“Sustainability is essential,” says Jan-Bart Verkuyl, Feadship Director / CEO of Royal Van Lent Shipyard. “If we don't do it, we become complacent. There is pressure from our clients, there's pressure from ourselves, there is pressure from our workers, there is pressure from our children. It needs to be done.”

Exploring energy-efficient solutions for building better and more eco-responsible yachts is something Feadship takes very seriously. You could say it is their passion, especially for Giedo Loeff, head of Research & Development: “I believe that de-carbonisation has to be at the heart of our industry,” says Loeff. “The central question is how do we reduce the ecological footprint of superyachts and by doing that also preserve the natural wonders of the world’s oceans, because that’s what yachting is all about.”

Sustainability vs Luxury

Sustainability and luxury products do not ordinarily go hand in hand and the questions raised about superyachts are no different than those surrounding private jets, for example. But at Feadship they are working hard to reduce the environmental impact of their yachts to the bare minimum. This is done in two ways: by investigating alternative fuels and power systems, and by taking a long hard look at how the yachts are manufactured and fitted out.

“We are eager to learn as much as we can and act on what we learn,” says Bram Jongpier, Feadship Senior Specialist Design and the initiator of the Yacht Environmental Transparency Index (YETI), which scores and compares yachts based on their environmental credentials. “The essential thing to realise is that ‘zero’ doesn't exist. This may shock some people, but zero impact is impossible. You cannot walk on the grass without some degree of impact, but you can do it sustainably if you give the grass the time to recover. And that is how we should treat our oceans.”

Feadship closely monitors how are yachts are used and this tells a lot about where the energy used on board is coming from – shore power, generators or propulsion engines – and how that impacts on the environment in terms of emissions. Burning fossil fuel is clearly the main culprit in terms of both Well-to-Wake (the production, transportation and distribution of fuel, including the final combustion of energy) and Tank-To-Wake (the direct combustion of energy and associated release of CO2).

Fuel flexible

“The challenge for yacht builders, the entire marine industry in fact, is to design vessels that are fuel flexible or fuel agnostic,” says Loeff. “That means building yachts today that will be able to make the transition to the alternative fuels of tomorrow. Feadship has already received approval-in-principle from Lloyds Registry for an agnostic fuel system, which represents the second stage in our roadmap to building a carbon-neutral superyacht by 2030.”

Some of these alternative fuels are already readily available. Hydrotreated Vegetable Oil (HVO), for example, is a diesel-like fuel that can be produced without fossil resources by processing renewable feedstocks. With longer storage times and greater resistance to bacterial contamination, they represent a leap forward compared to first-generation (FAME) bio-fuels.

“Regular marine diesel engines built since around 1990 can run on HVO without any major modifications,” says Joost Schapendonk, Marketing & Technology Director at Pon Power BV. “And another benefit is that if your engine is not completely ready for this, you can also run it in different blends.”

Pon Power BV has investigated the feasibility of fuels such as Liquid Natural Gas on superyachts, but the challenge here is that LNG requires much bigger storage volumes than fossil fuels, a problem that is even more acute in the case of hydrogen. Ammonia is another possibility, but has very long flame speeds (the measured rate of expansion of the flame front in a combustion reaction) that makes it unsuitable for high-speed engines, not to mention its toxicity.

“We have come to the conclusion that bioethanol is a great candidate as a transitional fuel for the marine industry, including superyachts,” says Schapendonk. “We've been working together in a joint industry project, together with Feadship, on the Green Maritime Methanol program and we’ve even converted an engine ourselves to 100 per cent methanol engine to really learn and understand what's involved. But the methanol engine of the future needs to come from our original equipment manufacturer (OEM), Caterpillar, and that will be in around three years.”

Converting an engine to burn methanol involves half a dozen different technologies and they all have their pros and cons. “A large part of choosing the right technology is understanding what sacrifices you’re prepared to make in terms of performance, range and power density,” adds Schapendonk.

“Methanol has the highest hydrogen to carbon ratio of all liquid fuels,” says Eelco Dekker, the Methanol Institute’s chief representative Europe. “Methanol is also liquid at atmospheric pressure and ambient temperatures, and it contains a lot of hydrogen, which makes it a very good hydrogen carrier for fuel cells.”

Furthermore, methanol burns with a very clear flame. That means that it basically produces no soot, no particulate matter, no SOx, and hardly any NOx. So, it's a very clean fuel that has no impact on the local environment. “And since we're talking about environmental credentials, methanol is biodegradable,” adds Dekker. “Accidents happen, but in the case of a methanol fuel spill, it is very benign to the marine environment, so you basically wouldn't notice it.”

The power technology of the future

No discussion of alternative fuels is complete without a look at hydrogen and fuel cells, which many deem the power technology of the future. “The hydrogen fuel cell as an electrochemical device is actually quite mature and has been widely adopted in different industry sectors,” says Johan Burgren, Business Manager Marine at Powercell Sweden. “Thousands of forklifts running on pure hydrogen are in operation, for example, and the automotive industry is also moving into pure hydrogen solutions.”

In a yachting context, however, the question of storage remains a significant hurdle to overcome. Pure hydrogen can be stored in compressed form, or as a liquid. Cars use compressed hydrogen gas, but current maritime legislation limits the compression, meaning the hydrogen storage tanks would need to be roughly fourteen times bigger than conventional diesel tanks. Super-cooled liquid hydrogen occupies less space, but the energy and cost to produce and store at -253°C  is not offset by the energy it provides.

Johan Burgren believes we are likely to see a combination of different systems: “Solid oxide fuel cells run at a higher temperature, so you can utilise this temperature in the reforming process of the total fuel cell plant. On the other hand, they are a bit slower in terms of power dynamics and you might have to combine them with the batteries, or even low-temperature PEM fuel cells that are more dynamic and deal with the instant loads. So, we’ll have to see what combination works best in the long run.”

Enter the energy hybrid with two or more kinds of energy on board. That means, for instance, methanol for long-range, zero net-carbon operation, and a battery bank or hydrogen fuel cell for local range. The average distance of a superyacht trip is only 30 nautical miles with longer trips usually made during transfers without guests on board. Because of this operational profile, most trips could be in zero emission mode, enabled by electrical propulsion that is most adept at running on power from different sources.

Full life-cycle

Building a Feadship actually starts with mining activities and the extraction of iron ore to make the steel for the hull, but there is also the manufacturing of other products such as paints, fairing compounds and the luxury materials that are used for the interiors. Any discussion of sustainability must also consider these energy-intensive activities. The aluminium used for superstructures, for example, is both an important input to a number of technologies critical to the energy transition, and a significant source of CO2. But could superyacht superstructures be made from recycled aluminium beer cans?

“That would be brilliant, but unfortunately we cannot,” says Amanda Mackintosh, HR Manager at Bayards Aluminium Constructions. “It is true that one of the biggest advantages of aluminium is its recyclability, but for yachts we need a very high grade of alloy and today we can’t do that with recycled aluminium. So we really need to invest in this technology and work together with research centres so that in the years to come we can increase the use of recycled aluminium.”

Feadship analyses the production process from a full life-cycle perspective, meaning from the extraction of the raw materials to the production of a product or component, to the actual use of that product and the end-of-life phase when it is hopefully recycled or reused. This in-house knowledge can be combined with a database of global information materials and processes to estimate the total environmental impact of yacht production.

“We are still at the outset of actually discovering the full spectrum of challenges and opportunities regarding transparency and traceability of materials,” says Charlotte van de Kerk, Feadship Sustainability Manager. “But I believe that when clients and their interior designers actively seek to incorporate sustainable principles into their designs, we can have a direct and positive impact while still aiming for the exclusivity that we are looking for.”

Last but not least, is the energy consumption of the shipyards themselves. Currently three of Feadship’s four yards are partially powered by solar panels, 30 per cent in the case of the facility in Amsterdam, with the aim of reaching net zero by the end of the decade.

The next years

What do all these measures mean for the near future? Bram Jongepier believes that if Feadship’s environmental impact is defined today at 100 per cent and we subtract our renewable fuels, our zero emission modes, our green aluminium, our carbon capture and utilisation (CCU) materials, and so on, that impact can be reduced by 80 per cent within the next five years. And that’s just by applying the technology we already have at our disposal.