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Environmental system analysis The application of linear programming to life cycle assessment
Abstract
Thesis (Ph. D.)--University of Surrey, 1996.
... The marked categories are ionizing, freshwater eutrophication, land use, and mineral, fossil, and renewable resource depletion. In the literature, there is a similar study done by Azapagic (1996) [39] concerning the LCA of boron mining for BA, BD, and BP. They employ the mid-point approach of Heijungs et al. (1992) [40], which corresponds to the CML 1992 method [41]. ...
... The marked categories are ionizing, freshwater eutrophication, land use, and mineral, fossil, and renewable resource depletion. In the literature, there is a similar study done by Azapagic (1996) [39] concerning the LCA of boron mining for BA, BD, and BP. They employ the mid-point approach of Heijungs et al. (1992) [40], which corresponds to the CML 1992 method [41]. ...
... They employ the mid-point approach of Heijungs et al. (1992) [40], which corresponds to the CML 1992 method [41]. Azapagic's Ph.D. thesis [39] was used for the comparative study with the literature. Azapagic created the inventory using certain data from Borax-Europe Ltd. ...
Although there are a lot of studies in literature related to the life cycle assessment (LCA) of mining, there are only a few studies done on the boron mining industry. This paper presents an LCA of the boron mining industry including the extraction, beneficiation, and refinement processes. The main purpose is to identify and compare the environmental impacts associated with the production of 1 ton of refined products (boric acid, borax pentahydrate, borax decahydrate, and sodium perborate) starting from an open pit mine located in Turkey. The life cycle inventory (LCI) was obtained from the data collected from the related literature sources and the company’s reports. This cradle-to-gate analysis has been carried out using the commercial software called SimaPro employing the International Reference Life Cycle Data System (ILCD) 2011 Midpoint+ Life Cycle Impact Assessment (LCIA) method. The results showed that the environmental impact of the refinement process is critical compared to the mining and beneficiations processes. Sulphuric acid, steam, hydrogen peroxide, and sodium perborate which are used in refined boron production cause most of the impact and emission into the environment. Among the refined boron products investigated, the impact of sodium perborate is quite high.
... Although LCA is not mentioned explicitly in EMAS, its use is implied in Annex 1, section C (see [2]).Fig. 1. Stages in the life cycle of a product (from Azapagic [20]). analysis, such as Environmental Impact Assessment (EIA) or Environmental Audit (EA), lies in broadening the system boundaries to include all burdens and impacts in the life cycle of a product or a process, and not focusing on the emissions and wastes generated by the plant or manufacturing site only. ...
... 13. Pareto curve obtained in multi-objective optimisation (from Azapagic [20]). optimum, however, does mean that the set of best possible options has been identi®ed for a system in which both objectives should be improved. ...
... Non-inferior curve for optimisation of a nitric plant (from Kniel et al. [100]). Azapagic [20] and Azapagic and Clift [136,137] have taken this approach further by optimising on a number of environmental and economic objectives, thus avoiding Valuation. This is illustrated on a real mining and processing example of the system producing ®ve boron products: 10 mol borate (Na 2 B 4 O 7 Á10H 2 O), 5 mol borate (Na 2 B 4 O 7 Á 4.67H 2 O), boric acid (H 3 BO 3 ), anhydrous borax (Na 2 B 4 O 7 ), and anhydrous boric acid (B 2 O 3 ). ...
As the pressures on the chemical and process industries to improve their environmental performance are increasing, the need to move away from narrow system de®nitions and concepts in environmental system management is becoming more apparent. Life Cycle Assessment (LCA) is gaining wider acceptance as a method that enables quanti®cation of environmental interventions and evaluation of the improvement options throughout the life cycle of a process, product or activity. Historically, LCA has mainly been applied to products; however, recent literature suggests that it can assist in identifying more sustainable options in process selection, design and optimisation. This paper reviews some of these newly emerging applications of LCA. A number of case studies indicate that process selection must be based on considerations of the environment as a whole, including indirect releases, consumption of raw materials and waste disposal. This approach goes beyond the present practice of choosing Best Practicable Environmental Option (BPEO), by which it is possible to reduce the environmental impacts directly from the plant, but to increase them elsewhere in the life cycle. These issues are discussed and demonstrated by the examples of end-of-pipe abatement techniques for SO 2,NO x and VOCs and processes for the production of liquid CO 2 and O 2. The integration of LCA into the early stages of process design and optimisation is also reviewed and discussed. The approach is outlined and illustrated with real case studies related to the mineral and chemical industries. It is shown that a newly emerging Life Cycle Process Design (LCPD) tool offers a potential for technological innovation in process concept and structure through the selection of best material and process alternatives over the whole life cycle. The literature also suggests that LCA coupled with multi-objective optimisation (MO)
... The methodological developments in this respect are still underway and the published literature on this subject is limited (e.g. [3,4]). ...
... Moreover, modelling a system through LP allows for complex interactions between different parts of a system and so closely describes the behaviour of the system. The value of LP in the Inventory and Impact assessment stages of LCA has already been demonstrated by the authors [3,5,[8][9][10][11][12]. This paper illustrates the application of multiobjective LP to analysing and managing the environmental performance of a system, as a part of the Improvement (or Interpretation) stage in LCA. ...
... A simplified flow diagram of the process is shown in Fig. 1. Further details are given by Azapagic [3] and Azapagic and Clift [12]. Boron minerals, borax (Na 2 B 4 O 7 ·10H 2 O) and kernite (Na 2 B 4 O 7 ·4H 2 O) are extracted in the mine, crushed and transported to the adjacent plant. ...
Life cycle assessment (LCA) is a method to identify and quantify the environmental performance of a process or a product from “cradle to grave”. Its main potential in environmental decision-making lies in providing a quantitative basis for assessing potential improvements in environmental performance of a system throughout the life cycle. This paper introduces the use of multiobjective system optimisation in LCA as a tool for identifying and evaluating the best possible options for environmental management of the product system. A life cycle of a system is optimised on a number of environmental objective functions, defined in terms of the usual LCA burden or impact categories, and a range of environmental optima is found on the Pareto or non-inferior surface. As a result, possibilities for improving the environmental performance of the system are identified. Since system improvements cannot be carried out on the basis of environmental LCA only, it is also shown in this paper that the compromise between environmental and economic performance can be found on the non-inferior surface. The value of multiobjective optimisation in system analysis lies in providing a set of alternative options for system improvements rather than a single prescriptive solution, thus enabling the choice of the Best Practicable Environmental Option (BPEO) and Best Available Technique Not Entailing Excessive Cost (BATNEEC). This approach is illustrated by application to a real case study of a system producing five borate products.
... Problem shifting can occur when analysing only one activity, one area, one substance, one environmental problem or effects over a limited period of time. So the LCA model tries to cover all activities related to a product or function; stating effects anywhere in the world; covering all relevant substances and environmental themes; and having a long time horizon 3 . This encompassing nature of LCA in place, time and effect mechanisms has as a corollary that the model used should be relatively simple to keep the analysis feasible. ...
... In most guidebooks on LCA, the focus is on structural choices. The approaches that have been developed by Azapagic (1996) and by Weidema et al. (1999) may particularly be useful for LCA's with occasional choices as a starting point. ...
... The software used was SimaPro V.6.0. developed by Pré Consultants [3]. A LCA study is performed to assess the environmental and energy performance of hybrid poplar crop biomass production in short rotation coppice in southern Europe. ...
... The allocation problems were the most difficult to resolve in the development of the international standard ISO 14041 [1]. They have also been the topic for many scientific papers and several Ph.D. theses (e.g., [2][3][4][5][6]). ...
... This text can be considered to be part of this research and harmonization process. Other contributions have been made by, e.g., Azapagic [2], Azapagic & Clift [21], Ekvall [20], and Weidema et al. [24]. Thorskog Castle is a conference hotel near the West Coast of Sweden. ...
The choice of system boundaries, allocation methods and data sources in a life cycle inventory analysis (LCI) depends on basic, ethical views. From the viewpoint of teleological situation ethics, an effect-oriented LCI - with system expansions and marginal data - provides relevant information. From the viewpoint of rule ethics, the methodological choices depend on what rules are considered to be good. In an effect-oriented LCI, the starting point for an assessment of the environmental consequences of actions should be the specific action at hand or the foreground system. A radically effect-oriented LCI probably requires the co-operation between economists and engineers.
... Examples of the application of MADA methods in LCA or in conjunction with LCA-based environmental indicators to support multiple-criteria decision making can be found in work by Miettinen and Hämäläinen (1997), Seppälä (1997Seppälä ( , 1999, Spengler and colleagues (1998), Basson and Petrie (1999a, 1999b, 2000, and . Examples of the application of MOO in LCA or in conjunction with LCA-based environmental indicators are found in work by Azapagic (1996), Azapagic andClift (1998), Stewart (1999), and Alexander and colleagues (2000). ...
... Examples of the application of MADA methods in LCA or in conjunction with LCA-based environmental indicators to support multiple-criteria decision making can be found in work by Miettinen and Hämäläinen (1997), Seppälä (1997Seppälä ( , 1999, Spengler and colleagues (1998), Basson and Petrie (1999a, 1999b, 2000, and . Examples of the application of MOO in LCA or in conjunction with LCA-based environmental indicators are found in work by Azapagic (1996), Azapagic andClift (1998), Stewart (1999), and Alexander and colleagues (2000). ...
Life-cycle impact assessments (LCIAs) are complex because they almost always involve uncertain consequences relative to multiple criteria. Several authors have noticed that this is precisely the sort of problem addressed by methods of decision analysis. Despite several experiences of using multipleattribute decision analysis (MADA) methods in LCIA, the possibilities of MADA methods in LCIA are rather poorly elaborated in the field of life-cycle assessment. In this article we provide an overview of the commonly used MADA methods and discuss LCIA in relation to them. The article also presents how different frames and tools developed by the MADA community can be applied in conducting LCIAs. Although the exact framing of LCIA using decision analysis still merits debate, we show that the similarities between generic decision analysis steps and their LCIA counterparts are clear. Structuring of an assessment problem according to a value tree offers a basis for the definition of impact categories and classification. Value trees can thus be used to ensure that all relevant impact categories and interventions are taken into account in the appropriate manner. The similarities between multiattribute value theory (MAVT) and the current calculation rule applied in LCIA mean that techniques, knowledge, and experiences derived from MAVT can be applied to LCIA. For example, MAVT offers a general solution for the calculation of overall impact values and it can be applied to help discern sound from unsound approaches to value measurement, normalization, weighting, and aggregation in the LCIA model. In addition, the MAVT framework can assist in the methodological development of LCIA because of its well-established theoretical foundation. The relationship between MAVT and the current LCIA methodology does not preclude application of other MADA methods in the context of LCIA. A need exists to analyze the weaknesses and the strengths of different multiple-criteria decision analysis methods in order to identify those methods most appropriate for different LCIA applications.
... See also Dyckhoff and Ahn (1998). Azapagic and Clift (1998, 1996) developed a system optimization approach to facilitate the identification and choice of the Best Practicable Environmental Option (BPEO) in improvement assessment. This multi-objective optimization approach generates a number of optimal solutions, which show explicitly what can be gained a nd what lost by choosing each alternative. ...
... ustrial problems. The dismantling and recycling planning model is based on linear activity analysis and is formulated using a mixed integer linear programming m odel. The recycling management model is based on a multistage capacitated warehouse location problem and was applied to the German iron and steel industry. See also Dyckhoff and Ahn (1998). Azapagic and Clift (1998, 1996) developed a system optimization approach to facilitate the identification and choice of the Best Practicable Environmental Option (BPEO) in improvement assessment. This multi-objective optimization approach generates a number of optimal solutions, which show explicitly what can be gained a nd what lost by choosing eac ...
An innovative mathematical programming decision support model - Life Cycle Activity Analysis (LCAA) - is presented, integrating considerations of optimal allocations of resources and impacts upon the environment during the life cycle of products. LCAA is based on the classical formulation of activity analysis and on the life cycle assessment framework. The concept of linear activities is extended to embrace mass and energy fluxes over the entire life cycle of products including their environmental impacts. Special attention is given to the presence of loops in the product chains, such as those occurring when materials/products are recovered (reused, recycled.). An application brought from the Portuguese bottled water industry is described. The model features alternative activities for production technologies and product recovery strategies and permits the joint consideration of monetary costs and environmental burdens. The results obtained under five scenarios, including distinct disposal strategies and environmental constraints, are discussed.
... Many different solutions to this allocation problem have been suggested [5][6][7][8][9][10][11][12][13][14][15][16][17]. The choice of solution can have a decisive impact on the results of an LCI [17][18][19][20]. ...
... A comparison of Eqs. (11) and (12) shows that the system expansion produces additive results in this case: the environmental burdens credited to a product delivering OCC to the market correspond to the environmental burdens assigned to the product where the OCC is used. ...
Changes in the amount of recycled material delivered by, or used in, the life cycle of a product will affect the environmental burdens of other product life cycles. These indirect effects can potentially be taken into account through expansion of the system investigated to include the activities affected. Presently, the assessment of the indirect effects is often based on inaccurate assumptions. The indirect effects depend on, e.g. how the market for the recycled material reacts to a change in the supply of, or demand for, the recycled material. This, in turn, depends on political constraints, price elasticities, etc. in the markets for recycled material. This paper presents a model that takes the market aspects into consideration. It can be used in a life cycle assessment (LCA) to model the indirect effects either through system expansion or as a basis for allocation. It is designed for the use in change-oriented LCAs, but it can also be used in accounting type LCAs. The model is demonstrated in two theoretical cases: increased local collection for recycling of old corrugated containers and newsprint, respectively.
... 29 Whereas, other research not only considered ecological objectives but also economic objectives. For example, optimising a nitric acid plant with the goals of financial returns and environmental index function, 30 optimising an mining and processing system to minimise impacts from the system, while maximising production and lowering the costs, 31 optimisation for building retrofitting with consideration of economy, energy and environment criteria, 32 optimisation for hydrogen supply chain design with objectives of cost and global warming potential using epsilon-constrain method, 33 optimising the design of biofuel supply chains with objectives of the cost, the greenhouse gas emissions, and the number local jobs, 34 and optimising the design of CHP-based microgrids with the global warming potential and the acidification potential serving as the objectives. 35 Despite of the previous published work, research gap remains open on LCA optimisation tool development, which harnesses state-of-the-art LCA database and offers potential for end-users to derive optimal solutions considering site-specific value chain data and multiple sustainability criteria. ...
Historically, optimisation processes for supply chains have primarily focused on maximising economic objectives. However, with the challenges posed by climate change, there has been a shift towards integrating environmental considerations into optimisation processes alongside economic criteria, which can be facilitated by life cycle assessment. This approach enables supply chain managers to move beyond solely analysing emissions from individual plants, instead considering all life cycle stages. Yet, despite the advancements made in incorporating environmental considerations, the challenge lies in identifying the most effective improvement strategies and selecting optimal alternatives within decision environments characterised by multiple and often conflicting objectives. Real-life scenarios frequently demand simultaneous economic and environmental criteria considerations to ensure products' sustainability over their entire life cycle. Striking a delicate balance between these divergent objectives requires careful evaluation, innovative solutions, and robust decision-making processes. One of the solutions is combining multi-objective optimisation with life cycle assessment because of its ability to balance environmental and economic performance. By leveraging this approach, decision-makers can navigate the trade-offs between these two crucial aspects, empowering them to select the most appropriate solution that aligns with their specific requirements, constraints, and objectives. A decision-aid toolkit has been developed in this paper and validated using a real-life case study focused on electricity generation in the UK. This practical application showcases the methodology's effectiveness and provides tangible evidence of its potential to drive improvements in the real world.
... Therefore, to deal with this and other complexities often encountered in LCA, it is helpful to use system optimisation in LCA as an aid for identifying optimum solutions for improvements. Because of the multiobjective nature of the problem in which optimum solutions are sought for a number of often conflicting objectives, it is necessary to use multiobjective optimisation whereby the system is simultaneously optimised on a number of environmental objective functions subject to the constraints in the system (Azapagic, 1996;Azapagic and Clift, 1995, 1996a, 1996b. ...
The 1997 workshop of the International Association of Technology Assessment and
Forecasting Institutes, IATAFI, was held in Rio de Janeiro and Buzios, Brazil. The focus
of this meeting was “Technological Assessment and Zero Emissions in a Global World.”
This book presents the proceedings of this meeting, and contains many papers which
examine the role of technology in achieving zero emissions, and the importance of zero
emissions for sustainable development, and the ever present question of technological
assessment.
... If the prospective methodology were to be preferred for this application, a long-term solution would be to develop a theoretical foundation for detailed prospective LCAs and then to try to establish a standard based on this foundation. This article can be regarded as one contribution, among others, to such a solution (Ekvall et al., 2005, Weidema et al., 1999, Ekvall, 1999, Azapagic, 1996. ...
In the past few decades, world-wide interest in environmental preservation has involved researchers in a great challenge to find new approaches to manage the environmental impact of human activities. This challenge has been significantly highlighted in the construction sector. Lifecycle Assessment (LCA) has developed a variety of methodologies and tools to quantify and manage rates of consumption and emissions during the process of a building’s construction, service-life, and disposal. However, the building sector is not yet satisfied with the results of these methods and tools, due to the low level of sensitivity, lack of user-friendliness and precision.
The principal goal of this research is to determine the level of confidence in prospective building lifecycle assessment (BLCA) methodologies and tools in the UK and their applicability to design and decision making. In addition, it investigates the differentiation of the results according to climatic and geographical variation. Therefore, it introduces a new prospective semi-quantitative framework to calculate some key factors such as total energy (including embodied energy and operational energy) during the building’s lifecycle, as well as the embodied carbon, and total environmental impact. The capability of this framework was tested through 132 modelling scenarios of a real case study (‘The Arts Tower’ of Sheffield, United Kingdom).
In the study, a quantitative measurement approach was developed (an Excel-based spreadsheet) with a great flexibility in micro-detail modelling. This spreadsheet benefits from validated updatable databases and various-unlimited modelling programmes (such as Envest 2 and Ecotect 2011, in this research) to reach a more realistic decision in design. The results of this measurement approach were compared based on different modelling scenarios. The differences are based on the variety of building material scenarios through the case study building in Sheffield. The main outcome of this research is a framework of semi-quantitative prospective BLCA developed to achieve more precise results applicable to design and decision-making. The determination of the sensitivity and capability of this framework was conducted through both quantitative (132 modelling scenarios) and qualitative (surveys including questionnaires and interviews) approaches.
... If the prospective methodology were to be preferred for this application, a long-term solution would be to develop a theoretical foundation for detailed prospective LCAs and then to try to establish a standard based on this foundation. This article can be regarded as one contribution, among others, to such a solution (Ekvall et al., 2005, Weidema et al., 1999, Ekvall, 1999, Azapagic, 1996. ...
Over the past few decades, world-wide interest in environmental, social and economic preservation has involved researchers in a great challenge to find new approaches to manage the impact of human activities. This challenge has significantly impressed the construction sector, as a considerable educator of its surrounding society. The concept of Sustainability has called for a variety of debates and efforts to develop methodologies and tools in order to manage the human social, environmental and economic impacts during the process of buildings’ construction, service-life, and disposal. This book presents the key aspects of sustainable building design, resulted by ten years of research work, conducted by the author, in Practical Factors of Sustainable Design and Decision-making such as Time-Based Architecture and Building Life Cycle Assessment (BLCA). Furthermore, it argues the Regenerative Design, as a more recent concept which intends in going further than Sustainability. This concept, goals not only to save the existing world but to recover the previous damages to the society, environment and economy, caused by the process of industrialisation. Moreover, it intends in development of the new potentials to deal with future social, environmental and economic changes. Hence indeed, the book presents a side-by-side comparison between Conventional BLCA (to be sustainable) vs. Regenerative BLCA (to be regenerative).
... The assessment begins with the raw materials input, proceeds through the manufacturing processes, energy use, maintenance, and transportation. It considers use, reuse, and recycling, and concludes with waste management, the environmental impact of packaging, and ultimate disposal of the product (Azapagic, 1996). LCA provides an adequate instrument for environmental decision support. ...
... It was suggested by IFP in the late 1970s (Leprince et al., 1981). It was the subject of the thesis of Azapagic (1996) 4 who analyzed its potential contributions and computation methods by linear programming. Yet, surprisingly, she does not seem to ask the question as to the extent to which the marginal contents of emissions concerned could constitute a means of allocation of all the emissions. ...
The risks of climate change are pressing the refining industry to minimize its greenhouse gas emissions, and chiefly CO2. To gain a closer understanding of these emissions, Total and IFP have joined hands to develop an appropriate linear programming model, tested on a French refinery. One element of the study addressed the problem of allocating CO2 emissions to the different refinery products. An infinite number of allocation methods are available. The one proposed by the authors, who demonstrate its relevance, is based on the calculation of a "marginal emissions content" of each product, which can be determined by linear programming models. The authors (using a very simple "theorem") identify the conditions in which marginal contents have an average content structure, and go on to provide details about the results obtained.
... Modelling complex material systems has also been carried out using linear programming (LP) techniques. In the case where relationships between activities in the material system in question and environmental burdens is linear, this approach may appropriate for several reasons (Azapagic 1996). Firstly, modelling the whole product system using linear programming allows for interactions between different parts of a multi-component system with multiple-outputs. ...
The authors develop a methodological framework for the environmental assessment of materials recycling systems. Typically such systems exhibit both dynamic and non-linear behaviour. By contrast, many existing environmental assessment techniques (such as Life Cycle Assessment and Materials Flow Analysis) employ a static linear model of the underlying system. This paper first reviews some of the attempts to develop dynamic non-linear models for materials systems. It then discusses the structural peculiarities of recycling systems drawing attention in particular to the presence of dynamic features (such as time lags between production and disposal) and non-linearities (such as the dependency of scrap collection energies on the flow of material through the recycling loop). The principal analytic task of this paper is to construct an illustrative case study, in which different modelling techniques are used to assess the energy requirements of a hypothetical recycling system possessing both dynamic and non-linear features. The difference in system energy intensity derived using the different types of model are analysed. Finally, the paper discusses the policy implications of these results.
... More precisely, the sum of the products of every marginal equivalent investment cost times the quantity of the corresponding finished product produced is equal to the equivalent investment cost (and similarly for marginal operating costs). This breakdown is made using a very simple idea on duality in linear programming (presented in the form of a theorem), which was initially formalized by Babusiaux [2] for allocating CO 2 emissions from a refinery to the various oil products produced (developing suggestions by [1] and [5]). ...
In linear programming, a simple observation on duality allows us to break down a long-run marginal cost into a marginal operating cost and a marginal equivalent investment cost. This marginal equivalent investment cost is an acceptable means of allocating the equivalent investment cost to the different finished products (and similarly for the marginal operating cost). It is useful for determining the products on which a sales campaign should focus and for analyzing short-run marginal costs once an investment decision has been taken. As an example, we will examine a simplified investment model in the oil refining industry.
... Allocation was brought to the attention of the LCA community during its early development era (see, e.g., Heijungs et al. 1992;Huppes and Schneider 1994;Lindfors et al. 1995;Azapagic and Clift 1999). By the late 1990s, international standards were published that included specifications for allocation (ISO 1998), and a number of Ph.D. theses were published that focused on allocation aspects (see, e.g., Azapagic 1996;Frischknecht 1998;Ekvall 1999). In the course of the concept's development in the 1990s, the LCA community recognized two major classes of allocation methods: the partitioning method, and system expansion (Frischknecht 2000;Ekvall and Finnveden 2001;Guinée et al. 2002). 1 In the partitioning method, inputs and outputs of a process are assigned to its multiple products according to a ratio based on the economic value of the products (Huppes 1994), internal cost accounting principles (Frischknecht 1998), or any other factor that is considered to represent the relative share of responsibility. ...
Allocation in life cycle inventory (LCI) analysis is one of the long-standing methodological issues in life cycle assessment (LCA). Discussion on allocation among LCA researchers has taken place almost in complete isolation from the series of closely related discussions from the 1960s in the field of input−output economics, regarding the supply and use framework. This article aims at developing a coherent mathematical framework for allocation in LCA by connecting the parallel developments of the LCA and the input−output communities. In doing so, the article shows that the partitioning method in LCA is equivalent to the industry-technology model in input−output economics, and system expansion in LCA is equivalent to the by-product-technology model in input−output output economics. Furthermore, we argue that the commodity-technology model and the by-product-technology model, which have been considered as two different models in input−output economics for more than 40 years, are essentially equivalent when it comes to practical applications. It is shown that the matrix-based approach used for system expansion successfully solves the endless regression problem that has been raised in LCA literature. A numerical example is introduced to demonstrate the use of allocation models. The relationship of these approaches with consequential and attributional LCA models is also discussed.
... Many books and papers which discuss the principles of life cycle inventory analysis describe the allocation problem as the fact that one process provides more than one valuable function (see, for instance, CONSOLI et al., 1993;HUPPES & SCHNEIDER, 1994;LINDFORS et al., 1995;ANONYMOUS, 1998 andAZAPAGIC, 1996). This then immediately offers a starting point to discuss solutions to the allocation problem: the multi-function process must be split into a number of virtual processes by means of so-called allocation factors, or a process must be subtracted from the product system so that the coproduced function avoids that some other system produces it. ...
One of the remaining important problems of life cycle inventory analysis is the allocation problem. A proper solution of this
problem calls for a proper understanding of the nature of the problem itself. This paper argues that the established definition
of the allocation problem as the fact that one unit process produces more than one function, is not appropriate. That definition
points to an important reason of the occurrence of the problem, but the situation of internal (closed-loop) recycling already
indicates that there may be product systems which contain multifunction processes, but which nevertheless need not exhibit
an allocation problem. The paper proceeds by examining a number of simple hypothetical cases, and proposes a precise and operational
definition of the allocation problem. This enables a systematic categorization of approaches for dealing with the allocation
problem.
... They also state that marginal data are to be used where relevant to describe the consequence of a decision. Consequential approaches to allocation problems are presented by, for example, Azapagic (1996), Azapagic & Clift (1999), Weidema (2000), Ekvall (2000b), and Ekvall & Finnveden (2001). A procedure for identifying marginal data is described by Weidema et al. (1999). ...
Goal, Scope and BackgroundA consequential life cycle assessment (LCA) is designed to generate information on the consequences of decisions. This paper
includes a comprehensive presentation of the consequential approach to system boundaries, allocation and data selection. It
is based on a text produced within the SETAC-Europe working group on scenarios in LCA. For most of the methodological problems,
we describe ideal methodological solutions as well as simplifications intended to make the method feasible in practice.
MethodWe compile, summarize and refine descriptions of consequential methodology elements that have been presented in separate papers,
in addition to methodological elements and general conclusions that have not previously been published.
Results and ConclusionsA consequential LCA ideally includes activities within and outside the life cycle that are affected by a change within the
life cycle of the product under investigation. In many cases this implies the use of marginal data and that allocation is
typically avoided through system expansion. The model resulting from a consequential life cycle inventory (LCI) also includes
the alternative use of constrained production factors as well as the marginal supply and demand on affected markets. As a
result, the consequential LCI model does not resemble the traditional LCI model, where the main material flows are described
from raw material extraction to waste management. Instead, it is a model of causal relationships originating at the decision
at hand or the decision-maker that the LCI is intended to inform.
... If the prospective methodology were to be preferred for this application, a long-term solution would be to develop a theoretical foundation for detailed prospective LCAs and then try to establish a standard based on this foundation. This article can be regarded as one contribution, among others, to such a solution [21,22,45,46]. ...
Prospective life cycle assessment (LCA) provides information on the environmental consequences of individual actions. Retrospective LCA provides information about the environmental properties of the life cycle investigated and of its subsystems. In this paper we analyse the links between the choice of methodology and different theories of normative moral philosophy. The choice of electricity data in an LCA of a conference site with local hydropower production is discussed as an illustration. The two types of LCA can be related to different theories on the characteristics of a good action. Each type of LCA, as well as each of the moral theories, can be criticised from the alternative point of departure. Decisions based on retrospective LCA can have environmentally undesirable consequences. On the other hand, prospective LCA can appear unfair and result in environmentally sub-optimised systems. Both types of LCA also have methodological limitations. We cannot conclude that one type is superior to the other, but the choice of methodology should be consistent with the information sought in the LCA.
... Therefore, we have chosen to leave the elaboration of this class of choices to other projects. We think that the approaches that have been developed by Azapagic (1996) and by Weidema et al. (1999) may particularly be useful for LCAs with occasional choices as a starting point. Strategic choices, on the other hand, call for an approach that would draw more heavily on elements of scenario analysis and partial or general equilibrium modelling. ...
The life cycle assessment (LCA) guide of Heijungs et al. has been renewed to the latest methodological developments, aiming to make the ISO 14040 series on life cycle assessment operational. For this, a closer look was taken at intended applications in relation to required and practicable modelling options. Applications determine the required theoretical model, but the theoretical model required often comes into conflict with the available practical models and the needed operationality for decision support. To ease the tension between these requirements, simplifications need to be made in a guide on LCA. Two levels of sophistication have been worked out in the new guide documents: a detailed LCA with some options for extensions, and a simplified version.
... Examples of the application of MOO in LCA or in conjunction with LCA-based environmental indicators include e.g. Azapagic (1996), Azapagic and Clift (1998), Stewart (1999) and Alexander et al. (2000). However, the focus of this thesis is on MADA methods due to the fact that MOO is not associated with the typical LCIA problems in which the alternatives have been predetermined. ...
Life cycle assessment (LCA) is a popular tool for evaluating environmental impacts of products and services. However, the methodological choices and framework to assess environmental impacts in LCA are still under discussion. Despite intensive development worldwide, few attempts have been made hitherto to systematically present the theoretical bases of life cycle impact assessment (LCIA). In this study, the decision analytic foundations for LCIA are illustrated. It is shown that the typical aggregation equation used in LCIA for calculating indicator results can be derived from multiattribute value theory (MAVT) if certain simple assumptions hold. The decision analysis framework presented in this work offers additional values for all the phases of LCIA. A value tree, a tool used for structuring multicriteria decision making problems, can be helpful for selection of impact categories and classification. MAVT can clarify the debate concerning marginal and average approaches in the determination of characterisation factors. On the basis of MAVT, normalisation is needed before weighting. The methods and experiences of preference elicitation derived from the field of decision analysis can be utilised in the determination of subjective characterisation factors and impact category weights. Furthermore, experiences and techniques for the sensitivity analysis of multi-criteria decision models can be utilised in LCIA. In addition, MAVT assists in the calculation of impact category indicator results and total impact indicator results according to the appropriate aggregation equations. The decision analysis framework presented in this work is flexible and suitable for different impact assessment approaches developed in LCIA and it can help the methodological development with which the non-linearity aspects of impact assessment are taken into account. It is shown in the work that site-dependent characterisation methods can easily be fitted into the framework. In a case study of the Finnish forest industry a Finland-specific impact assessment model utilising the results of other tools, such as air quality and transport models and even expert judgements, was developed. In addition, the so-called ratio estimation method for the elicitation of impact category weights was applied and developed so that interval-valued ratio judgements could be used in the uncertainty analysis of the model. In the case of the Finnish metals industry, decision analysis impact assessment was applied to produce a solution in which global, regional and local environmental problems were assessed in the same framework. In both case studies, experts working with the environmental issues valuated impact category weights with the help of decision analysis techniques. In the work it was shown that MAVT provides a foundation for a logical and rational approach to impact assessment in LCA. In the future, there is a need to demonstrate quantitatively the differences between LCIA conducted according to MAVT and according to current practices. Furthermore, there is a need for research to study the strengths and weaknesses of the different decision analysis methods for LCIA purposes. Research reports / Helsinki University of Technology, Systems Analysis Laboratory. A, ISSN 0782-2030; 86
... At the material/product life cycle scale, both MIM and Rio Tinto are increasingly interested in life-cycle based approaches in their operations. For example, MIM (in conjunction with Britannia Refined Metals, one of its subsidiary companies) is undertaking a life-cycle based environmental assessment of its lead product stream (Robertson et al., 1997), and individual commodity groups at Rio Tinto (borates and copper) are examining the flow of their products in the physical environment related to anthropogenic and natural processes (Azapagic, 1996). However, as noted above, at present recycling of products is not a primary interest of MIM or Rio Tinto, reflecting the historical core competencies of these companies in minerals and metals extraction. ...
The sustainability concepts of the "Brundtland-Report" and the "Rio documents" call for a combination of ecological, economic, social and institutional aspects of social development. This paper describes briefly, several models of sustainability and discusses social sustainability as conceptualised in selected sustainability indicators. In an attempt to remedy the lack of sociological theory, the paper proposes a sustainability concept, which is based on the concepts of needs and work, as an activity to fulfil these needs and as the principal exchange process between society and nature. Moreover, this paper argues in favour of recognition of social sustainability as both a normative and analytical concept.
... financial, technical and/or social issues) and/or to provide an overall indication of the performance of a set of alternatives to facilitate decision making [e.g. Azapagic, 1996;Alexander, et al., 2000]. For discrete decision problems (i.e. ...
This paper presents an approach for the integrated consideration of both technical and valuation uncertainties during decision making supported by LCA-type environmental performance information. Key elements of this approach include "distinguishability analysis" to determine whether the uncertainty in the performance information is likely to make it impossible to distinguish between the activities under consideration, and the use of a multivariate statistical analysis approach, called principal components analysis (PCA), which facilitates the rapid analysis of large numbers of parallel sets of results, and enables the identification of choices that lead to similar and/or opposite evaluations of activities. The integrated approach for the management of uncertainty is demonstrated for a technology selection decision for the recommissioning of a coal-based power station. Distinguishability analysis showed that it was not possible to obtain a conclusive answer with regard to the preferred technology due to the extensive uncertainty in the LCA-based environmental performance information. PCA of the ranking of the design scenarios demonstrated that valuation uncertainties associated with choices made during intra- and inter-criterion preference modelling had a more significant effect on the ranking of the design scenarios than the inclusion/exclusion of environmental indicators reflecting local concerns or the choice of the position of the LCIA impact indicators in the cause-effect network. The results suggest that stakeholder involvement in intraand inter-criterion preference modelling is important, and that the "encoding" of value judgements and preferences into LCA environmental performance information is to be avoided. As a whole, the paper supports a call for diversity...
In diesem Kapitel wird das Vorgehen in der Sachbilanz, der zweiten Phase der Ökobilanz, beschrieben. Zu diesem Zweck werden zunächst die in einem technischen Prozess auftretenden Energie- und Stoffflüsse charakterisiert und klassifiziert (Abschn. 3.2). In Abschn. 3.3 werden die mathematischen Grundlagen der Ökobilanzmodellierung beschrieben und in Abschn. 3.4 deren Verknüpfungen zu Produktsystemen erläutert.
Life Cycle Activity Analysis (LCAA) combines classical Activity Analysis with environmental Life Cycle Assessment (LCA). It provides a structured approach to economic and environmental optimization of the entire supply chain of products, processes or services. LCAA considers all activities from “cradle to grave” including alternative methods of production, distribution, reuse and recovery. This paper builds on the previous work by the authors and applies the LCAA approach to assess alternative end-of-life options for plastic components used in electronic equipment. The environmental and economic consequences associated with these end-of-life options, such as remanufacturing, mechanical recycling, feedstock recycling and incineration, are evaluated for the entire supply chain and opportunities for closing the material loop are highlighted. A mathematical programming model is formulated and solved numerically to determine the optimal supply chain configurations for several scenarios. Solutions are proposed which reduce both environmental and economic impacts when compared to current practice.
Although Life Cycle Assessment (LCA) has been developed primarily as a tool for product development and comparison, it has much wider scope. This paper addresses the application of LCA to the selection, design and optimisation of process operations, with examples from the chemical, water and mining sectors. Of particular interest is the problem of reconciling incommensurable environmental impacts - known as the “valuation” problem - in LCA. For optimisation problems, rather than attempting to reduce impacts to a single metric constituting the objective function, the non-inferior (or “Pareto”) surface can be used to define the space within which optimal solutions lie, and thus to provide the basis for implementing environmental improvements in process design and operation.
The new millennium marked a new Knowledge-Based Society (KBS), which mainly consists of the non-material software and technology. In this paper is given analysis and architecture for the Environment Information System EnvIS), analysis, review and architecture of the system to support decision-making for the Environment (EDSS) and the analysis, review and architecture of software tools for life cycle assessment (LCA).
How to cite this article:
Dašić, P.; Nedeff, V. and Petropoulos, G.: Software systems and management technology in environment. Plenarno predavanje i rad po pozivu. U: Zborniku radova 1. naučne konferencije Ekološka bezbjednost u postmodernom ambijentu, Knjiga 1: Rapovi po pozivu i plenarna predavanja, Banja Luka (Republika Srpska), 26-27. jun 2009. Banja Luka (Republika Srpska): Panevropski APEIRON univerzitet, 2009, str. 53-66. ISBN 978-99955-49-06-0.
A preliminary Life Cycle Assessment (LCA) of nuclear-based hydrogen production via thermochemical water decomposition is presented. The copper-chlorine (Cu-Cl) thermochemical cycle is considered in the LCA, which examines the environmental impacts of the nuclear plant and the thermochemical hydrogen production plant. The environmental impacts from the thermochemical plant are determined by examining data and applying several assumptions on inventories of raw materials and chemicals. The results indicate that the nuclear fuel cycle contributes significantly to the total environmental impacts, and the improvement analysis stage of LCA suggests the need for the development of more sustainable processes, particularly in the nuclear plant.
One of the main potential uses of life cycle assessment (LCA) in environmental management is for identifying options for environmental improvements of a system in which complete supply chains are considered. The main problem, however, lies in finding the optimum improvement strategies and choosing the best alternative in a decision environment with multiple, and often conflicting, objectives. To aid the decision-making process, this paper proposes the use of multiobjective optimisation (MO), whereby the system is simultaneously optimised on a number of environmental objective functions, defined and quantified through the LCA approach. This results in a Pareto or noninferior surface, with a range of environmental optima, from which the best compromise solution for improving the environmental performance of the system can be chosen. However, system improvements cannot be based solely on environmental considerations and other factors, including socio-economic, must be considered in parallel. This paper also shows that MO coupled with LCA provides a powerful tool for balancing environmental and economic performance, thus enabling the choice of best practicable environmental option (BPEO) and best available technique not entailing excessive cost (BATNEEC). The value of this approach in environmental system analysis lies in providing a set of alternative optimal options for system improvements rather than a single prescriptive solution, which may be optimal but not necessarily appropriate for a particular situation. A decision–aid tool–optimum LCA performance (OLCAP)–has been developed for these purposes. OLCAP is tested and demonstrated by application to a case study of an existing mineral-processing system producing boron products. It is shown that LCA can successfully be combined with optimisation techniques to satisfy both economic and environmental criteria for more sustainable performance of the product system over the whole life cycle.
Environmental Life Cycle Assessmen (LCA) of products has become an important tool for assessing the environmental impact of products and services from cradle-to-grave. One of LCA’s Leitmotivs is to get a full picture of the impacts of a product or service in order to find the best solutions for their improvement without shifting the impacts to other fields. LCA has become a core topic in the field of environmental management. In this article, the topic of LCA is introduced. The focus is on a discussion of LCA methodology. The four methodological phases (goal and scope definition, inventory analysis, impact assessment, and interpretation) are explained. Steps distinguished within each phase are discussed with respect to methodological issues. These issues are illustrated with brief examples. Aspects of data, software, and procedures are separately discussed. Finally, LCA applications and the future of LCA are addressed.
Background, aim and scopeThe reliability of the results of Life Cycle Assessment (LCA) studies is highly dependent on the appropriateness of the data
that are used for Life Cycle Inventory (LCI) modelling. In practice, the modelling of background systems is commonly based
on generic data—which are often outdated and rarely provide information on the current situation in a representative manner.
Meanwhile, an increasing number of policy directives, international agreements and national legislations to regulate the reporting
of environmentally relevant data for companies and economies entered into force over the past few years. The purpose of this
study is, therefore, to compare data reported in such a manner from selected sources with detailed existing generic LCI data
and to evaluate their usability as a reference for LCI modelling on a unit process level. Depending on the scope of the selected
reports, the study reflects considerations on a national scale.
Materials and methodsSelected data from an existing LCI study are compared with data from environmental reporting approaches, in order to analyse
the degree of variation between generic data and related reporting data. Two selected reporting obligations are described
in more detail and characterised methodologically from the LCI perspective: (1) the ‘United Nations Framework Convention on
Climate Change’ (UNFCCC) and (2) the European Union’s Directive on ‘Integrated Pollution Prevention and Control’ (IPPC). The
national data that can be derived from these two reports are compared with generic LCI data provided by the ‘Environmental
Profile Report for the European Aluminium Industry’ from European Aluminium Association (EAA).
ResultsThe number of processes and elementary flows is originally different across the three data sources due to divergent system
boundaries. Therefore, in order to perform the comparison against a common reference, the analysis is done at a unit process
level: only the emissions featured in all three sources are analysed (i.e. emissions of CO, CO2, PFCs and SO2 resulting from anode production, electrolysis and cast house). The comparison of data from this limited number of processes shows differences across the three data sources.
DiscussionA key reason for the differences is the divergent scopes considered in the different data sets (i.e. geographical coverage
and time period). Still, despite the differences in scale and scope, the deviation between the data from IPPC and EAA is found
to be within reasonable and acceptable margins—especially when also the different technological conditions are considered.
Thus, the dataset of EAA is judged to be reliable—within its original scope. However—with the exception of PFCs—the differences
between the data from the EAA report and those derived from UNFCCC cannot be explained this way.
ConclusionsThis study exemplifies drawbacks and opportunities of the usability of data from environmental reporting as a national reference
for existing LCI data. By comparing reporting data and existing LCI data, deviations can be explained and inappropriate or
outdated data can be detected. For this procedure, knowledge about temporal coverage and individual system boundaries of the
data is required. Also, expert knowledge about the processes themselves and technologies applied within these is indispensable,
in order to explain differences between data sources.
Recommendations and perspectivesFrom an LCA perspective, the referencing of generic LCI data provides an important informative basis to focus data collection
and update. However, inconsistencies due to the limited amount of elementary flows covered in reporting still need to be resolved—keeping
in mind the individual aim of the study. Additional data from upcoming Pollutant Release and Transfer Registers provide a
promising perspective.
This paper uses an industrial case study of a boron system producing five co-products to examine different allocation methods
recommended by ISO 14041 and compare them with the allocation methods most commonly used by LCA practitioners. In particular,
allocation by physical causality is discussed. The paper illustrates how the use of whole system modelling can help to identify
the correct type of causality for allocation. The case examined here concerns marginal changes of product-related parameters
in the system, in this case represented by the output of boron co-products. The analysis shows that in some cases it can he
correct to allocate the burdens on the basis of a simple physical quantity, such as mass, as long as the allocation parameter
is based on physical causation and is not chosen arbitrarily. In whole system modelling, the correct causality is identified
by the model itself, so that the possibility of allocation by an arbitrary parameter is avoided. However, as for system disaggregation
and expansion, allocation through mathematical modelling may only be possible if detailed data for the system are available.
This paper explores the use of LCA as a tool for process environmental management, thereby moving the focus from product to process oriented analysis. The emphasis is on Improvement Assessment in which the “hot spots” in the system are targeted for maximum environmental improvements. In this context, it is useful to use multiobjective optimisation which renders Valuation unnecessary.
The approach is illustrated by the case study of the system processing boron ores to make five different products. The results of Inventory Analysis and Impact Assessment are presented and discussed. In Improvement Assessment, a number of improvement options are identified and evaluated, using system optimisation. It is shown that the site environmental performance can be improved over current operation by an average of 20% over the whole life cycle. Thus the study demonstrates that the optimisation approach to environmental process management may assist in identifying optimal ways to operate a process or plant from “cradle to grave”. This may help the process industries not only to comply with legislation but also provide a framework for taking a more proactive approach to environmental management leading to more sustainable industrial operations and practices.
Linear Programming (LP) is a powerful mathematical technique that can be used as a tool in Life Cycle Assessment (LCA). In
the Inventory and Impact Assessment phases, in addition to calculating the environmental impacts and burdens, it can be used
for solving the problem of allocation in multiple-output systems. In the Improvement Assessment phase, it provides a systematic
approach to identifying possibilities for system improvements by optimising the system on different environmental objective
functions, defined as burdens or impacts. Ultimately, if the environmental impacts are aggregated to a single environmental
impact function in the Valuation phase, LP optimisation can identify the overall environmental optimum of the system. However,
the aggregation of impacts is not necessary: the system can be optimised on different environmental burdens or impacts simultaneously
by using Multiobjective LP. As a result, a range of environmental optima is found offering a number of alternative options
for system improvements and enabling the choice of the Best Practicable Environmental Option (BPEO). If, in addition, economic
and social criteria are introduced in the model, LP can be used to identify the best compromise solution in a system with
conflicting objectives. This approach is illustrated by a real case study of the borate products system.
Allocation in joint production is still one of the unresolved and often discussed methodological issues in Life Cycle Inventory
Analysis. Using the many years of experience of man agement sciences, a new classification scheme is proposed. It is postulated
that companies perform allocation in joint production in view of optimising the products’ performance (economic and/ or environmental),
which helps them to maximise their profits. Therefrom it is derived that value judgements and negotiations are inevitable.
The proposed classification scheme differentiates between the number of decision-makers involved, and the type of markets
for joint products. Several decision-makers have to find fair allocation factors for their commonly operated joint production,
whereas individual decision-makers may choose allocation factors considering the (economic and/ or environmental) competitiveness
of their joint products. Applied on the case of a small-scale gas-fuelled combined heat and power plant, the methodology proposed
shows a strong dependency on the disutility function, i.e., private costs, environmental damage costs or a combination of
the two.
Allocation of environmental burdens is a recognised methodological problem in Life Cycle Assessment (LCA). It is the process of assigning to each of the functions of a multiple-function system only those environmental burdens and impacts that each function generates. It is argued in this paper that allocation is an artifact of applying LCA to individual products rather than to the whole productive system. To solve this problem, a new “marginal allocation” approach is proposed, based on whole system modelling. Marginal allocation is applicable when marginal changes about some defined state of the product system are to be considered and when the functional outputs can be varied independently. The specific approach developed here is based on representing the system by a model in the Linear Programming (LP) format. The allocation coefficients are equivalent to the marginal values calculated at the solution of the LP model. Marginal values represent a realistic description of the causal relationships between burdens and functional outputs and thus reflect the behaviour of the system. Changes in the system behaviour can also be modelled by LP. The approach is illustrated on three simple examples of multiple-function systems: combined waste treatment, co-production and recycling.
This paper presents an approach for the integrated consideration of both technical and valuation uncertainties during decision making supported by environmental performance information based on Life Cycle Assessment (LCA). Key elements of this approach include “distinguishability analysis” to determine whether the uncertainty in the performance information is likely to make it impossible to distinguish between the activities under consideration, and the use of a multivariate statistical analysis approach, called principal components analysis (PCA), which facilitates the rapid analysis of large numbers of parallel sets of results, and enables the identification of choices that lead to similar and/or opposite evaluations of activities. The integrated approach for the management of uncertainty is demonstrated for a technology selection decision for the recommissioning of a coal-based power station. The results of the case study decision suggest that stakeholder involvement in preference modelling is important, and that the “encoding” of value judgements and preferences into LCA environmental performance information is to be avoided. The approach presented in this paper provides a foundation for the consideration of the implications of diversity in values and preferences as part of an overall approach to promote effective decision making based on LCA environmental performance information. However, the approach is more universally applicable – it can be used wherever multiple criteria decision analysis is used to assist in the resolution of complex decision situations.
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