It has been over a year since the Enviu-initiated SWIM project launched the world’s first hydrogen-fueled watertaxi. Just after World Port Days 2023, we look back at the hydrogen watertaxi’s journey from the Enviu meeting rooms to the busiest waterway in Europe.

What started as an idea to retrofit and demonstrate an inland vessel run on ammonia culminated in an operational hydrogen-fueled water taxi in 2022. That may seem like scaling down in size. But that’s Enviu — ambitious yet realistic, calculated yet bold in frontrunning sustainable change. This is the story of how Enviu floated the world’s first hydrogen-fueled water taxi on August 30, 2022, at Europe’s biggest port in Rotterdam, amid a fledgling market for this fuel source. ”The first hydrogen-powered boat that operates in the largest Port of Europe, physically, shows that the transition to the sustainable maritime sector has kicked off,” says Maarten Fonteijn, Program Lead and Venture Builder. Today, the SWIM watertaxi runs every Saturday between Hotel New York and Leuvehaven in Rotterdam, just like any other watertaxi.

Credit: Ries van Wendel de Joode/Watertaxi Rotterdam
From inland ships to watertaxi
In 2018, Enviu started an initiative called Future Proof Shipping, with the idea of running cargo vessels fueled by hydrogen. This initiative was later coined ‘THRUST’ — Towards Hydrogen-based renewables Used for Ship Transportation, which was financially backed by the Gieskes Strijbis Fund. The team decided it had to be bold to make system changing impact and decided to skip the intermediate steps and get to the final solutions right away — something that would change the world. “That sounded ambitious,” recalls Tim van Vrijaldenhoven, who was the THRUST program lead at the time. “The more we started developing the idea, the more we realized that this might test our patience to the extreme.”
However, the team had one goal in mind: To prove that sailing on hydrogen-based fuels is possible and safe and operationally attractive. The team wanted to create an example that people could associate with and help them understand that sailing on hydrogen is possible today. As they explored options, they deliberated on what would be a great calling card: A watertaxi fueled by a zero-emission and renewable fuel.
From ammonia to hydrogen fuel
Enviu considers both hydrogen and ammonia as sustainable and promising fuel sources. The venture-building studio looked for ways to demonstrate both in a live environment. However, considering the challenges of implementing ammonia and that no-one seemed up for the challenge at the time, Enviu felt the need to step in. Enviu applied for an experimental subsidy from the Municipality of Rotterdam, the City Lab 010. It allowed innovation and experimenting with demonstrating hydrogen or ammonia in a vessel.
The team won the grant to build an engine (along with other companies) and test it with ammonia. Enviu’s ambition aligned with the ambition of Rotterdam to reduce emissions. It was a tangible project that would be realized within two years, and not in 2030 or 2050. Enviu immediately started off by exploring the options.
At the time, talks with Watertaxi Rotterdam had already started and they offered to lend one of their watertaxis that was no longer in active service. However, the Municipality of Rotterdam and Watertaxi Rotterdam were hesitant about using ammonia within crowded areas, recounts Tim. The team shifted to a demonstrator farther down the port area.
The ammonia plans were not shelved, but we shifted to a demonstrator farther down the port area. As the team dove into it further, they soon encountered another hurdle.
“The environmental impact agency (DCMR) said we could not fuel a watertaxi with ammonia anywhere within the city limits. We could not bring ammonia tanks into populated areas, although it was a small quantity. From a legal and regulatory perspective, though, it was still possible since it was a small quantity,” says Tim.
If the refuelling of a watertaxi had to take place more than 20 kilometres away from where the watertaxi operates, it would become a completely inefficient demonstrator. Hence, the Watertaxi Rotterdam lost their interest in participating in the project.
Enviu did not abandon the idea but pivoted to hydrogen. DCMR was not immediately enthusiastic but did not reject the idea. With this new idea, Enviu re-approached Watertaxi Rotterdam. While their boats then ran on batteries and diesel, hydrogen had been a long-term agenda of the water transport company. They opted for the scenario of building a new future-proof vessel instead of retrofitting an old vessel. This renewed Enviu’s direction, including exploring hydrogen as a fuel, a sustainable alternative to ammonia.
“Watertaxi Rotterdam was more enthusiastic about hydrogen than ammonia, and the environmental agency, too, was on board with the idea. Besides, Rotterdam already had plans to develop a hydrogen hub,” says Tim. “Things started coming together.”
The Enviu team received a subsidy from the Province of South Holland and further support from Gieskes Strijbis Fund, which would help them finance the development of a new vessel and give a fillip to their ambitions to change the maritime sector.
That was the basis to take the project in the direction it has culminated today, says Tim.
Making it market-ready
Incidentally, the original ambition was not to make the watertaxi market-ready but to test and demonstrate it. In a technical sense, develop hydrogen-electric propulsion systems that pave the way for other developments in zero-emission sailing. But, with hydrogen in the picture, the team decided to extend its potential for market-readiness.
“We needed partners who have a vision, saw the bigger picture, and are willing to invest in it to make it market-ready,” says Tim.
The biggest challenge was divvying up the responsibilities into smaller elements. For instance, Partner A would take over the design aspect, while Partner B would build the watertaxi. Enviu partnered with two expert partners, Zepp.solutions and Flying Fish, and formed a consortium called SWIM, along with Watertaxi Rotterdam.

Zepp.solutions designed the hydrogen fuel cell system; Flying Fish built the electric powertrain; and Enviu initiated the project, leading other fundamental aspects such as funding and stakeholder engagement. Watertaxi Rotterdam took care of the vessel itself.
With Watertaxi Rotterdam onboard this ambitious journey, SWIM could sell their story to Port of Rotterdam, although the latter was uncertain about setting up a permanent fueling station as it was impossible for any company to become price-competitive.

Launching the watertaxi
It was early 2020. While COVID-19 hit the globe, things started falling into place for the project. The work to give Rotterdam its first hydrogen-fueled watertaxi was in full swing.

However, the boat itself was only a part of the story. While the boat was being built, the external conditions had to fall in place to ensure the boat could sail. This included a technical solution for refuelling, the hydrogen itself, and the funding to compensate for the difference in costs with fossil fuels.

Meanwhile, the team procured the permits to let the watertaxi sail, as well as for the refuelling process, which was dependent on the exact location and solution that would be implemented. A hectic period of discussions with potential partners, suppliers, and relevant authorities ensued, finally leading to a concept that all stakeholders agreed on.

On the sunny morning of August 30, 2022, SWIM’s hydrogen water taxi ventured into the waters of Rotterdam for the public.

The impact over the past year
Exposure and awareness: Through national and international media, the news of SWIM hydrogen watertaxi reached over 200 million people worldwide in 2022, creating awareness globally for the need and possibility to sail on green fuels.
Development of hydrogen infrastructure for maritime use: Enviu kicked off the development of the Green Energy Refueling Station (GERS), but is now adopted by the Port of Rotterdam, who are committed to making this a reality soon.
More fleet owners consider running vessels on hydrogen: Several maritime service providers and the Port Authority are now considering to start sailing on hydrogen, too. The big hurdles to make that decision can be overcome especially when the infrastructure is in place.
International traction for green hydrogen for maritime propulsion: Besides companies and organizations like hydrogen developers and governments across Europe, those in the Middle East, the US, and South America were inspired to kick things off in their geographies.

What’s next for hydrogen watertaxi
Enviu is currently engaged in the SWIM watertaxi and other projects to develop zero-emission technologies in Rotterdam. However, with the watertaxi, establishing a permanent hydrogen fuel station remains challenging due to the lack of immediate profitability associated with hydrogen investments.
Currently, hydrogen is being supplied from a temporary refuelling station located at the Werkhaven at Hebo Maritiemservice terrain. “It is a great lean way to show that it works and that it is safe,” says Maarten. “However, the infrastructure needs to come in place, not just in Rotterdam but also in other ports and water-rich cities worldwide. We are keen to develop new groundbreaking cases for hydrogen, but as a commercial product, the conditions need to catch up,” he insists.
The key is in the volume, points out Tim. “The more the volume of hydrogen, the easier it becomes to integrate the fuel into other modes of transport,” he says, hinting at the hydrogen trucks. “We need a cross-sectoral collaboration to make this happen,” Tim adds.
Meanwhile, Enviu is exploring to use its experience in clean propulsion, circularity, and social impact in solving urban mobility issues, especially in the cities where Enviu has its offices — Bangalore, Jakarta, and Nairobi.
“We realized that the SWIM watertaxi is a great bridge between our two strategic focus areas: maritime and urban mobility,” says Maarten. “We want to expand impact in the wider mobility space. So, going forward, we add urban mobility as a strategic focus area while continuing efforts within the maritime sector — both under the umbrella of Enviu Mobility.”