Manufacturing and Disposal of Building Materials and Inventorying Infrastructure in ecoinvent (8 pp)

Goal, Scope and Background The present paper describes the goal and scope of building material inventories in the ecoinvent database and gives an overview of its content. The ecoinvent database provides generic life cycle inventories for building material production and related processing. They can be used as background data for different LCA applications. Their geographical and temporal scope is Switzerland or Europe and the year 2000.Methods Data is inventoried as unit processes. Consistency throughout different sources is heeded by systematically estimating missing data. Infrastructure is consequently considered. Different disposal options are modelled.Results and Conclusion The ecoinvent data provide a harmonised basis for different kinds of building materials. Even though not all datasets could be established on the same quality level, the results generally are believed to be comparable. Since data are generic, they are, however, not suitable to directly compare specific products. Disposal is relevant for the environmental burdens of uses of building materials. Complete life cycles have to be assessed. For this purpose, cumulative energy demand (CED) is not a suitable indicator.Recommendation and Perspective In future versions of ecoinvent, data quality could be further improved. The database should be extended to include further building materials from secondary materials. To do so, the methodological treatment of secondary materials needs special attention.     

The Quebec Life Cycle Inventory Database Project

Purpose

Life cycle assessment (LCA) in Quebec (Canada) is increasingly important. Yet, studies often still need to rely on foreign life cycle inventory (LCI) data. The Quebec government invested in the creation of a Quebec LCI database. The approach is to work as an ecoinvent “National Database Initiative” (NDI), whereby the Quebec database initiative uses and contributes to the ecoinvent database. The paper clarifies the relationship between ecoinvent and the Quebec NDI and provides details on prioritization and data collection.

Methods

The first steps were to select a partner database provider and to work out the modalities of the partnership. The main criterion for partner selection was database transparency, i.e., availability of unit process data (gate-to-gate), necessary for database adaptation. This and other criteria, such as free access to external reviewers, conservation of dataset copyright, seamless embedding of datasets, and overall database sophistication, pointed to ecoinvent. Once started, the NDI project proceeded as follows: (1) data collection was prioritized based on several criteria; (2) some datasets were “recontextualized,” i.e., existing datasets were duplicated and relocated in Quebec and linked to datasets representing regional suppliers, where relevant; (3) new datasets were created; and (4) Canadian environmentally extended supply-use tables were created for the ecoinvent IO repository.

Results and discussion

Prioritization identified 500 candidate datasets for recontextualization, based on the relative importance of relative contribution of direct electricity consumption to cradle-to-gate impacts, and 12 key sectors from which about 450 data adaptation or collection projects were singled out. Data collection and private sector solicitation are underway. Private sector participation is highly variable. A number of communication tools have been elaborated and a solicitation team formed to palliate this obstacle. The new ecoinvent database protocol (Weidema et al. 2011) increases the amount of information that is required to create a dataset, which can lengthen or, in extreme cases, impede dataset creation. However, this new information is required for the new database functionalities (e.g., providing multiple system models based on the same unit process data and regionalized LCA).

Conclusions

Being an NDI is advantageous for the Quebec LCI database project on multiple levels. By conserving dataset copyright, the NDI remains free to spawn or support other LCI databases. Embedding datasets in ecoinvent enables the generation of LCI results from “day 1.” The costs of IT infrastructure and data review are null. For these reasons, and because every NDI improves the global representativity of ecoinvent, we recommend other regional or national database projects work as NDIs.

     

Hygiene aspects of packaging in the food industry

The microbiology of a food can be profoundly influenced by the surrounding package. The microorganisms present on the packaging material may need to be considered along with those of the product.This paper considers the microbial flora of the package. It describes some of the hygiene problems which have arisen in a large company manufacturing packaging and the measures taken to overcome them.Types of packing covered include: metal containers; paper and board; metal/board composites; plastic packaging materials; glass and caps. Whilst much of the information had been derived from many years of manufacturing experience, some published data are included to complete the survey.     

Waste Treatment and Assessment of Long-Term Emissions (8pp)

Goal, Scope and Background The disposal phase of a product’s life cycle in LCA is often neglected or based on coarse indicators like ‘kilogram waste’. The goal of report No. 13 of the ecoinvent project (Doka 2003) is to create detailed Life Cycle Inventories of waste disposal processes. The purpose of this paper is to give an overview of the models behind the waste disposal inventories in ecoinvent, to present exemplary results and to discuss the assessment of long-term emissions. This paper does not present a particular LCA study. Inventories are compiled for many different materials and various disposal technologies. Considered disposal technologies are municipal incineration and different landfill types, including sanitary landfills, hazardous waste incineration, waste deposits in deep salt mines, surface spreading of sludges, municipal wastewater treatment, and building dismantling. The inventoried technologies are largely based on Swiss plants. Inventories can be used for assessment of the disposal of common, generic waste materials like paper, plastics, packaging etc. Inventories are also used within the ecoinvent database itself to inventory the disposal of specific wastes generated during the production phase. Inventories relate as far as possible to the specific chemical composition of the waste material (waste-specific burdens). Certain expenditures are not related to the waste composition and are inventoried with average values (process-specific burdens). Methods The disposal models are based on previous work, partly used in earlier versions of ecoinvent/ETH LCI data. Important improvements were the extension of the number of considered chemical elements to 41 throughout all disposal models and new landfill models based on field data. New inventories are compiled for waste deposits in deep salt mines and building material disposal. Along with the ecoinvent data and the reports, also Excel-based software tools were created, which allow ecoinvent members to calculate waste disposal inventories from arbitrary waste compositions. The modelling of long-term emissions from landfills is a crucial part in any waste disposal process. In ecoinvent long-term emissions are defined as emissions occurring 100 years after present. They are reported in separate emission categories. The landfill inventories include long-term emissions with a time horizon of 60’000 years after present. Results and Discussion As in earlier studies, the landfills prove to be generally relevant disposal processes, as also incineration and wastewater treatment processes produce landfilled wastes. Heavy metals tend to concentrate in landfills and are washed out to a varying degree over time. Long-term emissions usually represent an important burden from landfills. Comparisons between burdens from production of materials and the burdens from their disposal show that disposal has a certain relevance. Conclusion The disposal phase should by default be included in LCA studies. The use of a material not only necessitates its production, but also requires its disposal. The created inventories and user tools facilitate heeding the disposal phase with a similar level of detail as production processes. The risk of LCA-based decisions shifting burdens from the production or use phase to the disposal phase because of data gaps can therefore be diminished. Recommendation and Perspective Future improvements should include the modelling of metal ore refining waste (tailings) which is currently neglected in ecoinvent, but is likely to be relevant for metals production. The disposal technologies considered here are those of developed Western countries. Disposal in other parts of the World can differ distinctly, for logistic, climatic and economic reasons. The cross-examination of landfill models to LCIA soil fate models could be advantageous. Currently only chemical elements, like copper, zinc, nitrogen etc. are heeded by the disposal models. A possible extension could be the modelling of the behaviour of chemical compounds, like dioxins or other hydrocarbons.     

Establishing Life Cycle Inventories of Chemicals Based on Differing Data Availability (9 pp)

Goal, Scope and Background In contrast to inventory data of energy and transport processes, public inventory data of chemicals are rather scarce. Chemicals are important to consider in LCA, because they are used in the production of many, if not all, products. Moreover, they may cause considerable environmental impacts. For these reasons, it was one goal of the new ecoinvent database to provide LCI data on chemicals. In this paper, the methods and procedures used for establishing LCIs of chemicals in ecoinvent are presented.Methods Three different approaches are suggested for situations of differing data availability. First, in the case of good data availability, the general quality guidelines of ecoinvent can be followed. Second, a procedure is proposed for the translation of aggregated inventory data (cumulative LCI results) from industry into the ecoinvent format. This approach was used, if adequate unit process data was not available. Third, a procedure is put forward for estimating inventory data using stoichiometric equations from technical literature as a main information source. This latter method was used if no other information was available. The application of each of the three procedures is illustrated with the help of a case study.Results and Conclusion When sufficient information is available to follow the general guidelines of ecoinvent, the resulting dataset is characterized by a high degree of detail, and it is thus of high quality. For chemicals, however, the application of the standard procedure is possible in only a few cases. When using industrial data, the main drawback is the fact that those data are often available only as aggregated data, thus being out of tune with the quality guidelines of ecoinvent and its main aim, the harmonization of LCI data. As a third approach, the use of the stoichiometric reaction equation is used for the compilation of LCI datasets of chemicals. This approach represents an alternative to neglecting chemicals completely, but it contains a high risk to not consider important aspects of the life cycle of the respective substance.Outlook Further work in the area of chemicals should focus on an improvement of datasets, so far established by either of the two estimation procedures (APME method; estimation based on technical literature) described. Besides the improvement of already established inventories, the compilation of further harmonized inventories of specific types of chemicals (e.g. solvents) or of chemicals for new industrial sectors (e.g. electronics industry) are in discussion.     

Life Cycle Inventories of Metals and Methodological Aspects of Inventorying Material Resources in ecoinvent (7 pp)

Goal, Scope and Background The ecoinvent database provides harmonised generic life cycle inventories for metal production and processing. They can be used as background data for different LCA applications. The goal of this paper is to provide an overview of the metals inventoried in ecoinvent. Beside, some methodological background information is given. The focus lies on a new methodology developed to inventorying joint resources. The implementation is shown in a case study of the production of primary copper on a global average. The respective process is assessed with Eco-indicator 99 (H,A) to identify dominant impacts within the production chain.Methods In ecoinvent, a coupled production is inventoried in multi output unit processes. For database calculation, an allocation by economic revenue is applied. Elementary flows for resources, especially joint resources, include information on type and quality of the resources.Results and Conclusion With the presented method, the extraction of resources can be valuated based on the cost of restoration or the change in the future impact due to the extraction of a specific resource. The case study indicates, for copper / molybdenum production, that the mineral extraction is of minor importance compared to the metallurgical step according to the LCIA results. Air emissions of heavy metals are identified as main impacts. Also, the resource depletion shows a notable impact. The environmental impacts of metals from sulphidic ores, however, are underestimated by neglecting emissions from tailings for lack of reliable data.Recommendation and Perspective Impact assessment methods will have to be updated to account for different grades of ore. The ecoinvent database should be enlarged by more inventories of technically important metals and alloys, e.g. by gold, silver, solders, etc. for the electronics industry and by specific steel and aluminium alloys. Reliable composition data of sulphidic tailings and transfer coefficients for their disposal considering Acidic Rock Drainage (ARD) are to be developed as well.     

生态设计家具的碳足迹核算与减排效果分析——以木质家具为例

我国的木质家具不仅产量大,而且碳排放强度也相对较高,利用生态设计理念可以降低木质家具的碳足迹。为了定量化生态设计所带来的减排效果,按照减少资源消耗和环境污染、节省住宅空间等木质家具生态设计原则,通过在一款多功能家具的框架内安装不同面板,形成了4种不同材质和结构的设计方案,利用生命周期分析方法核算了4种方案的碳足迹,并进一步量化了改进方案的减排效果。结果表明:4种家具设计的碳足迹从小到大为三聚氰胺板家具、木皮板家具、拼板家具、嵌条板家具,其中,实木类家具原材料碳排放较低,人造板类家具加工过程电力碳排放较低(主要来源于喷涂工段,占电力排放的83%—92%);通过各种减排方案的减排效果分析,发现采用"可拆卸无胶连接方式"改进方案减排效果显为明显;同时发现,合理的"低碳设计"(采用以实木板为基板,以三聚氰胺纸为贴面制作面板),可以避免中纤板喷涂过程的碳排放,从而减少产品整体碳足迹。     

Life cycle inventories of electricity generation and power supply in version 3 of the ecoinvent database—part II: electricity markets

Purpose

Representative, consistent and up-to-date life cycle inventories (LCI) of electricity supply are key elements of ecoinvent as an LCI background database since these are often among the determining factors with regard to life cycle assessment (LCA) results. ecoinvent version 3 (ev3) offers new LCI data of power supply (electricity markets) in 71 geographies. This article gives an overview of these electricity markets and discusses new ecoinvent features in the context of power supply.

Methods

The annual geography- and technology-specific electricity production for the year 2008 specifies the technology shares on the high-, medium- and low-voltage level electricity markets. Data are based on IEA statistics. Different voltage levels are linked by transformation activities. Region-specific electricity losses due to power transmission and voltage transformation are considered in the market and transformation activities. The majority of the 71 power markets are defined by national boundaries. The attributional ecoinvent system model in ev3 with linking to average current suppliers results in electricity markets supplied by all geography-specific power generation technologies and electricity imports, while the consequential system model generates markets only linked to unconstrained suppliers.

Results and discussion

The availability of LCI data for 71 electricity markets in ev3 covering 50 countries reduces the “Rest-of-the-World” electricity supply not covered by country- or region-specific inventories to 17 % for the year 2008. Specific power supply activities for all countries contributing more than 1 % to global electricity production are available. The electricity markets show large variations concerning contributions from specific technologies and energy carriers. Imports can substantially change the national/regional power mix, especially in small markets. Large differences can also be observed between the electricity markets in the attributional and the consequential database calculation. Region-specific total power losses between production on the high voltage level and consumer on the low voltage level are on the order of 2.5–23 %.

Conclusions

Electricity supply mixes (electricity markets) in the ecoinvent database have been updated and substantially extended for v3. Inventories for electricity supply in all globally important economies are available with geography-specific technology and market datasets which will contribute to increasing quality and reducing uncertainties in LCA studies worldwide and to allow more accurate estimation of environmental burdens from global production chains. Future work should focus on improving the details of country-specific data, implementation of more countries into the database, splitting of large countries into smaller regions and on developing a more sophisticated approach specifying country-specific electricity mixes in consequential system models.

     

LCA Software tool for corrugated board

FEFCO, Groupement Ondulé and Kraft Institute have integrated the data from their recently published updated “European Database for Corrugated Board Life Cycle Studies” into a software tool that has been developed especially for the corrugated board industry. The tool links input and output data reported in the Database to average European data for upstream and downstream processes from BUWAL 250 [3]. The tool is intended to support environmental management of companies since it provides a possibility to find opportunities for improvements and to take environment into consideration when designing corrugated board boxes. The entire system of corrugated packaging is the basis for the calculations. It is assumed that the fibres that are used for the production of the corrugated base papers are produced and recycled only within this system. This simplified so-called closedloop approach, which is described in detail in the Database report, avoids the problem of allocating impacts caused by primary fibre production and the final treatment of corrugated packaging that is not recycled between primary and recovered fibre based paper grades. This means that with the software tool it is not possible to make comparisons between the production of primary fibre and recovered fibre based materials as such. The tool enables the user to vary parameters such as transport, box design, logistics and waste management according to his personal circumstances. In this way he can use the tool to introduce parameters for possible alternatives he wants to investigate. The LCA results of these alternative cases can then be compared and analysed at inventory, characterisation, normalisation and weighing level. The user cannot change the basic data nor the methodology.     

Electric passenger car transport and passenger car life cycle inventories in ecoinvent version 3

Purpose

Due to the large environmental challenges posed by the transport sector, reliable and state-of-the art data for its life cycle assessment is essential for enabling a successful transition towards more sustainable systems. In this paper, the new electric passenger car transport and vehicle datasets, which have been developed for ecoinvent version 3, are presented.

Methods

The new datasets have been developed with a strong modular approach, defining a hierarchy of datasets corresponding to various technical components in the vehicle. A vehicle is therefore modelled by linking together the various component datasets. Also, parameters and mathematical formulas have been introduced in order to define the amount of exchanges in the datasets through common transport and vehicle characteristics. This supports users in the choice of the amount of exchanges and enhances the transparency of the dataset.

Results

The new transport dataset describes the transport over 1 km with a battery electric passenger car taking into account the vehicle production and end of life, the energy consumption due to the use phase, non-exhaust emissions, maintenance and road infrastructure. The dataset has been developed and is suitable for a compact class vehicle.

Conclusions

A new electric passenger car transport dataset has been developed for version 3 of the ecoinvent database which exploits modularisation and parameters with the aim of facilitating users in adapting the data to their specific needs. Apart from the direct use of the transport dataset for background data, the various datasets for the different components can also be used as building blocks for virtual vehicles.

     

The ecoinvent database version 3 (part I): overview and methodology

Purpose

Good background data are an important requirement in LCA. Practitioners generally make use of LCI databases for such data, and the ecoinvent database is the largest transparent unit-process LCI database worldwide. Since its first release in 2003, it has been continuously updated, and version 3 was published in 2013. The release of version 3 introduced several significant methodological and technological improvements, besides a large number of new and updated datasets. The aim was to expand the content of the database, set the foundation for a truly global database, support regionalized LCIA, offer multiple system models, allow for easier integration of data from different regions, and reduce maintenance efforts. This article describes the methodological developments.

Methods

Modeling choices and raw data were separated in version 3, which enables the application of different sets of modeling choices, or system models, to the same raw data with little effort. This includes one system model for Consequential LCA. Flow properties were added to all exchanges in the database, giving more information on the inventory and allowing a fast calculation of mass and other balances. With version 3.1, the database is generally water-balanced, and water use and consumption can be determined. Consumption mixes called market datasets were consistently added to the database, and global background data was added, often as an extrapolation from regional data.

Results and discussion

In combination with hundreds of new unit processes from regions outside Europe, these changes lead to an improved modeling of global supply chains, and a more realistic distribution of impacts in regionalized LCIA. The new mixes also facilitate further regionalization due to the availability of background data for all regions.

Conclusions

With version 3, the ecoinvent database substantially expands the goals and scopes of LCA studies it can support. The new system models allow new, different studies to be performed. Global supply chains and market datasets significantly increase the relevance of the database outside of Europe, and regionalized LCA is supported by the data. Datasets are more transparent, include more information, and support, e.g., water balances. The developments also support easier collaboration with other database initiatives, as demonstrated by a first successful collaboration with a data project in Québec. Version 3 has set the foundation for expanding ecoinvent from a mostly regional into a truly global database and offers many new insights beyond the thousands of new and updated datasets it also introduced.

     

Estimation of the size of error introduced into consequential models by using attributional background datasets

Purpose

A systematic comparison is made of attributional and consequential results for the same products using the same unit process database, thus isolating the effect of the two system models. An analysis of this nature has only recently been made possible due to the ecoinvent database version 3 providing an access to both unallocated and unlinked unit process datasets as well as both attributional and consequential models based on these datasets. The analysis is therefore limited to the system models provided by ecoinvent.

Methods

For both system models, the analysis was made on the life cycle inventory analysis (LCIA) results as published by ecoinvent (692 impact categories from different methods, for 11,650 product/activity combinations). The comparison was made on the absolute difference relative to the smallest absolute value.

Results and discussion

The comparison provides quantified results showing that the consequential modelling provides large differences in results when the unconstrained (marginal) suppliers have much more/less impact than the average, when analysing the by-products, and when analysing determining products from activities with important amounts of other coproducts.

Conclusions

The analysis confirms that for consequential studies, attributional background datasets are not appropriate as a substitute for consequential background. The overall error will of course depend on the extent to which attributional modelling is used as part of the overall system model. While the identified causes of differences between the attributional and consequential models are of general nature, the identified sizes of the errors are specific to the way the two models are implemented in ecoinvent.

     

Biotechnology in the wood industry

Wood is a natural, biodegradable and renewable raw material, used in construction and as a feedstock in the paper and wood product industries and in fuel production. Traditionally, biotechnology found little attention in the wood product industries, apart from in paper manufacture. Now, due to growing environmental concern and increasing scientific knowledge, legal restrictions to conventional processes have altered the situation. Biotechnological approaches in the area of wood protection aim at enhancing the treatability of wood with preservatives and replacing chemicals with biological control agents. The substitution of conventional chemical glues in the manufacturing of board materials is achieved through the application of fungal cultures and isolated fungal enzymes. Moreover, biotechnology plays an important role in the waste remediation of preservative-treated waste wood.     

Modelling Representative Life Cycle Inventories for Swiss Arable Crops (9 pp)

Goal, Scope and Background Life cycle inventories (LCIs) of agricultural products, infrastructure, inputs and processes are required to optimise food supply chains. In the past, the use of LCA was hindered by the limited availability of databases with LCIs for such agricultural inputs, processes and products in combination with LCIs of other major economic sectors. The ecoinvent database covers this need for the Swiss, and to an extent, the European context. A suitable approach had to be outlined for defining representative datasets for products from arable crops, since there was no comprehensive survey of agricultural production.Methods No single data source was available for defining representative datasets for arable crops. It was therefore decided to define model crops on the basis of a variety of sources in collaboration with experts on the crops in question. The datasets were validated by experts and by comparison with literature. Field emissions were calculated using a set of models taking into account situation-specific parameters. Data defined by this procedure are more generally usable, but their definition is also more laborious. Results and Discussion Selected results (inventories and impact assessment) are presented for infrastructure (buildings, machinery), work processes, fertilisers, pesticides, seed and arable crop products. Infrastructure has a higher share of environmental impacts than in typical industrial processes, often due to low utilisation rates. Energy use is dominated by mechanisation, the use of mineral fertilisers (particularly nitrogen) and grain drying. Eutrophication is caused mainly by nitrogen compounds. In general, field emissions are of decisive importance for many environmental impacts. Conclusion and Outlook The ecoinvent database provides representative agricultural data for the Swiss, and to an extent, the European context. It also provides the meta-information necessary for deciding whether a dataset is suitable for the purpose of a particular LCA study. To further improve the representativeness of the datasets, an environmental farm monitoring network is required.     

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

Purpose

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

Methods

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

Results and discussion

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

Conclusions

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

Temporal differentiation of background systems in LCA: relevance of adding temporal information in LCI databases

Purpose

Because the potential impacts of emissions and extractions can be sensitive to timing, the temporal aggregation of life cycle inventory (LCI) data has often been cited as a limitation in life cycle assessment (LCA). Until now, examples of temporal emission and extraction distributions were restricted to the foreground processes of product systems. The objective of this paper is to evaluate the relevance of considering the temporal distribution of the background system inventory.

Methods

The paper focuses on the global warming impact category for which so-called dynamic characterization factors (CFs) were developed and uses the ecoinvent v2.2 database as both an example database to which temporal information can be added and a source of product systems to test the relevance of adding temporal information to the background system. Temporal information was added to the elementary and intermediate exchanges of 22 % of the unit processes in the database. Using the enhanced structure path analysis (ESPA) method to generate temporally differentiated LCIs in conjunction with time-dependent global warming characterization factors, potential impacts were calculated for all 4,034 product systems in the ecoinvent database.

Results and discussion

Each time, the results were calculated for (1) systems in which temporal information was only added to the first two tiers, representing studies in which only the foreground system is temporally differentiated, and (2) systems in which temporal information was also added to the background system. For 8.6 % of the database product systems, adding temporal differentiation to background unit processes affected the global warming impact scores by more than 10 %. For most of the affected product systems, considering temporal information in the background unit processes decreased the global warming impact scores. The sectors that show most sensitivity to the temporal differentiation of background unit processes are associated with wood and biofuel sectors.

Conclusions

Even though the addition of temporal information to unit processes in LCI databases would not benefit every LCA study, the enhancement can be relevant. It allows for a more accurate global warming impact assessment, especially for LCAs in which products of biomass are present in substantial amounts. Relevance for other impact categories could be discussed in further work.     

Life cycle inventories of electricity generation and power supply in version 3 of the ecoinvent database—part I: electricity generation

Purpose

Life cycle inventories (LCI) of electricity generation and supply are among the main determining factors regarding life cycle assessment (LCA) results. Therefore, consistency and representativeness of these data are crucial. The electricity sector has been updated and substantially extended for ecoinvent version 3 (v3). This article provides an overview of the electricity production datasets and insights into key aspects of these v3 inventories, highlights changes and describes new features.

Methods

Methods involved extraction of data and analysis from several publically accessible databases and statistics, as well as from the LCA literature. Depending on the power generation technology, either plant-specific or region-specific average data have been used for creating the new power generation inventories representing specific geographies. Whenever possible, the parent–child relationship was used between global and local activities. All datasets include a specific technology level in order to support marginal mixes used in the consequential version of ecoinvent. The use of parameters, variables and mathematical relations enhances transparency. The article focuses on documentation of LCI data on the unlinked unit process level and presents direct emission data of the electricity-generating activities.

Results and discussion

Datasets for electricity production in 71 geographic regions (geographies) covering 50 countries are available in ecoinvent v3. The number of geographies exceeds the number of countries due to partitioning of power generation in the USA and Canada into several regions. All important technologies representing fossil, renewable and nuclear power are modelled for all geographies. The new inventory data show significant geography-specific variations: thermal power plant efficiencies, direct air pollutant emissions as well as annual yields of photovoltaic and wind power plants will have significant impacts on cumulative inventories. In general, the power plants operating in the 18 newly implemented countries (compared to ecoinvent v2) are on a lower technology level with lower efficiencies and higher emissions. The importance of local datasets is once more highlighted.

Conclusions

Inventories for average technology-specific electricity production in all globally important economies are now available with geography-specific technology datasets. This improved coverage of power generation representing 83 % of global electricity production in 2008 will increase the quality of and reduce uncertainties in LCA studies worldwide and contribute to a more accurate estimation of environmental burdens from global production chains. Future work on LCI of electricity production should focus on updates of the fuel chain and infrastructure datasets, on including new technologies as well as on refining of the local data.

     

Comparative environmental performance of semi-trailer load boxes for grain transport made of different materials

Background, aim, and scope  

Semi-trailers with load boxes are the most important mode of grain transport by land in the world. Load boxes can be produced with different materials such as: wood, steel, and synthetic material. They are responsible for effectiveness retention and quality of grains during the transport. Among the main aspects to be considered and valued when selecting materials for load boxes are the final mass of the semi-trailer, loss of grains, and mechanical properties. Environmental performance is another important aspect to be taken into account for developing and selecting new materials in this kind of application. This study presents a comparative environmental evaluation of load boxes built from two different materials (a wood panel and a three-layer synthetic (TLS) panel). Mass balance and life cycle assessment (LCA) were used in this study.