=Paper=
{{Paper
|id=Vol-2945/52-RW-ConfWS21_paper_16
|storemode=property
|title=Integrating Sustainability Information in Configurators
|pdfUrl=https://ceur-ws.org/Vol-2945/52-RW-ConfWS21_paper_16.pdf
|volume=Vol-2945
|authors=Robin Wiezorek,Noemi Christensen
|dblpUrl=https://dblp.org/rec/conf/confws/WiezorekC21
}}
==Integrating Sustainability Information in Configurators==
https://ceur-ws.org/Vol-2945/52-RW-ConfWS21_paper_16.pdf
Integrating Sustainability Information in Configurators
Robin Wiezorek1 and Noemi Christensen1
Abstract. Consumers are increasingly demanding sustainability in- In the context of MC, product configurators are often used to de-
formation for products. Thus, pressure on companies increases to termine feasible combinations of product components [13]. It seems
evaluate the sustainability of their products and supply the infor- appropriate to utilize these configuration solutions for the provision
mation in an appropriate way. The complexity of sustainability as- of sustainability information as well, since central information on the
sessments, especially in the ecological dimension, poses a specific prod. However, these lack a methodology on how to deal with the
challenge for Smart and Medium Enterprises (SMEs), which only complexity of conducting a sustainability assessment for MC prod-
increases in the context of Mass Customization (MC) products due ucts and to provide the results to the user in a comprehensible man-
to the large number of variants. Product configurators hold the po- ner.
tential to answer both challenges of sustainability assessment and We address this question while adopting some limitations. Sus-
presentation of its results by taking advantage of the product model tainability can be divided into three dimensions: economic, ecolog-
knowledge. ical, and social [20]. We focus on the ecological dimension by only
For this, we suggest extensions of the classical configurator archi- considering the Ecological Scarcity Method (ESM) as a Life Cycle
tecture in the areas of data integration, processing, and user interfaces Assessment (LCA) method. The ESM has been developed in close
to expand configurator functionalities for sustainability information cooperation with industry partners which makes it less complex than
integration. The assessment process, illustrated by the example of the other LCA methods [2].
Ecological Scarcity Method (ESM), is guided by ISO standards for The paper proceeds by providing a theoretical background on the
Life Cycle Assessment (LCA), but is not strictly adhered to, as there areas of LCA and the respective ISO norms, explains the ESM and
are currently no procedures for specifically assessing MC products. how generic data is available in the sustainability database ecoinvent,
The extension of the configurator enables the modeler to perform and details the basics on product configurators. Then, an overview
the LCA directly within the configurator. Allocation of sustainability on the current state of research of configuration and sustainability
values is a main challenge both regarding assessment of product char- is given. Building on these foundations, we propose an extension
acteristics and comprehensibility of results for users. Configurators of classic configurator system architecture and outline how a sus-
can aid in providing sustainability information to users for MC prod- tainability assessment process within the system can be carried out.
ucts during the configuration process, but many questions related to Based thereon, challenges related to mapping the sustainability val-
the assessment of large product variant spaces remain. ues and LCA-related challenges are discussed in the context of MC
product configuration.
1 INTRODUCTION
Sustainability is understood as a principle of action in which re- 2 THEORETICAL BACKGROUND
sources are only used to the extent that their natural regenerative
capacity is not restricted [19]. This ensures that future generations 2.1 Sustainability Assessment
will also be able to meet their needs by means of the available re-
LCA is the best-known method for evaluating the environmental im-
sources [26]. A large proportion of environmental problems result di-
pact of a product system, taking into account its entire life cycle [22].
rectly or indirectly from people’s consumption behavior [30]. There-
The result of an LCA supports decision-making, the improvement of
fore, consumers can make a significant contribution to environmental
products and processes, and communication regarding ecological as-
protection by deciding to buy more environmentally friendly prod-
pects [10]. The publication of LCA information is mandatory since
ucts. However, this requires companies to provide information about
March 2017 for publicly traded companies with more than 500 em-
the sustainability of their products. Unfortunately, this is still not
ployees according to the Corporate Social Responsibility Directive
widespread nowadays.
Implementation Act in Germany [4, 15]. The framework for con-
For companies that produce standardized mass products, the as-
ducting life cycle assessments are described in the ISO standards
sessment of sustainability is limited to a few products. In the area of
14040 and 14044. According to these, an LCA is divided into four
Mass Customization (MC), on the other hand, a single product has a
phases [10, 11]:
large number of variants [32]. Therefore, assessing the sustainability
of each possible product variant is necessary. However, due to the 1. Goal and Scope Definition: the system to be investigated, its sys-
high number of variants and the complexity of the methods, carry- tem boundary and the necessary level of detail are determined.
ing out an individual sustainability assessment for each variant can 2. Inventory Analysis: all inputs and outputs of the system are spec-
hardly be considered feasible in practice, especially not for SMEs ified.
with limited resources [12]. 3. Impact Assessment: based on the inventory analysis, the environ-
mental impact of the system is determined in the form of indicator
1 CAS Software AG, Germany, email: noemi.christensen@cas.de
values.
Copyright 2021 for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0)
4. Interpretation: the results of the inventory analysis and the impact national level by the Federal Environment Agency, and at the supra-
assessment are discussed and recommendations are made on the national level by decisions of the European Union [1]. The scarcity
basis of the initially defined objectives. situation of the environment in a region is described by eco-factors,
which represent weightings for resource consumption or pollutant
The inventory analysis records all material and energy flows that emission [25]. Typical eco-factors are, for example, the consump-
cross the system boundary and are thus added to or removed from tion of energy resources or the emission of greenhouse gases [17].
the system [16]. In order to make the inventory analysis practically By multiplying the inputs and outputs determined during the inven-
applicable, individual inputs and outputs may be neglected under cer- tory analysis with their corresponding eco-factors, their environmen-
tain conditions [10]. The extent to which this is allowed depends pri- tal impact is determined. Thus, the result is provided in a single
marily on the objective as well as on the required level of detail of the value: Eco-Points (EP). The more resources are consumed or pol-
LCA and is defined by cut-off criteria. These indicate which inputs lutants emitted, and the more acute their local scarcity situation is,
and outputs of the LCA are negligible due to their low influence on the higher are the EP.
the result. ISO 14044 lists mass, energy, and environmental relevance A significant advantage of the ESM is the simple handling of EP.
as possible cut-off criteria. These can be aggregated as desired, similar to business cost theory,
In practice, inputs and outputs often cannot be allocated to a single and allow structuring in hierarchies [1]. Aggregation is possible be-
product, but must be distributed among several products [11]. For this cause the EP are to be considered equivalent, as they provide infor-
purpose, allocation methods are used. ISO 14044 specifies a clear mation about the ”relative deterioration of the scarcity situation” [2,
procedure in three steps for the allocation of inputs and outputs that p. 6]: according to ESM, 10 EP resulting from the consumption of
cannot be clearly assigned [10]. First, if possible, allocation should freshwater have the same relevance for the environment as 10 EP
be avoided. In this case, the product system can either be further de- resulting from the emission of radioactive substances into the air.
tailed or extended. Second, if allocation cannot be avoided, inputs Thus, by means of the EP, a simple comparison of alternatives un-
and outputs should be allocated to products based on their physi- der ecological aspects can be carried out, which makes ESM highly
cal relationships. A frequently used physical relationship is the mass attractive for the application in the context of product configuration.
distribution of products [12]. Third, if an allocation on the basis of Another advantage of ESM is, that generic EPs for a large
physical relations is not possible, other relations should be searched. number of materials and activities are available in the ecoinvent
One possibility is the economic value of products [3]. database [31]. In its current version 3.6, which was published on
The LCA must be understood as an iterative process in which sys- September 12, 2020, the database contains 18,121 data records [8].
tem boundaries, influencing parameters, assumptions, and methods Each data record describes an activity that can occur in the life cy-
are continuously adjusted in order to ultimately achieve the most cle of a product. Data is offered as inventory analysis data as well
accurate estimate of environmental impact possible [11]. However, as fully evaluated LCA data. The ESM data belongs to the latter: for
its user-friendliness in practice is controversial [12]. SMEs in par- each activity, a generic impact assessment has been performed and
ticular often lack the human and financial resources to perform de- thus the environmental impact has been quantified.
tailed LCAs of their whole product portfolio [12]. Therefore, Feifel
et al. [12] see the LCA in a conflict of objectives between the sci-
entifically required accuracy and the feasibility and communicability 2.3 Product Configurators
of the results in practice. Furthermore, the LCA methodology leaves
room for interpretation, so that several LCAs of the same product can A product configurator is a software solution for the individual com-
come to different results [7]. position of a product from a set of predefined components [32]. A
configurator presents all possible components and applies rules to
check whether the current selection is feasible. During the configu-
2.2 Ecological Scarcity Method and Ecoinvent ration process, components can be selected according to the user’s
individual requirements towards the product.
A particularly important phase of an LCA is the impact assessment: Configurators are used wherever variant manufacturing is the pre-
this is when the the examined system’s influence on the environment dominant production type [13]. In variant manufacturing, each prod-
is evaluated. ISO 14044 does not specify a particular impact assess- uct belongs to a product family, which is characterized by a high
ment method, but merely states the requirements that such a method degree of similarity between its products [23]. Product families rely
must fulfill [10]. An overview of all scientifically recognized assess- on a modular design: their products have a common basic structure,
ment methods can be found in [16]. which can be customized with modules [14]. The high number of
In the context of this work, the ESM was chosen. A major rea- possible combinations results in a high level of complexity. Config-
son for this decision was that ESM has been developed specifically urators make this complexity manageable while at the same time ex-
for use in industry, which makes it stand out from other assessment ploiting the potential of customized products. In this context, the term
methods due to its simpler applicability [2]. It also meets the high sci- mass customization (MC) is often used [14].
entific demands placed on impact assessment in accordance with ISO Product configurators typically aim at users with a limited tech-
14040 [1]. Furthermore, awareness of the method and its dissemina- nical understanding. Thus they are confronted with the ambivalence
tion are increasing. For example, ESM is already used by legislators that, on the one hand, they must enable the user to configure the prod-
in Switzerland to assess sustainability activities and grant tax relief uct easily and, on the other hand, they must describe a product in a
based on the results [17]. technically complete manner so that it can be manufactured in pro-
ESM regards the environment as a limited resource. Every con- duction [32]. Therefore, the product model often consists of a sales
sumption of resources or emission of pollutants leads to a scarcity. model and a technical model [29]. The sales model is visible to the
For an examined region, the scarcity situation is determined by its user. It includes all features that can be configured by the user. The
current demands on the environment as well as its environmental pol- technical model, on the other hand, is not visible to the user. It in-
icy goals. In Germany, environmental policy goals are set both at the cludes all features that are necessary to describe a product, but which
2
cannot be selected directly by the user. The selection of these char- In the research domain associated more closely to MC, sustain-
acteristics is implemented over predefined rules, which represent the ability in general has already received some attention. Three main
relationship between sales and technical characteristics [29]. Regard- research streams have been identified [20]: the impact of mass cus-
ing the configuration interface, the two models are referred to in the tomization on sustainability, research on sustainable MC business
following as the sales view and technical view. models, and analyzing consumer decisions. The research and discus-
Product configurators usually consist of several basic components, sion on MC’s impact on sustainability is mostly focused on whether
which are described based on [13]. MC products actually have a better or worse sustainability assess-
The knowledge base brings together the domain knowledge from ment than mass production objects [6]. A majority of works includes
the various specialist areas and stores it in a product model. The prod- economic and social sustainability, while the ecological dimension is
uct model forms the basis for configuration. It contains the product only considered in a third of the analyzed cases [20].
structure in the form of components as well as rules on their compat- Few works actually deal with the question on how to assess the
ibility [24].The components are described by features and their char- sustainability of MC products. Boër er al. [5] present a very detailed
acteristics [28]. For example, the component ’seat’ has the features sustainability assessment model for MC products. It covers a mul-
’size’ and ’color’, whereof the latter has the characteristics ’black’ titude of indicators from all three sustainability dimensions. Due to
and ’blue’. Rules can describe both technical and economic relation- the selection of indicators, there is a stronger focus on the production
ships. Components with a common basic structure can be represented phase compared to other life cycle phases [20]. [5] present several
in an inheritance hierarchy, in order to reduce complexity and adjust- use cases on how to apply the developed assessment model, where
ment expenditure [28]. the main focus is on execution of the method, less on the techni-
The solver receives the product model from the knowledge base cal perspective of supporting the assessment. Furthermore, it aims at
on which the product configuration is to be performed. The task of evaluating the complete solution space of MC products, not at pro-
the solver is to compute valid configurations [32]. A configuration is viding sustainability information on individual configurations from
valid if it does not contradict any rules of the product model. that solution space.
On the configuration interface, the user creates a configuration by Hänsch et al. [21] present a preparatory approach for an LCA as-
selecting components and specifying their characteristics. This con- sessment of MC products with the help of Excel. They point out the
figuration is then sent to the solver for verification and the result is importance to communicate the results of the sustainability assess-
returned. Thus, the user gets direct feedback on their configuration ment for example by use of a configurator, but the realization of this
and can - if necessary - adjust it directly. suggestion is not within the scope of their work.
The modeling interface offers modelers the possibility to manage In summary, the problem landscape of sustainability and config-
the knowledge base. They bring together domain knowledge from the uration hast gained some attention in general, but few works have
areas of product management, sales, and marketing, and thus enrich addressed the question on how to make the results available for in-
the product model [14]. dividual product configurations for users. The need to make sustain-
ability information available to users has been acknowledged [27],
but insights on possible implementations are still scarce.
3 Literature on Configuration and Sustainability
Assessment
4 SUSTAINABILITY INFORMATION IN
The topic of sustainability information within product configuration
CONFIGURATORS
is starting to gain traction. There are a few works that specifically
deal with the integration of systainability information into product 4.1 System Architecture
configurators. In the most cases, the works deal with integrating a
specific indicator into the configuration [18, 27]. For example, Ganter The basic system architecture of product configurators needs to be
et al. [18] propose an approach to include information on Life Cycle extended in order to include sustainability information. The proposed
Costs (LCC) in product configuration for product-service-systems. extensions are illustrated in Fig. 1. Basic system components that
LCC belong to the economic dimension of sustainability. The ap- usually exist in a configuration solution, as presented in section 2.3,
proach allows users to consider their desired maintenance interval in are marked with an asterisk. The suggestions for extension in the con-
addition to technical requirements during product configuration. figurator system architecture were developed to allow an assignment
In addition to price as an economic indicator, Rousseau et al. [27] of LCA data to the product model. It is based on the assumption that
integrate the Global Warming Potential (GWP) as an ecological in- generic LCA data from a sustainability database, like the ESM activ-
dicator in their configurator for 3D printing applications. The imple- ities in ecoinvent, are used for the assessment of the product model.
mented product model is a 3D printed ship with variations to mate- The same two User groups are addressed by the proposed exten-
rial, print quality, and number of items. After entering all relevant sions: modelers and users. The former build the knowledge base of
input, the user is presented GWP for different time horizons and the the configurator, but now also perform the LCA within the config-
price. Regarding the low complexity of the product, it remains open urator. Whether these tasks can be performed by the same person
how well this approach can be transferred to products with a larger depends on the individual expertise with regard to product knowl-
number of variants. edge, modeling experience, and LCA expertise. Users benefit from
Erdle et al. [9] extend a configurator by a sustainability view. They the availability of LCA information during their configuration. It en-
identify eight relevant sustainability indicators covering all three sus- ables them to integrate sustainability information into their decision
tainability dimensions, that they assess as suitable for an SME con- process during configuration.
text. Within the product configuration it is then possible to weight A variety of Data is required for the integration of sustainabil-
the importance of the different indicators according to the individual ity information into product configurators. This includes the product
preferences. They neither report where the sustainability information model, product life cycle data, and LCA data. The product model is
is obtained from, nor how it is assigned to the product model. already given by the product knowledge base in product configura-
3
Figure 1. Extended configurator system architecture to enable sustainability assessment.
tors. It contains information about the product family with all its vari- the attribute.
ants. It represents all modules that must be evaluated within the scope
of the inventory analysis. The product life cycle data has the potential
4.2 Process for LCA within a Configurator
to enable the holistic assessment of a product from cradle-to-cradle
by providing information on each product life cycle phase. This data The starting point for the process is that the modeler creates a prod-
can for example come from ERP or PLM systems, and consist of uct model in the configuration knowledge base. If product life cycle
bills of materials or routings. The LCA data includes the sustainabil- information from other systems is to be integrated in the assessment,
ity activities that are used for inventory and impact assessment. It a suitable mapping of data needs to be implemented. For example, in
comes from sustainability databases, but can also be complemented the case of an ERP system, a mapping can be achieved by including
with own sustainability evaluations. the material numbers in the configuration knowledge base.
The Graphical Interfaces include extensions of the user interfaces By starting the LCA component, all relevant data from the knowl-
for modeling and product configuration. The extension of the mod- edge base, product life cycle data from integrated systems and unbal-
eling interface for the sustainability assessment allows the modeler anced sustainability activities from the sustainability database. Based
to define the inputs and outputs of a module over the entire life cy- on this data, the modeler performs an inventory assessment for mod-
cle. The definition of inputs and outputs is based on the unbalanced ules of the product model over the entire product life cycle. Suitable
sustainability activities provided by the sustainability database. The sustainability activities are selected and balanced by entering the cor-
modeler identifies the most suitable activities and balances them by responding quantities. This is the main activity in the sustainability
quantifying the flow of inputs and outputs that cross the system assessment process. After the modeler has created inventory analy-
boundaries. The configuration interface needs to be extended to dis- ses for the entire product model, impact assessments are conducted
play sustainability information. Further research is needed on how and the sustainability value for each characteristic is determined by
this can be realized in a way that it actually supports the user. For aggregation. When a product is configured, the sustainability values
example, as EP can be displayed as a single total value but also are displayed in the the user interface and recalculated for every con-
be decomposed into 18 dimensions, integrating sustainability indi- figuration step.
cators can add significant complexity to the information displayed in
the configuration. For example, displaying several sustainability im- 4.3 Mapping of Assessment to the Product Model
pact indicators from an LCA might be desirable from a holistic LCA
perspective. However, for a user, the complexity of this information The aim of the sustainability assessment in the product configurator
could be overwhelming. is to provide information on the sustainability of the configuration
The Processing assigns a sustainability value to each attribute in for the user. However, it must be taken into account that the sustain-
the product model. This value is calculated from the sum of the sus- ability assessment is carried out for features of both the technical and
tainability values of all balanced sustainability activities assigned to the sales model. But it must be considered that the consumption of
sustainability information takes place exclusively for the features of
4
Figure 2. Process for LCA within a configurator executed by a modeler.
the sales model. The features and thus also the sustainability values be shown to them. This contradicts the idea of reducing the complex-
of the technical model are not visible to the user. In order to make the ity of the sales-based model. However, if the user does not receive
complete sustainability assessment of a product configuration visible information about allocations of sustainability ratings that have been
to the user, the sustainability values of the technical model must be made, the sustainability values given can be incomprehensible and
transferred to the sales model. confusing. This is illustrated by the following example. Taken by it-
In principle, there are two cases in which sustainability values are self, a trailer coupling has a significantly lower sustainability value
assigned to features. First, there is the case in which the sustainability than an engine. However, if the sustainability value of the chassis
values are directly available in the sales view. This is always applica- is fully allocated to the sustainability value of the trailer coupling,
ble when an element is modeled directly in the sales view as a feature the trailer coupling suddenly has a significantly higher environmental
and therefore cannot be changed. This can, for example, apply to the impact than the engine. Secondly, when allocating the technical sus-
selection of car tires. The user can choose between summer, win- tainability values, the question arises as to how an allocation should
ter and all-season tires. However, she has no option to configure the be made. In many cases, it is practically impossible to make an allo-
tread depth or the rubber compound. These properties are predefined cation that is fair to the cause. For example, it is questionable how the
for the characteristic. sustainability value of the engine should be allocated to its properties
In the second case, however, the assignment is not possible di- fuel consumption and performance. This would require an isolated
rectly. In this case, the sustainability ratings refer to the technical consideration of the properties, which is hardly possible. Thirdly,
view, which means that the sustainability values are not visible to the ISO 14044 makes it clear that allocations - if possible - should be
user. This case always occurs when a characteristic is only modeled avoided [10].
in the technical model and its integration into the configuration is The second possibility is not to carry out an allocation, but to
thus implemented via rules defining the relationship with the sales assign the sustainability values of the technical characteristics to a
model. For example, the selection of a trailer coupling in the sales dummy feature created specifically for this purpose in the sales view.
model leads to the installation of a reinforced instead of a standard If only one such dummy exists for a product, which includes the sus-
chassis in the technical model in the background of the configuration. tainability values of all technical characteristics, the user can hardly
The question now arises how the sustainability ratings from the tech- understand how the sustainability rating of his product comes about.
nical model can be assigned to the sales model and thus made visible Therefore, the product is broken down into meaningful components,
and comprehensible to the user. Two principles can be identified for with each of these product components receiving its own dummy
the assignment: feature for allocation. This procedure is based on the system space
extension recommended in ISO 14044 [10], since the sustainability
• Causal Allocation: Only those sustainability values may be allo- rating of each technical characteristic is mapped to its correspond-
cated to a characteristic for which it is primarily responsible. ing sales-related product component. Thus, the allocation is cause-
• Comprehensible Allocation: The user must be able to understand appropriate. At the same time, the decomposition of the product into
how the sustainability value for a characteristic is formed. components allows the user to better understand the full impact of
One possibility is to allocate the sustainability values of the tech- a configuration step on the sustainability value based on the individ-
nical characteristics to the sales characteristics by means of an allo- ual product parts. The extent to which detailing makes sense depends
cation rule. This possibility must be rejected for three reasons. First, on the complexity of the product on the one hand and on the prod-
a user cannot understand the allocation. In order for users to under- uct knowledge and information requirements of the user on the other
stand the allocation of sustainability values from the technical model, hand.
the relationship between the different characteristics would have to
5
4.4 LCA-related Challenges these cases, the environmental impact must be allocated to the prod-
ucts involved. For this purpose, ISO 14044 prescribes an allocation
Due to the high complexity of LCA, there are several challenges according to the physical relationships between the products [10].
that make it difficult to apply the methodology in configurators in There are different physical relationships that can be considered for
practice. A key challenge is that a LCA must fully capture all inputs an allocation. Mass could be used because the information is proba-
and outputs of a product over its entire life cycle. A typical product bly available. Another possibility would be the use of volume, since
consists of thousands of sustainability activities, all of which must this is usually also mapped in the ERP system. Which physical rela-
be captured [31]. Another challenge is allocating the sustainability tion should be used for the allocation has to be decided by the mod-
value of processes involving multiple products. Solutions for these eler depending on the use case.
two complexities are presented below in the context of product con- If an allocation according to the physical relationships is also
figuration. As an aside, it should be noted that another challenge lies not possible, other relationships between the products must be
in the variety of enterprise processes possible in practice [31]. For found [10]. For this purpose, the economic value of a product can
example, several alternatives can exist for a process, which in the be used [3]. One way to determine the economic value would be to
end lead to the same product, but which differ greatly in terms of use prices. These are already available and easily accessible in sales-
their sustainability. Therefore, the use of process alternatives must related product configurators. However, it should be noted that these
be taken into account during the LCA. However, this aspect will not are usually assigned to the sales perspective and often value product
be dealt with in this paper. functions rather than technical modules. However, in order to use the
prices to determine allocation, it would be necessary for the prices to
4.4.1 Level of Detail in LCA be assigned to the individual technical modules, since it is for these
that the assessment is performed. Therefore, in general, the use of
A major complexity in the LCA of a product is that, in general, all
the product configurator prices for allocation should be avoided. A
its inputs and outputs have to be considered. One way to reduce the
better option is to use costs. These are also frequently mapped in
complexity is to define the required accuracy for the LCA, where
sales-related product configurators for the purpose of margin calcu-
ISO 14040 allows mass, energy, and environmental relevance as cut-
lation. In contrast to the prices, the costs are directly assigned to the
off criteria. Since the mass of individual materials is most probably
technical modules. Therefore, the costs can be used for the allocation
available from an existing ERP system, it is obvious to use the cut-off
of sustainability values.
criterion mass. If a material has a lower share in the mass of the prod-
uct than the cut-off criterion specifies, no LCA needs to be performed
for it. To verify the correct application of the cut-off criterion, a sen- 5 DISCUSSION
sitivity analysis must be performed according to ISO 14044 [10].
For the modeler, such an analysis is very time-consuming and can We analyzed integrating sustainability information into configurators
be classified as difficult to implement with regard to the target group in a way that enables SMEs to include sustainability information into
of SMEs. Therefore, automation of the sensitivity analysis should be their product configuration process. The considerations were based
considered in the future. on the assumptions of an existing configuration solution integrated
However, the cut-off criterion of mass cannot be used without fur- in the company’s system landscape, ecoinvent as a sustainability
ther considerations for the evaluation in the product configuration. database, and ESM as an exemplary impact assessment methodol-
For products from mass production, the materials that go into the ogy. In addition, the examinations were aimed at being compliant
product are known. In the case of MC, the total weight cannot be de- with the state-of-the-art LCA standards as much as possible.
termined before the configuration is completed. However, since the An important step is to verify the proposed configurator archi-
LCA is performed before the configuration is completed by the user, tecture in an industrial application scenario. This would enlighten
the question arises as to what total weight should be used. According whether the suggested components can realize the intended function-
to the strict guidelines of LCA, the total weight of the product variant alities. The topic of system and, related to this, data infrastructure,
with the lowest weight must be used. This is the only way to ensure has only been treated superficially. It is necessary to evaluate closer
that the cut-off criterion is used correctly for all variants. how the information needed for an LCA can be obtained in different
infrastructure scenarios and what data is usually available for inte-
gration.
4.4.2 Allocation Problems
The choice of ESM as an LCA methodology is advantageous in
LCA pursues the goal of assigning exactly that sustainability value the context of the proposed modular product assessment, as EP val-
to a product which corresponds to the environmental impact caused ues of inputs and outputs related to one characteristic can simply be
during its complete life cycle. However, if processes exist in which summed up. Application of the findings to indicators with other fea-
several products are involved, the question arises as to which prod- tures is not possible on a one-to-one basis. For example, the recycling
uct must be attributed which share of the environmental impact. For rate describing the share of recycled material in a part, cannot be
example, several products may be moved in a transport process. Like- summed up over all components and requires a different aggregation
wise, a machine can manufacture different products and consume a functionality. Future work should also strive for a holistic view of
certain amount of auxiliary materials, which must be allocated to the sustainability and expand the considerations to complementary sus-
individual products. tainability indicators. For this purpose, the social and economic di-
The occurrence of such a case is an allocation problem. In princi- mensions of product configurations should be considered in addition
ple, according to ISO 14044, an allocation should be avoided by de- to the ecological dimension. For example, with regard to the eco-
tailing or expanding the product system [10]. The modeler can make nomic dimension, an evaluation of the total cost of ownership for the
such an adjustment in the product configurator by modifying the customer could be helpful. This would enable the customer to take
product structure stored in the product model. However, this proce- into account not only the purchase price but also the costs of using the
dure is not expedient for the examples described at the beginning. In product over its entire life cycle when making a purchase decision.
6
Concerning the execution of the LCA, concepts have to be devel- [2] Stephan Ahbe, Simon Weihofen, and Steffen Wellge, The Ecological
oped that facilitate the handling of the identified complexities. The Scarcity Method for the European Union, Springer Fachmedien Wies-
baden, Wiesbaden, 2018.
focus was laid on enabling SMEs to integrate sustainability informa- [3] Anders Bjørn, Andreas Moltesen, Alexis Laurent, Mikołaj Owsianiak,
tion in their configurators, but the high complexity of both inventory Andrea Corona, Morten Birkved, and Michael Z. Hauschild, ‘Life Cy-
analysis and impact assessment call for additional user support for cle Inventory Analysis’, in Life Cycle Assessment, eds., Michael Z.
a correct execution of the LCA. With regard to the variety of alter- Hauschild, Ralph K. Rosenbaum, and Stig Irving Olsen, 117–165,
native business processes, it should be investigated how their envi- Springer, (2017).
[4] BMJV. Stärkung der unternehmerischen Verantwortung
ronmental impact can be correctly assigned to products. With regard durch neue nichtfinanzielle Berichtspflichten, 2016. https:
to the cut-off criteria, the extent to which the sensitivity analysis re- //www.bmjv.de/SharedDocs/Pressemitteilungen/DE/
quired by ISO 14040 can be automated should be examined, so that 2016/09212016_CSR-RL.html, last accessed 05.06.2021.
the modeler can concentrate on the actual LCA. For the handling [5] Claudio R. Boër, Paolo Pedrazzoli, Andrea Bettoni, and Marzio Sorlini,
Mass customization and sustainability: An assessment framework and
of allocation problems, further research can shed light on how func- industrial implementation, Springer, London, 2013.
tionalities can be provided to support the modeler in the allocation [6] Claudio R. Boër, C. Redaelli, D. Boër, and M. T. Gatti, ‘Mass Cus-
of environmental impacts to several products. For the identification tomization and Personalization: A Way to Improve Sustainability Be-
of possible solutions, an analysis of existing LCA software has the yond a Common Paradox’, in Customization 4.0, eds., Stephan Han-
potential to provide valuable insights, since these already address the kammer, Kjeld Nielsen, Frank T. Piller, Günther Schuh, and Ning
Wang, pp. 237–250. Springer International Publishing, (2018).
given problems for non-configurable products. [7] Mary Ann Curran, ‘Strengths and Limitations of Life Cycle Assess-
Seeing all these challenges, taking a step back to consider the role ment’, in Background and Future Prospects in Life Cycle Assessment,
of the considered standards can be a reasonable step. So far, ISO ed., Walter Klöpffer, LCA Compendium – The Complete World of Life
14040 and ISO 14044 only describe the assessment of products and Cycle Assessment, 189–206, Springer Netherlands, (2014).
[8] Ecoinvent. Organisation, 2021. https://www.ecoinvent.
services in general. However, it has been shown repeatedly in this org/about/organisation/organisation.html, last ac-
work that the modular structure as well as the high number of vari- cessed 06.05.2021.
ants in product configuration raise special requirements towards the [9] Claudia Erdle, Samuel Mathes, Dominik Morar, Heiner Lasi, and Hans-
execution of an LCA. Two main approaches can be followed: not Georg Kemper, ‘Erweiterung des Produktkonfigurationsprozesses um
supporting standard compliance or extending the standard to the area Aspekte der Nachhaltigkeit Konzeption eines Prototyps für die in-
dustrielle Produktion’, in IT-gestütztes Ressourcen- und Energieman-
of MC products. The latter approach is probably the more desirable agement, eds., Jorge Carlos Marx Gómez, Corinna Lang, and Volker
one, as it would create a uniform framework and increase the reliabil- Wohlgemuth, 199–208, Springer, (2013).
ity of sustainability information for customers. It would also promote [10] European Committee for Standardization. Environmental management
the exchange and comparison of LCA results for product variants. – Life cycle assessment – Requirements and guidelines DIN EN ISO
14044:2018-05.
Reliability points towards a more general issue: trust. The pre- [11] European Committee for Standardization. Environmental management
sented approach is based on the assumption that the offering compa- – Life cycle assessment – Principles and framework DIN EN ISO
nies themselves are performing the LCA. Currently, there is no inde- 14040:2009-11, 2009.
pendent party involved to check the correctness of the sustainability [12] Silke Feifel, Wolfgang Walk, and Sibylle Wursthorn, ‘Die Ökobilanz
information provided in the configurator. Measures are needed to in- im Spannungsfeld zwischen Exaktheit, Durchführbarkeit und Kommu-
nizierbarkeit’, Environmental Sciences Europe, 22(1), 46–55, (2010).
crease the trustworthiness of the presented information. [13] A. Felfernig, G. Friedrich, and D. Jannach, ‘Intelligente Produktkon-
figuratoren als Voraussetzung für maßgeschneiderte Massenprodukte’,
e & i Elektrotechnik und Informationstechnik, 116(3), 201–207, (1999).
6 CONCLUSION [14] Alexander Felfernig, ‘Standardized Configuration Knowledge Repre-
sentations as Technological Foundation for Mass Customization’, IEEE
The integration of sustainability information in configurators aims at
Transactions on Engineering Management, 54(1), 31–53, (2007).
providing users with decision-relevant sustainability information in [15] FIS. Bilanzierung ökologischer Nachhaltigkeit, 2020. https:
the context of MC products. The importance of this kind of informa- //www.forschungsinformationssystem.de/servlet/
tion will probably significantly increase in the future. The sustain- is/449353/, last accessed 06.05.2021.
ability assessment of MC products with a high number of variants [16] Rolf Frischknecht, Lehrbuch der Ökobilanzierung, Lehrbuch, Springer
Berlin Heidelberg, Berlin, Heidelberg, 2020.
poses a considerable challenge, especially for SMEs. Configurators [17] Rolf Frischknecht, Sybille Büssner Knöpfel, and treeze Ltd.
can clearly support the undertaking by providing system integra- Ökofaktoren Schweiz 2013 gemäß der Methode der ökologischen
tion, assessment functionality, and information display. But further Knappheit: Methodische Grundlagen und Anwendung auf die Schweiz.
research in this area is necessary. Bern, 2013.
[18] Nicola Ganter, Daniel Kloock-Schreiber, Paul Christoph Gembarski,
and Roland Lachmayer, ‘Including Maintenance Services in the Solu-
ACKNOWLEDGEMENTS tion Space - Considering Life Cycle Costs in Product Configuration’, in
22nd International Configuration Workshop, eds., Cipriano Forza, Lars
This research was conducted in the scope of the research project Hvam, and Alexander Felfernig, p. 68, (2020).
”ConCirMy - Configurator for the Circular Economy” (project [19] Martin Geissdoerfer, Paulo Savaget, Nancy M.P. Bocken, and Erik Jan
Hultink, ‘The Circular Economy – A new sustainability paradigm?’,
identifier 033R236) which is funded by Federal Ministry of Journal of Cleaner Production, 143, 757–768, (2017).
Education and Research (BMBF) within the funding measure [20] Paul Christoph Gembarski, Thorsten Schoormann, Daniel Schreiber,
”Resource-efficient Circular Economy – Innovative Product Cycles” Ralf Knackstedt, and Roland Lachmayer, ‘Effects of Mass Customiza-
(ReziProK). tion on Sustainability: A Literature-Based Analysis’, in Customization
4.0, eds., Stephan Hankammer, Kjeld Nielsen, Frank T. Piller, Günther
Schuh, and Ning Wang, pp. 285–300. Springer International Publish-
REFERENCES ing, (2018).
[21] Alena Hänsch, Maike Hora, Alessandro Fontana, Stephan Hankam-
[1] Stephan Ahbe, Liselotte Schebek, Nadine Jansky, Steffen Wellge, and mer, Luca Canetta, and Shirin Gomez, ‘A Preparatory Approach to
Simon Weihofen. Methode der ökologischen Knappheit für Deutsch- Environmental Assessment for Sustainable Mass Customization’, in
land – Eine Initiative der Volkswagen AG. Berlin, 2014.
7
Customization 4.0, eds., Stephan Hankammer, Kjeld Nielsen, Frank T.
Piller, Günther Schuh, and Ning Wang, pp. 315–337. Springer Interna-
tional Publishing, (2018).
[22] Walter Klöpffer and Isa Renner, ‘Lebenszyklusbasierte Nach-
haltigkeitsbewertung von Produkten’, Technikfolgenabschätzung –
Theorie und Praxis, 16(3), 32–38, (2007).
[23] Khaled Medini, Thorsten Wuest, David Romero, and Valérie Lafor-
est, ‘Integrating Sustainability Considerations into Product Variety and
Portfolio Management’, Procedia CIRP, 93, 605–609, (2020).
[24] Sanjay Mittal and Felix Frayman, ‘Towards a Generic Model of Con-
figuration Tasks’, Proceedings of International Joint Conference on Ar-
tificial Intelligence (IJCAI’89), 1395–1401, (1989).
[25] Marco Muhl, Markus Berger, and Matthias Finkbeiner, ‘Development
of Eco-factors for the European Union based on the Ecological Scarcity
Method’, The International Journal of Life Cycle Assessment, 24(9),
1701–1714, (2019).
[26] United Nations. Report of the World Commission on Environment and
Development: Our Common Future, 1987.
[27] Maxence Rousseau, Khaled Medini, David Romero, and Thorsten
Wuest, ‘Configurators as a means to Leverage Customer-Centric Sus-
tainable Systems - Evidence from the 3D-Printing Domain’, Procedia
CIRP, 96, 103–108, (2021).
[28] Daniel Sabin and Rainer Weigel, ‘Product Configuration Frameworks:
A Survey’, IEEE Intelligent Systems, 13(4), 42–49, (1998).
[29] Stephan Schwarze and Paul Schönsleben, ‘Recent Developments in the
Configuration of Multiple-Variant Products: Application Orientation
and Vagueness in Customer Requirements’, in Advances in Produc-
tion Management Systems, eds., Norio Okino, Hiroyuki Tamura, and
Susumu Fujii, IFIP - The International Federation for Information Pro-
cessing, 243–254, Springer, (1998).
[30] Ines Weller, ‘Konsum im Wandel in Richtung Nachhaltigkeit?
Forschungsergebnisse und Perspektiven’, in Nachhaltigkeit als
radikaler Wandel, ed., Hellmuth Lange, 43–69, VS Verl. für Sozial-
wiss, (2008).
[31] Gregor Wernet, Christian Bauer, Bernhard Steubing, Jürgen Reinhard,
Emilia Moreno-Ruiz, and Bo Weidema, ‘The ecoinvent database ver-
sion 3 (part I): overview and methodology’, The International Journal
of Life Cycle Assessment, 21(9), 1218–1230, (2016).
[32] Linda L. Zhang, ‘Product Configuration: A Review of the State-of-
the-Art and Future Research’, International Journal of Production Re-
search, 52(21), 6381–6398, (2014).
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