IEEE Electrification Magazine - December 2019 - 23

alternative fuels, electrification, and an increased level of automated systems (with the additional objective of reducing the number of accidents).
As electrification and automation of transportation systems in cities are likely to become a reality in the
near future, Gothenburg and its proximity to Göta älv could serve as an example for how waterways could
be utilized to effectively implement new, environmentally friendly ferries. Currently, the transriver traffic in
Gothenburg is operated by the local company Styrsöbolaget, which has a clear environmental policy and is
actively working with energy optimization on its fleets. Two of its ferries, one of which is shown in Figure 1,
are also prepared for battery operation but have yet to be converted due to technical challenges associated
to energy storage and minimization of consumption.
To overcome these limitations, the problem of automation and electrification of ferries can be approached
as an optimization problem, one in which the objective is to reach the destination with minimal cost, while
maintaining efficiency and safety. The purpose of this article is to give a better understanding of the problems
associated with the transition to battery-operated ferries and suggest possible research lines, whereas the
final long-term goal, in a potential continuation of the project, is to prepare a demonstrator for automated
transverse river ferries to operate on Göta älv, which would tie different parts of Gothenburg together.

Motivation

MAP-©ISTOCKPHOTO.COM/FRANK RAMSPOTT, WHEEL-©ISTOCKPHOTO.COM/EKAZANSK

Energy efficiency is currently one of the most important topics in the shipping industry. As illustrated in Figure 2, maritime transportation is responsible for emitting approximately 1,016 million tons of carbon dioxide (CO2) annually, which accounts for roughly 3.1% of global greenhouse
gas emissions. Even more relevant are the sulphur oxide and nitrogen
oxide emissions, which represent 5-10% and 17-30% of total global emissions, respectively. Emissions from shipping are estimated to increase by
50 to 250% by 2050, depending on future economic growth in the sector.
This is not consistent with internationally agreed-upon goals, however,
which require worldwide emissions to be at least halved from 1990 levels
by 2050. The European Union has recommended that CO2 emissions from
maritime transportation be cut by at least 40% from 2005 levels by 2050
(and, if feasible, by 50%). Related to this, Gothenburg has a clear vision of
increasing public transportation use within the city.
For all these reasons, industry and research are working together to
further the electrification and automation of shipping as a means to
reduce pollution. Unfortunately, full electrification is not yet considered
economically feasible due to the high cost of batteries and the low energy
density of electrochemical storage compared to that of fossil fuels; but,
fortunately, automation and related technologies are contributing toward
achieving this ambitious target by increasing the global efficiency of vessels. Intelligent control does help to reduce battery requirements via consumption optimization as well as their onboard weight by reducing the
size of the deck house, crew quarters, and elements of the ventilation,
heating, and sewage systems to a minimum.
It is worth mentioning that while driverless cars require high computational capacity to work at a reasonable velocity, the cruising speed of vessels is relatively low, making modern computing technology applicable for
autonomous shipping in the near future. Automation and electrification
are likely to play a very important role in the future of maritime vessels.
Already, by the end of this decade, fully autonomous shipping may
become a reality, whereas full electrification may take longer due to difficulties in the development of new battery technologies.
In recent decades, automation and electrification in maritime technology have been investigated using common control theory approaches that
expand the possible domain of robotic technologies to the maritime field.
Classical control theory offers a solution to the autonomous navigation
problem when all of the parameters of the system, including the vessel, the
sea, and the environment, are fully known. Still, even with the use of novel
optimal control strategies, the gap between navigation assistance and fully
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IEEE Electrification Magazine - December 2019

Table of Contents for the Digital Edition of IEEE Electrification Magazine - December 2019
