The hydrogen-powered Oslo ferry is uncharted waters for ship designers

Knud E. Hansen will be the unifying force in a project for which standards do not yet exist. At the same time, Ballard will partner with ABB to scale up fuel cell modules to double-digit megawatt sizes.

The following article, written by me, was first published in Danish in the leading Danish maritime trade media Søfart ( December 2020. The illustrations were provided by DFDS and produced by Knud E. Hansen.

“In several areas, this project does away with the way we usually design a ferry. For instance, we are working on new technology for which there are no standards yet,” explains Kasper Fønss Bach, Naval Architect at Knud E. Hansen.

He is one of the ship designers at the Danish consulting naval architect company Knud E. Hansen, who is participating in DFDS’ Europa Seaways project together with five other project partners. This is an ambitious development project, aiming for DFDS to deploy a 100% hydrogen-powered and so potentially fully CO2-neutral ro/pax ferry between Copenhagen, Frederikshavn and Oslo from 2027.

“On ro/pax ferries of this size, we are usually dealing with machinery that has to produce electricity for propulsion. This calls for some fixed and unavoidable elements in the general arrangement, for example, leading exhaust gas up through a funnel. It will not be relevant in this project, and therefore the casing does not have to take up so much space all the way up through the ship, and this offers new opportunities.”

“We must also consider that many of our reference data from previous projects are invalid in this context. Therefore, there are elements in this project that are all about finding completely new solutions,” explains Kasper.

New territory

DFDS’ Europa Seaways project is entirely new territory regarding class and other regulations, which set the framework for designing and building large passenger ships for international routes.

So far, there have been few projects with 100% hydrogen operation on commercial ships, and they have been about either small local ferries or non-passenger-carrying small vessels. Furthermore, many of the sub-components of the hydrogen system still lack type approval for maritime use.

“Based on the input from the various stakeholders, we will play a unifying and integrating role in the project, as none of us have the final solution. However, it is our job to ensure that the ship meets the operational requirements of DFDS,” explains Kasper Fønss Bach.

Essential ventilation

He explains that the hydrogen must be stored pressurised in tanks under the main deck and, to a certain extent, also externally on the open deck.

“After all, the basic principle of having space available under the main deck, where the electrically-based machinery is to be placed, applies to this project as well.”

However, new ventilation solutions are required, as hydrogen is flammable, and additionally, hydrogen also requires significantly more space compared to, for instance, conventional oil-based bunkers, and therefore we also operate with deck tanks.

“Operation wise, it is atypical for such large ships to have a 48-hour cycle regarding bunkering,” he points out.

The “eye-catching” absence of a funnel and the containerised hydrogen deck storage on the open deck aft.

According to DFDS, the ro/pax ferry must have a tank capacity of a total of 44 tonnes of pressurised hydrogen, which in weight is far less than the bunker oil capacity of a conventional ferry of the same size. This is because, in terms of volume, hydrogen takes up far more space per tonne than oil.

The specified hydrogen capacity, including a operational safety margin, corresponds to consumption during a 48-hour round trip on the Oslo route.

Very ambitious

Ballard Power Systems Europe, headquartered in Hobro, Denmark, is a fuel cell partner in the Europa Seaways project. Kristina Fløche Juelsgaard, Director of Business Development, explains that DFDS’ project is the most ambitious project the industry has seen so far.

“This is in relation to fuel cell power, hydrogen quantity and the zero-emission ambition, and we are talking double-digit megawatts here. Therefore, as a fuel cell manufacturer, we also need larger ‘Lego bricks’ to build with,” Kristina explains.

She refers to Ballard’s modular fuel cell systems. The company’s new 200 kW module for maritime use is expected to obtain type approval in 2021. However, the use of 200 kW modules, intended for small and medium-sized vessels on short routes, is not an optimal solution in the large 23 MW driveline that DFDS’ upcoming hydrogen-powered Oslo ferry must have. Therefore, larger ‘Lego bricks’ are needed.

“ABB and Ballard are working together to develop these large fuel cell modules. The actual fuel cell technology will be the same as we use today, but it will be assembled into much larger modules. Therefore, we need to develop completely new components with a larger capacity for all the systems that are placed around the fuel cell modules, for example, pumps, compressors, valves and filters,” explains Kristina Fløche Juelsgaard.

Batteries are included

As in other land or sea transport drivelines where fuel cells must supply electricity for propulsion, the Europa Seaways project is based on a so-called hydrogen fuel cell/battery hybrid setup. This means that the fuel cell modules replace the diesel generator in the diesel-electric/battery hybrid setup commonly found in many small new ferries.

The fuel cell technology is optimal for a constant and continuous load where variations in power consumption onboard can be offset by charging the battery pack. In turn, the battery pack can then act as a synthetic generator, which can generate a power boost much faster than a diesel generator by, for instance, sudden manoeuvres or accelerations.

As mentioned, the Europa Seaways project uses pressurised hydrogen, which is stored in several modules of cylinder pressure bottles below atmospheric temperature. Other maritime hydrogen projects are based on liquid hydrogen at minus 253 degrees Celsius.

According to Kristina Fløche Juelsgaard, there are two parallel tracks in the development of hydrogen in the maritime part of the transport industry, both of which are given equal priority by Ballard.

“We let the customer decide which way they want to go. In this project, the hydrogen will be supplied by the upcoming electrolysis plant near Copenhagen, where it will be stored under pressure. Therefore, it makes sense to keep the entire supply chain under pressure. Right now, this solution has the advantage that it has clearly come the furthest in development. This means that there are several off-the-shelf products and many different suppliers from land transport,” Kristina concludes.

Partners in the Europe Seaways project
ABB Marine & Ports
Ballard Power Systems Europe
Hexagon Purus
Knud E. Hansen
Lloyd’s Register

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