The Green Fuel That Can Revolutionize The Shipping Industry

Which leaves hydrogen and other synthetic fuels made from clean electricity. The gas is already widely used in industrial processes across the globe – demand for it has increased three-fold since 1975. But nearly all hydrogen, which is already used heavily in industry, is produced using fossil fuels. In fact, 6% of global natural gas and 2% of coal currently goes to hydrogen production. While this kind of hydrogen could be used to power ships with zero emissions from the ship itself, obviously it is not low-carbon since fossil fuels are used to produce it.

Producing Hydrogen with renewable energy

But hydrogen also can be produced without fossil fuels, using renewable energy to split water in a process called electrolysis. This process is expensive, and currently just 0.1% of hydrogen is made using it, but this is where the main hope lies for a climate-friendly shipping fuel. “Green hydrogen can be really emission-free on a full lifecycle basis,” says Marie Hubatova, a shipping emissions expert at the Environmental Defence Fund. “That means from the point of where the fuel is extracted, or produced, until the point of combustion.”

The problem is that right now, the availability of green hydrogen is just not there, says Xiaoli Mao, a researcher on the marine team at the International Council on Clean Transportation (ICCT). “Fuel producers need to see some legitimate demand in order to invest into its production, so it’s sort of like a chicken/egg problem – whether the ship technology develops first or the fuel side develops first,” she says.

CMB itself is already acting as an early mover by building its own maritime refuelling station for hydrogen cars, buses and ships in Antwerp port, which will produce its own hydrogen using an electrolyser. “We first need to show, look, we are customers and we are willing to pay that amount for hydrogen,” says Campe. “And then you see, ‘Oh, there’s a business case for the electrolysers’.”

How it works

Once the hydrogen is produced, there are several ways it can be used to power ships.

It can be burnt in an internal combustion engine, as Hydroville is currently doing. One downside to this is that burning anything in air, which consists largely of nitrogen, inevitably produces some level of nitrogen oxides – which are major air pollutants.

Reducing Emissions

These emissions could be tackled by fitting some kind of after-treatment device, says Mao. But hydrogen can also be used in a fuel cell – a device which chemically converts the fuel into electricity without the need to burn it, and the only emission is water. “The main challenges of making that work on a ship are just to make it big enough,” says Smith, noting the huge expense of installing enough fuel cells to power a ship. “There’s a real question as to whether or not that is an option that is going to work at the scales of vessels.”

But the real challenge for using it in long-distance shipping is how tricky it is to store. Hydrogen cannot simply replace bunkering fuel in the current system. To store it on board a ship as a liquid, it needs to be frozen using cryogenic temperatures of -253C (-423F), says Hubatova. And even then, it takes up a lot of space – around eight times more than the amount of marine gas oil needed to give the same amount of energy, according to EDF analysis.

Can the issues be solved?

The extra space needed by hydrogen has caused concern in the industry that it might need to clear out cargo to make room for the fuel. But an analysis from the ICCT has found that this barrier could be overcome. It found that 43% of current voyages between China and the United States – one of the world’s busiest shipping lanes – could be made using hydrogen without the need for cargo space or to stop more times to refuel. Nearly all the voyages could be powered by hydrogen with only minor changes to fuel capacity or operations, it found.

Ammonia alternative

 Hydrogen is often used as a catch-all term for synthetic fuels, but many experts believe another option is actually better: using the green hydrogen to make green ammonia, another fuel which can be either combusted or used in a fuel cell. Ammonia is far easier to store than hydrogen (it needs refrigeration but not cryogenic temperatures), and takes up around half the space since it is far denser. It can also be converted back to hydrogen onboard a ship, meaning it could be loaded and stored on the ship as ammonia but ultimately used in a hydrogen fuel cell.

“At the moment, the best bet is to just turn [hydrogen] into ammonia, which is this ‘Goldilocks fuel’,” says Smith. “Ammonia is so much cheaper to store; you can store it at a pressurised tank, so you don’t need to have any sort of cryogenics. It’s only a small amount more expensive to make than hydrogen.”

The caveats

First, ammonia is toxic to both humans and to aquatic life, so care will be needed. Second, the extra step to convert hydrogen to ammonia will use more renewable electricity, making ammonia that extra bit more expensive.

Still, ammonia is seen by many in the industry as the most viable option: a consortium of companies were recently granted EU funding to install the world’s first ammonia-powered fuel cell on a vessel in 2023.

Fall in Green hydrogen Prices

Green hydrogen itself is already pricey, and for a long time many have doubted whether it could ever be cheap enough to see widespread use as a fuel. But the huge cost reductions in wind and solar over the past few years have helped to challenge this view, with some experts projecting the cost of green hydrogen to fall significantly more in the next decade.

Necessary change

 After a lethargic start to climate action over the past decades, there are some signs the shipping industry is beginning to pay attention to risks posed to it by the climate crisis. According to Smith, large percentages of the industry now think they will need to get off fossil fuels, with hydrogen-derived fuels such as ammonia considered the most likely alternatives. “There are a million questions about how we get from where we are today to that end goal,” he says. “But the idea that that’s where we’re heading, is now very, very, very, very mainstream.”

But in the absence of stronger regulation for the shipping industry’s emissions, the speed of decarbonisation will be limited. “The role of the top-down approach in the form of regulations is also crucial, as it will ensure everybody transforms to zero-carbon, not just the most progressive players,” says Hubatova.

In fact, Smith argues that the main constraint for shipping emissions comes not from technological barriers but from the political process – most significantly, the International Maritime Organisation, the UN body responsible for addressing shipping’s climate impact. “We’ve got options: we can either essentially progressively ban fossil fuels on vessels, or we can try and incentivise the market for hydrogen-derived fuels,” he says.

A future for Green Hydrogen 

Smith himself foresees three stages over the next 15 years for hydrogen-derived fuels in shipping: an increase in trials and first-of-a-kinds from now to 2025; an uptake of hydrogen by early movers in the industry by 2030; then a wider scale roll out after 2030, as costs come down and the infrastructure for refuelling becomes more widespread. Already, shipping companies are talking about ordering “zero ready” ships that are ready to easily retrofit for ammonia, he adds. “Their mindset is, I know that in 10 years’ time I’m going to have to do something to run that vessel on ammonia,” he says.

Factors affecting decarbonization 

The result for shipping emissions depends on a whole range of factors, from regulations to the uptake of other technologies. But there is a growing body of evidence of how fast the shipping sector could decarbonise if it set its mind to it, with one major report finding it could almost completely decarbonise by 2035 using currently known technologies, including alternative green fuels such as hydrogen.

Gilpin thinks the sector could reduce emissions by half by 2030. “If we treated this climate emergency, like we’ve treated the Covid emergency, then absolutely we could,” she says. “But we don’t, we go ‘Oh it’s a bit difficult, let’s have another meeting about it.’”

Mao agrees that to ensure widespread uptake of lower emissions shipping technology, stringent mandatory regulations are vital. Even though hydrogen fuels may not see widespread use for a decade or more, she says, “we really need to start now”.

“There are many barriers, let’s face it,” she says. “We should devote our research money into making this a reality into the future.”

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Source: Future Inc