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Shipping on a voyage to low-carbon fuel options

As with other hard-to-abate sectors, the shipping industry is facing many challenges to decarbonise sufficiently by 2050. Currently, the alternative fuel of choice for many is liquified natural gas (LNG) but the short-term gains negate the persistent long-term emissions. There are genuine low-carbon alternatives at hand if shipping can adjust its outlook

Green ammonia offers the best long-term solutions for a decarbonised shipping sector


SHORT HAUL
Like heavy road transport, some ships on shorter routes can use battery power LEAKAGE ISSUE
LNG-powered vessels will suffer from significant leakage of methane—one of the most potent greenhouse gases KEY QUOTE
Almost all the fuels that the market is contemplating for the future are not available as such right now and if you want them on the scale required, the economics do not make sense


The international shipping sector still largely relies on burning heavy fuel oil (HFO) as bunker fuel—any fuel used on board a ship—but has been trying to pivot to cleaner options, particularly liquefied natural gas (LNG). However, depending on who you talk to, those plans are either a step in the right direction or complicate the issue further, as current alternative fuel choices are also fossil fuels. According to a World Bank report, the maritime industry emits a massive 15% of global sulfur oxide (SOx) and as much as 13% of global nitrogen oxide (NOx) emissions. SOx are pollutants that contribute to the formation of acid rain, while NOx forms a family of poisonous, highly reactive gases. Combined with other air pollutants, such as particulate matter (PM), emissions caused by the 70,000 plus ships in operation worldwide are responsible for an estimated 15% of premature deaths globally from air pollution, according to the International Council of Clean Transportation (ICCT), a technical analysis non-profit organisation. Meanwhile, the International Renewable Energy Agency (IRENA) predicts that maritime trade up to 2050 could increase between 50% to 115% compared to 2020 levels. As such, IRENA estimates that greenhouse gas (GHG) emissions associated with the shipping sector could grow between 50% and 250% by 2050. Shipping’s dismal environmental record has forced it to seek solutions. ALTERNATIVE FUELS Some of the alternative fuels available for the shipping sector include liquefied biomethane—otherwise known as bio-LNG—which is produced using biomass that then utilises the methane to create the fuel so it has much the same chemical makeup as traditional LNG. There is also synthetic LNG where electricity, ideally renewable energy, is used to combine CO2 and hydrogen to form the fuel. However, headwinds remain for both of these fuels. Globally there’s a concern about how much bio-LNG will be available in the long term,” says Hemant Gupta of Drewry Maritime Consultants, a research group. Even if available, the production cost of synthetic LNG is expected to be more than that of green ammonia, because the carbon produced for synthetic LNG is then encapsulated by Direct Air Capture (DAC), which is an energy-intensive process, thereby increasing its production cost,” Gupta adds. GREEN AMMONIA Green ammonia, meanwhile, where the main feedstock is green hydrogen, appears to be a better choice than any of the other LNG alternatives because it will be the cheapest zero-carbon fuel in the long run. Ship engines that burn ammonia are not readily available despite some in the development stage. Furthermore, the use of ammonia comes with its own concerns since it is highly toxic and proper precautions need to be put in place. Additionally, the quantity of green ammonia production is insufficient, though there are some plants under construction. Some shipping companies have started building ammonia-ready vessels, which initially will use conventional fuels to be retrofitted to use ammonia at a later stage, according to both Gupta and Aman Sud, also from Drewry. EXPENSIVE OPTION Ajay Singh of Mitsui OSK Line, a Japanese transport company, points to the problems with green marine fuels”. Green marine fuels are currently an expensive option and not enough is available for any of the large shipping companies to make a complete switch away from traditional bunker fuels,” he said at the Argus Green Marine Fuels conference in Rotterdam in May 2022. Almost all the fuels that the market is contemplating for the future are not available as such right now and if you want them on the scale required, the economics do not make sense,” he added. However, in the long-term, it appears that ammonia offers the best alternative to replace fossil fuel usage by the shipping industry. A report by the Institute of Electrical and Electronics Engineers (IEEE) found that ammonia is already gaining favour in some parts of the shipping industry, as, unlike hydrogen, it can be stored at a lower pressure, while it has ten-times the energy density of a lithium-ion battery. However, since ammonia has only half the energy density of traditional fuels, storing it on board would currently require significantly larger fuel tanks. The report cites the LNG-fueled supply vessel Viking Energy, owned by Norwegian gas giant Equinor, which is being retrofitted with a two-megawatt ammonia fuel-cell system. By 2024, it will become the first ship propelled by ammonia fuel cells. [The initiative] will open up a completely new option for zero-emission shipping,” says Henriette Undrum from Equinor. However, the IEEE warns that using ammonia for shipping will come at a considerable price tag because of the need to build the plants to produce the ammonia and the cost of building new ammonia-based engines as well as the cost of retrofitting current ship engines.

Batteries included Battery-powered vessels for short routes, such as the Ellen e-ferry, are operating today


BATTERY LIFE Despite their weight, large battery packs for the international shipping industry could offer a plausible alternative, especially since battery storage technology is making headway in both the power and EV sector. But global shipping presents unique challenges that, currently, limit battery storage in shipping. Gupta points out that batteries are not yet powerful enough for large ocean-going vessels in deep seas and are only appropriate for short sea voyages. Bureau Veritas, a shipping classification society and offshore safety and verification body, reports that over 150 ships are already operating with batteries on board, with another 100 battery-equipped vessels under construction. Danish firm Danfoss has been showcasing its zero-emission electric ferry, nicknamed Ellen. Ellen sailed a record 50 nautical miles (92 kilometres) on a single battery charge recently, on its way back to the islands of Ærø and Als in Southern Denmark where it operates from the IEA conference on energy efficiency in Sønderborg. Challenges remain, Bureau Veritas claims. Key concerns include safety, cost, installation and battery lifecycle which must be addressed before batteries can be regularly integrated onboard ships. Moreover, today’s batteries largely serve either as backup power, providing the energy needed for short voyages or for ships sailing closely to populated areas,” the company says. Batteries are not yet suitable for providing the required power for long voyages, and are mostly found onboard ferries, tugs and other small or specialised vessels,” it adds. LONG JOURNEY The London-based International Maritime Organisation (IMO), the UN body that is tasked with improving international shipping safety and security as well as preventing pollution from ships, pledged to cut the industry’s GHG emissions by 50% by 2050, make cuts before 2030 to curb pollution and to get emissions to peak as soon as possible. Critics, however, claim these targets are still not enough to reach the required targets agreed at the UN Climate talks in Paris in 2015. A joint statement from a group of six non-governmental organisations warned the IMO proposal would not cap, let alone reduce, the shipping sector’s one billion tonnes and rising of annual emissions this decade. Johanna Christensen of the Global Maritime Forum, an international not-for-profit organisation, told the World Economic Forum in February 2022 that the cost of meeting the current goal is around the $1.4 trillion mark—substantially less than global subsidies currently paid to fossil fuels. A Hellenic Shipping News report adds more concern, stating in May 2022 that at least 90% of all world trade is transported by sea, adding that if shipping were a country, it would be the world’s sixth largest climate polluter. HERE TO STAY Not only does it appear that the shipping sector will fall short of IMOs 2050 benchmarks, but the fuel of choice pegged to replace HFO—LNG—raises further concerns over the enormous methane emissions in natural gas extraction and production, in addition to the emissions from across the entire LNG value chain. The year 2021 saw a record high 240 LNG-fueled vessels placed on order with shipyards, outnumbering 48 liquefied petroleum gas-fueled ships, 22 for methanal and only four for hydrogen, says classification society DN Alternative Fuel Insight. The Asia-Pacific region is readily adopting LNG bunkering as an alternative fuel choice. Singapore, which accounted for around 25% of global bunker sales in 2020, has adopted various policies that will allow the city-state to transform itself into an LNG bunkering hub. It began offering ship-to-ship bunkering at the end of 2020 and opened dedicated LNG bunkering capabilities last year. While LNG as a bunker fuel emits significantly fewer pollutants and contains 30% less carbon than HFO, it is still categorically a fossil fuel. There is also growing evidence that LNGs theoretical GHG benefits might not materialise in practice. METHANE LEAKAGE The World Bank points to additional methane emission problems when using LNG as bunker fuel, estimating that it is 86 times more potent than CO2 over a 20-year-period. Methane has grave climate change implications as a GHG, especially on a near-term basis,” it says. Moreover, many LNG-fueled ships in operation today are equipped with the leakiest type of engine.” Methane slippage refers to unburned LNG leaking into the environment from ship engines. If 1.8% of the gas is assumed to slip, well-to-wake GHG emissions of LNG ships are 1-10% lower than ships running on HFO or Marine Gas Oil (MGO). However, under a 3.5% methane slip assumption, total well-to-wake emissions of LNG ships are 0.3-9% higher than MGO and HFO ships, according to a white paper by Brussels-based NGO Transport and Environment. The World Bank released a report in 2021 raising methane leakage/slip concerns to back up a call to stop LNG bunkering investments and instead divert resources to developing ammonia and hydrogen. SHORT TERM GAINS However, despite growing evidence against using LNG for the shipping sector, those in the industry often push back, claiming that LNG might not be a perfect choice but it is the most readily available fuel at the moment, a view shared by Drewry shipping consultancy analysts Gupta and Sud. LNG has negligible sulphur emissions and much less other air pollutants and therefore meets the current regulations,” says Gupta. However, Gupta admits that the fuel does have a methane leakage problem and, given it is a fossil fuel, has significant CO2 emissions so will not be compatible with long-term standards. Complicating matters, Gupta adds that methane is around 30 times more harmful to the environment than CO2, but current IMO targets are only for CO2 and GHG emissions, without any specific regulations for methane—a key issue that was discussed during the COP26 climate negotiations meeting in November 2021. During the meeting in Glasgow, the US and the UK launched a partnership to cut global methane GHG emissions by 30% by 2030 compared to 2020 levels. More than 100 countries signed up to join the initiative, with China, India and Russia abstaining. Gupta, however, points out that the shipping industry is also trying to address the methane leakage problem. Research is ongoing by engine manufacturers to reduce methane leakage,” he says. IMO regulations are only covering the emissions from the vessels tank to its combustion in the engine. However, the menthane slip from the well to tank (from its extraction to loading the fuel into the vessels tanks), is less regulated.” Yet, according to both Gupta and Sud, LNG is still needed, at least as a transition fuel over the next ten years, possibly more, while other fuel choices are developed and brought into use.•


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Tim Daiss