The availability of liquid hydrogen could support the use of fuel cells in zero-emission vessels for North American owners, but initial capex and near-term opex present hurdles
When it comes to the availability of liquid hydrogen, North American vessel owners have a distinct advantage over other owners. “Right now, more than 85% of the world’s liquid hydrogen production is in North America,” says Golden Gate ZERO Emission Marine chief executive and CTO Joe Pratt.
Mr Pratt notes that the number of liquefaction facilities are “a legacy of the space programme.” In the 1950s, NASA began using liquid hydrogen as a rocket fuel. The US space agency was one of the first to use hydrogen fuel cells to power the electrical systems on spacecraft.
Mr Pratt’s firm, Golden Gate ZERO Emission Marine, is building the first hydrogen fuel-powered ferry in the US.
Fuel cells, like batteries, are a form of solid-state power, explains Mr Pratt. “Solid-state power can scale very easily,” he says, “from a single cell that can power your cell phone to multiple megawatts hours.”
While working at Sandia National Laboratories, Mr Pratt says a study was conducted assessing the limits of the scalability of a fuel cell. “Surprisingly, we didn’t find one,” he says.
“Short-sea shipping feeder vessels could convert to liquid hydrogen and fuel cells today”
There are two ways hydrogen can be stored on a vessel, either as a liquid or a gas.
Mr Pratt says that the study conducted by Sandia National Labs examined the power requirements of ropax vessel Pride of Hull. Installed with 37.8 MW of power, the ropax required 237 MWh to complete one 211 nautical mile trip. Using gaseous hydrogen, the vessel could complete one trip between Hull and Rotterdam. Using liquid hydrogen, which has half the weight and 25% of the volume of gaseous hydrogen, allowed the vessel to make five trips.
“Liquid hydrogen gets you the advantage of scale,” he says. “You can fit more energy on a vessel than gaseous hydrogen. You get better performance and reduce weight and volume.”
Mr Pratt points out this is particularly important for large vessels.
North America’s eight large existing liquefaction plants, producing between 5,000 to 70,000 kg of hydrogen per day, are “uniquely suited to supply fuel for large vessels,” says Mr Pratt.
While he notes that large ships will need the availability of liquid hydrogen at seaports, other vessels could also take advantage of the availability of the fuel.
“What this does mean is that short-sea shipping feeder vessels could convert to liquid hydrogen and fuel cells today, if these vessels were centred in North America,” he says, noting that such vessels would create demand, expertise and a knowledge base.
Capital for zero-emission vessels
“We believe in electrification,” says SWITCH Maritime chief executive Pace Ralli. “Hydrogen gives the electrification movement the ability to address the hard-to-decarbonise high-horsepower transportation,” he says. Mr Ralli says SWITCH Maritime’s role is to serve as a “capital platform” for zero-emission vessels.
The firm develops fuel-switching opportunities in collaboration with existing ship operators and provides capital for the replacement of carbon-intensive fleets with next generation zero-carbon vessels and supporting fuel infrastructure.
“We’ll make those new or converted vessels available back to the existing vessel owners through a bareboat lease or charter,” says Mr Ralli, “along with the hydrogen fueling infrastructure to provide a capital efficient solution for fleet renewal and to lower the hurdles to fuel switching.”
SWITCH uses quantifiable fuel consumption volume of diesel annual gallons reduced (DAGR) as a key performance metric to measure its success and profitability.
While an advocate of electrification and hydrogen fuel-cell technology, Mr Ralli also notes some of the hurdles faced by being a first mover in the marine market. “It is not easy to build in a US shipyard. There’s risk involved. You need a shipowner and a capital provider who are able to handle the execution risk. There’s also technology risk. While the technology is not new, the application is.”
On the commercial side, Mr Ralli notes the need to secure the first charter for the vessel and to properly structure the financing. “How do you work with the banks? Is there a need for private equity? How expensive is the capital?” he asks. “If it is too expensive, the project won’t get done.”
He also says operating costs – crew, maintenance, fuel – have to be cost competitive. “And, the infrastructure has to be available to supply the fuel.”
SWITCH is working with Golden Gate ZERO Emission Marine to build an 84-passenger ferry for a route between Oakland and San Francisco, California. The hull and superstructure for Water-Go-Round were completed at Bay Ship and Yacht in Alameda, California, and electrical and outfitting is being carried out at All-American Marine in Bellingham, Washington.
“A study conducted to assess the limits of the scalability of a fuel cell found that there wasn’t one”
He says that ferries are well suited for hydrogen fuel-cell technology because they operate on short routes and have low power requirements. In the case of the e-ferry, it will have a Hydrogenics 360 kW PEM fuel cell, Xalt Energy 100-kW energy storage system, H2 Storage 264-kg gaseous hydrogen storage and two BAE Systems 300-kW electric propulsion motors.
Mr Ralli says capex for the ferry would be about 30 to 35% above that of a similar diesel-powered ferry. “We expect that to come down over time,” he says.
One area where the hydrogen fuel-cell ferry will excel is in maintenance, with costs expected to be 15% lower than a diesel-powered vessel.
Fuel, however, will be at a premium, costing at about US$4 to US$6 per kg. A large part of the vessel’s opex, hydrogen fuel will be about 40% more in the near term, but should come down over time. Mr Ralli says: “Cost could plummet over time, with advances in technologies such as electrolysis.”
Glosten senior marine engineer Sean Caughlan cites two design feasibility studies Glosten performed on research vessels that used hydrogen fuels for all or part of their propulsion requirements. Working with Sandia National Laboratories, Glosten designed a trimaran that would be capable of performing as a Regional Class research vessel for the Scripps Institute. “The reason for the trimaran (hull) was we needed the deck area to hold the liquid hydrogen,” says Mr Caughlan. Funded by the US Maritime Administration, the vessel was designed with two 1.8 MW fuel cells and 10,800 kg of liquid hydrogen for an operating range of 2,500 nautical miles. The vessel underwent both US Coast Guard and DNV GL reviews.
A second research vessel was designed as a hybrid with diesel-electric propulsion and hydrogen fuel cells. The result was a Coastal Class research vessel with 3,200 nm range. Using just the fuel cells, the vessel could operate for 300 nm with zero emissions. Mr Caughlan says this was notable because the vessel could achieve “75% of its missions on hydrogen alone.”
The US Coast Guard does not have existing rules for fuel cells or batteries, notes Mr Caughlan. “The way forward is that you need to show an equivalent level of safety,” he says, “and have a regulatory path forward.” This is done by obtaining a Basis for Design Letter from the Coast Guard, which is extremely important and a big hurdle, he explains. He notes that the Coast Guard also leaned heavily on the IGF code for their requirements: “They are looking for a risk assessment on the vessel design and the bunkering.”
Mr Caughlan says some strong guidance was available from class rules to address issues about how to handle hydrogen and integrate fuel cells into a vessel design. He notes that the current development stage of hydrogen in marine applications is “reminiscent of the early days of LNG.”
This article is based on comments made during the webinar The Challenges North American Shipowners Face with the Adoption of Fuel Cell Technology, produced as part of Riviera Maritime Media’s Maritime Hybrid, Electric and Fuel Cell Webinar Week in July 2020, supported by US naval architectural firm Glosten