SWITCH’s first hydrogen-powered vessel, the SEA CHANGE, is a 75-passenger catamaran ferry featuring 600 kW of electric motor propulsion, powered by 360 kW of fuel cells with 246 kilograms of gaseous H₂ (GH₂) storage at 250 bar pressure. The SEA CHANGE successfully started public passenger service as part of the San Francisco Bay Ferry system in July 2024, after receiving its final Certificate of Inspection (COI) from the US Coast Guard in May 2024. It is currently fuelled once a week using a mobile compressed GH₂ storage trailer towed behind a pickup truck. Each fuelling takes approximately 2 hours to transfer 150 kilograms, allowing for three consecutive days of passenger operation. When ferry service increases to seven days per week in coming months, the SEA CHANGE will be fuelled twice per week.

While SWITCH is supportive of all zero-emissions vessel technologies, they focus on hydrogen since they believe in its potential to serve as a viable option where other battery-only solutions fall short due to space and weight constraints. Generally, hydrogen as a fuel source can support greater range and power requirements due to its high energy density. Additionally, it simplifies zero-emissions vessel operations by eliminating the need for fixed shoreside charging infrastructure, allowing for fuelling through established truck-to-ship or ship-to-ship practices. Compressed GH₂ is well suited for small- to medium-sized vessels; however, as vessel size and energy demand increases, cryogenic LH₂ becomes the preferred storage solution. Similar to Liquefied Natural Gas (LNG), cryogenic LH₂ supports faster refuelling speeds for large volumes (e.g. tons per hour).

In addition to the SEA CHANGE, SWITCH is working on a 150-passenger, 25-knot catamaran to build for the SF Bay Ferry service, using the same gaseous H₂ (GH₂) storage and fuel cell equipment as the first vessel (to be revealed in Q1 2025). When designing larger zero-emissions harbourcraft such as 300+ passenger ferries, vehicle ferries and harbour tugs, SWITCH plans to transition from gaseous storage to cryogenic liquid H₂.

“Our first H₂ vessel was the result of years of close collaboration with the US Coast Guard, demonstrating the viability and safety of hydrogen fuelling. While the LH₂ ro-pax ferry design is already DNV-classed, there is still some work to do to bring it into US Coast Guard compliance,” says Pace Ralli. “What I like about LH₂ fuelling is that it will follow the same IGF Code that applies to cryogenic LNG fuelling of ships in the US, so we have a precedent regulatory framework to work from.”

The larger steel hull of the vehicle ferry offers more flexibility in terms of space and weight compared to aluminium catamaran fast ferry designs, making it an ideal platform for introducing LH₂ fuelling in the US. The LH₂ from the cryogenic storage tanks is vaporized onboard and used in the PEM fuel cells to create electricity for the electric motors. Like the GH₂ fast ferries, the vessel’s only emissions will be pure H₂0 vapor, with zero carbon or other diesel-related emissions.

The ro-pax vehicle ferry will have a service speed of 14 knots, and is expected to require fuelling only once per week (volume of 3,000 kilograms from one LH₂ truck) in a typical operation, with no requirement for shoreside electric charging infrastructure. It’s Norwegian predecessor, the HYDRA, is owned by Norled and performs a triangular six nautical mile round-trip vehicle ferry service, fuelling LH₂ only once every two weeks. The four tonne LH₂ tank (about the size of a 40 ft container) fits easily on the top deck, and receives fuel from a LH₂ truck via a bunkering system using over-pressure in the truck to push the liquid to the ship. To date, HYDRA has successfully received LH₂ fuel approximately 50 times since starting hydrogen-powered operation in March 2023, and notably, has not been out of service since operations started, other than for planned maintenance.

© Shippax