Putting propulsion on the pathway to survival

It was a bold claim, but Georgios Plevrakis, global sustainability director at class society ABS, made it: “we have identified three fuel pathways that can save the future of marine propulsion.”

Until he said it, I had not realised that something as fundamental as marine propulsion was at risk of demise, not least because if ships could not be propelled, that’s about it for the world’s economy.


He said it during a webinar last week (29 April) titled ‘Pathway to sustainable shipping’ and he and his colleague Sotirios Mamalis, ABS’ global sustainability manager, talked us through the decarbonisation solutions they believe will avert that calamity.

But just as the world economy needs shipping, so shipping needs the world economy. Shipping, Georgios said, “may not be able to meet the absolute CO2 reduction goals without the contribution of other sectors of the global economy.”

The webinar reflected on the 107-page report of the same name that ABS published on 25 March and the webinar’s moderator, ABS strategic marketing director Jesse Lashbrook, explained that, among other things, the report “identifies the gaps in current solutions to meet IMOs sustainability goals.”

Georgios clarified what those gaps are. He said that ABS’ research “suggests the industry will meet the targets for reduction in carbon intensity by 2050, but it might miss the target for the total GHG emitted annually.” That leaves a gap “between the industry’s present course and its stated ambition for 2050,” he said.

To fill that gap, there must be “accelerated decarbonisation policies that span the value chain, not just shipping,” effectively taking account of actions across the whole supply chain and beyond. “This could include changes in consumer behaviour, the energy sources used for power generation [and] new materials used for manufacturing.”

The report itself does not use the word ‘gap’ to describe this situation but it does make the point (on page 86, if you are looking it) that “the broader decarbonisation of the global economy … can contribute to the reduction in seaborne transportation of carbon-based fuels by reducing the required fleet and, by extension, the absolute CO2 emissions.”

That is a bigger statement than it might seem: it is making an argument in support of a smaller industry as a vital step towards plugging a gap that we cannot fill on our own.

Yet it may already be on the way to being fulfilled. The report was written before the current global pandemic took hold, during which the global economy has been drastically decarbonised in just a few weeks thanks to the downturn in trade.

A couple of weeks ago (21 April) my colleague Malcolm Latarche predicted that when this is all over, “there will be an inevitable restructuring of world manufacturing and trade” and that shipping “may need to adapt to fewer imports of manufactured goods from Asia” as manufacturing moves closer to consumers. If he’s right, and shipping volumes do not return to business-as-normal levels, by how much will the gap that ABS identified be narrowed?

So what are ABS’ three pathways? They involve light gas, heavy gas and bio/synthetics, with each of those categories having its own transition to future fuels. The light gas pathway starts with LNG, moves on to bio- or electro-methane in the medium term and eventually to hydrogen. The heavy gas pathway moves from LPG and alcohols to bio-LPG or bio-methanol with ammonia as its destination.

The bio/synthetic pathway is based around “a very interesting family of fuels,” Georgios said, starting with bio- or renewable diesel, with gas-to-liquid fuels in the medium term and finally second- and third-generation bio-diesel that would be made in such a way that they do not compete with food crops.

But here’s the snag: because they are hydrocarbons “they do not offer any benefits in terms of CO2 reduction from combustion or particulate matter.” So for these types of fuel, “lifecycle assessment of carbon footprint is of utmost importance,” he said. Regular readers can hear me saddling up my hobbyhorse to ride alongside Georgios on this journey.

Sotirios assessed the merits of the other two pathways. The light gas one, for example, takes us from LNG, which we know how to use, to hydrogen, which will need novel fuel storage and supply systems. And it must be produced from water or a renewable feedstock.

In the heavy gas pathway, the use of LPG as a main fuel is limited to LPG carriers, he said, “and this is expected to continue in the future.” Methanol has lower energy content so needs bigger tanks, but at least those two fuels can be produced renewably, which may eventually allow them to be counted as zero-carbon. But he put his money on ammonia as a promising long-term solution, although that is not without its problems as I discussed a few days ago.

These were not the only technologies discussed in the webinar and the March report and I urge you to follow the links in this commentary to get the full picture. But the details I have selected left me with a sense of unease. These pathways, remember, “can save the future of marine propulsion,” yet each leads to a place where current technology is not even close to guaranteeing global fuel security. Yet the timescales ABS has in mind match those in IMO’s GHG strategy, in which ‘long term’ means 2030 and beyond.

I cannot see hydrogen, ammonia or second- and third-generation bio-diesel becoming mainstream fuels in a decade from now and, to be fair, ABS does not make that prediction either. For each of its options, it details their challenges and there are plenty of those to be overcome.

So if these are the only potential pathways available to us, we need to put on some heavy boots and start tramping along them.

• What are the waypoints on your preferred pathway to sustainable shipping? Email me now with your thoughts.

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