The International Journal of Life Cycle Assessment

Published by Springer Nature

Online ISSN: 1614-7502

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Print ISSN: 0948-3349

Articles


Data quality
  • Article

December 1996

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119 Reads

Dale J. Kennedy

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Douglas C. Montgomery

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A methodology is presented that enables incorporating expert judgment regarding the variability of input data for environmental life cycle assessment (LCA) modeling. The quality of input data in the life-cycle inventory (LCI) phase is evaluated by LCA practitioners using data quality indicators developed for this application. These indicators are incorporated into the traditional LCA inventory models that produce non-varying point estimate results (i.e., deterministic models) to develop LCA inventory models that produce results in the form of random variables that can be characterized by probability distributions (i.e., stochastic models). The outputs of these probabilistic LCA models are analyzed using classical statistical methods for better decision and policy making information. This methodology is applied to real-world beverage delivery system LCA inventory models. The inventory study results for five beverage delivery system alternatives are compared using statistical methods that account for the variance in the model output values for each alternative. Sensitivity analyses are also performed that indicate model output value variance increases as input data uncertainty increases (i.e., input data quality degrades). Concluding remarks point out the strengths of this approach as an alternative to providing the traditional qualitative assessment of LCA inventory study input data with no efficient means of examining the combined effects on the model results. Data quality assessments can now be captured quantitatively within the LCA inventory model structure. The approach produces inventory study results that are variables reflecting the uncertainty associated with the input data. These results can be analyzed using statistical methods that make efficient quantitative comparisons of inventory study alternatives possible. Recommendations for future research are also provided that include the screening of LCA inventory model inputs for significance and the application of selection and ranking techniques to the model outputs.
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Data Quality

December 1997

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41 Reads

A methodology is presented to develop and analyze vectors of data quality attribute scores. Each data quality vector component represents the quality of the data element for a specific attribute (e.g., age of data). Several methods for aggregating the components of data quality vectors to derive one data quality indicator (DQI) that represents the total quality associated with the input data element are presented with illustrative examples. The methods are compared and it is proven that the measure of central tendency, or arithmetic average, of the data quality vector components as a percentage of the total quality range attainable is an equivalent measure for the aggregate DQI. In addition, the methodology is applied and compared to realworld LCA data pedigree matrices. Finally, a method for aggregating weighted data quality vector attributes is developed and an illustrative example is presented. This methodology provides LCA practitioners with an approach to increase the precision of input data uncertainty assessments by selecting any number of data quality attributes with which to score the LCA inventory model input data. The resultant vector of data quality attributes can then be analyzed to develop one aggregate DQI for each input data element for use in stochastic LCA modeling.


Life Cycle Assessment of Wood Floor Coverings - A Representative Study for the German Flooring Industry (11 pp)

May 2006

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626 Reads

Goal, Scope and Background The goal of the study is a life cycle assessment according to ISO 14040 –14043 for wood floor coverings (solid parquet, multilayer parquet, solid floor board and wood blocks). The representative study covers approximately 70% of all wood flooring production in Germany. The comparison of the floor coverings among each other was not the aim. Instead the study provides basic data for all wood floor coverings for a possible comparison with other floor coverings later on. The main focus was a hot spot analysis to help the involved industry partners to improve their environmental performance, and to use the results for marketing purposes. -Inventory Analysis. The study covers the whole life cycle from forest management, sawmilling, manufacturing, laying and surface finishing through to refurbishment and end-of-life. The end-of-life scenario is the thermal utilisation of the floor coverings. The energy gained in the end-of-life scenario is accounted for by system expansion (avoided burden approach). -Impact Assessment. In the Impact Assessment the following categories were considered: global warming (GWP), acidification (AP), eutrophication (EP), ozone depletion (ODP) and photo-oxidant formation (POCP) following the CML baseline 2000 method. Furthermore the use of primary energy is presented. The low emissions of greenhouse gases during the life cycle can lead to a negative contribution to the global warming potential if more emissions are avoided through the substitution process than are emitted during the life cycle of the product. Mainly energy consumption and the use of solvents influence the environmental impacts of the systems under analysis. The most relevant unit processes for the issue of energy consumption are 'production' and for photo-oxidant formation 'laying', 'surface finishing' and 'refurbishment'. These are therefore the unit processes with the greatest potential for improvement. -Normalisation and Sensitivity Analysis. The normalisation results show that the photo-oxidant formation potential is most significant in comparison to the other impact categories. Improvement options and the choice of the functional unit have been further explored in a sensitivity analysis. Discussionand Conclusions. The most important opportunities for improvements are located in the unit processes laying, surface finishing and refurbishment. The POCP result can be reduced significantly depending on the choice of glue and varnish at each of these stages. The results of the sensitivity analysis showed a potential for improvement in this category. No data for the production of an oil and wax finish was available. This option would be interesting to consider at in a further study. The time aspect of storing CO2 for a period of time is not considered in this paper, but will be addressed in a forthcoming paper (Nebel and Cowell 2003).

A Method for Technology Selection Considering Environmental and Socio-Economic Impacts (11 pp)

January 2006

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45 Reads

Goal, Scope, and Background In Japan, the abatement of CO2 emission by households is a significant problem. Hence, it is necessary to formulate a long-term policy on the use of long-life and highly-insulating technologies for houses; these technologies are expected to reduce CO2 emission. The conventional LCA methodology can evaluate the environmental impact of these technologies, while not necessarily providing sufficient information to support policy-making because of its analytical perspective. The aim of the present study is to first develop a new methodology to examine the optimal use of technologies to formulate an environmental policy by considering dynamic socio-economic conditions. Second, as a demonstration, such a developed methodology is applied to explore an environmentally conscious housing policy for CO2 abatement in Japan. Methods A new methodology was developed, considering the context of a society where technologies are introduced, in order to determine the optimal configuration of technologies to minimize the cumulative environmental burden over time on a social scale. An inter-temporal linear programming model using an input-output table was formulated to make the methodology operational. Using the new model, the optimal use of long-life and thermal-insulating technologies for houses is examined to minimize CO2 emissions across the entire life cycle of all the houses in Japan. Results and Discussion The results of the model simulation indicate that not only long-life and highly-insulating technologies, but also short-life and poorly-insulating technologies, are required to minimize CO2 emissions over a long period. According to the conventional LCA, a house with a short life is inferior to that with a long life, and a house with poor insulation is inferior to that with high insulation. However, houses with a short life and/or poor insulation are introduced in a transition phase to a certain extent before the final stage is reached that is completely dominated by highly-insulated houses with a long life. In other words, the existing houses that were built in the past are gradually replaced with highly-insulated houses with a long life after first building houses with a short life and/or poor insulation. It is not always feasible or not necessarily an optimal solution on a social scale to introduce only a technology that is best evaluated by using the conventional LCA. Inferior technologies can also play a significant role because of various socio-economic conditions and requirements, e.g. population decline, limited housing budgets, and employment stability. Dynamic socio-economic conditions significantly influence the optimal mix of technologies for CO2 minimization in the entire society. Conclusion and Recommendation The present study suggests that it is critical to consider dynamic socio-economic conditions when examining technologies for selection with the aim of a long-term reduction of the environmental burden. The new methodology proposed can provide valuable information to support policy-making toward a sustainable society.

Fig. 1: Different subsystems investigated for photovoltaic power plants installed in Switzerland. The future scenario is shown with dotted arrows. MG-silicon: metallurgical grade silicon, EG-silicon: electronic grade silicon, SoG-silicon: solar-grade silicon
Fig. 3: Share of process stages for Swiss grid-connected, pc-Si photovoltaic 3 kWp power plants for selected results of the inventory and an LCIA for the CED
Fig. 4: Share of process stages for grid-connected pc-Si photovoltaic 3 kWp power plants evaluated with different LCIA methods
Fig. 5: Comparison of Eco-indicator 99 (H,A) scores for different 3 kWp PV power plants
Life Cycle Assessment for Emerging Technologies: Case Studies for Photovoltaic and Wind Power (11 pp)
  • Article
  • Full-text available

January 2005

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699 Reads

Goal, Scope and Background This paper describes the modelling of two emerging electricity systems based on renewable energy: photovoltaic (PV) and wind power. The paper shows the approach used in the ecoinvent database for multi-output processes.Methods Twelve different, grid-connected photovoltaic systems were studied for the situation in Switzerland. They are manufactured as panels or laminates, from mono- or polycrystalline silicon, installed on facades, slanted or flat roofs, and have a 3kWp capacity. The process data include quartz reduction, silicon purification, wafer, panel and laminate production, supporting structure and dismantling. The assumed operational lifetime is 30 years. Country-specific electricity mixes have been considered in the LCI in order to reflect the present situation for individual production stages. The assessment of wind power includes four different wind turbines with power rates between 30 kW and 800 kW operating in Switzerland and two wind turbines assumed representative for European conditions – 800 kW onshore and 2 MW offshore. The inventory takes into account the construction of the plants including the connection to the electric grid and the actual wind conditions at each site in Switzerland. Average European capacity factors have been assumed for the European plants. Eventually necessary backup electricity systems are not included in the analysis.Results and Discussion The life cycle inventory analysis for photovoltaic power shows that each production stage may be important for specific elementary flows. A life cycle impact assessment (LCIA) shows that there are important environmental impacts not directly related to the energy use (e.g. process emissions of NOx from wafer etching). The assumption for the used supply energy mixes is important for the overall LCIA results of different production stages. The allocation of the inventory for silicon purification to different products is discussed here to illustrate how allocation has been implemented in ecoinvent. Material consumption for the main parts of the wind turbines gives the dominant contributions to the cumulative results for electricity production. The complex installation of offshore turbines, with high requirements of concrete for the foundation and the assumption of a shorter lifetime compared to onshore foundations, compensate the advantage of increased offshore wind speeds.Conclusion The life cycle inventories for photovoltaic power plants are representative for newly constructed plants and for the average photovoltaic mix in Switzerland in the year 2000. A scenario for a future technology helps to assess the relative influence of technology improvements for some processes in the near future (2005-2010). The differences for environmental burdens of wind power basically depend upon the capacity factor of the plants, the lifetime of the infrastructure, and the rated power. The higher these factors, the more reduced the environmental burdens are. Thus, both systems are quite dependent on meteorological conditions and the materials used for the infrastructure.Recommendation and Perspective Many production processes for photovoltaic power are still under development. Future updates of the LCI should verify the energy uses and emissions with available data from industrial processes in operation. For the modelling of a specific power plant or power plant mixes outside of Switzerland, one has to consider the annual yield (kWh/kWp) and if possible also the size of the plant. Considering the steady growth of the size of wind turbines in Europe, the development of new designs, and the exploitation of offshore location with deeper waters than analysed in this study, the inventory for wind power plants may need to be updated in the future.
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Fig. 1: Procedure for the generation of a set of unit process scenarios
Fig. 2: Cornerstone scenarios and corresponding levels of socio-economic impact variables and technology impact variables for the investigation of future regional transport alternatives. In addition, the resulting unit process input data is presented for selected unit processes
Fig. 3: Climate Change and Nitrogen Oxide emission scores for the investigated options and alternatives of regional rail transport in four cornerstone scenarios (continued from prevous page)
Scenario Modelling in Prospective LCA of Transport Systems. Application of Formative Scenario Analysis (11 pp)

September 2005

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575 Reads

Background Tools and methods able to cope with uncertainties are essential for improving the credibility of Life Cycle Assessment (LCA) as a decision support tool. Previous approaches have focussed predominately upon data quality. Objectiveand Scope. An epistemological approach is presented conceptualising uncertainties in a comparative, prospective, attributional LCA. This is achieved by considering a set of cornerstone scenarios representing future developments of an entire Life Cycle Inventory (LCI) product system. We illustrate the method using a comparison of future transport systems. Method Scenario modelling is organized by means of Formative Scenario Analysis (FSA), which provides a set of possible and consistent scenarios of those unit processes of an LCI product system which are time dependent and of environmental importance. Scenarios are combinations of levels of socio-economic or technological impact variables. Two core elements of FSA are applied in LCI scenario modelling. So-called impact matrix analysis is applied to determine the relationship between unit process specific socio-economic variables and technology variables. Consistency Analysis is employed to integrate unit process scenarios, based on pair-wise ratings of the consistency of the levels of socio-economic impact variables of all unit processes. Two software applications are employed which are available from the authors. Results and Discussion The study reveals that each possible level or development of a technology variable is best conceived of as the impact of a specific socio-economic (sub-) scenario. This allows for linking possible future technology options within the socio-economic context of the future development of various background processes. In an illustrative case study, the climate change scores and nitrogen dioxide scores per seat kilometre for six technology options of regional rail transport are compared. Similar scores are calculated for a future bus alternative and an average Swiss car. The scenarios are deliberately chosen to maximise diversity. That is, they represent the entire range of future possible developments. Reference data and the unit process structure are taken from the Swiss LCA database 'ecoinvent 2000'. The results reveal that rail transport remains the best option for future regional transport in Switzerland. In all four assessed scenarios, four technology options of future rail transport perform considerably better than regional bus transport and car transport. Conclusionsand Recommendations. The case study demonstrates the general feasibility of the developed approach for attributional prospective LCA. It allows for a focussed and in-depth analysis of the future development of each single unit process, while still accounting for the requirements of the final scenario integration. Due to its high transparency, the procedure supports the validation of LCI results. Furthermore, it is well-suited for incorporation into participatory methods so as to increase their credibility. Outlookand Future Work. Thus far, the proposed approach is only applied on a vehicle level not taking into account alterations in demand and use of different transport modes. Future projects will enhance the approach by tackling uncertainties in technology assessment of future transport systems. For instance, environmental interventions involving future maglev technology will be assessed so as to account for induced traffic generated by the introduction of a new transport system.

LCA of Ex-Situ Bioremediation of Diesel-Contaminated Soil (11 pp)

November 2005

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128 Reads

- DOI: http://dx.doi.org/10.1065/lca2004.09.180.12 Goal and Scope Primary and secondary environmental impacts associated with bioremediation of diesel-contaminated sites were assessed using a retrospective life cycle assessment (LCA) as a function of the duration of treatment and the achievement of regulatory criteria. The case study was the remediation with biopiles of 8000 m3 of subsurface soil impacted with an average of 6145 mg of diesel fuel/kg soil during a two-year period. Methods Two scenarios were compared; the construction of a single-use treatment facility on site or the use of a permanent treatment center that can accept 25000 m3 soil/year. Moreover, since bioremediation is never 100% efficient, different efficiency scenarios, including the transportation of partially treated soil to landfill were analyzed. The primary impact of residual soil contamination was determined by developing a specific characterization factor (ecotoxicity and human toxicity categories in the EDIP method) based on the toxic components of diesel. Secondary impacts were assessed with an LCA software. Results and Discussion One major observation was the fact that the soil itself is responsible for an important fraction of the system's total impact, suggesting that it is beneficial to reach the highest level of remediation. The reutilization of the treatment facility is also an important issue in the overall environmental performance of the system. In the case of a single-use treatment center, the analysis showed that site preparation and site closure were the major contributing stages to the overall impact, mainly due to the asphalt paving and landfilling processes. Results indicated that off-site transport and the biotreatment process did not contribute notably to the level of environmental impact. The use of a permanent treatment center is preferred since it allows a significant decrease of the secondary impact. However, when soil had to be transported for a distance greater than 200 km from the site, global impacts increased significantly. Conclusion – Results from this study allowed identifying several process optimizations in order to improve the environmental performance of the biopile technology including: the achievement of low level of residual contaminants, the minimization of asphalt or the use of a permanent treatment center. Recommendation and Outlook LCA was found to be an efficient tool to manage contaminated soil in a sustainable way. However, because of the major contribution of residual soil contamination, additional spatial and temporal data should be collected and integrated in the substance characterization models.

Life Cycle Assessment of the District Heat Distribution System - Part 2: Network Construction (11 pp)

November 2005

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593 Reads

-Part 1: Pipe Production [Int J LCA 9 (2) 130–136 (2004)] Part 2: Network Construction [Int J LCA 10 (6) 425-435 (2005)] Part 3: Use Phase and Overall Discussion [DOI: http://dx.doi.org/10.1065/lca2005.08.225] -Preamble. This series of three papers is based on research performed for the Swedish District Heating Association with the purpose of mapping the environmental life cycle impacts from the different phases involved in district heat distribution. Part 1 concerns production of district heating pipes while Part 2 describes construction of the district heating pipe network. In Part 3, the use phase is evaluated based on heat losses from the network during heat distribution. Part 3 also includes a discussion in which the three evaluated life cycle phases are compared. Goal, Scope and Background In a district heating network, hot water is transported from a central heat generation plant to buildings where the heat is utilised for space heating and domestic hot water generation. This paper presents a life cycle assessment of the construction of district heating pipe networks, based on a gate-to-gate life cycle inventory commissioned by the Swedish District Heating Association. In the literature, environmental studies on district heating mainly consider emissions from heat generation; environmental impacts from construction of the distribution system are seldom discussed. The purpose of the study is to identify environmentally significant parts in the construction of district heat distribution networks and to provide information for a larger study including more parts of the life cycle of such district heat distribution. No external review has been performed, but a reference group of district heating experts familiar with the practice was involved in the choice of systems to be studied as well as in reviewing parts of the study. Methods The study covers construction of the main pipe system according to the guidelines from the Swedish District Heating Association. Construction of the pipe system was assumed to take place in Sweden by Swedish entrepreneurs during the time period 1999–2000. Transport of the district heating pipes from the factory to the excavation site is included in this study, but not the production of the pipes. The functional unit used in the study is 100 metres of pipe system (flow and return pipe). The studied systems are: twin pipe of the dimension DN25 and single pipes of the dimensions DN25, DN100 and DN500. Two different surroundings were studied: urban environment, characterised by the need to break open and to restore asphalt cover and to remove excavated material from the site, and green areas, without any asphalt and where some of the excavated material might be left at the site and reused. Results and Discussion A short description of the inventory, some inventory results and life cycle impact assessments are presented. Characterisations according to GWP, AP, POCP and resource depletion are given as well as two weightings: EcoIndicator99 and Ecoscarcity. Emissions from production and use of the diesel needed for excavation of the pipe trench gives rise to a dominating part of the environmental impact. Recommendations and Perspective To minimise the need for excavation is the most important feature in order to reduce the environmental impact from construction of the district heating pipe network. A twin pipe uses a narrower pipe trench than the equivalent two single pipes, and is an already available option. Co-utilising the trenches with cables for electricity, for instance, will not make the environmental impact from the trench any smaller, but will decrease the total need for excavation in society. It is important to make sure that environmental improvements from changes in the network construction phase are not off-set by other effects in the total life cycle of district heat distribution.

Life Cycle Inventory for Use of Waste Solvent as Fuel Substitute in the Cement Industry - A Multi-Input Allocation Model (11 pp)

January 2005

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185 Reads

Background The Swiss chemical industry produces large amounts of organic waste solvents. Some of these solvents cannot be recovered. A common option for the treatment of such organic waste solvents is the incineration in hazardous waste incinerators. Alternatively, the waste solvents can be used as fuel in cement production. On the one hand, solvent incineration in cement kilns saves fossil fuels such as coal and heavy fuel oil. On the other hand, fuel-bound emissions may change as well. These emission changes can either have a negative or a positive net ecological impact, depending on the chemical nature of the waste solvent used.Goal and Scope The aim of our work was to develop a multi-input allocation model, which allows one to calculate life cycle inventories for specific waste solvents. These LCIs can then be used in further applications, e.g. a comparison of different waste solvent treatment options. Results and Discussion A multi-input allocation model was developed that takes into account the physico-chemical properties of waste solvents such as elementary composition and net calorific value. The model is based on a set of equations and data on fuel mix, fuel composition as well as transfer coefficients for heavy metals. The model calculates “avoided inputs” and “changes in emissions” which arise from substituting fossil fuels with waste solvents. Life cycle inventories can be calculated for specific waste solvents if the elementary composition and the net calorific value are known. The application of the model is illustrated in a case study on four waste solvents. The results show that solvent incineration in cement kilns generally reduces the overall impact of clinker production because fossil fuels are replaced. A sensitivity analysis revealed that the model is especially sensitive to the fuel mix and coal properties, such as net calorific value as well as the content of nitrogen and carbon. The transfer coefficients are also uncertain, but this uncertainty is not relevant as the amount of heavy metal emitted into the atmosphere is small. Conclusions and Outlook The proposed model serves to calculate inventory data for the combustion of liquid alternative fuels such as waste solvents in cement kilns. Although our model represents Swiss cement production conditions, it can be applied to other countries by fitting the most sensitive parameters of fuel mix and coal properties. In case the technology used is very different to the Swiss situation, the transfer coefficients also need to be adapted.


Environmental Assessment of Freight Transportation in the U.S. (11 pp)

July 2006

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357 Reads

Goal, Scope and Background This study provides a life cycle inventory of air emissions (CO2, NOx, PM10, and CO) associated with the transportation of goods by road, rail, and air in the U.S. It includes the manufacturing, use, maintenance, and end-of-life of vehicles, the construction, operation, maintenance, and end-of-life of transportation infrastructure, as well as oil exploration, fuel refining, and fuel distribution. Methods The comparison is performed using hybrid life cycle assessment (LCA), a combination of process-based LCA and economic input-output analysis-based LCA (EIO-LCA). All these components are added by means of a common functional unit of grams of air pollutant per ton-mile of freight activity. Results and Discussion Results show that the vehicle use phase is responsible for approximately 70% of total emissions of CO2 for all three modes. This confirms that tailpipe emissions underestimate total emissions of freight transportation as infrastructure, pre-combustion, as well as vehicle manufacturing and end-of-life account for a sizeable share of total emissions. Differences between tailpipe emissions and total system wide emissions can range from only 4% for road transportation's CO emissions to an almost ten-fold difference for air transportation's PM10 emissions. Conclusion Rail freight has the lowest associated air emissions, followed by road and air transportation. Depending on the pollutant, rail is 50-94% less polluting than road. Air transportation is rated the least efficient in terms of air emissions, partly due to the fact that it carries low weight cargo. It emits 35 times more CO2 than rail and 18 times more than road transportation on a ton-mile basis. It is important to consider infrastructure, vehicle manufacturing, and pre-combustion processes, whose life-cycle share is likely to increase as new tailpipe emission standards are enforced. Recommendation and Outlook Emission factors, fuel efficiency, and equipment utilization contribute the most to uncertainty in the results. Further studies are necessary to address all variables that influence these parameters, such as road grade, vehicle speed, and vehicle weight. A focus on regional variation, end-of-life processes, fuel refining processes, terminals, as well as more accurate infrastructure allocation between freight and passenger transportation would strengthen the model.

Fig. 1: System boundary of the PHA production systems. (A) reference system and (B) integrated system
Fig. 2: Carbon sequestered by corn culture under no-tillage practice (IA-1: Pottawattamie county in IA, IA-2: Sioux county in IA, IL-1: Iroquois county in IL, IL-2: McLean county in IL, IN-1: Knox county in IN, IN-2: White county in IN, MI-1: Branch county in MI, MI-2: Lenawee county in MI, MN-1: Blue Earth county in MN, MN-2: Freeborn county in MN, OH-1: Darke county in OH, OH-2: Madison county in OH, WI-1: Dane county in WI, WI-2: Grant county in WI)
Fig. 3: N 2 O emissions from soil during corn cultivation under no-tillage practice
Table 3 : Photochemical smog, acidification and eutrophication associated with corn grain-based PHA
Fig. 4: Global warming in the PHA production system based on 100-year time horizon global warming potentials (Intergovernmental Panel on Climate Change 2001) [Gerngross (1999): PHA fermentation technology given by Gerngross (1999), Current (Metabolix): PHA fermentation technology given by Metabolix Inc. (van Walsem 2003), Akiyama (2003): PHA fermentation technology given by Akiyama et al. (2003), Near future (Metabolix): PHA fermentation technology given by Metabolix Inc. (van Walsem 2003)] Note: PHA fermentation includes fermentation and recovery
Life Cycle Assessment Study of Biopolymers (Polyhydroxyalkanoates) - Derived from No-Tilled Corn (11 pp)

May 2005

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2,628 Reads

Goal and Scope This study attempts to estimate the environmental performance of Polyhydroxyalkanoates (PHA), from agricultural production through the PHA fermentation and recovery process – “cradle to gate”. Two types of PHA production systems are investigated: corn grain based PHA and corn grain and corn stover based PHA. Methods Corn cultivation data are taken from 14 counties in the Corn Belt states of the United States – Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio, and Wisconsin. The environmental burdens associated with the corn wet milling process, in which dextrose, corn oil, corn gluten meal and corn gluten feed are produced, are allocated to dextrose and its coproducts by the system expansion approach. Greenhouse gases include carbon taken up by soil, nitrous oxide (N2O) released from soil during corn cultivation, carbon contents in biobased products as well as carbon dioxide, methane and nitrous oxide released from industrial processing. The soil carbon and nitrogen dynamics in corn cultivation are predicted by an agro–ecosystem model, the DAYCENT model. The environmental performance of the PHA production system is compared to that of a conventional polymer fulfilling an equivalent function. The environmental performance is addressed as nonrenewable energy and selected potential environmental impacts including global warming, photochemical smog, acidification, and eutrophication. The characterization factors are adapted from the TRACI model (Tools for the Reduction and Assessment of Chemical and Other Environmental Impacts) developed by the United States Environmental Protection Agency. Results and Discussion Global warming associated with corn grain based PHA is 1.6–4.1 kg-CO2 eq. kg–1. The primary contributing process to most environmental impacts except for photochemical smog and eutrophication is the PHA fermentation and recovery process. For photochemical smog and eutrophication, the primary contributing process is corn cultivation due to nitrogen related burdens from soil. The trend of PHA fermentation development shows that the PHA fermentation technology is still immature and continues to improve, thereby also decreasing the environmental impacts. PHA produced in an integrated system, in which corn stover is harvested and used as raw material for PHA along with corn grain, offers global warming credits (negative greenhouse gas emissions), ranging from –0.28 to –1.9 kg-CO2 eq. kg–1, depending on the PHA fermentation technologies employed and significantly reduces the environmental impacts compared to corn based PHA. The significant reductions from the integrated system are due to 1) less environmental impacts in corn cultivation and wet milling, and 2) exporting surplus energy from lignin–rich residues in corn stover process. Conclusions and Outlook Under the current PHA fermentation technology, corn grain based PHA does not provide an environmental advantage over polystyrene. Corn grain based PHA produced by the near future PHA fermentation technology would be more favorable than polystyrene in terms of nonrenewable energy and global warming due to improvement in the PHA fermentation and recovery process. However, corn grain based PHA produced in even the near future technology does not provide better profiles for other environmental impacts (i.e., photochemical smog, acidification and eutrophication) than polystyrene. One of the primary reasons for high impacts of PHA in photochemical smog, acidification and eutrophication is the environmental burdens associated with corn cultivation. Thus other approaches to reduce these burdens in the agricultural process (e.g., use of buffer strips, etc.) are necessary to achieve better profiles for photochemical smog, acidification and eutrophication associated with corn cultivation. PHA produced in the integrated system is more favorable than polystyrene in terms of most environmental impacts considered here except for eutrophication.

Development of an Environmental Assessment Method for Consumer Electronics by combining Top-down and Bottom-up Approaches (11 pp)

July 2006

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88 Reads

Goal, Scope and Background Ecodesign requires environmental assessment methods, which are often time consuming and cost intensive. In this paper we proposed a method that combines top-down (e.g. LCA) and bottom-up (e.g. UNEP) approaches that allows one within short period of time to generate ecodesign ideas by identifying what to improve, how much to improve, and how to improve within a short period of time. The proposed method incorporates an environmental assessment method for use in the ecodesign of consumer electronics that employs the top-down and bottom-up approaches simultaneously. Method The proposed method consists of five modules: A. a life cycle thinking for a product, B. environmental benchmarking, C. checklist method, D. ecodesign strategies, and E. environmental design information. A key life cycle stage with significant environmental impact is identified in module A. When the identified key life cycle stage is not product manufacturing, environmental benchmarking is used; however, a checklist method is applied if product manufacturing is identified as the key life cycle stage. Ecodesign strategies for consumer electronics are obtained in module D. Environmental design information is produced by linking both the top-down and bottom-up information in module E. Results and Discussion The applicability of the proposed method was evaluated using mobile phones. First, the key life cycle stage of the mobile phone was identified as the raw material acquisition stage. Next, environmental benchmarking was carried out for 10 parameters belonging to the raw material acquisition stage. Environmental target specifications for the 10 parameters were set, ranging from 14% to 60%. Finally, environmental design information for the mobile phone was determined by linking the target specifications of the environmental benchmarking parameters and the corresponding ecodesign strategies. The proposed method was also compared with the LCA and the UNEP/promising approaches, which are representative examples of the top-down approach and the bottom-up approach, respectively. Based on the results of this comparison, the proposed method was judged to be an advanced method in facilitating the generation of ecodesign ideas. Environmentally significant benchmarking parameters correspond to what to improve, target specifications to on how much to improve, and ecodesign strategies ton how to improve. It was found that the use of the proposed method minimizes the time and money expenditure by confining the identification of environmental weak points within the key life cycle stage. Conclusion and Outlook An environmental assessment method for consumer electronics in ecodesign was proposed and applied to mobile phones. The advantages of the proposed method are as follows: it is efficient and cost-effective, and it allows designers to generate ecodesign ideas more easily and effectively by simultaneously identifying the specific environmental weak points of a product and corresponding ecodesign strategies. The proposed method can be envisaged as a useful ecodesign approach when electronic companies identify the environmental aspects of their products and integrate them into product design and development process.





Life cycle management of energy-consuming products in companies using IO-LCA. International Journal of Life Cycle Assessment, 13(5), 432-439

August 2008

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204 Reads

Background, aim, and scopeToday, the effective integration of life cycle thinking into existing business routines is argued to be the most critical step for more sustainable business models. The study tests the suitability of an input–output life cycle assessment (IO-LCA) approach in screening life cycle impacts of energy-using products in companies. It estimates the life cycle impacts of three products and assesses the suitability of such approach in a company environment. Materials and methodsThe multiple case studies evaluate the suitability of an IO-LCA method in a company environment. A comprehensive life cycle cost and impact study of three product systems (building ventilation system, information and communication technology (ICT) network product, and welding machine) is conducted and the life cycle phases with highest economical and environmental contribution are determined. Scenario analysis is performed in order to assess the sensitivity of the results to major changes in the studied systems. Finally, the usability of the IO-LCA approach for environmental evaluations in companies is assessed by collecting data on workload and interviewing the participating workers and managers. ResultsThe results showed that the use phase with operating energy was environmentally important in all evaluated energy-using products. However, only in one case (ICT network product) the use was the single most significant life cycle phase. In two other cases, the sourcing was equally important. The results also indicated that the IO-LCA approach is much easier to adapt by current management of companies because it automatically links life cycle costs to environmental indicators and, by order of magnitude, reduces the workload in companies. DiscussionIt appears that the IO-LCA approach can be used to screen environmentally significant life cycle phases of energy-using products in companies by utilizing readily available accounting or other documented data. The IO-LCA approach produced comparable results with the ones published in traditional process-based LCA literature. In addition to the main results, some practical benefits of using the IO-LCA could also be suggested: the approach was very fast to use and would thus allow an easier adoption of environmental evaluations in companies as well as wider environmental testing of products in early conceptual design phase. ConclusionsThe results indicated that the IO-LCA approach could clearly offer added value to the environmental management of companies. The IO-LCA was found to provide a very fast access to the key life cycle characteristics of products. Similarly, it offered practical means to integrate life cycle thinking into existing business routines and to activate the decision makers in companies by giving them easily comprehendible results. Recommendations and perspectivesThe results would suggest that similar environmental IO tables, besides the US ones used here, would have value and should be collected for other major geographical and economical regions. The tables would enable a much larger share of companies to manage their environmental issues. It also seems that, because the user profile is so dominant in the case of energy-using products, more studies, both theoretical (How to valuate the future behavior in environmental studies?) and empirical (What really creates value for users?), should focus on the behavior of users.

Uncertainty in Impact and Externality Assessments - Implications for Decision-Making (13 pp)

May 2006

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58 Reads

Goal, Scope and Background Many disciplines, amongst them LCIA, environmental impact and external cost assessments, are often faced with evaluating trade-offs between two or more alternative options in terms of a range of incommensurable indicators. Using process modeling and valuation, these indicators are quantified at mid- or endpoint levels. Recent discussion amongst LCA experts showed that because of the mutually exclusive aspects of uncertainty and relevance, the midpoint/endpoint debate is controversial and difficult to reconcile. This article is aimed at a more quantitative analysis of mid- and endpoint impacts, and the implications of uncertainty for decision-making. Methods The consequences for decision-making of uncertainties of endpoints are analysed quantitatively for the example of ExternE results, by employing statistical hypothesis testing. The Analytic Hierarchy Process (AHP) is then used to demonstrate the use of multi-criteria techniques at midpoint levels. Results and Discussion Statistical hypothesis testing at the endpoint level shows that for the ExternE example, probabilities of mistakenly favouring one alternative over another when they are in reality indistinguishable can be as high as 80%. Therefore, the best estimate of external cost is inadequate for most policy making purposes. Indicators at midpoint levels are more certain, but since they are only \proxy attributes\, they carry a hidden uncertainty in their relevance. Conclusion If endpoint information is too uncertain to allow a decision to be made with reasonable confidence, then the assessment can be carried out in midpoint terms. However, midpoint indicators are generally further removed from people's experience, and less relevant to the question that people actually want to solve. Nevertheless, if this ultimate question is unanswerable (within the certainty required by the decision-maker), a decision can be made on the basis of stakeholders' subjective judgments about the more certain midpoint levels. The crucial point is that these judgments are able to intuitively incorporate many aspects that impact modeling and valuation has trouble quantifying, such as perceived risk, distribution of burdens and benefits, equity, ethical, moral, religious and political beliefs and principles, immediacy and reversibility of potential impacts, voluntariness, controllability and familiarity of exposure, or perceived incompleteness of human knowledge.

Social Indicators for Sustainable Project and Technology Life Cycle Management in the Process Industry (13 Pp + 4)

January 2006

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438 Reads

Goal, Scope and Background The importance of the social dimension of sustainable development increased significantly during the last decade of the twentieth century. Industry has subsequently experienced a shift in stakeholder pressures from environmental to social-related concerns, where new developments in the form of projects and technologies are undertaken. However, the measurement of social impacts and the calculation of suitable indicators are less well developed compared to environmental indicators in order to assess the potential liabilities associated with undertaken projects and technologies. The aim of this paper is to propose a Social Impact Indicator (SII) calculation procedure based on a previously introduced Life Cycle Impact Assessment (LCIA) calculation procedure for environmental Resource Impact Indicators (RIIs), and to demonstrate the practicability of the SII procedure in the context of the process industry in South Africa. Methods A framework of social sustainability criteria has been introduced for the South African process industry. The social sub-criteria of the framework are further analyzed, based on project and technology management expertise in the South African process industry, to determine whether the criteria should be addressed at project or technology management level or whether they should rather form part of an overall corporate governance policy for new projects and technologies. Furthermore, the proposed indicators for criteria that are considered appropriate for project or technology evaluation purposes are constrained by the type of information that is available, i.e. the calculation methodology relies on the availability of regional or national social information where the project will be implemented, as well as the availability of project- or technology-specific social information during the various phases of the project or technology development life cycle. Case studies in the process industry and statistical information for South Africa are subsequently used to establish information availability for the SII calculation procedure, demonstrate the SII method together with the RII method, and determine the practical use of the SII method. Results and Conclusion The case studies establish that social footprint information as well as project- and technology social data are not readily available in the South African process industry. Consequently, the number of mid-point categories that can be evaluated are minimal, which results in an impaired social picture when compared to the environmental dimension. It is concluded that a quantitative social impact assessment method cannot be applied for project and technology life cycle management purposes in industry at present. Recommendation and Perspective Following the outcomes of the case studies in the South African process industry, it is recommended that checklists and guidelines be used during project and technology life cycle management practices. Similar to the environmental dimension, it is envisaged that such checklists and guidelines would improve the availability of quantitative data in time, and would therefore make the SII procedure more practical in the future.

Fig. 2: Contributions of single species to total GHG emission per kWh from single steps in the nuclear fuel cycle of the Swiss BWR
Fig. 9: Cumulative CO 2 emissions and iron resource use per kWh electricity for selected natural gas power plants and estimated uncertainties from Monte Carlo simulation. Black error bars: uncertainty of total value. Grey error bars: uncertainty of power plant infrastructure. IT = Italy, NL = The Netherlands, UCTE = Union for the Co-ordination of Transmission of Electricity, CC = combined cycle
Life Cycle Inventories for the Nuclear and Natural Gas Energy Systems, and Examples of Uncertainty Analysis (14 pp)

January 2005

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871 Reads

Goal, Scope and Background The energy systems included in the ecoinvent database v1.1 describe the situation around year 2000 of Swiss and Western European power plants and boilers with the associated energy chains. The addressed nuclear systems concern Light Water Reactors (LWR) with mix of open and closed fuel cycles. The system model ‘Natural Gas’ describes production, distribution, and combustion of natural gas. Methods Comprehensive life cycle inventories of the energy systems were established and cumulative results calculated within the ecoinvent framework. Swiss conditions for the nuclear cycle were extrapolated to major nuclear countries. Long-term radon emissions from uranium mill tailings have been estimated with a simplified model. Average natural gas power plants were analysed for different countries considering specific import/export of the gas, with seven production regions separately assessed. Uncertainties have been estimated quantitatively. Results and Discussion Different radioactive emission species and wastes are produced from different steps of the nuclear cycle. Emissions of greenhouse gases from the nuclear cycle are mostly from the upstream chain, and the total is small and decreasing with increasing share of centrifuge enrichment. The results for natural gas show the importance of transport and low pressure distribution network for the methane emissions, whereas energy is mostly invested for production and long-distance pipeline transportation. Because of significant differences in power plant efficiencies and gas supply, country specific averages differ greatly. Conclusion The inventory describes average worldwide supply of nuclear fuel and average nuclear reactors in Western Europe. Although the model for nuclear waste management was extrapolated from Swiss conditions, the ranges obtained for cumulative results can represent the average in Europe. Emissions per kWh electricity are distributed very differently over the natural gas chain for different species. Modern combined cycle plants show better performance for several burdens like cumulative greenhouse gas emissions compared to average plants. Recommendation and Perspective Comparison of country-specific LWRs or LWR types on the basis of these results is not recommended. Specific issues on different strategies for the nuclear fuel cycle or location-specific characteristics would require extension of analysis. Results of the gas chain should not be directly applied to areas other than those modelled because emission factors and energy requirements may differ significantly. A future update of inventory data should reconsider production and transport from Russia, as it is a major producer and exporter to Europe. The calculated ranges of uncertainty factors in ecoinvent provide useful information but they are more indications of uncertainties rather than strict 95% intervals, and should therefore be applied carefully.


A comprehensive approach towards product and organisation related Environmental Management tools: Life Cycle Assessment (iso 14040) and environmental management systems (iso 14001)

May 1998

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31 Reads

The international standardisation of Environmental Management (EM) is documented by the ISO 14000 series. Within this series a number of Environmental Management tools are treated. Therefore, it can be seen as a “toolbox” which offers several options for sound Environmental Management practices in organisations. However, a number of questions remain because they are not treated by the standards themselves. Some examples are which of the tools should be applied to what kind of Environmental Management problem or what are the synergisms and antagonisms between these tools. To illustrate the importance of a comprehensive choice and a compatible approach towards EM-tools, Life Cycle Assessment (ISO 14040 series) is discussed in the context of Environmental Management Systems (ISO 14001). The focus of ISO 14001 are organisations, while LCA deals with products or processes. In principle, they are not compatible, since the life-cycle approach analyses one production chain from “cradle to grave” or even back to the cradle, while a management system according to ISO 14001 analyses organisations, i.e. a number of product chains, from “gate to gate”. LCAs, however, could be compiled by aggregating several “gate to gate” energy and material balances of companies. LCA can assist in prioritising and achieving the objectives of an EM-System. LCA can also help to understand the environmental impact of organisations and what share of their overall environmental burden is produced “inside the gates” or “outside the gates”, respectively.

Eco-labeling, Product Category Rules and Certification Procedures Based on ISO 14025 Requirements (6 pp)

January 2006

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524 Reads

Goal, Scope and Background The goal of the present paper is to demonstrate how environmental product declarations (EPDs) are developed based on a set of product category rules (PCRs) in accordance with the requirements in the ISO 14025-standard. This is demonstrated by examples from the furniture industry in Norway, where several case models are evaluated. To ease the capability of developing EPDs in this industry, a database with specific environmental data for materials in furniture is developed. The database is used to produce the LCA for selected furniture models, and further, the database is the backbone of a data-assistance tool used to create the EPDs. Methods The LCA-data are produced based on traditional LCA-methodology. The PCR is based on a stakeholder analysis and the proposed methodology in the ISO 14025-standard. The EPDs developed so far, are results of close collaboration between companies and research centres in the Nordic countries. For the verification of the EPDs, auditing methodologies are used as a part of the audit of the companies' environmental management systems (EMS). Results and Conclusion Based on a hearing of a set of suggested PCRs, a consensus document for seating accommodation is developed. This is further the model for how to develop PCR-documents for all types of furniture, for example sleeping accommodations. Likewise, the database shall contain the most important data for the parts of a furniture model. Within the goal of the project period, EPDs will be developed for 80% of Norwegian furniture. The verification of the EPDs is done as a part of the certification procedures of EMS in accordance with the ISO 14001. Recommendation and Perspective The results presented in the paper are mainly for the pilot models in the project. However, the results will be further tested and the data-tool will be developed as a part of a product design tool where environmental requirements will be combined with quality requirements. The product design tool will be implemented in the furniture industry. Information on how to use EPDs in public purchasing will also be a part of future work.

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