by Antonis Karamalegos

The ninth largest container shipping line in the world, according to Alphaliner’s data, Yang Ming has announced it has ordered fine new 15,000 TEU container ships, which will be equipped with dual-fuel liquefied natural gas (LNG) marine engines. With this shipbuilding plan, the Taiwanese liner operator will become the first shipping company in its country that owns LNG-powered container vessels.

Choosing to enter the LNG market, Yang Ming is taking another step to address climate change and move on to low-carbon transitions, following the trend of the shipping industry, which has set ambitious climate targets for the next years.

The International Maritime Organisation (IMO) is currently targeting a 50% cut in greenhouse gas emissions from the global fleet by 2050 compared with 2008 levels, following a 40% reduction in carbon intensity by 2030, but there is growing industry and political pressure to raise the 50% goal to 100%.

“We must upgrade our ambition, keeping up with the latest developments in the global community,” Secretary-General of IMO, Kitack Lim, said at the International Chamber of Shipping’s Shaping the Future of Shipping conference in Glasgow, in November 2021.

In its annual Sustainability Report 2021, Hapag-Lloyd AG said that part of the future lies in biofuels, but even more in alternative synthetic fuels.

While all the shipping companies have pursued strategies of achieving net zero CO2 emissions in 2050, several leading firms have accelerated their climate goals. Danish shipping company Maersk aims to achieve net zero greenhouse gas emissions in 2040, one decade ahead of its initial 2050 ambition, while German ocean carrier Hapag-Lloyd has recently announced it will intensify efforts to reduce all the emissions of its entire fleet and become climate-neutral by 2045, five years ahead of the IMO 2050 target.

The next day of the shipping industry will certainly see vessel owners using alternative fuels, such as LNG, ammonia, hydrogen and methanol, but the path to decarbonising the maritime transportation sector is still unclear. For now, all the new fuels have advantages and drawbacks in terms of emissions, safety, feasibility and cost.

Below, we have noted the main features of the major alternative fuels that exist now in the shipping market, including information and insights from a survey by the Union of Greek Shipowners (UGS), published in May 2021, under the title “Survey of Alternative Fuels-Technologies for Shipping.”


LNG can have 20-25% less tank-to-wake CO2 emissions, which is a significant benefit for transitional compliance with increasingly stringent regulations, according to the UGS survey. LNG is sulphur-free, so there are no SOx emissions, while it is mostly composed of Methane (CH4). However, the comparative impact of CH4 on climate change is more than 30 times greater than CO2 over a 100-year period. The survey said that careful consideration needs to be given to methane slip (release of unburnt methane into the atmosphere), while varying and low engine loads also impact methane slip.

“In view of the above, using LNG as a transitional marine fuel towards decarbonisation presents challenges, but should not be dismissed simply on account of the fact that it is a fossil fuel. ‘Green’ LNG production and the liquefaction of natural gas to -173 °C requires substantial energy input and storage capacity,” pointed out the UGS study.

According to the same survey, LNG seems more viable for tankers than for bulk carriers and general dry cargo ships, while for container ships LNG could be viable for certain routes. Additionally, the energy density of LNG is 40-45% lower than that of HFO and there is high Capital Expenditures (CapEx) cost of fuel storage and containment systems in non-LNG carriers.

“Therefore, the use of LNG as marine fuel can become a significant interim solution in conjunction with DF engines for some sectors only,” concluded the UGS in its survey.


Biofuels can be mixed with fossil fuels (the “drop-in” fuel option), enabling ships to start limiting their emissions provided these mixes-blends are safe and fit for purpose, with several studies predicting that at most biofuels could supply fuel for 30% of the global fleet.

“Depending on their prices, this makes them a partial solution for meeting sustainable decarbonisation targets for shipping,” said the UGS.

Biofuels as “drop-in” fuels can be used in container ships, according to the study, where cargo owners are requesting that shipowners use cleaner fuel and where ships have a fixed schedule or published ports of call. Ships operating near densely populated areas, such as cruise ships and ferries, can also benefit from biofuels, especially when operating in regions where biofuels are widely available and where passing on the cost is easier. The UGS survey noted that, for bulk/tramp shipping, biofuels can also be a partial solution, provided it is the responsibility of fuel suppliers to make sure that, when mixed with fossil fuels, the blends are safe and fit for purpose.


Black (conventional) ammonia is produced using natural gas in the nitrate fertiliser industry. The UGS noted that the future use of ammonia as a marine fuel presupposes a significant increase in global ammonia production, since its use in shipping will compete with the fertiliser industry using ammonia in agriculture and possibly other sectors as well.

Blue ammonia is produced by combining natural gas with Carbon Capture and Storage (CCS) technology, minimising carbon emissions by approximately 66%. It is more attractive, compared to conventional ammonia because of reusing a significant part of the initially released CO2 in the atmosphere, while green ammonia is zero-carbon ammonia, made by using sustainable electricity, water and air.

The UGS survey pointed out that “availability in adequate quantities and at viable cost, development of new bunkering infrastructure worldwide and of suitable marine engines, lack of predictability of the regulatory framework and issues related to the exposure of crew to toxic ammonia vapours during storage and handling of ammonia as fuel on board need to be addressed.”

The union’s survey added that the potential high cost of green ammonia is a major consideration, while low energy density must be factored in and the cost and space of bunker storage will impact negatively.

Ammonia has attracted wide interest as a source of zero emission fuel for shipping, source: DNV


Regarding potential contribution to GHG reductions, methanol produced using natural gas as a feedstock has Well to Tank (WTT) emissions similar to other fossil fuels such as LNG. Bio-methanol produced from biomass is a carbon-neutral fuel. Methanol does not contain sulphur and is a relatively pure substance that is expected to produce very low PM emissions during combustion.

According to the UGS study, in laboratory testing, emissions of SOx reduced by roughly 99%, NOx by 60%, particles (PM) by 95% and CO2 by 25% have been reported compared to fuels currently available.

Notwithstanding the absence of bunkering infrastructure and the lack of information regarding the future cost of carbon-neutral methanol, dual-fuel methanol engine and fuel-supply systems (DF methanol ICE) are an option being examined, according to the study, which showed that methanol can provide a very good stable and safe hydrogen carrier, since it is the simplest alcohol with the lowest carbon content and highest hydrogen content of any liquid fuel.

“It can be used to produce hydrogen for fuel cells and the methanol industry is working on technologies that would allow methanol to produce hydrogen for fuel cells. Safety concerns, lower energy density of methanol and increased costs of the fuel storage system continue to make this fuel unattractive for the ocean-going bulk fleet,” commented the UGS in its survey.

The Green Maritime Methanol (GMM)  project ran from January 2019 to December 2020 and was supported by TKI Maritime and The Netherlands Ministry of Economic Affairs, source: Royal IHC


The carbon footprint of hydrogen produced from natural gas is larger than those of HFO and MGO. The cleanest fuel is green hydrogen produced using renewable energy. Production of hydrogen by electrolysis is viewed as an opportunity to store and transport surplus renewable energy, thereby stabilising the energy output of solar or wind power plants.

“If the electricity used to produce H2 is green, the corresponding GHG emissions reduce by more than 85% compared to conventional fuels,” pointed out the UGS survey.

The low volumetric energy density of liquefied hydrogen (LH) and the high cost of the fuel storage system make it very difficult to use LH in deep-sea shipping. The situation is different for LH in short-sea shipping on fixed routes covering limited distances with frequent port calls, which due to their relatively low energy demand are more likely candidates.

Graphic design of Global Energy Ventures’ pilot scale 430-tonne hydrogen ship

Using green hydrogen to make green ammonia potentially has the advantage of making another fuel which can be either combusted or used in a fuel cell. However, the extra step to converting hydrogen to ammonia using renewable electricity will make ammonia more expensive, according to the study.

“Hydrogen can be considered a zero-carbon fuel with no carbon emitted when converted to electrical energy in fuel cells (section below). Several technical arrangements exist where different fuels are directly fed into the fuel cells, such as LNG or Methanol, which are used as chemical carriers/sources of the hydrogen,” concluded the UGS in its survey.

At the time of writing, there is a variety of alternative/new fuel options. We cannot know yet which one will dominate the market and which will be the major fuel in the shipping industry over the next years. It seems, however, that the global shipping sector is committed to the energy transition. The shipping stakeholders try to find the most efficient way to cross the decarbonisation path and meet climate targets.

There are two major pillars for the transformation of supply chains, digitalisation and decarbonisation. The digital age is upon us, but so is the clean shipping era. The kickoff of the “green” shipping era will be the reduction/elimination of carbon emissions, and completion of that stage is now a matter of time.

This article is published in the May/June 2022 issue of Greek Business File, available here.