Jesper Lidqvist presents his master’s thesis

Student: Jesper Lidqvist
Main Supervisor: Maria Granh
Examiner: Selma Brynolf
Opponent: Hugo Sandolf

Abstarct

With the drive to decarbonize the majority of transport sectors, the shipping industry
has developed a selection of different concepts to lower the emissions of different
ship-types. Different fuel in form of e-fuels, bio-fuels and gaseous fuels like hydrogen
and natural gas are promising developments. With the change of fuel types different
power conversion technologies comes in to question, with the fuel cell being of interest
thanks to it’s high efficiency and in the case of the PEM type fuel cell powered
by hydrogen, no emissions while producing power.
This work evaluates the implementation of a hydrogen fueled PEM fuel cell power
system onboard a cruise ship, describing the original studied ships system and the
parameters that governs the fuel cells, modeling the use of the fuel cells to meet
the power demand over several different case days in different setups, and testing
several types of system to fulfill the heat demand of the vessel for the same cases.
Also evaluating the effects of changed demand for heat and power, and resulting
fuel consumption and efficiency of the different setups are presented and discussed.
Higher efficiency where found where the load factors of the fuel cells where low, indicating
the potential of an oversized power generating system. The fuel cell capacity
is however the main system cost driver, highlighting the sensitivity to system costs
of fuel cells, and pointing to the trade-off that has to be made during design of a fuel
cell powered vessel between efficiency and investment cost. The heat flows of the
vessel are changed with the introduction of the low temperature waste heat expelled
from the fuel cells, highlighting the need to move away from steam use onboard in
favor of low temperature heat or electricity. The production of steam onboard can
however be fulfilled with the use of hydrogen fired boilers, and can be combined
with heat pumps and/or thermal energy storage.
The amount of systems evaluated in this work limits the accuracy of the results,
and is primarily used to evaluate different setups. The cases different power demand
are extracted as 15-min average data, and thus lacks the accuracy to evaluate the
demand response of the fuel cells in sub-minute scale.