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ScienceDirect
Available online at www.sciencedirect.com
Available online at www.sciencedirect.com
ScienceDirect
Procedia CIRP 00 (2017) 000–000
www.elsevier.com/locate/procedia
2212-8271 © 2017 The Authors. Published by Elsevier B.V.
Peer-review under responsibility of the scientific committee of the 28th C IRP Design Conference 2018.
28th CIRP Design Conference, May 2018, Nantes, France
A new methodology to analyze the functional and physical architecture of
existing products for an assembly oriented product family identification
Paul Stief *, Jean-Yves Dantan, Alain Etienne, Ali Siadat
École Nationale Supérieure d’Arts et Métiers, Arts et Métiers ParisTech, LCFC EA 4495, 4 Rue Augustin Fresnel, Metz 57078, France
* Corresponding author. Tel.: +33 3 87 37 54 30; E-mail address: paul.stief@ensam.eu
Abstract
In today’s business environment, the trend towards more product variety and customization is unbroken. Due to this development, the need of
agile and reconfigurable production systems emerged to cope with various products and product families. To design and optimize production
systems as well as to choose the optimal product matches, product analysis methods are needed. Indeed, most of the known methods aim to
analyze a product or one product family on the physical level. Different product families, however, may differ largely in terms of the number and
nature of components. This fact impedes an efficient comparison and choice of appropriate product family combinations for the production
system. A new methodology is proposed to analyze existing products in view of their functional and physical architecture. The aim is to cluster
these products in new assembly oriented product families for the optimization of existing assembly lines and the creation of future reconfigurable
assembly systems. Based on Datum Flow Chain, the physical structure of the products is analyzed. Functional subassemblies are identified, and
a functional analysis is performed. Moreover, a hybrid functional and physical architecture graph (HyFPAG) is the output which depicts the
similarity between product families by providing design support to both, production system planners and product designers. An illustrative
example of a nail-clipper is used to explain the proposed methodology. An industrial case study on two product families of steering columns of
thyssenkrupp Presta France is then carried out to give a first industrial evaluation of the proposed approach.
© 2017 The Authors. Published by Elsevier B.V.
Peer-review under responsibility of the scientific committee of the 28th CIRP Design Conference 2018.
Keywords: Assembly; Design method; Family identification
1. Introduction
Due to the fast development in the domain of
communication and an ongoing trend of digitization and
digitalization, manufacturing enterprises are facing important
challenges in today’s market environments: a continuing
tendency towards reduction of product development times and
shortened product lifecycles. In addition, there is an increasing
demand of customization, being at the same time in a global
competition with competitors all over the world. This trend,
which is inducing the development from macro to micro
markets, results in diminished lot sizes due to augmenting
product varieties (high-volume to low-volume production) [1].
To cope with this augmenting variety as well as to be able to
identify possible optimization potentials in the existing
production system, it is important to have a precise knowledge
of the product range and characteristics manufactured and/or
assembled in this system. In this context, the main challenge in
modelling and analysis is now not only to cope with single
products, a limited product range or existing product families,
but also to be able to analyze and to compare products to define
new product families. It can be observed that classical existing
product families are regrouped in function of clients or features.
However, assembly oriented product families are hardly to find.
On the product family level, products differ mainly in two
main characteristics: (i) the number of components and (ii) the
type of components (e.g. mechanical, electrical, electronical).
Classical methodologies considering mainly single products
or solitary, already existing product families analyze the
product structure on a physical level (components level) which
causes difficulties regarding an efficient definition and
comparison of different product families. Addressing this
Procedia CIRP 105 (2022) 464–469
2212-8271 © 2022 The Authors. Published by Elsevier B.V.
This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0)
Peer-review under responsibility of the scientific committee of the 29th CIRP Life Cycle Engineering Conference.
10.1016/j.procir.2022.02.077
© 2022 The Authors. Published by Elsevier B.V.
This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0)
Peer-review under responsibility of the scientic committee of the 29th CIRP Life Cycle Engineering Conference.
Available online at www.sciencedirect.com
ScienceDirect
Procedia CIRP 00 (2022) 000–000
www.elsevier.com/locate/procedia
2212-8271 © 2022 The Authors. Published by ELSEVIER B.V.
This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0)
Peer-review under responsibility of the scientific committee of the 29th CIRP Life Cycle Engineering Conference
29th CIRP Life Cycle Engineering Conference
Comparison of conventional and electric passenger aircraft for short-haul
flights –A life cycle sustainability assessment
Alexander Barke a,c,*, Christian Thies a,c, Sofia Pinheiro Melo b,c, Felipe Cerdas b,c,
Christoph Herrmann b,c, Thomas S. Spengler a,c
aInstitute of Automotive Management and Industrial Production, Technische Universität Braunschweig, Braunschweig 38106, Germany
bInstitute of Machine Tools and Production Technology, Technische Universität Braunschweig, Braunschweig 38106, Germany
cCluster of Excellence “SE²A -Sustainable and Energy-Efficient Aviation”, Technische Universität Braunschweig, Braunschweig 38108, Germany
* Corresponding author. Tel.: +49 531 391 2214; fax: +49 531 391 2203.E-mail address:a.barke@tu-braunschweig.de
Abstract
Due to the increasing demand for flights, the aviation sector will become one of the main emitters of harmful emissions such as carbon dioxide
(CO2) and nitrogen oxides (NOx)in the long term.Especially short-haul flights are particularly critical because of the high kerosene consumption
per passenger kilometer traveled. To counteract this development, the Flightpath 2050 strategy aims to reduce CO2emissions by 75% and NOx
emissions by 90% until 2050. To achieve these ambitious reduction goals, radical technological transitions are required. A promising strategy for
short-haul flights is the deployment of battery-electric powertrains, which replace conventional jet engines.In addition, sustainable aviation fuels
(SAFs) can replace fossil kerosene as energy carriers without changing the powertrain configuration and offer further reduction potentials.
However, both solutions can be associated with negative environmental and socio-economic impacts along the life cycle. Therefore, this article
aims to analyze the potentials of powertrain transition and alternative energy carriers to make the air transport system more sustainable. A well-
to-wake life cycle sustainability assessment is conducted to analyze the environmental and socio-economic impacts of an electric powertrain and
SAFs compared to a conventional powertrain powered by fossil kerosene. The assessment results indicate that especially the electric powertrain
offers huge reduction potentials. Besides, the results also show that SAFs can reduce the environmental impactsof conventional aircraft in the
short term. Therefore, both solutions will be required to achieve the short-and long-term reduction goals of Flightpath 2050.
© 2022 The Authors. Published by ELSEVIER B.V.
This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0)
Peer-review under responsibility of the scientific committee of the 29th CIRP Life Cycle Engineering Conference
Keywords: Life Cycle Sustainability Assessment; Well-to-wake assessment; Electric aircraft; Sustainable aviation fuel;
1. Introduction
Due to the increasing demand for flights, the aviation sector
is a continually growing industry [1].While this growth is
desirable from an economic perspective, it leads to new
environmental challenges for the air transport system (ATS).
The combustion of fossil kerosene causes large quantities of
harmful emissions to the atmosphere, such as carbon dioxide
(CO2) and nitrogen oxides (NOx), which cause damage to
climate and health. In 2019, the aviation sector was responsible
for 2.6% of the global CO2emissions [2]. This is particularly
critical because emissions at higher altitudes have a more
severe environmental impact than ground-level emissions [3].
Current studies predict that the volume of global air traffic
increases by 3.6% annually, which would lead to a doubling of
air traffic every 16 years. Considering an increase in fuel
efficiency of approximately 25% per new aircraft generation,
this would lead to a tripling of aviation-induced emissions by
2050, making the ATS one of the leading emitters of CO2and
NOxin the long term [4].
To counteract this increase, the aviation sector has set itself
ambitious emission reduction goals defined in the Flightpath
2050 strategy [5]. The strategy envisages the reduction of
emissions from aircraft by 75% for CO2, 90% for NOx, and
65% for noise by 2050 relative to anew aircraft from the base
Available online at www.sciencedirect.com
ScienceDirect
Procedia CIRP 00 (2022) 000–000
www.elsevier.com/locate/procedia
2212-8271 © 2022 The Authors. Published by ELSEVIER B.V.
This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0)
Peer-review under responsibility of the scientific committee of the 29th CIRP Life Cycle Engineering Conference
29th CIRP Life Cycle Engineering Conference
Comparison of conventional and electric passenger aircraft for short-haul
flights –A life cycle sustainability assessment
Alexander Barke a,c,*, Christian Thies a,c, Sofia Pinheiro Melo b,c, Felipe Cerdas b,c,
Christoph Herrmann b,c, Thomas S. Spengler a,c
aInstitute of Automotive Management and Industrial Production, Technische Universität Braunschweig, Braunschweig 38106, Germany
bInstitute of Machine Tools and Production Technology, Technische Universität Braunschweig, Braunschweig 38106, Germany
cCluster of Excellence “SE²A -Sustainable and Energy-Efficient Aviation”, Technische Universität Braunschweig, Braunschweig 38108, Germany
* Corresponding author. Tel.: +49 531 391 2214; fax: +49 531 391 2203.E-mail address:a.barke@tu-braunschweig.de
Abstract
Due to the increasing demand for flights, the aviation sector will become one of the main emitters of harmful emissions such as carbon dioxide
(CO2) and nitrogen oxides (NOx)in the long term.Especially short-haul flights are particularly critical because of the high kerosene consumption
per passenger kilometer traveled. To counteract this development, the Flightpath 2050 strategy aims to reduce CO2emissions by 75% and NOx
emissions by 90% until 2050. To achieve these ambitious reduction goals, radical technological transitions are required. A promising strategy for
short-haul flights is the deployment of battery-electric powertrains, which replace conventional jet engines.In addition, sustainable aviation fuels
(SAFs) can replace fossil kerosene as energy carriers without changing the powertrain configuration and offer further reduction potentials.
However, both solutions can be associated with negative environmental and socio-economic impacts along the life cycle. Therefore, this article
aims to analyze the potentials of powertrain transition and alternative energy carriers to make the air transport system more sustainable. A well-
to-wake life cycle sustainability assessment is conducted to analyze the environmental and socio-economic impacts of an electric powertrain and
SAFs compared to a conventional powertrain powered by fossil kerosene. The assessment results indicate that especially the electric powertrain
offers huge reduction potentials. Besides, the results also show that SAFs can reduce the environmental impactsof conventional aircraft in the
short term. Therefore, both solutions will be required to achieve the short-and long-term reduction goals of Flightpath 2050.
© 2022 The Authors. Published by ELSEVIER B.V.
This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0)
Peer-review under responsibility of the scientific committee of the 29th CIRP Life Cycle Engineering Conference
Keywords: Life Cycle Sustainability Assessment; Well-to-wake assessment; Electric aircraft; Sustainable aviation fuel;
1. Introduction
Due to the increasing demand for flights, the aviation sector
is a continually growing industry [1].While this growth is
desirable from an economic perspective, it leads to new
environmental challenges for the air transport system (ATS).
The combustion of fossil kerosene causes large quantities of
harmful emissions to the atmosphere, such as carbon dioxide
(CO2) and nitrogen oxides (NOx), which cause damage to
climate and health. In 2019, the aviation sector was responsible
for 2.6% of the global CO2emissions [2]. This is particularly
critical because emissions at higher altitudes have a more
severe environmental impact than ground-level emissions [3].
Current studies predict that the volume of global air traffic
increases by 3.6% annually, which would lead to a doubling of
air traffic every 16 years. Considering an increase in fuel
efficiency of approximately 25% per new aircraft generation,
this would lead to a tripling of aviation-induced emissions by
2050, making the ATS one of the leading emitters of CO2and
NOxin the long term [4].
To counteract this increase, the aviation sector has set itself
ambitious emission reduction goals defined in the Flightpath
2050 strategy [5]. The strategy envisages the reduction of
emissions from aircraft by 75% for CO2, 90% for NOx, and
65% for noise by 2050 relative to anew aircraft from the base
Alexander Barke et al. / Procedia CIRP 105 (2022) 464–469 465
2 Author name / Procedia CIRP 00 (2022) 000–000
year 2000. In this context, various programs have been adopted
in recent years to support the achievement of these reduction
goals [6]. However, these programs are predominantly aimed
at offsetting the emissions, which is not sufficient in the long
term. Further progress towards clean and sustainable aviation
requires more radical technological innovations [7].
A promising solution for short-haul flights in the future are
electric aircraft associated with low to no emissions in the use
phase [4]. Today, already feasible alternatives are drop-in
capable fuels based on renewable sources, also known as
sustainable aviation fuels (SAFs) [8]. Kerosene based on
biomass or hydrogen can significantly reduce harmful
emissions due to benefits during their production. However,
both solutions can cause negative environmental and socio-
economic impacts along with their life cycles [9]. These are
barely addressed in the scientific literature, and studies
comparing conventional and electric aircraft for short-haul
flights considering different fuel options are scarce [8].
Thus, this article aims to analyze and compare electric
aircraft and conventional aircraft powered by fossil kerosene
and SAFs to determine the potential of being a promising
solution for short-haul flights and thus contribute to the
sustainable development of the ATS. Using a holistic life cycle
sustainability assessment (LCSA), the environmental and
socio-economic impacts are captured in a well-to-wake
approach. Well-to-wake includes the energy carrier supply
chain, the powertrain supply chain, and the flight operation as
use phase. By analyzing a total of nine energy carriers, as
shown in Table 2, recommendations for action are derived for
both the long-term and short-term development of the aviation
sector.
The remainder of this article is structured as follows. The
system definition of the powertrain configurations, the energy
carriers as well as a description of the assessment method are
specified in Section 2. The results of the sustainability
assessment and the main findings are presented in Section 3. In
Section 4, the paper concludes with a discussion of the main
findings and an outlook on future research.
2. Method and materials
2.1. Assessment method and fundamentals of the study
The assessment is fundamentally based on the Life Cycle
Sustainability Assessment method, and its procedure is derived
from the ISO 14040/14044 standards. Explanations of the basic
LCSA approach can be found in the pertinent literature (e.g.
[10]–[12]). Since the electric powertrain is a technology that is
still under development, the approach is applied based on the
idea of a prospective LCA [13], transferred to a prospective
LCSA.
This study analyzes and compares the use of conventional
aircraft and electric aircraft powertrains for short-haul flights.
For this purpose, two types of supply chains are considered. On
the one hand, the supply chain of the powertrain is investigated,
from raw material extraction through production to use. In the
use phase, this overlaps with the supply chain of the energy
carrier required to operate the powertrain. It consists of energy
carrier production, distribution, storage, and use. The supply
chains and the required materials are modeled in the foreground
system. They are linked to the ecoinvent 3.7.1 database and the
Social Hotspots Database (SHDB) in the background system
[14], [15]. An overview of the considered systems and the
corresponding boundaries is given in Figure 1.
The configuration of the powertrains and their energy carrier
consumption in the use phase are designed for a typical mission
profile of a short-haul flight. A detailed description of the
powertrain configurations, the considered energy carriers, and
the mission profile of the flight operation are described in
subsections 2.2-2.4.
The functional unit for the analysis is 100 passenger
kilometers traveled (pkm) on a 1.000 km short-haul flight with
a load of 100 passengers, including luggage.
The conducted impact assessment is based on three types of
Life Cycle Impact Assessment (LCIA) methods, one for each
of the three sustainability dimensions. The environmental
impact assessment is based on three impact categories,
according to the ReCiPe Midpoint v1.13 method [16]. Here, the
impact category climate change (CC) is chosen due to the high
amount of climate-damaging CO2 resulting from the
Figure 1. Foreground and background system with corresponding boundaries including component, product, and resource flows
Powertrain
Energy carrier
Distribution & storageProduction
Energy carrier supply chain
Flight operation
Final assemblyComponent production
Powertrain supply chain
Ecosphere
Sociosphere
Marketsphere
Technosphere
Background system Foreground system
Resource flow (natural resource, emissions, money, etc.) Component and product flow Unit process Process group Database
Electricity production
Generation
Water
Miscanthus
Crude oil
…
Raw materials
production
ecoinvent 3.7.1
Social Hotspots
Database
466 Alexander Barke et al. / Procedia CIRP 105 (2022) 464–469
Author name / Procedia CIRP 00 (2022) 000–000 3
combustion of fuel, fossil resource depletion (FRD) is chosen
due to the fossil sources required for electricity generation and
the fossil character of conventional kerosene, and agricultural
land occupation (ALO) is chosen due to the required
agricultural land for cultivating the bio-feedstock. The
economic assessment is based on the life cycle costs (LC)
associated with the energy carrier supply chain, the powertrain
supply chain, and the flight operation [17]. The social impact
assessment is based on the impact assessment method of the
SHDB [15]. The impact categories risk of corruption (RoC)
and risk of poverty (RoP) are chosen due to socially critical
conditions in the country of origin of raw materials required for
the energy carriers and the powertrains. Table 1 provides an
overview of the considered impact categories within this study.
Table 1. Environmental and socio-economic impact categories
Dimension
Impact category
Unit
Environmental Climate change (CC) kg CO2-eq.
Fossil resource depletion (FRD) kg Oil-eq.
Agricultural land occupation (ALO) m2 per year
Economic
Life cycle costs (LC)
US-Dollar
Social Risk of corruption (RoC) Medium risk hour eq.
Risk of poverty (RoP) Medium Risk hour eq.
The calculation model for the inventory analysis and impact
assessment is implemented in python using the Brightway2
framework [18].
2.2. Conventional and electric powertrain
The conventional powertrain analyzed in this study is based
on an Airbus A318-100. This powertrain is chosen because the
A318-100 has a capacity of around 100 passengers and is a
typical short-haul aircraft [19]. The basic composition consists
of two jet engines, fuel tanks in the body and the wings, the
pipes, and the power electronics for engine control. The
powertrain production is based on the Airbus production
network with component manufacturing in England, Germany,
Czech Republic, Spain, and final assembly in France [20].
The configuration of the battery-electric powertrain is
derived from a reference aircraft defined within the cluster of
excellence "SE²A – Sustainable and Energy-Efficient
Aviation" [21]. The short-haul aircraft can transport up to 100
passengers over a distance of 1,000 kilometers. The powertrain
comprises two propellers driven by electric motors, a battery
system for energy storage, power electronics, and a cooling
system. Due to technical restrictions regarding the maximum
take-off and landing weight, high specific energy of the battery
is crucial, and therefore, a lithium-sulfur-all-solid-state battery
is selected for this study. The production of the components
takes place in Germany, Japan, and France [22].
For each of the raw materials, the country with the highest
share of global production according to the U.S. Geological
Survey [23] is assumed as the origin. The corresponding
transport routes are taken into account.
2.3. Kerosene, sustainable aviation fuel, and electricity
Each powertrain requires specific energy carriers for flight
operation. For this purpose, fossil kerosene is currently used in
conventional powertrains. Its supply chain begins with the
extraction of crude oil, which is processed into kerosene by
blending in various additives [24]. It is assumed that the crude
oil is extracted in Russia and processed in Germany.
In addition to fossil kerosene, three promising SAFs are
considered in this study. These fuels are produced via X-to-
liquid pathways, more precisely via biomass-to-liquid (BtL)
and power-to-liquid (PtL) [25]. The starting point of the
processes is the production of hydrogen, which is further
processed into kerosene using the Fisher-Tropsch synthesis
(FTS). In the FTS, the SAF is produced through different
pressures and using CO2, which is captured from the
atmosphere or as a waste product from other industries [26].
Concerning BtL, the focus is on 2nd generation biokerosene
[27]. The feedstock for biokerosene is miscanthus, which is
cultivated in Germany and processed into biogas. The biogas is
refined to biomethane by adding various additives and then
processed to hydrogen via steam methane reforming (SMR). In
the subsequent production step, the biokerosene is produced
using the FTS [28]. The production takes place in Germany.
Concerning PtL, two production pathways are investigated
[29]. The first pathway includes the SMR process but uses
natural gas and water instead of biomethane for hydrogen
production [30]. In the other production pathway, hydrogen is
produced via electrolysis. For this purpose, polymer electrolyte
membrane electrolysis (PEM) is used to produce hydrogen in
an energy-intensive production step from water (55 kWh
electricity input per 1 kg of hydrogen) [31] which is further
processed to synthetic kerosene via FTS. The whole synthetic
kerosene production takes place in Germany.
For each SAF, two scenarios are assumed for the
production: 1.) Using the current German electricity mix, and
2.) using an electricity mix generated 100% from renewable
energy sources (RE) as expected for the German mix in 2050
[32]. These two electricity mixes are also considered as energy
carriers for the electric powertrain.
Overall, nine different energy carriers are analyzed with the
fossil kerosene used as benchmark for the subsequent study:
Table 2. Considered energy carriers
Abbreviation
Description
Ker (fossil) Fossil kerosene
Ker (bio) Biokerosene produced by SMR
Ker (bio-RE) Biokerosene produced by SMR using RE
Ker (SMR) Synthetic kerosene produced by SMR
Ker (SMR-RE) Synthetic kerosene produced by SMR using RE
Ker (PEM) Synthetic kerosene produced by PEM
Ker (PEM-RE) Synthetic kerosene produced by PEM using RE
Elec Current German electricity mix
Elec-RE Forecasted German electricity mix for 2050
Alexander Barke et al. / Procedia CIRP 105 (2022) 464–469 467
4 Author name / Procedia CIRP 00 (2022) 000–000
2.4. Mission profile and flight operation
For the analysis, a reference flight over a distance of 1,000
km with a load of 100 passengers is considered. This
corresponds to a flight from Frankfurt, Germany to Barcelone,
Spain, which is potentially feasible with an electric aircraft
[21]. The flight lasts 135 minutes, with a take-off/ climb time
of 35 minutes and a cruise/ landing time of 100 minutes.
According to the Lufthansa Group, such a flight consumes
7.1 liters of kerosene (specific energy of 68 kWh) per 100 pkm
[33], representing the energy carrier consumption within this
study. The combustion behavior of the fuels and the resulting
emissions are derived from the scientific literature [34].
The energy consumption of a comparable electric flight is
estimated at 17 kWh per 100 pkm. The energy requirement of
electric aircraft is about 25% of the energy consumption of
conventional aircraft due to better efficiency. This efficiency
difference is similar in the automotive industry [35].
Next to the impacts related to energy carrier consumption,
further impacts resulting from the powertrain production must
be considered on a pro-rata basis. These are calculated based
on the duration of flight operation relative to the total service
life of the powertrain.
3. Results and discussion
3.1. Impact assessment results
An overview of the impact assessment results is given in
Table 3. For the investigated setting, the results show that the
electric powertrain offers significant environmental and socio-
economic improvements compared to the conventional
powertrain powered by fossil kerosene concerning the
functional unit of 100 pkm traveled.
Using the current German electricity mix, environmental
impacts can be reduced by 63% to 71%. Only for ALO,
deteriorations of 59% occur, which is due to the current
composition of the electricity mix. If the electricity is generated
from 100% RE, even higher improvements can be achieved.
Compared to the benchmark of conventional powertrain
powered by fossil kerosene, reductions of 91% (CC) and 92%
(FDP) can be reached, and also the impact of ALO can be
reduced by 48%. Overall, there is only one environmental
impact category where a higher reduction can be achieved by
using SAF. Concerning CC, the use of Ker (PEM-RE) can
reduce the environmental impact by 95%, which is due to the
high savings during production based on the use of electricity,
generated 100% on RE.
With regard to the socio-economic impacts, similar results
occur. Here, reductions of 6% to 91% can be achieved by the
electric powertrain compared to the benchmark. However,
there is no difference between whether the current electricity
mix or an electricity mix based on 100% RE is used for flight
operation. This is due to the assumption that the electricity is
generated in Germany and the electricity price is identical in
both cases. In addition, there is no SAF which is more
beneficial compared to the electric powertrain concerning a
socio-economic impact category.
The assessment results also show that some SAFs are
associated with high negative environmental and socio-
economic impacts. While the use of biokerosene (Ker (bio) and
Ker (bio-RE)) is consistently beneficial in terms of social
impacts, the LC are 160% higher compared to Ker (fossil). In
terms of environmental impacts, the biokerosene variants offer
30% to 73% reduction potentials concerning CC and FRD.
Still, they are associated with sixteen times higher impacts
regarding ALO due to the land use for the feedstock.
The results for the synthetic fuels show that based on the
current electricity mix, only the use of Ker (SMR) results in
improvements concerning the social impact categories and CC.
This is due to the high energy requirement of Ker (PEM) and,
which is responsible for high negative environmental and
economic impacts. Using an electricity mix based 100% on RE
can reduce the environmental impacts overall, while the socio-
economic impacts remain the same. Here, the Ker (PEM-RE)
offers reduction potentials of 95% concerning CC and 24%
regarding FRD. Ker (SMR-RE) results in almost identical
environmental impacts because only a small amount of
electricity is required for the process. From an economic
perspective, the LC are in any case higher than for fossil
kerosene (121% to 641%).
3.2. Analysis of environmental and socio-economic impacts
Figure 2 provides more detailed insights into the
environmental and socio-economic impacts by breaking down
the impact scores into the energy carrier supply chain,
including electricity generation, the powertrain supply chain,
and the final use stage.
For the conventional powertrain using fuels, the results
show that the energy carrier supply chain is mainly responsible
for the impacts for five of the six impact categories analyzed.
Especially regarding the environmental impacts FRD and ALO
of the SAFs, 90% to 99% of the total impacts can be attributed
to this stage. In the case of biokerosene, the cultivation of the
feedstock and kerosene production using SMR are primarily
responsible. Concerning synthetic fuels generated via PEM, the
Table 3. Environmental and socio-economic assessment results of the eleven use cases for the functional unit of 100 pkm traveled
Dim. Impact
category Unit
Per 100 passenger kilometers traveled
Ker
(fossil)
Ker
(bio)
Ker
(bio-RE)
Ker
(PEM)
Ker
(PEM-RE)
Ker
(SMR)
Ker
(SMR-RE)
Elec Elec-RE
Env. CC kg CO2-eq. 29. 91 20.83 17.36 105.77 1.35 25.92 24.69 11.10 2.44
FRD kg Oil-eq. 10.57 3.74 2.82 35.88 8.06 17.97 17.64 3.07 0.76
ALO m2 per year 0.30 5.18 5.05 5.12 1.27 0.53 0.49 0.47 0.15
Econ. LC US-Dollar 5.91 15.37 15.37 43.82 43.82 13.08 13.08 5.56 5.56
Social RoC Medium risk hour eq. 13.57 2.49 2.49 8.69 8.69 1.86 1.86 1.28 1.28
RoP Medium Risk hour eq. 1.36 0.57 0.57 1.84 1.84 0.44 0.44 0.28 0.28
468 Alexander Barke et al. / Procedia CIRP 105 (2022) 464–469
Author name / Procedia CIRP 00 (2022) 000–000 5
impacts are due to energy-intensive hydrogen production,
while for SMR, the upstream chain of natural gas is
responsible. Concerning fossil kerosene, the energy carrier
supply chain is responsible for 52% (ALO) and 92% (FRD).
This is due to crude oil extraction and petroleum production.
Similar results occur regarding the socio-economic impacts,
where 70% to 97% of the total impacts are attributable to the
energy carrier supply chain. Concerning LC, the energy-
intensive production processes, such as hydrogen production,
FTS, and kerosene production, are the main drivers of the
impacts. In the case of social impacts, this also applies, but it
should be noted that the social impacts are generally low, which
is because mainly Germany is used as a production site, where
the risk of socially disadvantageous situations is not very
pronounced. The exception is the RoC in the case of fossil
kerosene, which is generally due to crude oil extraction and
transport through several countries.
Concerning CC, however, the impact for every fuel is
chiefly due to the use stage, where around 3.15 kg of CO2 is
emitted during the combustion process. Ker (PEM) is an
exception. Here, the high energy requirement during PEM is
the main driver. The results also indicate that SAFs generated
by RE are associated with CC impacts smaller than zero in their
supply chain. This is because more CO2 is captured than
released during production. The exception here is Ker (SMR-
RE) since hydrogen production is based on fossil sources.
Concerning the electric powertrain, the results indicate that
the current electricity mix is mainly responsible for the
environmental impacts. This is due to the high proportion of
fossil energy sources used in current electricity generation. If
the electricity mix is generated via RE, the environmental
impacts can be reduced significantly, but the electricity mix is
again primarily responsible. This is due to the construction of
the renewable energy plants, which are considered in the life
cycle inventory datasets.
Similar findings can be made concerning socio-economic
impacts. The generation of electricity is mainly responsible for
the impacts of LC, RoC, and RoP. Overall, the socio-economic
impacts do not differ when RE is used to generate electricity.
In both cases, the generation is carried out entirely in Germany
under the same conditions.
3.3. Discussion
Overall, the results show that electrically powered aircraft is
a promising long-term solution to reduce the environmental
impacts of the ATS significantly. In addition, their use appears
to be economically competitive with conventional aircraft
powered by fossil kerosene. The results also show that SAFs,
which are already feasible today, are a good alternative for
reducing specific environmental impacts in the short term but
are associated with higher costs.
However, there are some uncertainties within this study,
especially concerning the electric powertrain. Thus, a
hypothetical electric powertrain was configured. Since there
are no practically tested electric passenger aircraft yet, the
configuration cannot be validated. In addition, novel
technologies usually cause far-reaching structural adjustments
to the aircraft, not investigated here. For example, lighter
materials such as fiber composites are needed to compensate
for the dead weight of the battery, but these are associated with
new negative environmental and socio-economic impacts. This
could significantly downgrade the performance of the electric
powertrain investigated in this study. To avoid a potential
burden shifting, the study's scope must be expanded to consider
the other aircraft components and assess the whole aircraft.
Figure 2. Environmental and socio-economic impacts divided between energy carrier supply chain, powertrain supply chain, and use
Climate change
[k g CO
2
-equivalents]
-40
-20
0
20
40
Fossil resource depletion
[k g Oil -equivalents]
-5
-2 ,5
0
2,5
5
Agr icult ur al la nd o ccup ation
[m
2
per year ]
-40
-20
0
20
40
Life cycle cost
[US-Dollar]
-20
-10
0
10
20
Risk of corruption
[m edium ri sk h our equiv alent s]
-2
-1
0
1
2
Risk of poverty
[m edium ri sk h our equiv alent s]
Energy carrier supply c hain (incl. electricity) Powertrain supply chain Use T o t al i mp ac t
-1 00
-50
0
50
100
Alexander Barke et al. / Procedia CIRP 105 (2022) 464–469 469
6 Author name / Procedia CIRP 00 (2022) 000–000
In addition, only 2nd generation biokerosene and hydrogen-
based synthetic fuels were investigated in this study. Research
on 3rd generation biofuels and alcohol-based synthetic fuels is
already available today and can be integrated into the study.
A significant uncertainty results from the spatial
consideration of only one country. Especially regarding
environmental and social impacts, Germany has advantages in
terms of SAFs, electricity, and the electric powertrain due to its
high share of RE in the electricity mix and less critical working
conditions. If countries with higher shares of fossil sources in
the electricity mix and more critical working conditions were
chosen as production locations, the advantages of SAFs and
electric powertrains could probably not be proven. In any case,
more research needs to be done on spatial differences.
4. Conclusion and outlook
The sustainability assessment conducted in this article aims
to identify the potential of an electric powertrain and SAFs for
short-haul aircraft. The well-to-wake analysis shows that
electric aircraft could lead to significant reductions in
environmental and socio-economic impacts. If the electricity
needed to charge the electric aircraft originates from renewable
sources, the reduction potentials are higher. At the same time,
it is shown that synthetic fuels have advantages over fossil
kerosene in terms of particular impact categories. Especially
when it comes to reducing CO2 emissions, these fuels can be
advantageous. However, this only applies if synthetic fuels are
produced using renewable energy. Biofuels, on the other hand,
offer reduction potential in various environmental and socio-
economic impact categories. Still, the question remains to what
extent these can be implemented globally due to the partial
conflict with food production. Possibly, 3rd generation biofuels
can provide a remedy here.
Therefore, both solutions will be required to achieve the
short- and long-term reduction goals of Flightpath 2050.
In the context of future research, four topics should gain
particular attention to further improve the analysis: 1.)
Expanding the study to include full aircraft, 2.) considering
other fuel alternatives (e.g., 3rd generation biofuels and alcohol-
based synthetic fuels), 3.) analyzing spatially diverse supply
chain configurations, and 4.) providing comparisons to other
modes of transportation (e.g., train or bus) on short-haul
distances.
Acknowledgements
We would like to acknowledge the funding by the Deutsche
Forschungsgemeinschaft (DFG, German Research
Foundation) under Germany's Excellence Strategy – EXC
2163/1- Sustainable and Energy Efficient Aviation – Project-
ID 390881007.
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