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Future Fuel: Towards Carbon Neutral Shipping

United Nations Conference on Trade and Development (UNCTAD) claims 80% of the world trade tonnage for sea transportation. The shipping sector uses four million barrels of oils per day which is 4% of global production. Even the highest portion of trade carried by water, it is the least CO2 emitting transport mean for one mile of cargo tonnage, which accounts for 2.9% of global CO2 emission.

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Future Fuel: Towards Carbon Neutral Shipping

With the maritime-related conventions and regulations, there has been a significant reduction of marine pollution, especially from the oil spills over the last 15 years. The building of larger vessels to achieve economies of scale and improved hull designs backed the pollution reduction.

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Image Credit: Statistica_Future Fuel: Towards Carbon Neutral Shipping

The shipping sector came up with the Pari agreement requesting all parties to work towards emission control while the Kyoto agreement which was the main climate agreement prior Paris agreement requested developed economies to be bound to the agreement.

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Future Fuel: Towards Carbon Neutral Shipping

In April 2018, IMO set a strategy to reduce the emission by 50% by 2050, compared with 2008 emission levels. This requires a 30% reduction by 2030 to achieve the 2050 target. Setting targets brings you nothing unless the industry acts urgently and carefully for the CO2 emission reduction. IMO has so far failed on adopting necessary regulations even after trying hard to meet the targets of the Paris agreement.

Energy Efficiency Design Index (EEDI)

Energy Efficiency Design Index (EEDI) is the 1st standard set to reduce climate change by ships. This came into force in July 2011 making more energy efficient ships.

Set targets for EEDI are as below:

Phase I: new ships built between 2015 and 2019; an overall 10% improvement target in vessel energy efficiency

Phase II: new ships built between 2020 and 2024; improve their energy efficiency by 15 and 20%, depending on the ship type

Phase III: Ships delivered after 2025 will have to be 30% more efficient;

The maritime industry is enthusiastically looking for options for decarbonization. These tendonous efforts include slow steaming, technical modifications on existing ship engines, new laws and regulations, and efficient vessels.

Slow Steaming
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Image Credit to: transportenvironment.org_ Future Fuel: Towards Carbon Neutral Shipping

Ship reducing its operational speed than the designed speed refers to the slow steaming. Slow steaming reduces the speed of vessels at sea by 12% on average reducing fuel consumption by 27% on average.  This will not only reduce the emission but also the operational cost of the owners.

During a seminar by T&E and Seas at Risk in 2011, Maersk had explained how they have practiced the concept of slow steaming since 2007 without any technical issues to the ships while reducing their overall cost and GHG emission. They have tried super-slow steaming by reducing the engine power by 90% without a problem.

Slow steam could reduce the emission of ships yet the question is does it actually reduce the overall GHG emission by economies?

The slow speed of ships results in a longer lead time in the supply chain. Industries may have to increase their inventories resulting in bigger warehouses, higher echelon inventories, and negligence on concepts like lean management and JIT. Higher the echelon inventories higher the problems of managing them. Hence it is very needed to bring such problems to the table while supporting the slow steaming for reduced GHG emission.

As per the world shipping council, the majority of new ships built by WSC Member companies since 2013 are approximately 30-40% more carbon-efficient than those ships they replaced.  Supporting the fact, IMO has announced GHG emission from international shipping has decreased by 10% from 2007 to 2012 while ocean freight volume has increased. During the period CO2 emission of shipping accounted for 1,000 MT per year

Yet, the Third IMO GHG Study, 2014 predicts an increase in the emission despite the ship efficiency mainly due to the increasing economic activities and international trade. Plus ships burning heavy fuel release black carbon which accounts for 21% of the CO2 equivalent emissions of ships.

Future Fuel: Towards Carbon Neutral Shipping_ decarbonized_ Daily Logistics
Image Credit to: transportenvironment.org_ Future Fuel: Towards Carbon Neutral Shipping

Closer production plants to markets would be always a good solution to minimize the transport movements. Thus the question remains on how to achieve competitive and comparative advantages while following the low shipping distance. And how the economies survive losing the production plants in the country and moving them to no or less beneficial locations.

Could LNG Solve the Problem?

More and more Gas takers add to the world ships fleet and experiments are in progress for future fuel.

There is a potential reduction of CO2 by 24% using LNG for bunkering. The expected greenhouse gas emissions reduction of LNG is up to 21% for 2-stroke slow speed engines and up to 15% for 4-stroke medium speed engines. 24 ports around the world have LNG bunkering infrastructure and are said to be the cleanest fuel at the moment as it could cut sulphur oxides emissions by more than 90%.

Hence LNG considered being the best alternative for marine gas oil (MGO) and heavy fuel oil (HFO). Some studies show increasing methane leakage may result in GHG emission of LNG more than the marine diesel fuel. The leakage of methane could happen during the transportation, bunkering, and even during the extraction of LNG.

Discussions of using LNG has become a hot topic after the cruise ship AIDA NOVA was added to the fleet.  The research finding of consultancy Thinkstep showed up to 21% GHG savings on a well-to-wake basis (Total upstream”Well to tank” and downstream “Tank to wake” emission)of LNG over other fossil fuels. Thus Dr. Elizabeth Lindstad, chief scientist at the SINTEF Ocean research organization in Norway had made a commentary to T&E on the methodology Thinkstep had used.  She argued on the possibility of LNG being a worse fuel than the MGO.

T&E had taken a further step to analyze the GGH emission of AIDA Nova based on her engine specifications and Dr. Lindstad’s comments on Thinkprint findings.  Research findings further confirmed LNG could be the wrong solution for decarbonizing the industry.

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Image Credit to: transportenvironment.org_Future Fuel: Towards Carbon Neutral Shipping

 Further, some studies say, the level of GHG emission reduction of LNG could become insignificant with the growing trade. Hence, whether the LNG could be the future fuel and whether it is worth converting into LNG become a question.

Other Alternative Fuel

Ammonia, Electric powered ships, Hydrogen, Biofuels, and wind power are a few more options under discussion and research as alternatives to marine fuel.


Hydrogen is the renewable energy generated by electrolysis and it is carbon-free. Hydrogen considers as the lowest emission generator during the combustion process. Bloomberg New Energy Finance estimates that the cost of hydrogen could drop as much as two-thirds by 2050. In the meantime, Shell and ITM Power are constructing the world’s largest hydrogen electrolysis plant at a German refinery, with support from the European Union.


Ammonia would be a zero-emission fuel if it produces from renewable energy such as wind, hydro, thermal, or solar.  Same as Hydrogen, ammonia release zero CO2 during combustion. Other than renewable energy, biomass and fossil fuel could release synthetic ammonia. Using ammonia for decarbonizing shipping might be a good option. Yet it requires a higher storage capacity reducing the cargo space of the ships. The corrosive nature of ammonia would be a challenge to handle it as bunker fuel, especially for cruise ships.


Biomass uses to produce biofuel. Varieties of biofuel include biodiesel and bioethanol. Biofuel is easy to store, transport, and handle. Due to its being renewable in nature and more than  99% emission-free, biofuel could be a viable option. Yet the availability to use as bunker fuel and the cost needs to be verified. In the current context, 70% of renewable energy is from biofuel, and 3% of transport fuel is also biofuel.

“Biofuels are fully renewable and an immediately available solution to cut carbon emissions from ground and air transportation. When produced from sustainable raw materials […] they emit at least 50% less carbon than fossil fuels.” Bernard Pinatel, President, Refining & Chemicals, Total


Methanol is also considered to be clean renewable energy with reduced emission of sulphur oxides and nitrogen oxides.  But there is no proper procedure set up on using methanol as bunker fuel towards decarbonization as it was not been widely used as a marine fuel so far.

Yet a project was done by Wärtsilä with a methanol engine in 2015 on the ro-pax vessel Stena Germanica which is successfully operating.  This has encouraged Wärtsilä on investigating further on methanol.

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Image Credit: Wärtsilä_ Future Fuel: Towards Carbon Neutral Shipping

What is Next?

Finding the best future fuel could not be done in a day. It requires days and months of researches and pilot tests. Contradictorily, the shipping industry has to act fast to meet the IMO 2050 target and decarbonize towards a carbon neutral shipping sector.

Setting IMO sulphur cap from 1st January of 2020 also made the industry to be lost for a while. Changing bunker fuel requires a whole lot of re-engineering of vessel engines and the superstructure of ports.  Air quality should not be the opportunity cost of reduced water pollution.  Hence, scrubbers may not be the viable solution for old ships and demolishing either. Proper studies and crystal cut regulations should be in place if the industry really requires to see carbon neutral shipping in the future.

Using and investing only in the decarbonized or carbon neutral future fuel will not only help as the impact of the carbon emission on the environment is very high. Plus carbon neutral shipping should not only speak on decarbonized bunkering. While the big steps are taken on fuel there are many more to do. Focusing on renewable energy to power warehouses, planting trees would be a good option. Even though the companies are unable to invest in carbon neutral projects, they can always follow carbon conscious guidelines to reduce the emission. Efficient technology and techniques like Cold ironing, reducing emissions at the workplace, could bring down the emission too.

It is better to be late than not forever. Be Responsible. Take the small step you could. Act today for tomorrow, for a carbon neutral shipping sector!

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