Conference PaperPDF Available

Comparison of conventional and electric passenger aircraft for short-haul flights – A life cycle sustainability assessment

Authors:

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 CO2 emissions 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 impacts of conventional aircraft in the short term. Therefore, both solutions will be required to achieve the short- and long-term reduction goals of Flightpath 2050.
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 scientic committee of the 29th CIRP Life Cycle Engineering Conference.
Available online at www.sciencedirect.com
ScienceDirect
Procedia CIRP 00 (2022) 000000
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) 000000
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) 000000
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
466 Alexander Barke et al. / Procedia CIRP 105 (2022) 464–469
Author name / Procedia CIRP 00 (2022) 000000 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) 000000
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) 000000 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) 000000
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.
References
[1] D. Scott and S. Gössling, What could the next 40 years hold for global tourism?, Tour.
Recreat. Res., vol. 40, no. 3, pp. 269285, 2015, doi: 10.1080/02508281.2015.1075739.
[2] M. d. Staples, R. Malina, P. Suresh, J. I. Hileman, and S. R. H. Barrett, Aviation CO 2
emissions reductions from the use of alternative jet fuels, Energy Policy, vol. 114, pp.
342354, 2018, doi: 10.1016/j.enpol.2017.12.007.
[3] D. S. Lee et al., The contribution of global aviation to anthropogenic climate forcing for
2000 to 2018, Atmos. Environ., vol. 244, p. 117834, Jan. 2021, doi:
10.1016/J.ATMOSENV.2020.117834.
[4] A. R. Gnadt, R. L. Speth, J. S. Sabnis, and S. R. H. Barrett, Technical and environmental
assessment of all-electric 180-passenger commercial aircraft, Prog. Aerosp. Sci., vol.
105, pp. 130, 2019, doi: 10.1016/j.paerosci.2018.11.002.
[5] Eur opean Commission, Flightpath 2050: Europes vision for aviation, Publication
Office of the European Union, Luxembourg, 2011. doi: 10.2777/50266.
[6] J. Scheelhaase, S. Maertens, W. Grimme, and M. Jung, EU ETS versus CORSIA -- A
critical assessment of two approaches to limit air transports CO 2 emissions by market-
based measures, J. Air Transp. Manag., vol. 67, pp. 5562, 2018, doi:
10.1016/j.jairtraman.2017.11.007.
[7] A. W. Schäfer et al., Technological, economic and environmental prospects of all-electric
aircraft, Nat. Energy, vol. 4, no. 2, pp. 160166, 2019, doi: 10.1038/s41560-018-0294-x.
[8] S. P. Melo et al., Sustainability Assessment and Engineering of Emerging Aircraft
Technologies - Challenges, Methods and Tools, Sustainability, vol. 12, no. 14, p. 5663,
2020, doi: 10.3390/su12145663.
[9] A. Barke et al., Life cycle sustainability assessment of potential battery systems for
electric aircraft, in Procedia CIRP, 2021, vol. 98, pp. 660665, doi:
10.1016/j.procir.2021.01.171.
[10] A. Barke, C. Thies, S. P. Melo, F. Cerdas, C. Herrmann, and T. S. Spengler, Socio-
economic life cycle assessment of future aircraft systems, in Procedia CIRP, 2020, vol.
90, pp. 262267, doi: 10.1016/j.procir.2020.01.096.
[11] UNEP/SETAC, Towards a Life Cycle Sustainability Assessment: Making informed
choices on products, 2011.
[12] W. Klöpffer, Life cycle sustainability assessment of products, Int. J. Life Cycle Assess.,
vol. 13, no. 2, pp. 8995, 2008, doi: 10.1065/lca2008.02.376.
[13] J. A. Bergerson et al., Life cycle assessment of emerging technologies: Evaluation
techniques at different stages of market and technical maturity, J. Ind. Ecol., vol. 24, no.
1, pp. 1125, Feb. 2020, doi: 10.1111/jiec.12954.
[14] G. Wernet, C. Bauer, B. Steubing, J. Reinhard, E. Moreno-Ruiz, and B. Weidema, The
ecoinvent database version 3 (part I): overview and methodology, Int. J. Life Cycle
Assess., vol. 21, no. 9, pp. 12181230, Apr. 2016, doi: 10.1007/S11367-016-1087-8.
[15] C. Norris and G. A. Norris, Chapter 8: The Social Hotspots Database Context of the
SHDB, in The Sustainability Practitioners Guide to Social Analysis and Assessment, J.
Murray, D. McBain, and T. Wiedmann, Eds. Champaign, IL, USA: Common Ground
Publishing LLC, 2015, pp. 5273.
[16] M. Goedkoop, R. Heijungs, M. Huijbregts, Schryver, J. Struijs, and R. van Zelm, ReCiPe
2008: A life cycle impact assessment method which comprises harmonised category
indicators at the midpoint and the endpoint level, Den Haag, 2013.
[17] V. Moreau and B. P. Weidema, The computational structure of environmental life cycle
costing, Int. J. Life Cycle Assess., vol. 20, no. 10, pp. 13591363, 2015, doi:
10.1007/s11367-015-0952-1.
[18] C. Mutel, Brightway: An open source framework for Life Cycle Assessment, J. Open
Source Softw., vol. 2, no. 12, p. 236, 2017, doi: 10.21105/joss.00236.
[19] Airbus S.A.S., Family Figures, no. May. p. 17, 2021.
[20] S. Buxbaum-Conradi, Global and local knowledge dynamics in an industry during
modular transition - A case study of the Airbus production network and the Aerospace
Cluster in Hamburg, Northern Germany, University of Hamburg, 2018.
[21] Y. Liu, A. Elham, P. Horst, and M. Hepperle, Exploring Vehicle Level Benefits of
Revolutionary Technology Progress via Aircraft Design and Optimization, Energies, vol.
11, no. 1, p. 166, 2018, doi: 10.3390/en11010166.
[22] A. Nordelöf, A scalable life cycle inventory of an automotive power electronic inverter
unit---part II: manufacturing processes, Int. J. Life Cycle Assess., vol. 24, no. 4, pp. 694
711, 2019, doi: 10.1007/s11367-018-1491-3.
[23] U.S. Geological Survey, Mineral commodity summaries 2019, Reston, Virgina, USA,
2019. doi: 10.3133/70202434.
[24] C. Koroneos, A. Dompros, G. Roumbas, and N. Moussiopoulos, Life Cycle Assessment
of Kerosene Used in Aviation (8 pp), Int. J. Life Cycle Assess., vol. 10, no. 6, pp. 417
424, 2005.
[25] Y. Bicer and I. Dincer, Life cycle evaluation of hydrogen and other potential fuels for
aircrafts, Int. J. Prod. Res., vol. 42, no. 16, pp. 1072210738, 2017.
[26] S. Farokhi, Future propulsion systems and energy sources in sustainable aviation, 1st ed.
Hoboken, NJ: Wiley & Sons, 2020.
[27] A. P. Bessette, A. Teymouri, M. J. Martin, B. J. Stuart, E. P. Resurreccion, and S. Kumar,
Life Cycle Impacts and Techno-economic Implications of Flash Hydrolysis in Algae
Processing, ACS Sustain. Chem. Eng., vol. 6, no. 3, pp. 35803588, Mar. 2018, doi:
10.1021/ACSSUSCHEMENG.7B03912.
[28] S. S. Doliente, A. Narayan, J. F. D. Tapia, N. J. Samsatli, Y. Zhao, and S. Samsatli, Bio-
aviation Fuel: A Comprehensive Review and Analysis of the Supply Chain Components,
Front. Energy Res., vol. 0, p. 110, Jul. 2020, doi: 10.3389/FENRG.2020.00110.
[29] C. Van Der Giesen, R. Kleijn, and G. J. Kramer, Energy and climate impacts of
producing synthetic hydrocarbon fuels from CO2, Environ. Sci. Technol., vol. 48, no. 12,
pp. 71117121, Jun. 2014, doi: 10.1021/ES500191G.
[30] M. Rutkowski, M. Penev, G. Saur, and D. Steward, Current Central Hydrogen from
Natural Gas with CO2 Capture and Sequestration: NREL. 2018, [Online]. Available:
https://www.nrel.gov/hydrogen/assets/docs/current-central-natural-gas-with-co2-
sequestration-v3-2018.20210104.xlsm.
[31] D. DeSantis, B. James, and G. Saur, Hydrogen Production from Central PEM
Electrolysis: NREL. 2019, [Online]. Available:
https://www.nrel.gov/hydrogen/assets/docs/current-central-pem-electrolysis-2019-v3-
2018.xlsm.
[32] M. Z. Jacobson et al., 100% Clean and Renewable Wind, Water, and Sunlight All-Sector
Energy Roadmaps for 139 Countries of the World, Joule, vol. 1, no. 1, pp. 108121, S ep.
2017, doi: 10.1016/J.JOULE.2017.07.005.
[33] Lufthansa Group, LH-Factsheet-Sustainability-2020. pp. 122, 2020, [Online].
Available: https://www.lufthansagroup.com/media/downloads/en/responsibility/LH-
Factsheet-Sustainability-2020.pdf.
[34] M. Braun-Unkhoff, U. Riedel, and C. Wahl, About the emissions of alternative jet fuels,
CEAS Aeronaut. J., vol. 8, no. 1, pp. 167180, Mar. 2017, doi: 10.1007/s13272-016-0230-
3.
[35] D. Bothe and T. Steinfort, Cradle-to-Grave Life-Cycle Assessment in the Mobility Sector
A Meta-Analysis of LCA Studies on Alternative Powertrain Technologies, Frankfurt,
Germany, 2020. Accessed: Sep. 06, 2021. [Online]. Available: www.frontier-
economics.com.
... Maintenance, repair, and overhaul of aircraft with novel propulsion concepts -Analysis of environmental and economic impacts technological innovations are needed to generate further progress toward sustainable aviation [6]. Promising approaches are battery-electric propulsion concepts consisting of propellers powered by electric motors and a battery system for energy storage applicable in regional and short-range aircraft [7][8][9] and hydrogen and fuel cell-based propulsion concepts consisting of propellers powered by electric motors, a battery system for energy storage and a fuel cell system for generating electricity from hydrogen applicable in short-and medium-range aircraft [10]. Furthermore, synthetic fuels burned in conventional jet engines are a promising solution for medium-and long-range aircraft [11]. ...
... The different components of the propulsion concepts are modeled in the foreground system and are taken from our previous studies [7,9,10]. Background data from the ecoinvent 3.8 database with the system model "allocation, cut-off by classification" is used to model raw materials and supplies [38]. ...
... As an illustration, Sustainable Aviation Fuels (SAF) are more expensive and rarer than conventional jet fuel, and their cultivation may compete with food crops and biodiversity for land and water resources (Chiaramonti et al., 2021). Given their infancy and the limitations imposed by their weight and energy density, electric and hydrogen aircraft may not be suitable for long-haul flights (Barke et al., 2022). Offsetting one's carbon footprint needs the existence and credibility of emission reduction initiatives in other sectors or regions, which may not bring long-term and extra benefits or may even have adverse consequences on local communities and ecosystems . ...
... Transport is responsible for a significant portion of greenhouse gas emissions, which poses a serious challenge for environmental protection and public health. In the European Union in 2021, transport accounted for approximately 24.1% of all greenhouse gas emissions, with the largest share coming from road transport emissions, constituting 76% of total transport emissions [1][2][3]. ...
Article
Full-text available
This paper presents a summary and review of life cycle sustainability assessment (LCSA) methods for the transport sector. The paper provides a comprehensive overview of articles that employ a variety of methods for assessing sustainable development in the transport sector, taking into account the economic, social, and environmental dimensions. In the sustainability assessment of transport, three methods were evaluated: life cycle assessment (LCA), life cycle cost analysis (LCC), and social life cycle assessment (SLCA). An overview of sustainability assessment methods in transport and a review of the indicators used in the life cycle sustainability assessment was conducted. It was found that the selection of indicators within the LCSA for assessing various aspects of sustainable development is dependent on various geographic and policy contexts. An overview of the application of multi-criteria decision analysis (MCDA) methods to assess LCSA in the transport sector was performed. MCDA methods are used to support decision-making regarding the selection of the most sustainable transport options and allow for the simultaneous consideration of multiple criteria, enabling a more sustainable assessment of different transport options. MCDA methods help to rank alternative transportation fuels and help decision-makers consider indicators encompassing economic, environmental and social aspects.
... However, most aircraft LCAs focus solely on climate change impacts and present a low level of detail and transparency (Rupcic et al., 2023). The carbon footprint of hybrid-electric aircraft is thus often performed in literature based on preliminary design outputs such as hybridization degree, energy requirements, fuel consumption, and weight (Barke et al., 2022;Johanning and Scholz, 2014;Melo et al., 2023;Ribeiro et al., 2020;Scholz et al., 2022). This limited the interpretation of these rough carbon footprints, which indicated that hybridization would perform better than conventional aircraft for a given mission but did not allow for hotspot analysis due to a lack of technical specifications of the power train technology and the coarse granularity of the impact assessment. ...
... Des analyses comparatives sont menées pour différencier les performances environnementales d'architectures avion. Par exemple, des avions électriques et conventionnels sont comparés dans [33]. De même, des avions à hydrogène sont comparés à des avions conventionnels [218] et plus électriques [30]. ...
Thesis
Full-text available
Le transport aérien est à ce jour responsable de 2 à 3 % des émissions mondiales de CO2, ainsi que d'autres impacts climatiques et environnementaux. Les nouveaux concepts d'architectures pouvant contribuer à la réduction de l’impact environnemental de l'aviation suscitent donc un grand intérêt. L’objectif de cette thèse est de contribuer au développement d’une approche holistique, allant de la modélisation et du dimensionnement de nouvelles architectures avion à la simulation de scénarios prospectifs durables pour le transport aérien. Cette approche permet ainsi de relier les enjeux de la conception avion à ceux de l’analyse de scénarios prospectifs pour l’aviation. Dans une première partie, des modèles d'estimation pour différents systèmes avion sont présentés dans le cadre d’un avion plus électrique. Des méthodes variées sont appliquées, par exemple basées sur l’utilisation de modèles énergétiques ou de modèles de régression. Les systèmes de conditionnement d’air et de protection contre le givre sont étudiés, tout comme les systèmes induits par l’électrification des avions (génération et distribution de puissance électrique, management thermique). Dans une deuxième partie, une architecture avion déployable à court terme est dimensionnée à travers une approche basée sur l’utilisation de la plateforme de conception avion FAST-OAD. Cette architecture intègre les systèmes décrits précédemment, dont les performances sont préalablement évaluées individuellement via des modèles spécifiques, ainsi que des améliorations propulsives et aéro-structurelles. Les caractéristiques de l'architecture complète sont alors analysées, notamment concernant ses impacts environnementaux à partir d'un module d'analyse de cycle de vie développé pour FAST-OAD.Dans une dernière partie, l'outil CAST développé dans cette thèse est présenté. Il permet de simuler et d'évaluer des scénarios prospectifs pour le transport aérien. Des modèles sont détaillés pour les différents leviers d’action permettant de réduire l'impact environnemental du transport aérien. Une attention particulière est portée sur l’introduction d’architectures plus efficaces dans la flotte. Pour évaluer la durabilité des scénarios, des méthodologies spécifiques sont proposées pour les enjeux climatiques et énergétiques, en s'appuyant par exemple sur la notion de budget carbone. Plusieurs applications montrent alors le bénéfice des nouvelles technologies mais aussi le besoin d’un arbitrage entre le niveau de trafic aérien et la part du budget carbone mondial allouée au secteur aérien.
Chapter
The aviation sector is responsible for 2.4 % of global anthropogenic greenhouse gas emissions. Based on current growth predictions, air traffic is expected to increase by 3.7 % annually, making the aviation sector one of the largest long-term emitters of anthropogenic greenhouse gases. Counteracting this trend is a crucial challenge the aviation sector has set itself with the Flightpath 2050 strategy. While offsetting mechanisms, optimized flight management, and improved propulsion concepts have already led to a slight reduction in emissions, technological innovations in propulsion concepts and energy sources will be necessary to achieve the Flightpath 2050 goal. One promising approach for regional-, short- and medium-range flights is the use of green hydrogen as an alternative energy carrier. Its production from renewable energy sources and subsequent use releases no carbon dioxide emissions. However, it is unknown much hydrogen will be needed for the aviation sector and how this demand will change over time. To this end, this paper develops forecasting approaches for the hydrogen demand of the German aviation sector until 2050. Growth forecasts for the aviation sector until 2050 are developed in the first step. Subsequently, market entry scenarios for hydrogen-based propulsion concepts are developed before determining the hydrogen demand for different flight distances. Based on the growth forecasts, the market entry scenarios, and the hydrogen demand per flight, demand forecasts for green hydrogen until 2050 are developed. Our analyses show that the demand for green hydrogen in the German aviation sector cannot be met with current production capacities. However, green hydrogen is also needed in other sectors for a transformation process towards a low-emission industry, making hydrogen imports mandatory to meet the overall demand.
Article
Reducing greenhouse gas emissions has become a priority for civil transport aviation. One of the possible solutions investigated by current aeronautics research is the introduction of electric propulsion, which would drastically reduce greenhouse gas emissions related to flight. This paper addresses this topic in depth; the work is structured in two intertwined parts. The first relates to an extensive review of the state of the art, starting with the analysis of electrical technology enablers for aviation applications, and leading to the investigation of current proposals of aircraft conceptual designs, both for short-medium range and regional class. This review section, which is presented with a critical approach, provides the relevant indications for the definition of the technical framework of the second part of the paper, in which the conceptual development of a novel hybrid-electric aircraft is proposed. Specifically, the outcomes from the analysis of the state of the art suggest that the hybrid-electric aircraft should belong to the regional category, and that energy efficient solutions for the airframe should be considered. Moreover, potentials and limitations of integrating hybrid-electric propulsion are carefully detailed, and reasonably realistic technology levels for the next decade have been selected for the design of the proposed aircraft. A box-wing airframe architecture has been adopted as it has the potential to minimize induced aerodynamic drag while increasing the load transport capacity, thus representing an aerodynamic efficient solution. A design and optimization framework has been developed to evaluate the integration of the hybrid-electric propulsion with the box-wing lifting system. The coupling of these two technologies, together with a paradigm change in the aircraft design approach, allow to identify conceptual solutions that minimize fuel consumption throughout the typical regional mission envelope, leading to a potential emission-free regional aircraft.
Chapter
From an environmental perspective, green hydrogen is a promising alternative energy carrier for short-to middle-range flights. Furthermore, hydrogen produced from renewable energy releases no carbon dioxide emissions during production and use. Therefore, hydrogen is a potential solution for reducing aviation-related emissions. Besides, the economic competitiveness of hydrogen against conventional fuels, mainly influenced by the hydrogen supply chain design, will be a key determinant for future hydrogen deployment. The supply chain consists of production, compression, transportation, and liquefaction, but these components’ exact order, sizing, and location are still insecure. Different transport options exist, which are associated with various economic impacts during their purchase and use, as well as various supply chain configurations result in different overall expenses. We analyze demand and distance scenarios using an expense-oriented economic evaluation with CAPEX and OPEX to determine the best transport configuration. The total expenses of hydrogen are highly influenced by the expenses caused by energy and transport volume. Here, pipeline transportation is a promising option, as well as liquid hydrogen truck transportation in cryogenic tanks. It turns out that distance and demand for hydrogen strongly influence the choice of transportation.
Article
Full-text available
Purpose This paper aims at assessing the alignment of eight of the Life Cycle Initiative’s ten principles for life cycle sustainability assessment (LCSA) and the LCSA practice as well as the challenges to reaching the full implementation of the principles as a basis for a harmonized framework. Materials and methods To understand the extent of alignment of existing LCSA studies with the principles, 193 case studies published before the Life Cycle Initiative’s ten principles’ publication were identified. Their levels of alignment were assessed against the criteria designed per principle: full, medium, or no alignment. The principles of “materiality of the system boundaries” and “consistency” could not be assessed as most studies lacked related background information; hence, no objective nor systematic criteria could be designed. Results The alignment of practice with the principles is variable: The vast majority of studies cover the 3 pillars (principle 3 on completeness). Principle 9 (communication of trade-offs) is well addressed in the case studies. Principles 2 (alignment with the phases of ISO 14040: 2006 standard), 4 (taking into account perspectives of key stakeholders), and 8 (transparency) were not properly addressed in a majority of case studies. Principles 1 (understanding the areas of protection and impact pathways), 5 (taking into account product utility beyond functional unit (co-benefits)), and 10 (caution when compensating negative and positive impacts) remain to be implemented as some methodological challenges have to be overcome. Principles 6 and 7 were not assessed. Conclusions LCSA is gaining momentum due to the communication and dissemination of LCSA among practitioners, potential users, and decision-makers in the public and private sectors. However, some key challenges remain for reaching the implementation of the principles: understanding of the inter-relationships between the three dimensions of sustainability to build impact pathways and select relevant impact categories for LCSA, guidance for communicating trade-offs and decision-making based on LCSA, and generalizing the (open) access to publications and related supplementary information.
Article
Full-text available
The use of novel battery technologies in short‐haul electric aircraft can support the aviation sector in achieving its goals for a sustainable development. However, the production of the batteries is often associated with adverse environmental and socio‐economic impacts, potentially leading to burden shifting. Therefore, this paper investigates alternative technologies for lithium–sulfur all‐solid‐state batteries (LiS‐ASSBs) in terms of their contribution to the sustainable development goals (SDGs). We propose a new approach that builds on life cycle sustainability assessment and links the relevant impact categories to the related SDGs. The approach is applied to analyze four LiS‐ASSB configurations with different solid electrolytes, designed for maximum specific energy using an electrochemical model. They are compared to a lithium–sulfur battery with a liquid electrolyte as a benchmark. The results of our cradle‐to‐gate analysis reveal that the new LiS‐ASSB technologies generally have a positive contribution to SDG achievement. However, the battery configuration with the best technical characteristics is not the most promising in terms of SDG achievement. Especially variations from the technically optimal cathode thickness can improve the SDG contribution. A sensitivity analysis shows that the results are rather robust against the weighting factors within the SDG quantification method.
Conference Paper
Full-text available
The Flightpath 2050 strategy sets ambitious goals for aviation to reduce its environmental impacts. Therefore, new propulsion concepts that avoid in-flight emissions are being developed. Particular attention is given to (hybrid) electric propulsion systems based on batteries, fuel cells, and synthetic fuels that replace the conventional jet engines. This paper assesses the environmental, economic, and social impacts of eight potential battery systems for short-range aircraft from a life cycle perspective and conducts a pre-selection of suitable technologies. The results indicate that lithium-sulfur batteries are advantageous compared to lithium-ion batteries in terms of environmental as well as social and economic impacts.
Article
Full-text available
Aviation is one of the most important global economic activities in the modern world. Aviation emissions of CO2 and non-CO2 aviation effects result in changes to the climate system (Fig. 1). Both aviation CO2 and the sum of quantified non-CO2 contributions lead to surface warming. The largest contribution to anthropogenic climate change across all economic sectors comes from the increase in CO2 concentration, which is the primary cause of observed global warming in recent decades (IPCC, 2013, 2018).
Conference Paper
Full-text available
The development of novel aircraft based on electric propulsion is a key strategy to achieve emission reductions in the aviation sector despite the continuously growing demand for air travel. Most sustainability assessments of aircraft focus on environmental indicators and neglect important socio-economic aspects. We address this gap by developing a conceptual framework for the socio-economic sustainability assessment of aircraft with novel propulsion systems. The framework considers the specific requirements for socio-economic sustainability in the aviation sector and builds on established methods such as life cycle costing and social life cycle assessment to complement the environmental perspective in sustainability assessments.
Article
Full-text available
Driven by concerns regarding the sustainability of aviation and the continued growth of air traffic, increasing interest is given to emerging aircraft technologies. Although new technologies, such as battery-electric propulsion systems, have the potential to minimise in-flight emissions and noise, environmental burdens are possibly shifted to other stages of the aircraft’s life cycle, and new socio-economic challenges may arise. Therefore, a life-cycle-oriented sustainability assessment is required to identify these hotspots and problem shifts and to derive recommendations for action for aircraft development at an early stage. This paper proposes a framework for the modelling and assessment of future aircraft technologies and provides an overview of the challenges and available methods and tools in this field. A structured search and screening process is used to determine which aspects of the proposed framework are already addressed in the scientific literature and in which areas research is still needed. For this purpose, a total of 66 related articles are identified and systematically analysed. Firstly, an overview of statistics of papers dealing with life-cycle-oriented analysis of conventional and emerging aircraft propulsion systems is given, classifying them according to the technologies considered, the sustainability dimensions and indicators investigated, and the assessment methods applied. Secondly, a detailed analysis of the articles is conducted to derive answers to the defined research questions. It illustrates that the assessment of environmental aspects of alternative fuels is a dominating research theme, while novel approaches that integrate socio-economic aspects and broaden the scope to battery-powered, fuel-cell-based, or hybrid-electric aircraft are emerging. It also provides insights by what extent future aviation technologies can contribute to more sustainable and energy-efficient aviation. The findings underline the need to harmonise existing methods into an integrated modelling and assessment approach that considers the specifics of upcoming technological developments in aviation.
Article
Full-text available
The undeniable environmental ramifications of continued dependence on oil-derived jet fuel have spurred international efforts in the aviation sector toward alternative solutions. Due to the limited options for decarbonization, the successful implementation of bio-aviation fuel is crucial in contributing to the roster of greenhouse gas emissions mitigation strategies for the aviation sector. Since fleet replacement with low-carbon technologies may not be a feasible option, due to the long lifetime and significant capital cost of aircraft, “drop-in” alternatives, which can be used in the engines of existing aircraft in a seamless transition, may be required. This paper presents a detailed analysis of the supply chain components of bio-aviation fuel provision: feedstocks, production pathways, storage, and transport. The economic and environmental performance of different potential bio-feedstocks and technologies are investigated and compared in order to make recommendations on short- and long-term strategies that could be employed internationally. Hydroprocessed esters and fatty acids production pathway, utilizing second-generation oil-seed crops and waste oils, could be an effective immediate solution with the potential for substantial greenhouse gas emissions savings. Microalgal oil could potentially offer far greater yields of bio-aviation fuel and reductions in greenhouse gas emissions, but the technology for large-scale algae cultivation is inadequately mature at present. Fischer-Tropsch production pathway using lignocellulosic biomass has the potential for the highest greenhouse gas emissions savings, which could potentially be the solution within the medium- to long-term plans of the aviation industry, but further research and optimization are required prior to its large-scale implementation due to its limited technological maturity and high capital costs. In practice, the “ideal” feedstocks and technologies of the supply chains are heavily dependent on spatial and temporal criteria. Moreover, many of the parameters investigated are interlinked to each other and the measures that are effective in greenhouse gases emissions reduction are largely associated with increased cost. Hence, policies must be streamlined across the supply chain components that could help in the cost-effective and sustainable deployment of bio-aviation fuel.
Article
Full-text available
Life cycle assessment (LCA) analysts are increasingly being asked to conduct life cycle‐based systems level analysis at the earliest stages of technology development. While early assessments provide the greatest opportunity to influence design and ultimately environmental performance, it is the stage with the least available data, greatest uncertainty, and a paucity of analytic tools for addressing these challenges. While the fundamental approach to conducting an LCA of emerging technologies is akin to that of LCA of existing technologies, emerging technologies pose additional challenges. In this paper, we present a broad set of market and technology characteristics that typically influence an LCA of emerging technologies and identify questions that researchers must address to account for the most important aspects of the systems they are studying. The paper presents: (a) guidance to identify the specific technology characteristics and dynamic market context that are most relevant and unique to a particular study, (b) an overview of the challenges faced by early stage assessments that are unique because of these conditions, (c) questions that researchers should ask themselves for such a study to be conducted, and (d) illustrative examples from the transportation sector to demonstrate the factors to consider when conducting LCAs of emerging technologies. The paper is intended to be used as an organizing platform to synthesize existing methods, procedures and insights and guide researchers, analysts and technology developer to better recognize key study design elements and to manage expectations of study outcomes.
Article
Full-text available
Ever since the Wright brothers’ first powered flight in 1903, commercial aircraft have relied on liquid hydrocarbon fuels. However, the need for greenhouse gas emission reductions along with recent progress in battery technology for automobiles has generated strong interest in electric propulsion in aviation. This Analysis provides a first-order assessment of the energy, economic and environmental implications of all-electric aircraft. We show that batteries with significantly higher specific energy and lower cost, coupled with further reductions of costs and CO2 intensity of electricity, are necessary for exploiting the full range of economic and environmental benefits provided by all-electric aircraft. A global fleet of all-electric aircraft serving all flights up to a distance of 400–600 nautical miles (741–1,111 km) would demand an equivalent of 0.6–1.7% of worldwide electricity consumption in 2015. Although lifecycle CO2 emissions of all-electric aircraft depend on the power generation mix, all direct combustion emissions and thus direct air pollutants and direct non-CO2 warming impacts would be eliminated. © 2018, The Author(s), under exclusive licence to Springer Nature Limited.
Article
Full-text available
Purpose A scalable life cycle inventory (LCI) model, which provides mass composition and gate-to-gate manufacturing data for a power electronic inverter unit intended for controlling electric vehicle propulsion motors, was developed. The purpose is to fill existing data gaps for life cycle assessment (LCA) of electric vehicles. The model comprises new and easy-to-use data with sufficient level of detail to enable proper component scaling and in-depth analysis of inverter units. The aim of this article (part II) is to describe the modeling of all production steps and present new datasets. Another objective is to explain the strategies for data collection, system boundaries, and how unit process datasets were made to interact properly with the scalable design model (part I). Methods Data for the manufacturing of the inverter unit was collected from a variety of literature, technical specifications, factory data, site visits, and expert interviews. The model represents current levels of technology and modern industrial scale production. Industry data dates back to 2012. Some older literature is referred to, but only if it was found to remain relevant. Upstream, new data has been gathered to the point where the Ecoinvent database can be used to model a full cradle-to-gate inventory. To make the LCI model easy to use, each flow crossing the system boundary is reported with a recommended linked flow to this database. Results and discussion The screening and modeling of manufacturing inverter units resulted in a substantial compilation of new inventory data. In close integration with the design model, which is scalable in size over a range of 20–200 kW in nominal power and 250–700 V in DC system voltage (part I), it forms a comprehensive scalable LCI model of a typical automotive power electronic inverter unit intended for traction motor control. New production data covers electroplating of gold, electro-galvanization, machining and anodizing of aluminum, ceramic substrate fabrication, direct copper bonding, photoimaging and regenerative etching, power module assembly with a two-step soldering process, and the assembly of automotive printed circuit boards. Conclusions Interviews with experts were found to be vital for effective data collection and the reporting of details a key to maintaining data usability over time, for reuse, rework, and criticism by other LCA practitioners.
Article
Aviation emissions contribute adversely to climate change and air pollution due to combustion emissions. While biofuels can reduce the lifecycle CO2 emissions and combustion soot emissions, and hybrid- or turbo-electric aircraft may result in reduced fuel burn and overall emissions, only all-electric aircraft offer a potential opportunity for zero in-flight emissions in the long term. Over the past decade, more than 70 all-electric conceptual, experimental, and commercial aircraft have been researched, with a particular focus on light aircraft. These designs are reviewed, along with progress in battery technology. An all-electric aircraft design and optimization program, TASOPTe, has been developed from an existing version for conventionally-powered aircraft, TASOPT. Both programs are largely based on first-principles, enabling the design of aircraft with unusually short design ranges. A series of optimized 180-passenger aircraft based on the Airbus A320neo configuration are designed and evaluated at 200–1600 nmi design ranges with 2–10 propulsors and 400–2000 Wh/kg batteries. The performance of these all-electric aircraft is compared to advanced conventionally-powered aircraft optimized for the same design ranges. Optimized all-electric aircraft are found to use two or four propulsors, depending on the design range and specific energy assumed. The design range limits for each specific energy are determined, which are restricted by aircraft weight and performance penalties. A factor of four increase in battery pack specific energy from current values of 200 Wh/kg to 800 Wh/kg enables 500 nmi flights. However, lower design ranges provide improved energy and environmental performance. The required grid power generation characteristics for commercial all-electric aircraft to become net environmentally beneficial are determined for each specific energy assumption. The entire energy conversion chain, including charging, transport, and discharging of electrical energy, is considered. Despite the higher total energy use, narrow-body all-electric aircraft have the potential for lower equivalent CO2 emissions than conventionally-power aircraft if the electrical grid transitions toward renewable energy. This is largely enabled by the complete elimination of all high-altitude emissions, which would remove associated non-CO2 warming.