VESSEL REVIEW | Hydra – Norled takes delivery of ferry designed to run on liquid hydrogen

Norwegian operator Norled recently took delivery of a new double-ended Ro-Pax ferry notable for being one of the first passenger vessels in the world to be designed from the outset with provisions for liquid hydrogen (LH2) propulsion.

Built by Westcon Yards to a design developed by naval architects LMG Marin, the DNV-classed Hydra currently operates on battery power but will run exclusively on LH2 once the new fuel becomes available at a later stage in the vessel's development. The designer clarified that the ferry is simply currently "hydrogen ready" and that the hydrogen propulsion will be separately furnished and installed by its owners.

"Hydra is based on one of our existing steel-hulled, double-ended car and passenger ferry designs," LMG Marin told Baird Maritime. "It is equipped with a battery-hydrogen hybrid propulsion solution that also includes Ballard 400kW low-temperature PEM type fuel cells and a Linde 80-cubic-metre, C-type LH2 fuel storage and processing tank."

The designer added that the ferry can operate in pure battery plug-in mode or alternatively in pure hydrogen mode without battery charging from shore, or a combination of the two, ensuring operational flexibility.

The ferry was developed by LMG Marin with the aid of CADMATIC Marine Design Software. LMG Marin spearheaded the design phase but with the close cooperation of the operator and key suppliers, particularly during the development of the hydrogen plant and the hydrogen bunkering solution, which used risk analysis methodology as the main tool to secure safe design. LMG Marin said that although the ferry was designed and built without maritime rules for hydrogen applications available, it still needed to comply with the requisite authorities' requirements concerning similar risk levels as those of diesel-powered ferries.

"Hydra was designed as a bid in a tender launched by Norwegian Road Administration (NRA) that called for the deployment of a hydrogen-powered vessel to serve the Hjelmeland ferry connection as part of a pilot project. This connection is short and can easily be operated by a pure battery plug-in ferry, but the tender had also required at least 50 per cent of energy consumption demand to be covered by hydrogen."

LMG Marin added that the main reason for the selection of hydrogen was to verify technology that can later be used on more challenging ferry connections to enable the NRA to reach its ultimate goal of zero emission for the whole Norwegian coastal ferry fleet.

"Also, we were required to place a premium of safety, and so we carefully selected the technology and systems used in the development of the ferry instead of resorting to the 'automatic' approach of resorting to a pre-established list of options, an approach applicable to vessels that are powered by more conventional fuels such as diesel."

The designer had cited the fact that hydrogen was more easily combustible, had a higher explosive risk, and was more challenging to contain compared to diesel. Since high concentration levels and the effects of ignition can be reduced in open atmosphere, the decision was made to place the hydrogen storage and processing machinery on the vessel's open upper deck instead of in the same level as the engines below deck.

More efficient bunkering was also required. Since LH2 is a cryogenic fluid at temperatures close to absolute zero (-253°C versus -273°C), it is inherently difficult to transfer the fuel from one container to another.

"This means that bunkering operations may be complicated and time-consuming," LMG Marin told Baird Maritime, "but we believe we have concluded on an efficient solution. By ensuring direct access to an externally located storage tank and the use of a shoreside solution that can be prepared for bunkering even without the vessel present, it is possible for bunkering to be completed in less time compared to a conventionally-powered vessel. We feel this attribute is important for a vessel that is required to operate close to 24/7."

LMG Marin claimed that development of the LH2 storage and processing facilities proved to be the biggest challenge it faced in designing the new ferry. Nonetheless, the project taught the company important lessons related to design methodologies and solutions of hydrogen-powered vessels – solutions that may also be applied to varying degrees to other vessels currently under development.

Hydra has a length of 82.4 metres, a beam of 17.5 metres, and capacity for 292 passengers and up to 80 cars, though the vehicle mix may also include trailers. The designer said the ferry's hull lines, structures, and systems are designed to guarantee minimal energy consumption, which is vital for obtaining a cost-efficient solution without installing oversized fuel cells or batteries.

The design also helps facilitate efficient loading and unloading of vehicles and passengers. The passenger lounge and crew accommodation are arranged over the full beam of the vessel above the main deck level but below the vehicle deck. The passenger lounge is located at same height above the waterline as is the case on traditional Norwegian ferries, but with the exception of the placement of window surfaces on both sides and easy access without stairs or lifts.

The large open vehicle deck over the vessel's full length and beam ensures very efficient loading and offloading. LMG Marin said this characteristic makes the design particularly attractive for short connections where swift terminal turnaround is essential.

"Hydra is the first newbuild project utilising this design solution, but not the first to actually implement it in regular operations. It is already in use on four ferries of the same design that currently operate on the Solavågen-Festøya and Mannheller-Fodnes connections in western Norway."

Norled had also wanted the ferry to possess an unconventional, eye-catching design. In the case of Hydra, and with the owner's approval, the designers settled on a "stealthy" appearance.

The propulsion system consists of one azimuth thruster with an L-drive in each end and powered by vertically oriented and frequency-controlled PM type electric motors. The electric system is based on DC-grid technology and includes two fully redundant main switchboards that draw power from either the onboard fuel cells or the lithium-ion air-cooled battery pack in addition to standby diesel generator sets that run on second-generation biofuel. Shore charging is possible thanks to an automatic type plug-in system on either end of the vessel.

LMG Marin said that the batteries will also function as an efficient shield to protect the fuel cells from rapid load changes and variable load levels, thus ensuring the cells' long operational life.

"We believe that the ferry operates with a significantly lower energy consumption compared to a traditional diesel-powered ferry of the same size. This is achieved by optimising hull shape through CFD analysis, selecting an efficient propulsion solution, minimising terminal turnaround by incorporating a new and registered design solution, the use of auto-mooring technology, and generally reducing hotel and auxiliary loads to a minimum. The energy-efficient features used on board meanwhile include heat recovery systems, a heat pump and demand-controlled HVAC system, frequency driven electric motors (main and auxiliary systems), LED lights, waterborne heating, hull-integrated keel cooling system (instead of sea chests), and silicone-based antifouling bottom paint to name a few."

Hydra is designed to be operated by a crew of eight. Its regular route will cover the ports of Hjelmeland and Nesvik with possible in-between visits to Ombo island in the Ryfylke archipelago. The vessel will be operating on a year-round basis under a 10-year contract with the NRA.

"In our opinion," LMG Marin told Baird Maritime, "this is a project that pave the way for a much-needed technology shift. Both hydrogen containment and hydrogen fuel cells will be commercially demonstrated through this project. It will also help spur alternative design approval processes with maritime authorities for hydrogen-powered ships and will define the path for other projects to follow."

The designer said the project has also been helping facilitate development of safe and efficient bunkering technologies applicable to LH2.

"The Hydra project was developed, designed, built, and operated in Norway, and we expect it to attract the same level of attention as Ampere, the world's first battery-driven car ferry."

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