A text by Marilyn Mower
Five years in the making, "Breakthrough" is the first answer to a fundamental question in yachting: How far can we push hydrogen technology? With a bold answer, Feadship was awarded the contract and chose an approach that reduces the environmental footprint from the selection of construction materials to operation. The Dutch shipyard delivered a solution that enables a zero-diesel approach to travelling between harbours or anchorages and running the yacht on zero-emission electricity from green hydrogen.
"Breakthrough" does pioneering work
"The aim was to develop a new, clean technology, not just for this project, but for the whole world," says Jan-Bart Verkuyl, Feadship Director and CEO of Royal Van Lent Shipyard. With a length of 118.80 metres and a volume of 7,242 gross tonnes, Breakthrough's size alone qualified it as a candidate for the implementation of fuel cells in combination with a hydrogen tank. And it fits in with Feadship's decarbonisation plans and the Amsterdam facility, which is powered almost entirely by district heating, waste heat and solar energy. The shipyard's own research and development team has set itself the goal of developing "net zero" yachts by 2030.
Although hydrogen-powered cars exist and fuel cells have been used as the primary power source in manned space travel for more than six decades, there were no high-performance applications in the maritime sector at the start of the project in 2019. Feadship therefore had to follow the risk-based "alternative design path" prescribed by the International Maritime Organisation (IMO). With the help of experts from related industries, the Dutch company and Lloyd's Register developed appropriately scaled equipment, protocols and safety assessments that served as the basis for new regulations. "We are proud to have made the value of research and the development of safety assessments for a completely new way of generating energy available to everyone," says Verkuyl. Next year, two 117 metre long passenger and car ferries will operate between Bodø and Lofoten using the system developed with the PowerCell Group.
Cryogenic tank with considerable volume
From the outset, one of the biggest hurdles was the storage of compressed liquid hydrogen on board a yacht - at -253 degrees Celsius. When green hydrogen is processed in a fuel cell, the only by-products are electricity and water in the form of vapour. Hydrogen is light, in liquid form one cubic metre weighs 70 kilograms compared to around 800 kilograms per cubic metre of non-fossil diesel fuel (HVO or e-diesel). For safe storage on a ship, however, a double-walled cryogenic tank in a special ventilated room is required. Although its volume is around eight times greater than that of double-bottom tanks for the equivalent amount of diesel (by energy), thirty times the volume of diesel is required to accommodate the entire system on the lower deck.
Considering that diesel is stored in a structural cavity that cannot be used for other purposes, the storage of gaseous fuels such as hydrogen would open up new ways of constructing and designing a yacht, says Giedo Loeff, head of Feadship's R&D team. The entire power-generating unit is located on a single level. The MAN Cryo vacuum-insulated tank holds 92 cubic metres of hydrogen, which is equivalent to around four tonnes when full. Together with the compact fuel cells, their connections to the DC grid and the vent stacks for the water vapour, the system required an extension of the original length by four metres. With a total output of three megawatts, the PEM fuel cells from the Swedish PowerCell Group contribute a full 30 per cent of the energy generated on board.
"Breakthrough" is ready for methanol
The fuel cells developed for "Breakthrough" could also be operated with methanol, a liquid fuel under ambient conditions. However, this would require a reformer that converts methanol into hydrogen using vapour. "Now that we have gained so much experience, the next development steps with other hydrogen carriers such as methanol are relatively easy to implement," R&D man Loeff is certain. The sustainability of super yachts today is all about how to get the most energy out of non-fossil fuels, the most efficient carrier and how to convert it into propulsion energy. Fuel cells cause high investment costs, but are very efficient for propulsion. "The fuel cell system used here already saves around 35 per cent energy compared to the operation of generators. With the next generation of methanol fuel cell systems, we even expect a reduction in energy consumption of 50-75 per cent. This will not only reduce emissions, but also significantly lower operating costs," emphasises Guido Loeff.
Even "Breakthrough" cannot carry enough liquid hydrogen for an ocean crossing, but Feadship could influence the CO2 footprint of a yacht where it is greatest: according to the Yacht Environmental Transparency Index (YETI), 70 to 78 per cent of total energy consumption is accounted for by the on-board network, with heating and air conditioning making up the largest share. There is also the advantage of lower noise emissions, as fuel cells generate energy through an electrochemical process rather than combustion, which requires very few rotating parts. For longer journeys or when pure hydrogen is not available, the power for the 3,200-kilowatt Azipods comes from five MTU generators that burn HVO. Various Feadships have already proven that the gensets can run on synthetic diesel.
Batteries and heat recovery system
While large battery banks are becoming increasingly popular in order to provide enough power for generator-free operation during quiet nights at anchor or for trips in marine protected areas, "Breakthrough" only stores 543 kilowatt hours of energy. By comparison, the 83.50 metre long "Savannah", Feadship's first diesel-electric hybrid yacht, was fitted with batteries with a capacity of one megawatt hour in 2015. The engineers of the 119-metre yacht rely entirely on fuel cell technology for a whole week at anchor or emission-free cruising at up to ten knots out of harbours or in protected marine areas. The on-board batteries are connected to the power grid and are used to cap peak loads so that no second generator starts or two gensets run when power demand drops. Breakthrough" also operates heat recovery. This is used to heat everything from indoor rooms, pools and steam rooms to towel rails and floors in the guest bathrooms. Further savings on the hotel load are achieved by an intelligent air conditioning system that links the cabins' sensors with the energy management system.
At 118.80 metres in length, "Breakthrough" is the largest motor yacht ever launched in the Netherlands and is just ahead of the 118-metre Feadship "Launchpad". Although the two yachts are almost the same length, the new flagship has around 30 per cent more volume. With five decks above and two below the waterline, she is very high - the owner's deck is around 15 metres high - but the designers at RWD have managed to keep the profile flowing and flat. She also has the most hull openings of any Feadship to date: 14 balconies that take their side rails or walls and nine massive hatches that move upwards and seven that move downwards to form platforms. Deploying the balconies requires no crew and involves raising the floors, levelling them with the interior and making them vibration-free as per the contract. RWD's design ethos matched Feadship's holistic approach to development. As both the exterior and interior were in the hands of the British studio, there are no awkwardly positioned spaces or poor transitions from inside to outside on 'Breakthrough'. The crack is modern but not radical, just as the interior is chic and simple but not minimalist. It is a reassuring platform for exploring the world, based on the understanding that true luxury is being on the water. And doing so as quietly as possible and with low CO2 emissions.
