Dr Lynn Loo, chief executive of the Singapore-based Global Centre for Maritime Decarbonisation (GCMD), has a daunting task. The centre she leads has been tasked with helping accelerate shipping’s decarbonisation effort.

It is a task the Malaysian-born chemical engineer and professor of chemical and biological engineering at the prestigious Princeton University — and her team of engineers and scientists — take in their stride.

Loo admits she had never thought about shipping before she was invited to join an international panel looking at maritime decarbonisation while in Singapore on sabbatical from running Princeton’s Andlinger Center for Energy and the Environment.

What inspired her to join the industry was its global nature.

“If there’s a chance to pass a global carbon policy, it would be in a global industry such as shipping. It was that promise that something big can happen,” she said.

Loo believes alternative fuels are the pathway forward for shipping to reach its decarbonisation goals.

GCMD, she explained, looked across all available and potential decarbonisation solutions, and alternative fuels were “an obvious one”.

“With alternative fuels, the promise for abatement is huge because that’s the Scope 1 emissions, the largest piece for shipping,” she explained.

“It’s the biggest bang for the buck, but it is the riskiest … if we get one or a set of these fuels to work, then that’s what’s going to significantly move the needle in terms of carbon emissions reduction for shipping,” she said.

“I think one thing we’ve recognised is that the future is going to be very heterogeneous — it’s not going to be a single fuel. It’s going to depend on the ship type, the route they’re going to take, the availability of natural resources at these different ports along the routes they take.”

Loo said GCMD is mapping all this information to see whether it can provide more certainty when people seek guidance on the best fuel type they should be investing in.

“If we look at all these green fuels, they’re not going to be available in 2030, they are certainly not going to be at scale by 2040. Everything hinges on green hydrogen, so there is a lot of uncertainty,” she said.

GCMD’s first project is an ammonia bunkering study that will be piloted in Singapore.

So why ammonia?

“If you look at green fuels, they all start with green hydrogen. You need to produce green hydrogen, and then you can make these hydrogen carriers. You can make methanol, you can make ammonia,” Loo explained.

“It became clear the bottleneck is green hydrogen production, which relies on renewable electrons. If green hydrogen production is your bottleneck, then you want to be very efficient with how you use it.

“For every three equivalents of green hydrogen you use, you produce two equivalents of green ammonia. For every three equivalents of green hydrogen you use, you produce one equivalent of methanol.”

The 20% difference between the energy densities of methanol and ammonia means ammonia is the more energy-efficient fuel to produce, Loo said.

“That said, it’s still a long way away,” she added.

“There’s not a single drop of green ammonia that exists today. And then we’re talking about the scale that we need for the maritime sector. That’s why we chose to focus our first effort on green ammonia — not because we believe it’s the only fuel that’s going to be at play — but it is the more energy-efficient green fuel to be produced.

As production of green ammonia is scaled up, Loo expects engines will run on a blend of green and grey ammonia derived from natural gas.

The focus of the study is to demonstrate that a toxic substance such as ammonia can be safely bunkered.

Others, Loo said, are piloting the combustion of ammonia and developing the engines and the vessels.

“Where I think we can add value is to look across the supply chain and say, okay, assuming ammonia is going to be used as a fuel, how are we going to move ammonia around safely,” she said.

“If you look at the chemical industry, they figured out how to deal with chlorine, a super toxic gas. The microelectronics industry figured out how to deal with silane, another super toxic gas. I think the shipping industry could figure out how to deal with ammonia …We can train the operators so they know how to responsibly handle it. That’s what we want to demonstrate.”