IEEE Electrification Magazine - June 2020 - 33

fire during the test run, the FC and hydrogen storage
were not harmed, which attests to the suitability of the
hydrogen concept.

Cell Voltage (V)

In 2006, during a joint program, Nemo H 2 , was introduced
to demonstrate the successful integration and safe operation of a PEMFC, energy storage system, and hydrogen
storage onboard. Nemo H 2 is an 82-passenger ferry with a
65-kW PEMFCs using hydrogen as a fuel, 30-50-kW battery, and 40-kg hydrogen storage onboard at 350 bars.

The Raicho Project at Tokyo University of Marine Science
and Technology has developed two pure electric boats
with a lithium-ion battery that can be charged rapidly on
the CHAdeMO protocol since 2008. The third-version boat
Raicho N (19 ton) was built in 2014. It has twin main
thrusters and one side thruster that are controlled and
maneuvered fully by electronics, even out of the boat. The
power system was designed as a double system, which
means that the port and starboard sides have a similar
powertrain and control system, respectively, for realizing
high redundancy. It was also a hybrid power system that
had two power sources, a 132-kWh lithium-ion battery in
total and small gasoline engine as a range extender. The
engine was removed and converted to the FC package in
2017. The FC package operation has been checked under
actual sea conditions in salty atmosphere, pitching and
rolling, and various load fluctuation conditions.

The Hybrid Power Lab at the Norwegian
University of Science and Technology
Two 30-kW (60 kW) PEMFCs are used at the Hybrid Power
Laboratory at the Norwegian University of Science and Technology (NTNU) to test a complete marine power system in a
scaled-down laboratory environment. Integration, control,
and safety of FC technology in marine applications are
some of the main objectives of this joint project. The project
is a collaboration of the ABB, SINTEF Ocean, and NTNU.
When it comes to a global scale, FC technology is still
immature. Hence, to become a realistic alternative to the
existing power supply for ships, several technical challenges

0.8

Voltage Drops Linearly

0.7

Voltage Starts to
Fall Highly

0.6
0.5
0.4
0.3

MARANDA

The Raicho Project for Next-Generation
Water Transportation

Rapid Initial Fall in Voltage

0.9

Nemo H2

MARANDA focuses on the major obstacle for the implementation of FCs in marine applications, which is the
hydrogen infrastructure. A total of 165 kW (2 × 82.5 kW) of
hydrogen-fueled PEMFCs were installed and hybridized
with a battery pack on both bench tests and onboard in
conditions similar to an Arctic marine environment.
MARANDA included ABB Marine and Ports and other companies from the whole FC value chain with the aim of
increasing the market potential of hydrogen FCs in the
marine sector.

Polarization Curve

0.2

200 400 600 800 1,000 1,200 1,400 1,600
Current Density (mA/cm2)

Figure 5. The polarization curve of a typical PEM FC.

that exist in FC technology must be sorted. This article
reviews some of these challenges and control strategies
related to promoting FC efficiency and operation.

Power System Integration and
Energy Conversion
FCs can be fully integrated into an all-electric hybrid
power system though power electronics. The FC output
voltage and current are defined based on the FC's polarization curve, which is a plot of the FC voltage against
current density under specific operating conditions.
The polarization curve is obtained based on three types
of losses in the FC including activation polarization,
ohmic, and concentration polarization losses. A polarization curve of a typical PEM FC is provided in Figure 5.
At low current densities up to 200 mA /cm 2, which is
called the active polarization region, there is a rapid initial
fall in the stack output voltage because of the oxygen
reduction reaction. The voltage loss in the middle part of
the curve is dropping almost linearly with current density.
This loss is due to the ohmic resistance to the ions flowing
inside the electrolyte. This region is called ohmic polarization. During higher current densities, the voltage experiences a dramatic drop due to the transport of the reactant
gas through the electrocatalyst layers. Mostly, the FC is
operating optimally in the ohmic polarization region since
both the rapid initial voltage drop during startup and current increase can be avoided.
To see the maximum power density that a cell can
reach, the power density versus current density can be
plotted with the polarization curve, which is demonstrated
in Figure 6. It is not optimal for the FC to work beyond
this maximum power operating point, as the power will
be the same at a lower current and higher voltage. At this
point, the internal resistance of the cell is equal to the
electrical resistance of the external circuit. Hence, there
is always a tradeoff between high power and high efficiency, and FC designers should select the proper

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IEEE Electrification Magazine - June 2020

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