Container ship powered by dirty oil, updated April 27, 2023

Cargo and cruise ships represent 2.6 percent of global emissions and could reach 17 percent by 2050.  Nearly all these ships use cheap dirty heavy oil with high sulphur content.   International regulations aren’t helpful as they are lax and difficult to enforce.  Fortunately, Maersk, the largest container shipping company in the world, has created the conditions for an industry-wide sectoral revolution by setting 2040 as a target to achieve net-zero emissions, requiring all new vessel acquisitions be carbon-neutral and has already ordered 12 green methanol powered ships.  Concurrently, many new technological solutions are under development including ones associated with electric, wind and biofuel energy sources.  Stringent territorial waters and docking standards, Maersk technological catalysts, financing of emerging remedies, could advance clean technologies quickly.  Finally, open-loop scrubbers are widely used as a band-aid to remove sulphur from the exhausts to transfer the pollutants into the sea.

International Maritime Organization (IMO) and Greenhouse Gases

Commercial shipping and cruise ships account for 940 metric tonnes of greenhouse gas emissions (GHG)/year, or 2.5 percent of global emissions.  Left unchecked, by 2050, the industry would represent 17% of global GHGs by 2050, corresponding to 90-130% GHGs of 2008 levels.  Yet, these sectors operate in a near environmental anarchy.  It doesn’t have to be that way.

The International Maritime Organization (IMO) “governs” the seas for the 60,000 ships on the planet’s waters.

But IMO regulations are lax, and it is difficult to apply their rules in international waters.

This laxity is exemplified by the extraordinary low levels of emissions targets associated with the highest CO2 polluting, least refined, high sulphur content heavy oil, consumed by both the commercial shipping industry and cruise ships.   Approximately 95% of ships use heavy oil and shipping emissions have increased by one-third this century.  Heavy oil is the inexpensive yucky residue at the bottom of the barrel of crude oil after all the gas products are refined.

The IMO total annual CO2 emission reduction from ships for 2050 are only set to be at least halved relative to 2008 levels.

There is an IMO 2030 interim target to reduce the average carbon intensity across the shipping industry by 40% based on 2008 levels.  This is not to be confused with absolute emissions, just emissions per unit of consumption.  That leaves the industry with plenty of wiggle room to increase emissions over the next decade.  One can’t get more timid than that.

IMO and sulphur: Cure not better than the disease

The IMO sulphur environmental global standards, effective as of January 1, 2020, call for a sulphur content reduction from 3.5 percent to 0.5 percent mass by mass (m/m).

Nitrogen oxides limits for ships built on, or after January 1, 2000, became incrementally more stringent for ships built on or after January 1, 2011 and January 1, 2016.

For The Sulphur Emission Control Areas (SECA), since 2015, the IMO sulphur limit is 0.10 percent m/m. The SECAs include the coastal waters of Canada and the U.S. (200 nautical miles out from shorelines), the North Sea and the Baltic Sea.

Similarly, beginning January 2022, South Korea will require 0.10 percent sulphur content in its control zones.

China, with 7 of the world’s top 10 container ports, and handling one-third of seaborne containerized trade, has 0.5% sulphur content for all ships in its territorial waters, within 12 nautical miles from its shores.

The industry response to these sulphur oxide emissions standards, has mostly been to install scrubbers on about 4000 ships to remove sulphur from the stacks and flush them into the sea.  These ships represents 4 percent of total vessels, but 21 percent of the fleet in terms of tonnage.

In the SECA areas, scrubbers are boosted to meet the more stringent requirements.

The IMO 2020 standard is 35,000 parts per million (ppm) of sulphur into the sea for a ship with an open-loop scrubber and 5000 ppm for ships without scrubbers that emit sulphur into the air.

For every tonne of fuel burned, the open-loop scrubbers emit approximately 45 tonnes of warm, acidic, contaminated water containing carcinogens including polycyclic aromatic hydrocarbons (PAH) and heavy metals.

PAH has been associated with skin, lung, bladder, liver, and stomach cancers, in addition to being toxic for coral reefs and a threat to the entire sea life food chain.

Since the heavy fuel oil version of diesel has 3,500 times more sulphur than road diesel, this “solution” is like exchanging cancer for a hardening of the arteries.  Those vessels equipped with scrubbers are primarily the historically the biggest polluters with big engines, such as oil tankers, container ships and bulk carriers.

At least US$12B had been spent by the industry on open-loop scrubbers by 2019.  To comply with IMO regulations, by March 2021 scrubber sales have doubled since January 2020.  Annual scrubber investments are expected to reach US$7 billion by 2026.

Surely, the US$12B could better be spent on lower emission and ultimately zero emission technologies.

Only 2 percent of ships have closed-loop scrubbers, which captures the sulphur in tanks, for disposal to unknown sites.  Another 17 percent have hybrid scrubbers which can switch from open-loop to closed loop functions.

Thus far, the only nation-specific rules concerning scrubbing discharges exist in the U.S., China, Germany, Belgium, and Ireland.  The UAE has banned the use of scrubbers in the Port of Fujairah.

A technologically simpler solution would be to use more costly low sulphur fuel.  Heavy oil is 30 percent less expensive than low sulphur fuel.

As for CO2 emissions, the environmental bottom line for scrubbers is dubious since scrubbers increase heavy oil consumption by 2%.

Cruise Ships

Cruise ships also primarily use heavy fuel oil, but some are capable of switching to auxiliary engines for cleaner burning to enter certain U.S. and European ports.

Removing one mid-size cruise ship with an all-electric one would be equivalent to removing 1 million passenger vehicles from the roads.  Passengers on board of a cruise ship breath in 20 times the emissions than people take in near a main road.

Cruise ships emit black carbon, which per unit of mass, have a warming impact 460-1500 times greater than CO2.  Co-pollutants are particulate matter, toxic air pollution.  While cruise ships only account for 1% of total ships, they represent 6% of black carbon ship emissions.

The average cruise ship consumes 227 tonnes of fuel/day.  One of the largest cruise ships, the Harmony of the Seas, at full power, consumes 55,000 imperial gallons/day.

Cruise ships with scrubbers consumed 3.6 million tonnes of fuel in 2020.

While the large cruise ships can cost up to US$1.4B to build, pollution remains an investment afterthought with only 34 percent of the world’s cruise ships having scrubbers installed. These “clean ships” account for 96 percent of scrubber discharges of contaminated water in 7 of the 10 ports with the highest discharges.

The world’s largest cruise ship companies, Carnival Corporation, Royal Caribbean Cruises Ltd., Norwegian Cruise Line Holdings Ltd., and MSC Cruises have installed, or will install, scrubbers for most of their ships.   Currently, 68 percent of the ships of these companies are equipped with scrubbers and 31 percent use low sulphur fuel.

In areas where scrubbers are banned, like California, cruise ship companies keep low sulphur fuel on board to make a switch in these areas.

Data from 2017 showed that vessels owned by Carnival Corporation & PLC emitted 10 times more sulphur dioxide in European sea than all of Europe’s 260M vehicles.

Maersk sets conditions for marine sector revolution and methanol

In January 2022, Maersk A/S, the world’s largest container ship company and one of the biggest oil consumers, announced that it would become carbon neutral by 2040, 10 years earlier than originally planned.  This is very significant Maersk burns 12 million tonnes of marine oil per year, an annual consumption that is the equivalent of global oil production/day.

Especially significant, this new target differs from the previous 2050 target which aimed at direct pollution production only.  The revised target covers indirect energy from companies from which Maersk procure products, plus energy associated with supply chains and customers’ uses.

An interim target for 2030 comprises reducing emissions by 50 percent for each transported container and 70 percent at port terminals.  This is expected to reduce net emissions 35 percent to 50 percent, based on 2020 levels.

This follows a February 2021, Maersk A/S, announcement that all future new vessels would be carbon-neutral.

In August 2021, Maersk placed a US$1.4 billion order for 8 vessels from Hyundai Heavy Industries., with a capacity of 16,000 containers, to be powered by green methanol for delivery in 2024.  The 8 ships may save one million tons of CO2 annually.

With an option for 4 more ships for completion in 2025, in early 2022, it was revealed that Maersk ordered 12 methanol-fueled container ships. These ships will account for 3 percent of Maersk capacity.

Total costs for this transition are expected to be in the order of an additional 10-12 percent/ship. Plus, green methanol is twice as costly as low-sulphur fossil fuel, translating into a 15 percent increase in shipping costs.

Maersk had indicated that the green methanol sources will be either biogas/biomass or green hydrogen combined with captured carbon dioxide.

Notwithstanding Maersk good intentions, carbon capture and storage (CCS) technologies have proven to be horrendously expensive and fall short on emission reductions to a point that CCS may actually increase emissions.  Concurrently, CCS provides the fossil fuel industry to continue business-as-usual with new sources of subsidies and opportunities for carbon credits.

Compared to green hydrogen and ammonia, green methanol is the most energy dense and easiest to manipulate.  The energy density of methanol is 16 megajoules/litre (MJ/L), not far off from LNG at 21-24 MJ/L.

But the e-methanol vessels with fuel derived from green hydrogen may run into supply problems and, as indicated below, green hydrogen is not a “green solution”.

According to Maersk, biomethanol may be the best bet for scaling up in the short and medium term.

By contrast conventional methanol is not an environmentally sound proposition.  Most methanol is derived from steam reformation of natural gas, meaning there are upstream emissions.  Thus, it may solve the problem with sulphur, but not necessarily resolve net greenhouse gas emissions. 

Energy efficiency

The majority of shipping industry environmental actions pertain to energy efficiency.  These actions operate at the margins of positive change and include routing vessels for better weather, improving the efficiency of hulls and propellers, and improving operations in the engine room.


While cheap electricity suggests that hydrogen cannot compete, a 2020 study by the International Council on Clean Transportation (ICCT) concludes that hydrogen could power all cargo ships traversing the Pacific Ocean.  This study indicates that only 5% of cargo space would need to be sacrificed for hydrogen storage, or by requiring one extra port to refuel.

However, 98% of hydrogen stems from steam reformation of natural gas and coal gasification, known as black hydrogen.  Black hydrogen is 30 percent blacker per unit of energy than the fossil fuel it was derived from.

The oil and gas industry majors (Big Oil) are lobbying hard for hydrogen.

The now in vogue blue hydrogen is produced by combining natural gas with carbon capture and storage (CCS) technologies.  But blue hydrogen net emissions reduction are marginal, carbon-neutral or may even increase emissions when upstream methane gases resulting from shale gas extraction, production and transportation leaks are taken into account.  Regarding natural gas, up to 10 kg of CO2 is generated for every kg of hydrogen.  The upstream methane emissions are 86 times worse than CO2.

To be entirely clean, the hydrogen would have to be green hydrogen produced via electrolysis.  Notwithstanding green hydrogen benefits, green hydrogen production to decarbonize the economy requires astronomical displacement of renewables that could otherwise generate clean power, is presently too expensive, is inefficient, entails many technological impediments, produces nitrous oxide emissions 265 to 298 times that of CO2 and may not be competitive until 2030.  The inefficiency is such that it has 45% the density of bunker fuel, meaning 2.2 times the volume of fuel required for producing green methanol from green hydrogen to go the same distance with bunker fuel.   Of the global 109 million metric tonnes of hydrogen produced annually, only 0.1 percent is presently green hydrogen.

Though hydrogen net environmental benefits are questionable, research continues on its potential for long-haul freight.  This is so despite the largest fuel cell remains far from the scale needed for freight shipping.  Scaling up fuel cells for the long-haul vessels may have merit, but the economics do not work for the short- and medium-haul ships.

Canada’s Ballard Power Systems has conceived the FCwave fuel cell products for the marine sector, but it has limited market applications.  Applications comprise ferries, river push boats, and fishing boats plus stationary power to support hotel and auxiliary loads for cruise ships and other vessels when docked at ports.

Also in Canada, in Fall 2020, Transport Canada has awarded a 3-year contract to Canadian Nuclear Laboratories (CNL) to explore the potential of hydrogen and other alternatives to replace fossil fuels for powering marine vessels.  Specifically, the project will focus on the development of the CNL Marine-Zero Fuel (MaZeF) Assessment Tool to analyze different energy options.

Further on fuel cells, a joint venture initiative of Samsung Heavy Industries and Bloom Energy to design and develop fuel cell ships is targeting 2022 for the introduction of these ships to clients.  The design has acquired approval in principle from DNV GL, the internationally accredited marine shipping registrar and classification society.

Another hydrogen stakeholder, the Norwegian ship designer, the Havyard Group, has created a new division, Havyard Hydrogen which believes it will have a complete hydrogen propulsion system of up to 3.2 megawatts of fuel cells, available for ships sometime in 2021. The Havyard Group has the know how for fully integrating hydrogen propulsion systems in designs for new ships, from the bridge to the propeller.  As for existing vessels, the Havyard concept is scalable rendering it possible for flexible placement of the hydrogen storage tank in the hull of the ship.

Ammonia and LNG

As for ammonia for shipping, ammonia is typically derived from hydrogen.  Thus, ammonia comes with all the failings of hydrogen as an energy source.  However, the IEA predicts that ammonia will account for 45 percent of shipping fuel demand by 2050.

Nevertheless, there is the option of green ammonia, but much needs to be done for this to be viable.  Green ammonia stems from green hydrogen and nitrogen oxide collected from ambient air.  But green hydrogen isn’t an interesting “green option” for reasons already mentioned.

The drawbacks of ammonia are that the fuel is dangerous if not handled correctly.  Its vapors being reactive and corrosive, can cause poisoning that can burn the respiratory system if inhaled.  If swallowed, it can burn and damage the digestive system.

Other potential fuels are liquified natural gas (LNG).

Volkswagen has two ships powered by LNG.  While LNG net emissions are greater than hydrogen, they are an improvement over heavy oil.

Euronav NV has put in an order for ships powered by ammonia or LNG.


Biofuels no longer displace food-based agriculture.

Volkswagen is using a biofuels for one of its ships.  These biofuels consist of a variety of certified feedstocks sourced from waste or residue.  No changes in ship hardware are required.  GoodFuels, the biofuels supplier, claims its products are scalable, affordable, technically compliant and ready for the market.

Affordable may be a question of perspective.  Biofuels are approximately 30% more expensive than fossil fuels.

Electric-powered ships

Electric marine vessels are making their entry into fray for emission reductions, but for short- and medium-haul transportation only.  Battery electric vessels are gaining market share for short-hauls, but not for long hauls due to insufficient energy density.

Canada is among the early adaptors.

By Summer 2021, BC Ferries took possession of its third hybrid electric ferry, manufactured in Romania.  A fourth hybrid electric ferry will join the fleet in late Summer 2021 with 2 more to come shortly afterward.   These BC ferries have capacity for 47 vehicles and 400 passengers.

One other BC ferry service to undergo electrification is that of the Kootenay Lake Ferry Service, for use between the Balfour and Kootenay Lake Terminals.

In Ontario, as of August 2021, the Merilyn Bell 1, the ferry between the Island Airport and downtown Toronto, was in the final retrofit phase to become an electric ferry.

Elsewhere in Ontario, terminal work is underway in 2021 to accommodate two electric ferries between Kingston and the Wolfe and Amherst islands.

Halifax is another to embark on an electric ferry project, scheduled to begin operation in 2024.

Electric ferry service operations elsewhere include Stena Line plans for its car ferries between Sweden and Denmark, beginning with one ferry and subsequently installing battery systems incrementally.

In port areas, specialty ships are good candidates for electrification too.

Flotte Hamburg, a division of Hamburg’s Port Authority, acquired two plug-in fire-fighting boats, manufactured by the Dutch company Damen.  These boats are capable of operating exclusively on electricity in the port area.  One of the boats will be operated by the HPA and the other by the city’s fire department.

Other examples of short distance specialty boats include an all-electric tugboat, one in Turkey and another in New Zealand; electric refuse boats to clean up the canals of Venice; and the London, U.K. hybrid pilot boats to escort large ships on the Thames River from Gravesend to Tower Bridge.

Regarding electric cargo ships, Norway’s Yara International launched a short-haul autonomous electric cargo ship in September 2021.  It’s maiden voyage between the Norway’s Herøya and Brevikv municipalities will take place in late 2021.  Humans are currently required for loading and unloading, but the plans call for autonomous technology for this as well.  Just this baby step to a transition to green shipping will displace 40,000 truck trips/year.

In November 2017, China launched its first all-electric cargo ship with a carrying capacity of 2000 tonnes and an autonomy of 80 km.  Ironically, it was tasked with transporting coal.  In April 2020, trial runs were undertaken on the Yangtze River for this all-electric cargo ship capable of transporting 900 tonnes.

For short haul cargo shipping too, Asahi Tanker, based in Tokyo, has developed a 60-metre-long lithium battery-powered ship, the e5, to be launched in 2022 to deliver diesel to fuel other cargo ships.

For long-haul shipping, electric power has potential if applied in a hybrid concept.   This would improve energy efficiency while requiring less generators.  One could alternately use the battery power rather than the generator and use the generator with battery power back-up.  This approach would be comparable to a plug-in hybrid vehicle which can be charged overnight for exclusive use of electric power for part of the next day.  As well, electric power can reduce emissions associated with acceleration.

Wind in the sails: Back to the future

Wind-powered ships may not be that far-fetched as some would think.

Presently in the making for sailing in 2023, Café William has ordered a 100 percent wind-powered ship under construction by SAILCARGO, the Ceiba, to transport its organic certified Fairtrade coffee from South America to its roasting plant in Sherbrooke, Quebec, Canada.  This will be the world’s largest zero-emission cargo vessel and a global first for zero-emission coffee.  SAILCARGO of Costa Rica, dedicated to green shipping practices, will use sustainable materials for the Ceiba.  For auxiliary power, the Ceiba will have an electric engine using battery and green hydrogen fuel cells regenerated by variable pitch propellers.

Other coffee companies experimenting with sail-powered ships are coffee roasters Javry and Belco, respectively of Belgium and France.  They are both using ships conceived by TransOcean Wind Transport, a French sailing freight transport company.

In Sweden, Wallenius Marine is developing the wind-powered Ocean Bird which the company claims can reduce emissions by 90 percent.  The remaining 10 percent of energy pertains to onboard energy requirements and assistance for certain maneuvers.  Ocean Bird is projected to set sail in 2024.

A novel windpower ship concept is that of Norsepower with tiltable Rotorsails.  The idea is to make it possible for ships equipped with sails to go under bridges.  This concept involves rotating cylinders, rather than cloth sails, that turn to best take advantage of the wind and, in turn, reduce demand on heavy oil engines.  The Rotorsail’s computers ensure the sails only work when sailing conditions can help reduce fuel consumption.  Studies have shown Rotorsails can reduce fuel consumption from 5% to 25%.  Existing ships can be retrofitted to have the Norsepower system installed.  The first ship to operate with these tilting sails will be the SC Connector to operate in the waters of Norway, Denmark, Sweden, the Netherlands and Poland.

Cargill intends to add wing sails for some of its fleet.

Docking and Territorial Waters Regulations

Evidently, more international collaboration is needed.  National legislation and enforcement offer paths for addressing some of the aforementioned challenges.

The Maersk commitment to the effect that all future ship acquisitions will be carbon-neutral will open the door to technological innovations that could form a basis for new regulatory measures within the realm of the possible.

That’s where national docking and territorial waters regulations come in.  If China, the U.S., and the European Union (EU) were to have some degree of agreement on national regulations, the entire international shipping paradigms would have to change.

Empirical evidence supports this.  Vehicle emission and plastics regulations in the EU and China are globally respectively engendering a massive and rapid transition to electric vehicles and plastics circular economy developments.

Ditto can be said for commercial shipping and cruise ships if enough countries adopt strict regulations.

On July 14, 2021, the European Commission revealed details on its proposed climate package, European Green Deal Investment Plan (EGDIP), aka Fit for 55, the first salvo, pulling together US$1.2 trillion over the 2021 to 2027, on a game plan to reduce emissions 55 percent by 2030, based on 1990 levels.  This 3,500-page climate action plan includes incrementally decreasing emission caps under the European Emissions Trading System (ETS) to the tune of 4.2 percent/year and new applications of the ETS to shipping and transportation at-large; and termination of fossil fuel tax exemptions for maritime transportation.

A study undertaken by the Europe’s non-profit Transport & Environment revealed that at worst 7% of ships would evade total trip emissions by going to an intermediate port since the additional costs associated with a trip diversion render the evasion option not cost-effective.

Unfortunately, the European Commission’s recommended measures translate into renewable and low-carbon sources to represent only 6-9 percent of the maritime energy mix by 2030.  More encouraging, that rises to 86-88 percent by 2050.  This formula suggests long-term solutions are possible, but the short-term is still problematic.

As indicated above, Maersk-related technological successes could inspire the EU to adopt more ambitious objectives for 2030.

The upshot

In the absence of effective regulatory solutions, Maersk, the largest container shipping firm in the world, is taking the plunge to explore how to revolutionize the shipping industry to be environmentally responsible.  The Maersk commitment to achieve net-zero emissions by 2040 will not only provide many catalysts for marine technological innovation, but will also pave the way for other shipping companies to be competitive.

That said, all of the preceding clean technology solutions are nascent.

With Maersk creating the conditions for emerging technological solutions, this may be what is needed for effective regulatory docking and territorial waters frameworks in critical jurisdictions.  A parallel can be drawn with the way the European Union and China have revolutionized the global vehicle sector to migrate to electric vehicles.

This approach would address the difficulties for regulating ships travelling in international waters and feeble IMO stipulations.

The European Union’s Fit for 55 is the first major political initiative to address the regulatory playing field in international waters as it applies to emissions/trip for ships docked in European ports.  But at present, Fit for 55 emission reduction projections remain too little too late.  On the other hand, Fit for 55, being a draft document, leaves much wiggle room to integrate technological advances into for legislative and policy initiatives.

It would be nice if most developed jurisdictions collaborated, the EU, SECA zones, South Korea, China and possibly other countries.

Lastly, on emerging technologies, electric, wind and biofuel power vessels, the public and private sectors should step up to the plate and support development on these technologies on larger scales.

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