data for transport services, which occur between nearly any two process steps of a product system. This paper presents and discusses the model structure, basic assumptions and results for selected freight transport services.Main Features Transport services are divided into several datasets referred to as transport components. In addition to vehicle operation (comprising vehicle travel and pre-combustion), infrastructure processes such as vehicle maintenance, manufacturing and disposal, as well as transport infrastructure construction, operation and disposal, are also modelled. In order to link the various transport components to the functional unit of one tonne kilometre (tkm), so-called demand factors are determined. In the case of transport infrastructure that is not exclusively used by freight transport, allocation is essential. The respective allocation parameters employed for line infrastructure construction/disposal and operation datasets (including land use) are yearly Gross-tonne kilometre performance (Gtkm) and kilometric vehicle/train performance. Results are presented for selected environmental exchanges related to gaseous emissions (climate change gases, nitrogen oxides, and hydrocarbons), heavy metal (zinc and cadmium) emissions to soil and air, as well as BOD (Biological Oxygen Demand), and land use. Particle emissions are further distinguished into fine (PM2.5) and coarse (diameter between 2.5 and 10 µm) particles. The results presented comprise both an intra- and inter-modal comparison.Results and Discussions A comparison of Swiss and European rail transport reveals considerably lower emissions from Swiss rail transport due to the almost exclusive use of hydropower as traction energy. For gaseous emissions, freight transport by water or rail exhibits considerably better performance than road transport (65-92% less gaseous emissions). As far as zinc and cadmium emissions to soil are concerned, water and rail transport produce less than 1% of the emissions resulting from road transport for either pollutant. For zinc and cadmium emissions to air, road transport has the highest emissions; however, the emissions due to water and rail transport range from 2 to 18% of the emission levels arising from road transport. Particle emissions show a more diverse pattern. Whilst fine particle emissions due to water and rail transport are considerably lower than road transport, rail transport with respect to coarse particles performs worse than road transport. Dominance analysis reveals the importance of infrastructure processes. For instance, the NMHC-emissions of infrastructure processes account for 40%, 30% and 50% of emissions for road, rail and barge transport, respectively. For the demand factor of infrastructure operation, a sensitivity analysis of the employed allocation factor was performed, revealing no sensitivity for gaseous emissions and particles. On the other hand, considerable changes in both emission levels and in the ranking of transport modes is observed for land occupation. Finally, we varied selected operation parameters for road transport, resulting in considerable reductions of CO2 and NOX emissions of up to 60%. In one extreme case (load factor: 100%), NOx emissions for vehicle operation of a lorry are lower than for inland water transport. Only as a result of the considerably higher NOx emissions occurring in infrastructure processes does road transport score worse than water transport, with the ranking remaining the same as for the generic data presented in ecoinvent 2000.Conclusions and Perspectives The provided datasets allow for a preliminary screening of the importance of transport processes within a product life cycle. In the cases for which transport processes are identified as sensitive for the overall outcome of certain product life cycle or for transport specific comparisons, the modular structure and transparent documentation of demand factors allows for an easy and transparent integration of more case-specific data for selected transport components.     

Environmental performance of a municipal wastewater treatment plant

Goal, Scope and Background  Nowadays, every strategy must be developed taking into account the global impact on the environment; if this aspect is forgotten, a change of environmental loads or their effect will be caused and no reduction will be attained. For instance, a wastewater treatment plant (WWIP), which is considereda priori as an ecological treatment system, gives rise to an environmental impact due to its energy consumption, use of chemical compounds, emissions to the atmosphere and sludge production, the post-treatment of which will also have diverse environmental effects. The goal of this study is to evaluate the potential environmental impact corresponding to a municipal WW1P and to identify the hot spots associated with the process. Methods  In this study, the Centre of Environmental Science (CML) of Leiden University methodology has been considered to quantify the potential environmental impact associated with the system under study. A comprehensive analysis of the WWTP was evaluated for the physico-chemical characterisation of the wastewaters as well as the inventory of all the inputs (energy, chemical compounds, ...) and outputs (emissions to air, water, soil and solid waste generation) associated with the global process. Regarding Life Cycle Inventory Assessment, SimaPro 5.0 was used and in particular CML factors (updated in 2002) were chosen for characterisation and normalisation stages. Results and Discussion  A comprehensive inventory of empirical data from water, sludge and gas flows during 2000 and 2001 was obtained. Two impact categories arise due to their significance: eutrophication and terrestrial ecotoxicity. Consequently, the aspects to be minimised in order to reduce the environmental impact of the system are the pollutant load at the watercourse discharge (mainly NH₃, PO₄ ^[3- and COD, even when all of them are below legal limits) and the emissions to soil (mainly Cr, Hg and Zn, even when they are present in low concentrations) when the sludge is used for agricultural application. Conclusions  As far as the environmental impact is concerned, differentiation between humid and dry season is not required as results are practically equal for both situations. Water discharge and sludge application to land have turned out to be the main contributors in the environmental performance of a WWTP. Regarding the former, the removal of nitrogen by means of a nitrification-denitrification system coupled to conventional biological aerobic treatment implies a high environmental impact reduction and, as for the latter, bearing in mind the proposed legislation, heavy metals as well as pathogens are supposed to be the key parameters to define the most adequate treatment strategies for the generated sludge. Recommendations and Outlook  This study can serve as a basis for future studies that can apply a similar policy to a great number of wastewater facilities. Besides, features such as different treatment systems and capacities can provide additional information with the final aim of including the environmental vector in the decision-making process when the operation of a WWTP is intended to be optimised. Moreover, sludge must also be a focus of attention due to the expected increase and its major contribution to the global environmental impact of a WWTP, which can determine other treatment alternatives.     

Exploring the Use of Ecological Footprint in Life Cycle Impact Assessment

Ecological footprint (EF) is a metric that estimates human consumption of biological resources and products, along with generation of waste greenhouse gas (GHG) emissions in terms of appropriated productive land. There is an opportunity to better characterize land occupation and effects on the carbon cycle in life cycle assessment (LCA) models using EF concepts. Both LCA and EF may benefit from the merging of approaches commonly used separately by practitioners of these two methods. However, few studies have compared or integrated EF with LCA. The focus of this research was to explore methods for improving the characterization of land occupation within LCA by considering the EF method, either as a complementary tool or impact assessment method. Biofuels provide an interesting subject for application of EF in the LCA context because two of the most important issues surrounding biofuels are land occupation (changes, availability, and so on) and GHG balances, two of the impacts that EF is able to capture. We apply EF to existing fuel LCA land occupation and emissions data and project EF for future scenarios for U.S. transportation fuels. We find that LCA studies can benefit from lessons learned in EF about appropriately modeling productive land occupation and facilitating clear communication of meaningful results, but find limitations to the EF in the LCA context that demand refinement and recommend that EF always be used along with other indicators and metrics in product‐level assessments.     

Consequential Life Cycle Assessment of Policy Vulnerability to Price Effects

The application of life cycle assessment (LCA) in a policy context highlights the need for a “consequential” LCA (CLCA), which differs from an “attributional” LCA (ALCA). Although CLCA offers some advantages over ALCA, such as a capacity to account for emissions resulting from both substitution and price effects, it entails additional assumptions and cost and may yield estimates that are more uncertain (e.g., estimates of impact of biofuel policies on greenhouse gas [GHG] emissions). We illustrate how a CLCA that relies on simple partial equilibrium models could provide important insights on the direction and magnitude of price effects while limiting the complexity of CLCA. We describe how such a CLCA, when applied early in the policy life cycle, could help identify policy formulations that reduce the magnitude of adverse price effects relative to the beneficial substitution effect on emissions because—as the experience with biofuel regulations indicates—regulating price effects is costly and controversial. We conclude that the salient contribution of CLCA in the policy process might lie in warning policy makers about the vulnerabilities in a policy with regard to environmental impact and to help modify potentially counterproductive formulations rather than in deriving the precise estimates for uncertain variables, such as the life cycle GHG intensity of product or average indirect emissions.