Will Scotland build a hydrogen ship?

A project aiming to put Scotland at the forefront of zero-emission hydrogen technology has delivered a design for a small ferry to Orkney. But will it happen?

‘Ferries’ has become something of a dirty word in Scotland in recent years. An increasingly unreliable fleet coupled with massive cost overruns and delays in building new ships regularly make headlines.

At the same time, a disparate group of organisations, private companies and academics – both in Scotland and Europe – are quietly working together on a much more optimistic vision of the future.

For a decade, they’ve been testing the feasibility of transporting people and vehicles across lakes and seas using hydrogen, a fuel where the only byproducts are oxygen and water so clean you can drink it.

The ship Shapinsay

HySeas III, the latest incarnation of the project, has a very specific goal – to build a small double-ended vessel to carry passengers and cars on a 25-minute journey between Kirkwall and Shapinsay in Orkney.

Orkney was chosen for a reason. The island community, just north of mainland Scotland, is a world leader in pioneering a hydrogen economy.

The islands have far more wind and tidal energy than they need for domestic electricity consumption, but the National Grid cannot always manage the surplus.

Instead of shutting down wind turbines for periods of time, they are used for electrolysis, breaking water molecules into oxygen and hydrogen.

Orkney uses electrolytes to produce ‘green hydrogen’.

This “green hydrogen” can then be used to generate electricity when needed using something called a hydrogen fuel cell.

Already fuel cells power a small fleet of municipal trucks, heat buildings and provide electricity to ships moored in Kirkwall Harbour. For a community so reliant on boats to get by the obvious next step is ferries.

Does it sound simple? It’s not that simple.

Challenges and options

First, there were technological challenges – and choices to be made.

Hydrogen can be mixed with other fuels and burned directly in an internal combustion engine, emitting much smaller amounts of CO2. But this method produces other harmful pollutants – oxides of nitrogen and sulfur, known as NOx and SOx.

Instead, the HySeas project opted for the much greener fuel cell approach – using hydrogen to generate electricity to drive electric motors.

diagram of the hydrogen ship

diagram of the hydrogen ship

Technological barriers have been largely overcome. A marine-certified hydrogen fuel cell, about the size of a closet, can yield 200 kilowatts of electricity. The output can be scaled like building blocks – the Orkney boat would require three of them.

In addition to the fuel cells, the ship would also need 7.5 tonnes of batteries to act as a buffer, smoothing the power supply to the engines, providing extra power when needed – but also ensuring the ship could reach port if the fuel cells collapsed.

A bigger headache was the regulations – or rather the lack of them. The team often struggles to achieve regulatory sign-off when the rulebook doesn’t keep up with the technology.

Despite these challenges, a training program for crews has been approved. A key milestone was reached last week when shipping regulator DNV gave the green light to the concept design.

The Hindenberg Fear

Hydrogen already has its place in transportation history.

The first modern airship, the Zepellin LZ1, took to the skies in 1900, three years before the Wright brothers and their winged aircraft.

For decades hydrogen-filled airships offered an economical means of air travel – but this crashed on May 6, 1937 when the Hindenberg exploded in a huge fireball on landing in New Jersey.


The Hindenburg disaster in 1937 shook public confidence in air travel

The 35 deaths, combined with the even deadlier crash of airship R101 seven years earlier, destroyed confidence in air travel, forcing a switch to the safer but more expensive helium gas.

Hydrogen is extremely flammable – but so are many other fuels such as gasoline. Hydrogen is already being used to fuel buses in Aberdeen.

Project leader Professor Martin Smith, of the University of St Andrews, points out that until the 1970s it was coal gas – which is 50% hydrogen – rather than natural gas that was piped into millions of homes.

“Your grandmother, your great-grandmother and your great-grandmother would use hydrogen as fuel,” he explains.

“It’s not the scary new fuel it’s sometimes made out to be — it’s been around for a long time.”

To satisfy regulators, designers plan to store the hydrogen in pressurized carbon fiber tanks located on the ferry’s wheelhouse deck.

The risks of leakage or, in the worst case, explosion have been carefully modeled and the pressure rating has been chosen to limit the potential for damage.

In one sense, using the lightest element on Earth as fuel has a safety advantage—if there’s a leak, it just floats away.

The momentum is gone

A few years ago it looked like the planned Orkney could be the world’s first hydrogen-powered ship, but, like the race for the South Pole in the early 20th century, that distinction will almost certainly go to the Norwegians.

HySeas III suffered a huge setback when its main design partner, Ferguson Marine shipyard in Port Glasgow, went into administration and was nationalized in 2019, affecting project funding and creating a mountain of red tape.

Scottish government ferry company CMAL took on the design role and started the process from scratch.

Meanwhile, Norwegian ferry company Norled has taken delivery of an 82m vessel called the Hydra, which looks set to become the world’s first hydrogen ship later this year.

Hydra’s fuel cells have been installed, but it currently runs on batteries due to a lack of locally produced hydrogen. They are currently finalizing the logistics for importing it from Germany.

While it may not be the world’s first hydrogen ship, the Orkney would still be unique as a model of sustainability – locally produced hydrogen powering a ship without the emissions that come from transporting fuel long distances.

Other future fuels

Hydrogen is not the only candidate when it comes to charting a path to a zero-emissions future for ships.

Ships powered entirely by batteries are increasingly common, especially in Scandinavia.

In Scotland, seven small replacement vessels currently being designed for west coast firm CalMac are expected to be battery-powered.

But currently all-electric boats are considered best for shorter trips or routes where recharging time is not a major issue.

For longer voyages, the shipping industry is also looking at ammonia or methanol as a future fuel because they are easier to store.

Charting a path to a greener future may involve many technologies and not “one size fits all”.

Helen, the electric ship

The battery-powered ship Ellen operates on a 25-mile route in southern Denmark

Cost is also an issue. Saving the planet doesn’t come cheap.

The price of green hydrogen, produced by electrolysis, is linked to the cost of electricity from renewable sources – which is currently higher than non-renewable energy.

Sustainable hydrogen is almost twice the cost of diesel right now, although as more wind power and electrolysis come along, some predict it will eventually become cheaper than fossil fuels.

Another challenge is to create enough. The west coast of Scotland lacks Orkney’s hydrogen infrastructure and installing it would require millions of pounds of investment.

Professor Smith, however, argues that there will also be wider economic benefits in job creation. Using wind power to create hydrogen, he says, is a cost-effective way to store green energy.

“You can’t build a battery the size of Ben Nevis on Skye. It’s much easier to store renewable energy as compressed gas.”

The prototype ship proposed for Orkney, along with the refueling infrastructure, would cost around £25 million – more than double the bill for a conventional ship of a similar size.

Will be built; That largely depends on whether politicians in Holyrood or Orkney think it’s a price worth paying.

Professor Smith is not an impartial voice, but he has strong opinions about what should happen next.

“We’ve ticked all the boxes, we’ve spent a long time doing this – and we’ve seen people in other parts of the world catch up,” he says.

“If we want to be a world leader in hydrogen technology, we need leadership and we need to do that.”

Such a vessel would do little to ease pressures on Scotland’s hard-pressed ferry network in the short term, but the technology at least offers a glimpse of what could be possible in the coming years.

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