New Marine Fuels?

By ir. W. de Jong


How to Comply with IMO’s 2050 CO2 Targets?

At this moment in time, ship owners still worry about how to comply with the IMO 2020 Sulphur Regulations and the Ballast Water Management Regulations. Yet, pretty soon they need to consider the consequences of the IMO 2050 CO2 emissions targets. Today, owners have to decide what fossil fuel to use after January 2020, with or without scrubbers. Well before 2050, they have to find fuels and propulsion systems using much less fossil content; an even more difficult task.

In April 2018, the IMO’s Marine Environment Protection Committee (MEPC) adopted a strategy on the reduction of greenhouse gas (GHG) emissions from ships. Total GHG emissions from international shipping should peak as soon as possible and be reduced by at least fifty per cent by 2050 compared to the total amount of these emissions produced in 2008, whilst pursuing efforts towards phasing them out entirely. This strategy is shipping’s answer to the international agreement reached at the 2016 Paris Climate Conference. In 2008, the total CO2 emissions of shipping amounted to some 900 million tons. This figure – for all international shipping – should at least be reduced to some 450 million tons or less by 2050. A very ambitious goal indeed.

The success of this strategy will depend on:

  • The conversion of the agreement into legally binding regulations in association with fair and proper enforcement by flag states to ensure compliance – Not an easy task for the IMO and the governments of maritime countries, but essential. Only putting down targets will not work; there have to be regulations and enforcement. Perhaps this process started from 1 January 2019, when vessels became obliged to submit data on their emissions to the IMO. In the European Union such a requirement (the monitoring, reporting and verification scheme (MRV)) was already introduced in 2018 and the first data obtained with that scheme will be published mid-2019.
  • The development of the demand for shipping – Will shipping continue to grow and how much? Seaborne trade in the past increased on average with some 3.2 per cent per year. According to Martin Stopford from Clarksons, this percentage could in future go down to 2.2 per cent. Others claim that it could go down more, taking into account changing economic models leading to more local manufacturing, agriculture, et cetera. Transport of fossil fuels may go down, but perhaps transport of various kinds of biomass for the production of low carbon fuels will increase. There could be more transport of grain, rice and other food because of a growing world population. Higher transport costs due to the increasing amount of environmental regulations might also have a damping effect on our transport needs. The more shipping grows, the more we have to reduce CO2 emissions per ship in order to reach the 2050 target. Stopford’s estimate of shipping growth would result in some 1800 million tons of CO2 emitted in 2050 when nothing would be done to limit carbon emissions. To reach the target of 450 million tons in 2050, with that transport growth assumption, on average, the emis­sions per ship or transport unit should go down by some 75 per cent. The ship owner association Bimco has also recognised the importance of this issue and has asked the IMO to base the Fourth International IMO Greenhouse Gas Study on realistic economic growth projections and not on some existing estimates claimed to be based on unrealistic projections.
  • Further improvements in ship energy efficiency – How much can we gain with better hulls, more efficient propulsion equipment, wind assistance, lower speeds? In some areas, we are perhaps nearing the limit of what is possible, in other areas, there may be ample room for further improvements, such as with auxiliary wind propulsion. According to an article in The Naval Architect of November 2018, lowering the speed of large container ships and Panamax tankers could result in a reduction of energy demand and CO2 emissions by approximately 20 to 25 per cent, taking into account realistic weather conditions and the extra tonnage needed for the same transport capacity .
  • Availability of alternative fuels – Low or zero carbon fuels will be required to substantially lower shipping’s CO2 emissions. These fuels should not just be of the zero or low carbon type when being burned on board, but also when being produced; from well to wake. This means that for the production of these fuels only renewable energy should be used.

Low and Zero Carbon Fuels
This section describes a number of fuels which may potentially help to reach the IMO’s target of fifty per cent less CO2 emissions by 2050. Batteries and methane (LNG or CNG) will not be considered. Although both these “fuels” are attractive for quite a number of applications, for large international deep sea shipping they are not expected to achieve the target of fifty per cent reduction, either because they are not sufficiently low carbon (methane), making them only suitable as an interim fuel, or because they are less suitable for larger ships requiring high power and sailing long distances (batteries). Dimethyl ether (DME) is not discussed either in spite of the good combustion properties claimed for use in diesel engines. Production is still very limited and there is insufficient information available to paint a useful picture of this product.


Low and zero carbon fuels can be produced as power-to-liquid (PTL) and power-to-gas (PTG) fuels from carbon dioxide and water or as biofuels from biomass. PTL and PTG fuels, also called electro fuels, are made by breaking down water into hydrogen and oxygen with the use of electrical energy (electrolysis). The hydrogen together with CO2 from a non-fossil source, is used to produce different types of energy carriers such as methanol and ammonia. In order to get zero carbon fuels, the electricity should come from renewable sources such as hydropower, sun or wind.

Unfortunately, these conversion processes have very low efficiencies. For instance, the overall efficiency of producing hydrogen with electrolysis from water, convert it for storage and transport and convert it to electricity again in a fuel cell, lies in the order of twenty per cent. The efficiencies of the production of ammonia and methanol from renewable energy are similar. A huge increase in the production of renewable electrical energy at an acceptable cost will be required to allow large scale use of such fuels.

Biofuels are made from biomass and include fuels like biodiesel, bio-methanol, bio-ethanol, bio-DME and biogas. Biofuels from the first generation are made from agricultural production otherwise available for food for humans and animals. Biofuels from the second generation are made from for example residues from harvests and forestry and do not compete with agricultural land. It has been calculated that the land required for production of enough biofuels of the first and second generation together for international shipping (300 million tonnes of fuel oil presently being used by shipping per year) would be somewhat larger than five per cent of the current total agricultural land in the world. This is evidently a non-starter, even more so when we think about other powerful industries that would like to use this energy source, such as aviation.

So the first and second generation biofuels will not really help us to achieve the IMO’s target and are only possible for a limited number of ships. More could perhaps be expected from third generation biofuels that do not compete with food production. Yet, these biofuels, for example produced from types of algae such as seaweed, are still in the development phase and it will take years before these may be used at an attractive scale. If ever, because there will also be a hefty price tag connected to this type of fuel. A further drawback of biofuels is that they can cause harmful NOX, CO, PM and black carbon emissions.


Methanol, also known as methyl-alcohol (CH3OH) is a transparent liquid at room temperature with a boiling point of 65°C and a density


  1. “Speed and Emission Reduction from Ships” by Hans Otto Kristensen; The Naval Architect, September 2018
  2. “Alternative Fuels: The Present and Future of Containment Sys­tems and Their Impact on the Design and Construction of Ships” by F. Cadenero, E. Fort, L. Blackmore; Lloyd’s Register EMEA; presented in January 2019 at a RINA Conference in London
  3. “Methanol as a Marine Fuel: The Shipyard Perspective” by Daniel Sahnen from the Methaship project; The Naval Archi­tect, January, 2019
“C-Job Explores Ammonia’s Fuel Potential”; The Naval Archi­tect, June 2018




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