Modelling environmental effects of selected agricultural management strategies with regional statistically based screening LCA

Purpose

Despite the farm being considered by many as the most suitable level of decision-making and strategic management in agriculture, there is an increasing interest in evaluating agricultural management strategies at the regional level. Recent initiatives attempted to aggregate and generalise farm-level lifecycle inventory (LCI) data and lifecycle impact assessment (LCIA) results to describe the environmental performance of agricultural regions. This article describes our development and application of a regional statistics-based approach for constructing virtual representative farms (VRFs), representing dominant farm types for a given region, as a tool for comparing alternative regional agricultural strategies in contexts of insufficient farm (e.g. LCI) data.

Methods

Based on statistical sources, we constructed VRFs of the dominant farm types in the largely agricultural region of Brittany, France. Environmental impacts of different agricultural management strategies were estimated at the regional level by modelling the strategies as changes in VRF-based LCIs, calculating LCIAs and extrapolating their mean per-ha impacts to the total land use in the region. Based on this assessment, performed using a regional lifecycle assessment framework, we analysed relative environmental impacts of each management strategy on the region. A strategy-comparison table was built to allow decision makers to understand the potential regional environmental consequences of implementing each strategy.

Results and discussion

Once VRFs impact assessment results were extrapolated to the regional level, all strategies show environmental impacts per ha similar to those of the baseline, with differences ranging from ?15 to +6%. The scenario featuring centralised fodder drying by 50% of cattle farms (50FOD) is the only one featuring surpluses for all products, due to associated cattle diet adjustments including reduced maize silage intake and partial substitution of concentrate feeds. The scenario featuring grass specialisation by all cattle farms (100GRA) shows a large deficit of grassland products, suggesting that a region-wide extensification strategy would not be self-sufficient.

Conclusions

The method developed enables comparing environmental consequences of region-wide implementation of agricultural strategies, yet, for our case study, it is particularly difficult to identify a “best” one. Nonetheless, the method serves as an initial step for preselecting strategies to investigate at a more detailed level. Prioritisation of a given strategy would likely be based on the environmental pressures considered most pressing by regional decision makers.

     

Categorizing water for LCA inventory

Purpose  

As impact assessment methods for water use in LCA evolve, so must inventory methods. Water categories that consider water quality must be defined within life cycle inventory. The method presented here aims to establish water categories by source, quality parameter and user.     

Sensitivity coefficients for matrix-based LCA

Background, aim, and scope  

Matrix-based life cycle assessment (LCA) is part of the standard ingredients of modern LCA tools. An important aspect of matrix-based LCA that is straightforward to carry out, but that requires a careful mathematical handling, is the inclusion of sensitivity coefficients based on differentiating the matrix-based formulas.     

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.     

Screening LCA for large numbers of products

CIBA’s Textile Dyes and Chemicals divisions use screening LCAs for their 1700 sales products to improve portfolio management and ecological process development. Material flow, energy, and waste data for in-house manufacturing processes are extracted from our company databases into our LCA system ECOSYS. For meaningful comparisons of whole life cycles, we must include LCA estimates for over 4000 raw materials from other suppliers. Even crude estimates are preferable to the frequently practiced omission of unknown process steps since they allow worst-case or sensitivity analyses. Sources for mass flows are (decreasing order of reliability): process literature (SRI-PEP Yearbook, Ullmann, Kirk-Othmer, patents), yields of analogous processes, theoretical stoichiometry. Energy demands come from literature, or from a set of standard operation estimates developed by our process engineers. Wastes/emissions, if not published, are derived from yields and elemental balances, estimated emissions of energy carriers (BUWAL-132), and typical end-of-pipe measures in CIBA. These data sets are kept as “added-burden modules” (ABM) in our system, each with a set of “inherent burdens”, which are transformed to step-specific burden estimates by a “propagation” program, before the overall burdens of the whole process tree are cumulated. This program checks every process for actually measured burdens, before applying the attached ABM estimates to fill the gaps. Centralization of estimates as ABM with inherent burdens facilitates maintenance and adaptation. At present, well over 250 important intermediates were estimated and used in our product trees; many more follow rapidly. This article is an example of how industry is using LCA to address environmental issues.     

Transportation in LCA

The purpose of this paper is to investigate whether transport and logistics substantially contribute to the environmental interventions and impacts identified in LCAs. Four LCAs, encompassing very different products in different countries, were screened for the relative contribution of transport to the overall environmental interventions and impacts. Aside from this, the contribution of transport within individual life cycle phases was investigated. In none of the LCAs did transport contribute to less than 5% of the energy related interventions or impacts, whereas contributions with more than ten percent occurred regularly, especially in events involving NO_x related impact. The importance of transport strongly depends on the kind of product studied. It seems to be especially important for agricultural products. With respect to individual phases of the life cycle, the study indicates that special attention is required for the transport of raw materials, for use phase of electronics and for the disposal phase of recyclable products.     

Scenario Modelling in Prospective LCA of Transport Systems. Application of Formative Scenario Analysis (11 pp)

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. Objective and 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. Conclusions and 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. Outlook and 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.     

Current LCA database development in Japan -results of the LCA project

In 1998, the Japan’s Ministry of Economy, Trade, and Industry (METI) launched a five-year national project entitled ‘Development of Life Cycle Impact Assessment for Products’ (commonly known as ‘the LCA Project’). The purpose of the project is to develop common LCA methodology as well as a highly reliable database that can be shared in Japan. Activities over these five years have resulted in the supply of LCI data on some 250 products. Industrial associations voluntarily provided data. The results of these activities are currently being made available on the Internet on a trial basis in the form of an LCA database. In addition, a method entitled ‘Life-cycle Impact assessment Method based on Endpoint modeling (LIME)’ was developed. It is expected that these results will be widely used in Japan in the future. This paper presents an outline of the results of the research and development that has been conducted in the LCA Project in Japan.     

Sensitivity coefficient-based uncertainty analysis for multi-functionality in LCA

Purpose

In LCA, a multi-functionality problem exists whenever the environmental impacts of a multi-functional process have to be allocated between its multiple functions. Methods for fixing this multi-functionality problem are controversially discussed because the methods include ambiguous choices. To study the influence of these choices, the ISO standard requires a sensitivity analysis. This work presents an analytical method for analyzing sensitivities and uncertainties of LCA results with respect to the choices made when a multi-functionality problem is fixed.

Methods

The existing matrix algebra for LCA is expanded by explicit equations for methods that fix multi-functionality problems: allocation and avoided burden. For allocation, choices exist between alternative allocation factors. The expanded equations allow calculating LCA results as a function of allocation factors. For avoided burden, choices exist in selecting an avoided burden process from multiple candidates. This choice is represented by so-called aggregation factors. For avoided burden, the expanded equations calculate LCA results as a function of aggregation factors. The expanded equations are used to derive sensitivity coefficients for LCA results with respect to allocation factors and aggregation factors. Based on the sensitivity coefficients, uncertainties due to fixing a multi-functionality problem by allocation or avoided burden are analytically propagated. The method is illustrated using a virtual numerical example.

Results and discussion

The presented approach rigorously quantifies sensitivities of LCA results with respect to the choices made when multi-functionality problems are fixed with allocation and avoided burden. The uncertainties due to fixing multi-functionality problems are analytically propagated to uncertainties in LCA results using a first-order approximation. For uncertainties in allocation factors, the first-order approximation is exact if no loops of the allocated functional flows exist. The contribution of uncertainties due to fixing multi-functionality problems can be directly compared to the uncertainty contributions induced by uncertain process data or characterization factors. The presented method allows the computationally efficient study of uncertainties due to fixing multi-functionality problems and could be automated in software tools.

Conclusions

This work provides a systematic method for the sensitivity analysis required by the ISO standard in case choices between alternative allocation procedures exist. The resulting analytical approach includes contributions of uncertainties in process data, characterization factors, and—in extension to existing methods—uncertainties due to fixing multi-functionality problems in a unifying rigorous framework. Based on the uncertainty contributions, LCA practitioners can select fields for data refinement to decrease the overall uncertainty in LCA results.     

Review of criteria for evaluating LCA weighting methods

Purpose

In the process of selecting where effective environmental measures should be directed, the weighting step of life cycle assessment (LCA) is an optional, controversial, but nevertheless important tool. A set of criteria for evaluating weighting methods has relevance in the process of acquiring meta-knowledge, and thus competence, in assigning relative weights to environmental impact categories. This competence is helpful when choosing between presently available weighting methods, and in creating new weighting methods.

Methods

Criteria in LCA-related literature are reviewed. The authors have focused on identifying lists of criteria rather than extracting criteria from bulks of text. An important starting point has been the actual use of the term “criterion”, while at the same time disqualifying certain definitions of the term which are too far removed from the two definitions provided in this article.

Results and discussion

Criteria for evaluating weighting methods are shown to fall into two general categories. The first being general criteria for weighting methods, demanding that weighting methods have a broad scope, are practical for users and scientists, are scientific and have ethical goals. The second being criteria proposing characteristics of concrete environmental damage which should be taken into account by a weighting method. A noteworthy example is reversibility.

Conclusions

While the comprehensive tables of criteria speak for themselves, it can be observed that the need for transparency is particularly highlighted in literature. Furthermore, ISO 14044’s statement that the weighting step is “not scientifically based” would appear to defy a significant proportion of the other criteria reviewed; this, however, depends on its interpretation.     

Functional priorities in LCA and design for environment

Aim, Scope and Background  The interest in environmental questions has increased enormously during the last decade. Environmental protection has become an issue of strategic importance within the manufacturing industry and many companies are now working in the field of Design for Environment (DFE). The main purpose of DFE is to create products and services for achieving a sustainable society. Designers are widely believed to have a key role in adapting products to a sustainable society and one of the major instruments in the context of Design for Environment is Life Cycle Assessment (LCA). However, product development creates particular challenges for incorporating environmental issues that combine functional and environmental assessment. A natural and important part of product design is to define and analyse the functions of the product. Consequently, the functional unit in LCA is a core issue in DFE. Most recent research in DFE has focused on how to reduce the environmental impact of products throughout their life-cycle by addressing environmental aspects, while little attention has been given to the functionality of the product. Additionally, early product development phases, so called re-think phases, are considered to have the influence on major changes in products in general. These phases have thus the highest potential for changing products and product systems towards a sustainable development. Main Features  This paper discusses an extended functional representation in design for environment methods to evaluate sustainable design solutions, especially in early (re-think) phases of product design. Based on engineering-design science and several case studies, a concept has been developed describing how functional preferences can be visualised in design for environment and product development. In addition, the functional unit in LCA is discussed. The concept is called Functional Profile (FP) and is additionally exemplified in a case study on radio equipment. Discussion  The new functional characterisation concept helps identify functional priorities in design for environment. The Functional Profile is a structured, systematic and creative concept for identifying the necessary functions of a new product. The FP is envisioned to complement existing design for environment methods, not to replace them. Instead of being a product-development tool or method, the concept is an approach that increases understanding of inter-reactions between functional characteristics of products and their environmental characteristics, which furthermore facilitates trade-off decisions. One of the objectives behind the concept is to highlight the importance of balancing functional requirements and environmental impacts, presenting both the advantages and disadvantages of the product. Outlook  A second paper will be produced to complement the functional-environmental characterisation concept in early product development phase, presenting the environmental characterisation part and illustrating correlations between the functional and environmental sides.     

LCA for Site Remediation: A Literature Review

Remediation of contaminated sites provides a cleaner local environment, but may also have negative environmental impacts on the local, regional, and global scales. Methods based on Life Cycle Assessment (LCA) are designed to take the negative effects into consideration when deciding how to treat a site, and to improve the environmental efficiency of remediation techniques. This paper reviews nine case studies that use LCA tools to evaluate alternative remediation techniques to summarize the findings of methodologies and results. The methodologies were found to differ in the limitation of the LCA for space, time and secondary processes. This strongly influenced the results. Bioremediation was the worst when the secondary process of producing electron acceptors was included; otherwise it was the best. The choice of impact categories heavily affected the results. Inclusion of land use was especially important in site remediation studies. In general, the negative impact of site remediation was due to energy consumption. For excavation combined with ex-situ treatment, the transport of contaminated soil to the treatment facility or landfill required the most energy. For in-situ treatment of soil and groundwater, pumping consumed the most energy. It is proposed that different methods be applied to the same site.