This document summarizes a comparative life cycle assessment of conventional and all-electric car ferries. The study compares an all-electric catamaran ferry made of aluminum to a conventional steel monohull ferry powered by either marine diesel oil or liquefied natural gas. The objective is to identify the most environmentally friendly alternative and areas for improvement. The analysis models four ferry alternatives according to LCA principles and assesses their impacts across 18 categories using the Ecoinvent database. Results show the all-electric ferry performs better in categories linked to fossil fuels but worse in toxicity categories. Operation has the largest contribution to impacts except for metal depletion in conventional steel ferries. The results are sensitive to electricity source modeling.

1. A Comparative Life Cycle
Assessment of Conventional and
All-Electric Car Ferries
Introduction
Increased environmental focus on the marine transport sector, and especially focus
on its effect on global warming, has initiated the deployment of all-electric
propulsion. This thesis quantifies the environmental impacts of four ferry
alternatives using the method of life cycle assessment (LCA). An all-electric
catamaran in aluminum is compared to a conventional monohull in steel run on
marine diesel oil (MDO), and the same lightweight design as the all-electric ferry
using liquefied natural gas (LNG) and MDO as energy carriers.
Objective
The objective of this work is to perform a comparative LCA of an all-electric ferry
in order to get insights to what alternative is the most environmentally friendly and
to identify where the largest improvement potential is. A transparent dataset should
also be provided as the current studies within the field are somewhat incomplete in
order to provide a basis for future studies.
Scope
In order to complete the objective of carrying out a comparative LCA a specific
ferry route and two ferry designs were chosen as the basis for the analysis. The
modelling of the different alternatives according to LCA principles as well as data
collection and estimation followed before the interpretation of the results.
Life Cycle Asessment
Life cycle assessment is a method to assess environmental impact from products and product
systems where emphasis has been put on consistency when comparing different technologies
(Strømman, 2010). All environmental impacts, both direct and indirect, are desirable to include in
an LCA. This is to avoid problem shifting which means to decrease impacts on expense of
increasing impacts either in other places in the value chain or other impact types. Examples of this
are increasing production impacts when trying to decrease the burdens from end of life treatment
or just looking at one impact category such as global warming and neglecting all other impacts.
In this analysis the impacts are given in 18 different categories, linked to different environmental
problems or public concerns, called mid-point indicators. The mid-point indicators can be
weighted further to evaluate the consequences for human life, ecosystems quality and resource
depletion. Three viewpoints are used: egalitarian, hierarchist and individualist. The egalitarian
represents a long term, careful and argument-based view. Individualists are looking at short-term
and require indisputable cause and effect relations in order to take actions. Hierarchists are
somewhere in between, being risk neutral and looking at intermediate time horizon.
The software used were Arda Gui, version 18.1, an educational LCA software developed at the
Industrial Ecology Programme under Department of Energy and Process Engineering at NTNU. It
requires an input template in Microsoft Excel and uses the Ecoinvent 2.2 database for
commodities such as materials and electricity.
Results
Results in all impact categories are presented in figure 1 for the hierarchist viewpoint, they all have different units of a typical pollutant or attribute relevant to the environmental issue or
public concern. The ferry is run on the average Norwegian electricity supply mix modelled by the Ecoinvent database and impacts are divided in the processes battery/engine, hull and
operation.
Figure 1: Results for all impact categories.
The all-electric ferry outperforms the conventional alternatives in impact categories linked to combustive stressors and fossil fuels such as climate change, photochemical oxidant formation,
particulate matter formation, fossil fuel depletion. When looking at terrestrial acidification the all-electric and LNG ferry are significantly better than the ferries run on marine diesel oil due to
no sulphur in the fuel. The electrical ferry has larger impact in all categories concerning toxicity except terrestrial ecotoxicity. Operation is the phase with largest contribution to all impact
categories except metal depletion for the conventional steel ferry.
0
100
200
300
EL Conv. LNG MDO
kgCO2eq
Climate Change
Operation Hull Battery/Engine
0,00E+00
2,00E-05
4,00E-05
EL Conv. LNG MDO
kgCFC-11eq
Ozone Depletion
Operation Hull Battery/Engine
0
10
20
EL Conv. LNG MDO
kgSO2eq
Terrestrial
Acidification
Operation Hull Battery/Engine
0
0,01
0,02
EL Conv. LNG MDO
kgPeq
Freshwater
Eutrophication
Operation Hull Battery/Engine
0
0,1
0,2
EL Conv. LNG MDO
kgNeq
Marine
Eutrophication
Operation Hull Battery/Engine
0
10
20
EL Conv. LNG MDO
kgU235eq
Ionising Radiation
Operation Hull Battery/Engine
0
10
20
30
EL Conv. LNG MDO
kg1,4-DBeq
Human Toxicity
Operation Hull Battery/Engine
0
0,01
0,02
EL Conv. LNG MDO
kg1,4-DBeq
Terrestrial Ecotoxicity
Operation Hull Battery/Engine
0
0,2
0,4
0,6
EL Conv. LNG MDO
kg1,4-DBeq
Freshwater Ecotoxicity
Operation Hull Battery/Engine
0
1
2
EL Conv. LNG MDO
m^2
Agricultural Land
Occupation
Operation Hull Battery/Engine
0
0,5
EL Conv. LNG MDO
m^2
Urban Land
Occupation
Operation Hull Battery/Engine
0
0,05
0,1
EL Conv. LNG MDO
m^2
Natural Land
Transformation
Operation Hull Battery/Engine
0
200
400
600
EL Conv. LNG MDO
m^3
Water Depletion
Operation Hull Battery/Engine
0
5
10
EL Conv. LNG MDO
kgFeeq
Metal Depletion
Operation Hull Battery/Engine
0
50
100
EL Conv. LNG MDO
kgoileq
Fossil Depletion
Operation Hull Battery/Engine
0
0,2
0,4
0,6
EL Conv. LNG MDO
kg1,4-DBeq
Marine Ecotoxicity
Operation Hull Battery/Engine
0
5
10
EL Conv. LNG MDO
kgNMVOC
Photochemical
Oxidant Formation
Operation Hull Battery/Engine
0
2
4
EL Conv. LNG MDO
kgPM10eq
Particulate Matter
Formation
Operation Hull Battery/Engine
Annelise Berentsen Kullmann (anneliseb.kullmann@gmail.com)
Supervisor: Prof. Bjørn Egil Asbjørnslett, Assistant Prof. Svein Aanond Aanondsen
Conclusion
A comparative LCA of an all-electric ferry has been carried out and the results show similar
tendencies as electrical cars with an decrease in categories linked to fossil fuel usage and
increases in many categories regarding toxicity.
References
Strømman, A. H. (2010). Methodological Essentials of Life Cycle Assessment.
Acknowledgements
I would like to thank my supervisors professor Bjørn Egil Asbjørnslett and assistant professor
Svein Aanond Aanondsen for help with my work. In addition researcher Linda Ager-Wick
Ellingsen has provided data on battery production and helped scaling these. Researcher Evert
Bouman has been of considerable help in LCA methodology and modelling. Lastly I would
like to thank professor Sverre Steen and professor Eilif Pedersen for being available for my
questions.
Discussion
Severeal methods of aquiring data have been utilized and the data used in the study
therefore have different quality. Sensitivity analysis on electricity mix, metal used for hull
and engines, the number of trips per lifetime and battery life were therefore executed. The
results prove to be sensitive to electricity mix used, and this is illustrated in figure 2 for
climate change.
Figure 2: Climate change impacts for different electricity mixes, CN is Chineese supply mix, UTCE is an
Europeean supply mix, NORDEL is the average production mix from Norway, Sweden, Denmark and Finland.