Launch of Feadship 821 Superyacht with Liquid Hydrogen Storage and Fuel Cells

On May 3rd there was a launch and naming party for the Feadship Build 821. With her 119 m she is larger than any other yacht so far built in the Netherlands. Among her many unique features are the 92 m3 liquid hydrogen storage tank to feed the 3 MW PEM fuel cell systems from PowerCell, representing the largest hydrogen storage and FC-power installed on a ship. When not operating on hydrogen, the main engines will run on HVO, a 2nd generation biofuel. The vessel is to be classed by Lloyd’s Register.

As stated by the Feadship announcement, the hydrogen systems allow for one week zero-emission operation at anchor with quiet nights, or cruising at 10 knots, which means she can visit for example the Norwegian World Heritage Fjords zero-emission zones (from 2026), whether or not a transition period allowing biofuels is concluded in final legislation.

At the launch party for Feadship and Royal van Lent Shipyard employees, subcontractors and owner’s representatives, HYEX Safety had the pleasure to celebrate together with many of those who have contributed. It was truly impressive to see the unique vessel built to perfection, learn fun facts e.g. about the yacht’s Beach club, Nemo lounge, the Sport (heli) deck, and hear about the whole construction process. The vessel has now been moved outdoors to install the tall hydrogen vent mast, with some interior finishing work still remaining as well.

HYEX Safety has supported the project with hydrogen safety analyses and advice from the start of the project almost five years ago. We are grateful for the opportunity to work with Feadship and the yacht owners in their dedication to develop the first superyacht that can run on hydrogen. For several reasons, as listed below, we consider the concept with liquid hydrogen storage below deck to be both safer and more practical than liquid storage above deck, or compressed storage above/below deck.

Current and future hydrogen vessel projects benefit from the technology development of the project.

Why we consider LH2 storage below deck far safer than above deck

1. An LH2 storage tank centrally below deck is well protected against collision and impact loads. For comparison a tank above deck may be more exposed to collisions with vessels or bridges, dropped objects and projectiles.
2. An LH2 storage tank below deck is better protected against external fires as major fires in the lower part of the vessel can be prevented by eliminating flammable substances near the tank, or by stopping FSHS ventilation.
3. A major impact breaking a tank placed above deck will form a cold hydrogen plume initially denser than air, potentially falling to lower deck areas representing a fire/explosion risk.

Why we consider LH2 storage a more practical solution than compressed hydrogen

1. Hydrogen is stored at a higher energy density as a liquid compared to a compressed storage, and much less space is required for a liquid tank.
2. A compressed storage will typically consist of numerous pressure vessels, each with valves and piping, at 300-500 bar. For an LH2 tank there are much fewer leak points at much lower pressure (< 10 bar). A lower likelihood for leaks would be expected with a liquid storage.

PS: For Torghatten ferries (see our previous news article) compressed hydrogen storage above deck was chosen. The main reason for this is that the project was a commercial tender in which 10+ years of operational cost were included in the tender. The cost of hydrogen therefore dominated the total tender cost, and the significantly higher cost of LH2 made it necessary to use compressed hydrogen to win. For a car ferry, a storage below deck would also reduce the capacity to carry vehicles. To limit the challenges transporting compressed hydrogen to the ferry, a hydrogen production plant will be built on a quay only 3 km away from the ferry terminal in Bodø.

LH2 compared to LNG

1. While hydrogen is more reactive than natural gas, the combustion energy of an LNG storage tank is 2.5-3 times higher than for an LH2 tank of the same size. A fire scenario from a ruptured LNG tank would thus be more of a concern.
2. LH2 tanks will generally be type C double shelled with vacuum insulation, which both protects against fire loads and impact, while LNG tanks on vessels are sometimes single tanks. LNG leaks may therefore be more likely.
3. Vented hydrogen through gas mast in case of overpressure and PSV activation, will form plumes lighter than ambient air, while for LNG, plumes are far denser than air and may fall towards decks at flammable concentrations.