15 December 2020
James Roy - Managing Director, Lateral Naval Architects
Every reader will be acutely aware of an increasing focus on our environment and the matter of sustainability. Shipping and the marine industry have traditionally had a fairly easy ride when it comes to emissions, perhaps by dint of the fact that the polluting aspects of marine operation happen over the horizon. This has progressively changed in the last decade and via MARPOL tier 3 standards coming into force, shipping is being brought into line. The regulatory landscape is tightening further, not just on emissions of nitrous oxides, sulphur and particulates, but also carbon. This is both at local and regional levels, such as the Norwegian Fjords who from 2026 will restrict entry to carbon-free vessels only, but also internationally via greenhouse gas emission regulations in 2050. The construct of regulations to decarbonise the shipping industry is therefore very much underway.
This points to the use of fossil fuels as not being part of our future. We can therefore say with some certainty, that the future is ‘Zero’; zero carbon, zero emissions.
Enter hydrogen. There is currently a technology race developing in the commercial marine market to find the solutions to enable zero emissions operation. In order to finance the required research, a considerable amount of funding has been made available at a governmental level, and from ship owners and operators seeking to pave the way for hydrogen to become a viable technical and economic solution.
In many areas of technology, the superyacht sector follows the lead of the commercial marine market. Whilst the commercial market is driven by both regulatory and revenue earning factors, the superyacht market is somewhat driven by emotive drivers. The demographic of the average superyacht purchaser, charterer or other future ‘stakeholder’ is shifting to a younger generation, with a very different belief system and buying motivation. Focus on ‘good for me good for the planet’ is becoming key. Clients are already asking for us to engineer, design and build yachts which can operate in a ‘leave no trace’ manner, perhaps even operate in a positive impact manner. We simply cannot wait for the commercial marine market to lead; the superyacht industry must be part of developing the solutions. There is a real opportunity here for our sector of the industry to be at the forefront of technical development and lead the way.
Against this backdrop Lateral Naval Architects have explored the viability of a fully hydrogen powered superyacht.
In collaboration with design partners SINOT Yacht Architecture & Design, Project AQUA was conceived. A key aim of the project was to explore the application of hydrogen to a design which had no operational restrictions relative to a ‘normal’ superyacht, and where the technology employed was available within a five-year window.
Early parametric studies indicated that the volumetric density of hydrogen created quite significant challenges to feasibility. To make the design concept viable every percentage point in energy efficiency needed to be realised across the whole design. Starting with the hull, Lateral opted for an optimised length in relation to the Gross Tonnage resulting in a modest 3530 GT set on a 112m waterline. Alongside this a propulsion system was developed to holistically minimise drag and increase efficiency. This comprises of a single-shaft design allowing the integration of enhanced hydrodynamics, with a highly efficient contra rotating propeller. Traditional stern gear was replaced by vertical axis propellers thereby removing the rudders and replacing with thrust vectoring units. This solution both reduces drag from the system whilst delivering instantaneous manoeuvring forces even at zero speed. In addition, a wide range of technology applications were employed to reduce hotel load as far as practical.
Development of the initial technical platform was undertaken, and from this efficient starting point the hydrogen system was realised. It was clear from an early stage that a compressed hydrogen solution was far too large for a vessel of this type.
Lateral worked closely with several hydrogen industry partners to identify the best form of hydrogen to use. Studies in the commercial marine market have shown that the most cost effective uses of hydrogen are those with the least process involved. These studies consider the value of lost cargo and the volume of the hydrogen tanks required concluding that for short range applications compressed hydrogen is a viable solution, as range and endurance increases then liquid hydrogen becomes more efficient, and finally ammonia becomes the most cost effective form for long ranges. Though these commercial studies have little application to yachting, what is apparent is that liquid hydrogen is going to be the predominant viable solution to serve large parts of the shipping market, which will operate in a similar space as superyachts. This work further reinforced the choice of liquefied hydrogen as the correct choice for AQUA.
The final system design employs two cryogenic tanks in the centre of the yacht, storing 28 tonnes of liquefied hydrogen at -253 degrees Celsius. Alongside this, a bank of low temperature Proton Exchange Membrane (PEM) fuel cells generate electrical energy for distribution via an all-electric architecture. Lithium-ion battery banks are used for energy storage and management.
AQUA represents a project that could be initiated today. It is not without technical or commercial risk, and as such it would require a ‘first mover’ client who would fit the profile of a true innovator.
However, building the yacht is only part of the story of achieving Zero, today. The real challenge lies in the fuel distribution network, because that does not exist. To be truly Zero AQUA would need to be fuelled by hydrogen generated from green energy, such as wind power. Laterals research and development continues in this area, challenging our engineering beyond the development of the yacht itself.
As an industry we need to widen our thinking. If we aspire to deliver yachts that have the capability to run on alternative fuels such as hydrogen, we need to play a part in development of the fuel distribution network and also the generation of green energy. Perhaps in the future we will be packaging the sale of a superyacht with a share in a wind turbine in a far-off wind farm!