There are choke points holding up the widespread adoption of hydrogen fuel cells, as Riviera’s Maritime Hydrogen and Fuel Cells Conference in Bergen heard from experts in the field, but there are ways forward, too
Because hydrogen fuel cells are modular, scaling them to meet higher power requirements is quite feasible, according to PowerCell business manager Johan Burgren. Presently, marine applications are seeing 1 MW and above systems being built and 25 MW to 30 MW systems being studied. It is only a question of time, he said, in response to queries over whether larger systems will be stable.
Mr Burgren said the production method for hydrogen is not a show stopper for marine fuel cells. He advocated for the oil industry to be brought in to build the infrastructure for a hydrogen economy, noting that the industry already produces hydrogen in very large quantities as part of its routine petrochemical processes. He said zero emissions should be first achieved from stem to stern until renewable methods and electrolysis are commercially ready to support zero emissions throughout the energy supply chain.
No definitive answer emerged when the question of gas or liquid was raised, but Mr Burgren asserted that liquid hydrogen is inevitable in the long run. His reasons? The amount of power envisaged for long-distance shipping routes cannot be met by on board production and storing hydrogen in gas form, due to the high volume and relatively low energy density, is not practical for larger applications.
Giving the perspective of a shipowner, Norled project manager Hilde-Kristin Sæter said gaseous hydrogen was cheaper than liquid and therefore attractive.
Proton Motor Fuel Cell sales manager Rohit Prasad agreed that the business case was key and that it required considering alternative engineering arrangements. If hydrogen in gaseous form is cheaper but the pressure is not enough for power density, he said, then the pressure could be doubled.
“We are all engineers but we are not [doing enough] playing in our labs,” he chided.
Another theme pervading many of the presentations and discussions in Bergen was that of safety, or the lack thereof. Lloyd’s Register’s senior principal consultant for risk management Olav Roald Hansen sought to dispel myths that hydrogen is safer than natural gas. He said an oft-cited statistic concerning hydrogen’s 18% to 59% limits pertained to detonation, not flammability. He said natural gas has a narrower range of flammability offering a higher probability that a leak would not lead to a fire. In the case of hydrogen, he said, a leak would more likely lead to a fire or an explosion, even though hydrogen is less reactive than natural gas in lower concentrations. To give some perspective, he said a 1-mm hole in a hydrogen gas tank would require a safety response within 57 seconds before an explosion could occur, leaving a very narrow window for remedial action to be taken.
Mr Roald Hansen said today’s risk assessment rules for hydrogen use are strict and require safety guarantees. Focus areas for safety in hydrogen are the tank connection space and low pressure fuel lines. Striking a positive note, Mr Hansen said many areas and operations such as bunkering can be made safe by taking practical safety measures.
A recent hydrogen explosion in Oslo at an H2 refilling station also consumed much of the conversation at the conference. Mr Hansen explained that a small leak from high pressure bottles gradually increased in size from 0.04 grams per second to 300-1,000 grams per second, at which point the seals on the bottles tore. As the hydrogen gas cloud ignited in a small area, the resulting explosion could be heard from miles away.
Giving her perspective on safety, Ballard’s director of business development Kristina Fløche Juelsgaard said 10 years ago no passenger wanted to enter a hydrogen-powered bus but today these vehicles are common in downtown London. Ms Juelsgaard suggested that one way to facilitate fuel cell adoption in the maritime industry was to begin with ports. Some ports may be looking to move off the main power grid as countries adopt policies targeting zero emissions, she theorised. Using hydrogen fuel cells in ports would facilitate this zero-emissions target and offer hydrogen availability for the ships using the ports, too, she said.
Ms Juelsgaard said she favoured low-temperature proton exchange membrane (PEM) fuel cells, admitting that she represented a PEM supplier. She said use in the road transport sector has allowed the technology to mature beyond that of solid oxide fuel cells (SOFC).
Drawing a sharp contrast to her assessment, Foreship head of new technologies Jan-Erik Rasanen said his company viewed SOFCs more favourably. Their high temperatures offered possibilities for waste heat recovery and the inbuilt reformer meant a ship running on LNG could be converted using the same LNG tank. If hydrogen were more readily available then the case would be different, he said.
A presentation from GE seemed to show that the future of fuel cells in ships is promising. GE passenger vessels market leader Renaud Cornu talked about the OEM’s interest in fuel cells including in the marine field. He said the company saw a decline in the market for gas turbines, which is the flagship product of its energy division, and saw a future in fuel cells.