Shipping - SUM: Sustainability Management Wiki

Authors: Alma Elizabeth Pelayo Avendano, Johannes Grunwald, Jonas Althusmann
Last updated: September 29th 2023

1. Definition and Relevance

The definition of sustainable shipping varies widely, but generally sustainable shipping means
meeting present needs without compromising the ability of future generations to meet their
own. Furthermore, it can be separated in environmental shipping and green shipping. First, environmentally sustainable shipping is characterized by minimizing damage to ecology and
health throughout the maritime transportation activities. Secondly, an environmentally sustainable way to handle and distribute cargoes is through green shipping, of which the main factor
is to reduce waste creation and conserves resources. ¹ To conclude, in this paper sustainable shipping is defined as:

“Sustainable shipping refers to the practice of conducting maritime operations in an environmentally and socially responsible manner, minimizing the negative impacts on the marine ecosystem, reducing greenhouse gas emissions, and promoting the well-being of both present and
future generations.”¹

Moreover, this paper focuses on the environmental, social and economic problems connected
to problems of unsustainable shipping and tries to give an overview to promote the importance
of sustainable shipping in the future.

2. Sustainable impact and measurement

This part will focus on the social and environmental sustainability implications of the shipping
industry. To begin with, the working conditions of employees in this industry differ from one
country to another due to the cultural and economic differences. Moreover, the environmental
problems relating to the shipping industry are massive and to mention and to discuss them is of
highest significance.

2.1 Social Sustainability in the shipping industry

A total of 50,000 cargo ships are currently crossing the oceans and transporting approximately
5 million containers that are destined for countries all over the globe. Consequently, there are
approximately 1.6 million people employed in this sector, many of them from developing countries as for example Indonesia, India and the Philippines. Global commerce depends on these
sailors for its success, and billions of people rely on them for their well-being.²
It has to be noted that many sailors sign fixed-term contracts, which means that they serve on a
ship for four to six months. After that, their term ends, and they return home to rest before
joining the next ship with a new contract. Often the working conditions are poor because of
long working hours and the enormous risks they face on sea. Around 2000 sailors lose their
lives every year while working on a ship based on different reasons, for example when the
sailors go overboard due to lack of safety regulations. In addition, many injuries and deaths stay
unreported. Another physically and physiologically threat for the sailors is the one of piracy
because even in protected areas ships and their crews on board are in danger because many
ships are capsized without any consideration for the shipping crew. In addition, seafarers are
rarely protected by their employers, since their workplace is almost always in international waters, where no country can enforce labor rights.²
Nonetheless, it should be noted that at the international level, the International Labor Organization (ILO) adopted the Maritime Labor Convention in 2006 to assure decent working conditions and living conditions for those on board for all sailors regardless of their nationality and
the flag of the ships on which they sail. Furthermore, this should lead to limit social dumping
to secure fair competitions for ship owners who respect seafarer’s rights.³ The concept of social
dumping refers to countries that attempt to gain a competitive advantage over other countries
with higher standards by offering lower wages, fewer social benefits and fewer occupational
health and safety regulations.⁴
On the other hand, the core of the plight of the modern mariner is the result of economic incentives. There are several aspects that contribute to the cost efficiency of maritime shipping, including the optimization of fuel consumption, the exploitation of economies of scale, as well as
the avoidance of all unnecessary costs. That means many ships save costs in the remuneration
of the sailors on board. The use of flags of convenience, used by many ships around the world
to engage in social dumping, is one example, as these flags allow shipowners to avoid expensive
laws and reduce their risk of legal action by registering their ships in countries with weak safety
regulations, lower taxes and lower minimum wages.²

Due to the fact that these ships generate a large amount of revenue, they are often not motivated
to change their regulations. The majority of the world’s ocean fleet is registered in Panama,
Liberia and the Marshall Islands, three small countries with few regulations concerning the
governing of their ships and crews. Hence, there is a lack of economic incentive to change the
status quo, which only contributes to regulatory stagnation and at the same time depriving maritime workers of many benefits, as for example fair compensation, rest and sleep between shifts
and good living conditions on board.² One example for this is that just recently in 2023 the IOL
agreed to raise the minimum basic wage for an able seafarer to US$ 658 as of 1st of January
2023.⁵
It is not possible to compare this international minimum wage with other countries’ minimum wages for seafarers because in every country there is a different buying power.
Theoretically, however, guidelines could be developed to reshape the incentive structure and
minimize negative externalities associated with labor in the global shipping industry. In the
absence of such regulations, the international order is clearly failing to protect the rights of
seafarers.²Hence, a goal would be to reform the working conditions for seafarers in the future
in order to create more sustainable working conditions on board of the respecting ships.

2.2 Environmental Sustainability in the shipping industry

Generally, shipping can impact the marine environment in two ways: catastrophically and
chronically. Catastrophic impacts on the marine environment can result from accidents that
involve ships, such as collisions, fires, foundering, and wrecks. The term “chronic impacts”
refers to impacts that result from the day-to-day operations of a ship without compromising its
integrity or ability to continue to function.⁶
There is no doubt that the shipping industry has many negative effects on the environment on
a daily basis as well as through catastrophic events. Some examples are oil spills, hazardous
substances, garbage, air pollution, invasive species and noise.
Oil spills from shipping have a wide range of impacts because an oil spill can happen through
a catastrophic event, an example would be a ship accident where all the oil spills into the ocean
which has an extreme impact on the marine environment. But it is also through day-to-day
shipping that smaller oil slicks enter the ocean. Although this has a smaller single impact, if this
occurs frequently, the effect on the environment is enormous and just as negative. Both, the
catastrophic impact and the chronic impact range from covering sea birds with oil, which often
leads to their death, through killing and tainting fish and shellfish, and making the stock of fish
farms unusable, to covering beaches and rocky shores with oil, which effects the coastal marine
ecosystems as well as the economic power of the tourism sector.⁶
Oil spills have a serious impact and usually result in high mortality rate of sea birds, marine
mammals, fish and benthic life forms, as well as coastal pollution and decreasing the water
quality. It is also important to consider the local circumstances of an oil spill; for example, that
rocky shores will be more adversely affected than sandy coasts. In addition, the impact on marine mammals, sea birds, and sessile biota will be greater if the spill occurs in areas where these
species are abundant and/or where breeding and nursery areas, as well as mitigation routes,
exist. Additionally, the local temperature is highly influential on the duration of the impact and
the recovery time of the affected ecosystem. The bacteria in warmer areas are more active and
can break down hydrocarbons faster and the ecosystem can recover faster compared to colder
areas. The bacteria activity there is much lower, and the effect of oil spills persists much
longer.⁶
An example for this is the oil spill in Kuwait and Saudi Arabia in 1991. The effect of this oil
spill had nearly disappeared after 18 months, although they could still find it salt marshes and
in the lower sediments of the coast after 5 years. But compared to the impact of the Exxon
Valdez oil spill in 1989, that could still be measured after 20 years, the recovery for the ecosystems in warmer areas is much faster. It can be said that shipping in connection with oil spills in
a catastrophic and a chronical way have a devastating impact on the environment.⁶
Another crucial effect of shipping on the environment is air pollution. NGO´s like the NABU
in Germany is criticizing this topic in the shipping industry for a long time already.⁷ But it has
to be noticed that the shipping via container ships is considered “climate-friendly” because they
are very efficient in comparison with other transport options which have a significantly higher
consumption per ton-kilometer than shipping, one example would be the aviation industry (as
can be seen in figure 1). There it is evident that the aviation industry has the highest CO2 emissions per Tons in Kilometer and the shipping industry the lowest.⁸

Figure 1: Container ships compared to other means of transportation
Source: Own illustration according to ⁸

As mentioned in the introduction, 90% of the world trade is shipped via Container ships, therefore even if the number of CO2 emissions per Ton of kilometer would be low, the amount of shipping is the problem and therefore the CO2 emissions of the total shipping industry is massive.¹

The global shipping industry produces around 1 billion tons of CO2 emission annually, and with 2.5% of the total share of the global greenhouse gas emissions, this industry has a significant influence on the global climate. As a comparison, if the shipping industry would be a country, it would be the sixth largest emitter in the world.⁹,⁸ Without any change in this industry or in the way how ships drive through new technologies, sustainable fuels and energy efficiency, the share of global CO2 emissions of shipping will rise until 2050 to 17%.⁷

As a result, it is important to understand that ships are fueled by heavy oils, which are residual oils from refineries, which is detrimental to the environment. These heavy oils contain significantly more Sulphur and other pollutants, for example heavy metals, than fuels used on land. Therefore, ships exhaust pollutes the air quality in coastal regions especially with Sulphur oxides, nitrogen oxides, soot and particulate matter.¹⁰ The environmental influence of these oxides is enormous on coastal and marine ecosystems, because Sulphur oxides lead to the acidification of soils and waters, change the pH value of rain and thus damage animals and plants in sensitive ecosystems. Furthermore, Nitrogen oxides also contribute to the acidification of soils and water bodies. In addition, they are leading to eutrophication, which has an over-fertilizing effect in lakes, soils and coastal areas. The acidifying effect of Sulphur and Nitrogen oxides and their over-fertilizing effect led to a threat to biodiversity in some areas and ecosystems. Especially salt marshes, mangroves, seagrass meadows and terrestrial areas at the coast have to face these dramatic consequences. In addition, these gases can affect people’s lung function and increase the risk of cardiovascular disease.⁷ Therefore it can be said that the effect of air pollution in the shipping industry an enormous threat for ecosystems, animals and humans is.

Therefore, it can be said that the effect of GHG emissions and the air pollution in the shipping industry is enormous and a threat for humans, animals and ecosystems. In addition, it leads for example to biodiversity loss and climate disruptions.¹¹,⁷ Moreover, the effect of air pollution has a chronical impact, and this happens every day, as for example 30.000 ships pass through the Kiel canal every year and 2000 ships sail in the Baltic Sea every day and night and produce a lot of pollution.¹⁰

Noise is another threat posed by shipping, and the marine environment is subjected to a wide range of human-made noises from activities such as commercial shipping, oil and gas exploration, and various types of sonar. In coastal waters and shallow waters, these human activities can dominate oceanic background noise. A long-term study of ambient ocean sound indicates that the level of low frequency anthropogenic noise has increased primarily as a result of commercial shipping. Both have been attributed to an increase in shipping and to improvements in vessel design (particularly propellers), which have not prioritized noise reduction. Therefore, this noise can travel high distances and influence many different species and areas.⁶ Furthermore, it is important to understand that shipping noise revolves around the 20 to 200 Hz frequency band, and that noise with these low frequencies can propagate effectively in the ocean and have a detrimental effect on all marine organisms. For example, baleen whales (e.g.: Humpback whales, fin whales and blue whales) use this same frequency band to communicate, therefore it could lead to disorientation and end in the stranding and death of these whales.⁶ The noise associated with the shipping industry affects many different species, as for example whales, seals and fish which use sound to communicate. As a result, the maritime industry has played a significant role in causing the worldwide noise pollution to increase by more than double between 2014 and 2019.¹²

In conclusion, it is generally accepted that the anthropogenic noise can be an important stressor for marine life and has a profound impact on many maritime ecosystems, making it a global issue that has to be addressed.

In the following chapter this paper will concentrate on technological solutions to reduce the impact of the shipping on the environment to be a more sustainable industry economical and ecological.

3. Practical Implementation

The following chapter presents a few widespread technological strategies which are applied in shipping to make this sector more sustainable. In many cases, the main target is to reduce the fuel consumption of the so-called heavy fuel oil (HFO), which is still used by many ships today. Since the measures here are also very diverse, some particularly important measures have been selected. In addition, some pioneering cases of the sustainable shipping sector are also presented.

3.1 Rotor Sails

In the future, it is not very likely that even larger ships will be built to reduce emissions due to lack of port capacity and also due to water-depth constraints.¹³ Therefore, alternatives must be found to overcome the sustainable challenges. Since wind is the most commonly available source of renewable energy offshore, many researchers and companies see wind propulsion technologies as a very attractive option to minimize the environmental effect of commercial shipping.¹⁴ For example, this can be done with the help of the so-called “rotor sails” or “Flettner rotors”. These are large cylinders that are installed on the ship and which provide the ship with an additional forward push due to the so-called “magnus-effect”, shown in the illustration below:

The airflow accelerates on one side of the rotor and decelerates on the opposite side, creating a pressure difference. In the presence of wind, the rotor, which is powered by an electric motor, is switched to “On”. The change in the speed of the airflow results in pressure difference, which creates a lift force that is perpendicular to the wind flow direction. This lift force is then used as an additional forward push to reduce fuel consumption. The energy needed to power the electric motor of the rotor gets subtracted from this benefit.¹⁵

Figure 2: Magnus effect in Flettner rotors
*Source: Own illustration according to* ¹⁵

There are many companies that manufacture, sell, and install Flettner rotors in ships. An example is the British company Anemoi, who has been providing the markets with its rotors since 2016. The company has a special patented folding system that allows the rotors to be moved or folded on the deck within minutes. Therefore, cargo operations are not hindered, and any damage caused by air draft or external objects such as bridges is minimized.¹⁶

3.1.1 Benefits and Challenges of Flettner Rotors

A practical example that exemplifies the fuel savings that can be achieved with Flettner rotors is the Wadi Alkarm, a bulk carrier which was built in 2011. The ship transports Coal, Iron Ore, and Grain from Damietta port in Egypt via Tunisia, Algeria, Morocco and Spain, and Portugal to Dunkirk port in France. A trip takes 13-15 days on average, and the ship makes 10 of such trips per year. An average of 1693 tons of fuel can be saved per year, which corresponds to a fuel saving of 22.28%.¹⁵ However, this is already an ideal example. Often, the reduction of fuel consumption is much lower, between 3% and 15%.¹⁷

The angle at which the wind blows on the rotors plays an important role in how much fuel can be saved. Angles of 120° and 240°, in relation to the direction of travel, give the best results. Which is roughly crosswind.¹⁵ A shipping route where crosswinds are to be expected frequently will therefore bring significantly better results. In unfavorable wind conditions, the effectiveness decreases significantly.¹⁸

Furthermore, the economic benefit derived from the Flettner rotors depends heavily on the development of fuel prices in the future. If the fuel price increases by an average of 10%, the investment of a Flettner rotor with average costs 750,000$ per piece would pay off after six years. If the future fuel price increases by only 5%, this amortization period increases to eight years and at a decrease of the fuel price of 5%, the investment of a Flettner rotor is already senseless from an economic point of view. It is also worth mentioning that the positive effect of the implementation of this technology decreases rapidly the fewer operating days the ship has per year, which may occur due to the impact of a slowdown in the growth of the global economy, as it was the case during the COVID-19 pandemic.¹⁵ This is one of the reasons why a not insignificant number of shipyards are not willing to take the risk of having Flettner rotors installed.

Moreover, not every ship is suitable for Flettner Rotors. The rotors must be very large for effective use. At least 20 meters high and 2 meters in diameter. For example, the 4 Flettner rotors of the Wadi Alkarm are 24 meters high and have a diameter of 4 meters each. This requires sufficient stability capacity, space capacity, and energy capacity, which means that there is only a narrow window on how wide the ship can be at minimum and maximum. Otherwise, the size of the rotors would create hydrodynamic instability on the ship. Due to the size of the rotors, there is also the risk of damaging them or the quay when the vessel is loaded and unloaded in port. Furthermore, electric capacity is needed for the rotor and the rotor motor without overloading the ship’s electrical system with the additional power of the rotors.¹⁸ In addition to the right type of ship, external factors also play an important role: Ships that run at a slow, steady speed are best suited for Flettner Rotors. The Wadi Alkarm, with an average speed of 13.5 knots, is an ideal example here.¹⁵

3.2 Wing Sails

Another strategy that harnesses the power of the wind to reduce emissions is Wing Sail technology. This technology was inspired by the conventional soft sails of sailing ships, which were combined with the design of airplane wings. The advantage of this “sail 2.0” is that its variable camber aerodynamic shape (aerofoil shape) provides more lift and a better lift-to-drag ratio than traditional sails, which in turn has a positive effect on fuel consumption. The use of wing sails is most relevant for tankers or carriers like bulk carriers, as a sufficiently large deck area is required for this technology.¹⁴ The “Orcelle Wind” is a ship concept of a zero-emission RoRo (Roll on Roll of) car carrier, which utilizes the power of Wing Sails. The vessel will have a car capacity of 7,000 vehicles and will achieve up to 90% reduced emissions under ideal conditions compared to today’s best vessels. It is expected to be operational in 2025.¹⁹

3.3 Air Lubrication

Another very effective technology, which is also widely used to reduce fuel consumption, is the “Air Lubrication System”. This technology minimizes the frictional resistance of a ship. This is triggered when sailing through the water, which leads to major braking, especially on slow-moving ships, such as oil tankers or container ships. The ALS reduces this frictional resistance by pumping microbubbles onto the hull. The direct contact of the hull with the water is reduced by the now wetted surface (lubrication) of the hull.²⁰

A distinction is made here between 3 different techniques:

1.) The air bubble concept: By injecting micro-bubbles into the bottom of the hull, the local density of the ship and skin friction gets reduced, and turbulence of the flow gets suppressed. This leads to an average fuel saving of 3-6%.

2.) The Air film concept:Here, the air bubbles gradually merge into a continuous layer of air that separates the surface of the hull from the water flow.It leads to average fuel savings of 4-12%.

3.) The Air cavity concept: Frictional resistance is reduced here by blowing air into a recess or cavity at the bottom of the hull. The effect strength is thus strongly dependent on the design of the ship’s hull. Fuel savings can ideally be 16-22%.²⁰

The ALS is produced and installed by many different companies in various designs. Wärtsilä is a Finnish marine and energy technology company that sells the Silverstream® system, a special version of the Air Lubrication System that can reduce fuel consumption by up to 10%. Moreover, it is suited for many ship types like Roll-on/roll-off (RoRo) vessels, bulkers, container vessels, and tankers.²¹

3.3.1 Requirements and challenges of Air Lubrication Systems

Despite the very widespread use of the ALS, there are some requirements and challenges that must be overcome for successful application. The effectiveness is very dependent on external weather conditions, such as swell. In favorable sea conditions, the energy savings can be twice as much as in unfavorable sea conditions. Secondly, the ship itself is also an important determinant. The effectiveness is highly dependent on the operational profiles of the ship, the details of the air lubrication arrangement, the type of the ship, and the shape of the hull. For example, the correct shape of the hull ensures that the bubbles adhere better to the underside of the ship, which leads to significant efficiency gains.²⁰

3.4 Smart Shipping

Digitalization and Industry 4.0 could also unfold in the shipping sector, which is known as “Smart Shipping”. Smart ships use the digitalization of ships to optimize operational processes on board and on land. Ships and ports are connected to one global system and operate in the most optimal way. Computer Centers in the port can process information coming from other ports, ships, weather services, cargo shippers, and other sources, and continuously inform the ships going to the port and leaving the port. For example, a common problem in the shipping sector is that ships have to wait days or even weeks in front of the harbor entrance before entering the port to load or unload. During the waiting process, fuel, time, and money are lost unnecessarily. With the help of digital solutions this problem can, at least partially, be solved. The port provides the ship with the necessary information, what should be its optimal speed, and other seagoing characteristics. The “smart ship” adjusts its sailing parameters based on the incoming information so that it reaches the port at exactly the right time.²²

Smart Shipping has many other advantages; for example, the amount and capacity of port warehouses can be minimized through an optimized port management. Moreover, the shipping trip itself can be optimized, which in turn reduces fuel consumption.²²

3.4.1 Digital Twins

A special part of smart shipping is the digital twin technology. A digital twin is a representation of a physical entity in a digital format. The aim is to create a digital copy of the physical original that is as exact as possible. The digital twin then includes all data and simulations that are available during the entire life cycle of the ship.

In the digital environment of the twin, a theoretically unlimited number of processes can then be carried out, for example, simulated system testing and virtual design integration, testing for security vulnerabilities, bringing in and storing operation-specific data such as weather and wave data or other asset-based data and developing forecasts for shipping routes.²³ An example from the field of risk management is the forecast calculation of damages from waves on the ship hull by combining ship and weather data with historical wave data.

A digital twin continuously learns and updates itself through sensor data that measure various operational aspects, through input data from similar assets, and from interaction with the environment. Especially in recent years, the concept has been used more and more often in shipping.²⁴

3.4.2 Disadvantages of Smart Shipping and digital Twins

However, due to the scope of the system, Smart Shipping and also digital Twins have the disadvantage that these systems are generally very complex because the system needs to coordinate simultaneously the personal interests of many different stakeholders. Potential vulnerability and instability can therefore be a major disadvantage of smart shipping. External factors like a hacker attack can lead to a collapse of the whole system in the worst-case scenario. Due to this complexity and the susceptibility to errors, human personnel who are trained in the IT sector as well as in the maritime sector should still always be available to monitor the AI systems and intervene if necessary.²²

3.5 Alternative fuels: LNG

Besides the strategy to reduce fuel consumption, there is currently also a lot of expansion going on in the area of alternative fuels. Alternative fuels such as methanol or biodiesel have potential, but there are still many hurdles to overcome. For example, the infrastructure for the respective alternative fuel has not yet been sufficiently developed or the characteristics of the substance make production or transport difficult. In addition, the C02 emissions of the entire product life cycle must be taken into account for alternative fuels, not just the emissions that arise during the combustion of the fuel. A very promising alternative fuel is liquefied natural gas or LNG.

3.5.1 Advantages and Challenges of LNG

LNG can obtain a reduction in NOx (nitrogen oxide) emissions of 24% compared to heavy fuel oil, which is a big advantage over other alternative fuels. It is also characterized by relatively low production costs, and the price of LNG is also more stable in the near future compared to the price development of renewably sourced fuels such as biodiesel. Estimates suggest that LNG will be the cheapest of all alternative fuels by 2030. LNG demonstrates the impact that large-scale investments in alternative fuels can have on their wholesale prices. Major restructuring in North American ports has ensured that the LNG price in North America is only half that of the LNG price in Asia. However, the conversion of ports to make them suitable for LNG remains expensive, and the bunkering infrastructure among global ports is currently limited. Especially for LNG, extensive restructuring processes for the supply, storage, delivery, and combustion are necessary, which have to be carried out in ports, at terminals, and on ships.²⁵

LNG is gaseous at room temperature and has an extremely low melting point. For an appropriate transport, it must be liquified and stored at temperatures below -162◦C, which requires a lot of energy. In addition, LNG is highly flammable, and the methane in the LNG can volatilize if stored poorly. Therefore, special “cryogenic” tanks in which the LNG can be stored at these extremely low temperatures must be installed in the ships. Furthermore, an extensive and expensive conversion of the ship’s engine must be carried out so that the ship can run on LNG. A replacement with an LNG-compatible engine can cost around $5 million, which is about 15% more than the price of an engine running with HFO.

Another problem is storage capacity. LNG has a lower Volumetric Energy Density than HFO and therefore requires 2-3 times more storage space to provide the same performance as HFO. This reduces either the space available for cargo or the range of the vessel between refueling. In general, LNG has relatively high life cycle emissions, making it difficult to achieve the long-term goal of decarbonization with LNG alone.²⁵

Since transport and commercial shipping have the largest (negative) impact on the environment, many technologies (and laws) also focus on solving the problems of this sector.¹³ ²⁶ Nonetheless, smaller sectors such as passenger transport and the cruise sector have become much more popular in recent decades as a result of the rise in tourism.²⁷ This, in turn, increases the urgency to take action in terms of sustainability in these sectors.

3.6 Electric Shipping

Especially in recent years, there has also been great technological progress in the field of electric shipping. Norway is a pioneer in this sector.²⁸ As an oil exporter, the country was hit hard by the 2014 oil crash, which led to an empty order book situation in the maritime sector, which in turn made alternative markets such as electric shipping more attractive.²⁹ Due to its large number of islands and fjords, ferries are also a key part of the transport system in Norway.³⁰ By mid-2021, 60 of Norway’s around 200 ferries were either electric or hybrid-electric, with a strong upward trend.³⁰ ²⁹

Besides reducing emissions, electrification in ships has many additional advantages. For example, the energy efficiency of the ship is increased. With a conventional combustion engine, the energy losses, which are caused by heat dissipation, for example, are between 40% and 60%. With an electric motor, these energy losses, which can occur during charging, for example, are significantly lower. Depending on factors such as air temperature, charging intensity, and type of battery, an electric drive can achieve an energy efficiency of 80% – 95%. Other advantages are noise and vibration reduction and that no auxiliary engines are needed to power electronics on board as this energy is already provided by the batteries.³⁰

Currently, full-electric ferries are mainly used on short routes with a duration of no more than 60 minutes.³⁰ Ships that are at sea for longer periods are equipped with battery-electric systems with back-up diesel or gas-electrical propulsion systems.²⁹ However, a shift to a broader range of routes due to technological progress is observable here.³⁰ In 2022, the world’s first fully electric fast ferry began operation in Norway. The ferry operates between the coastal city of Stavanger and its city islands and can carry about 150 passengers. The vessel is equipped with two electrical engines and a battery with 1.5 MWh capacity.³¹ The design of the lightweight propulsion system was based on the batteries used in electric cars, as many previous electric propulsion systems in ships have been very heavy, which led to performance loss.³²

Similar to the alternative fuel LNG, electric shipping also requires extensive restructuring of port facilities. In particular, it must be ensured that the charging stations are in close range to ship docks and ferry terminals.²⁹

3.7 Best Practice: Sea Zero Cruise Ship

Cruise tourism has grown in popularity in recent decades.²⁷ Despite the ongoing Corona pandemic, 20.4 million passengers sailed on cruise ships in 2022.³³ Along with this, the environmental problems that this sector entails have also increased. Similar to cargo ships, most cruise ships still use heavy diesel fuel, and attempts are made to reduce consumption or replace it completely.²⁷

For this purpose, the Norwegian company “Hurtigruten” has presented its concept for an eco-friendly cruise ship in 2023. The cruise ship named “Sea Zero” will have a total length of 135 meters and will be able to transport up to 500 passengers. In many future-oriented sustainable ships, or ship concepts like that of the “Sea Zero”, more than one sustainable technology is used simultaneously. The ship will be powered by several 60-megawatt-hour batteries, which can be recharged on land. It will be supported by three retractable wing sails with a total surface area of 750 m², which are additionally equipped with 1,500 m² of solar panels.³⁴

Other technologies, such as air lubrication and a high degree of artificial intelligence, will also be used. Since a high proportion of the total available energy on cruise ships is used to accommodate the passengers, the Sea Zero will have an intelligent ventilation system installed. This will enable passengers to monitor and control their power and water consumption with an app to reduce energy use in that area. Due to the high degree of automation, less crew will be needed to navigate the ship and also, in the harbors, there will be relief for the harbor personnel. The ship will operate along the Norwegian coast by 2030 and eventually replace the company’s entire cruise fleet.³⁴

4. Drivers and Barriers

4.1 Drivers

Factors that enable sustainable shipping at a global scale can be subdivided into political, legal, economic, technological, and environmental aspects.

4.1.1 Political and Legal Drivers

The shipping industry underlies an international regulatory framework that intends to promote sustainable shipping. These regulations incentivize innovation, research, and the integration of new technologies, including alternative fuels, to foster the global advancement of sustainable shipping. The International Maritime Organization (IMO) is a United Nations agency that was created in 1959 for developing and maintaining this regulatory framework. A central milestone was achieved when the IMO adopted in 1973 the International Convention for the Prevention of Pollution from Ships (MARPOL), which in 1997 was to be complemented by the Kyoto Protocol.³⁵ The Kyoto Protocol invited the IMO to:

Following its efforts, in July 2011, the IMO introduced compulsory measures to enhance the energy efficiency of international shipping through resolution MEPC.203(62). The resolution established the first global mandatory energy efficiency benchmark for an international industry sector. ³⁵

Further, in October 2016, a roadmap for the creation of an IMO strategy for the reduction of GHG emissions from ships was approved. It included three steps: 1) An inventory of ships’ fuel oil consumption, 2) an analysis of the data collected, and 3) decision-making based on the collected data.³⁵

In 2018, the IMO created an initial strategy to reduce GHG from the sector. It is a framework that sets levels of ambition and includes short-, mid-, and long-term measures to ensure the achievement of its goals. This Strategy is intended to be amended every five years. In 2023, it was revised and updated as follows:

Figure 3: IMO GHG reduction Strategy 2023
Source: Own illustration according to ³⁶

Best practice: The IMO strategy is relatively new, but there are some shipping companies leading the sector, showing that it is possible to reduce GHG emissions. One example is the CMA CGM Group. One of levels of ambitions of IMO is to reduce CO₂emissions per transport work by at least 40% by 2030. Since 2008, the company CMA CGM has reduced its carbon emissions per container by 50% compared to 2022. It has set the goal of becoming Net Zero by 2050 in all its activities. To achieve its goal, CMA CGM is working on innovation, doing research, investing in development, collaborations, and using existing solutions to use and make alternative energies available. ³⁷

Besides the GHG reduction strategy, IMO has created regulations that promote the energy efficiency of ships as well as to improve the operational efficiency of the sector, for example:

The Energy Efficiency Design Index (EEDI) defines technical requirements for ships. It sets a minimum energy efficiency level (e.g., CO2 emissions per ton mile) for different ship types and sizes. ³⁸
The Ship Energy Efficiency Management Plan (SEEMP) is a regulation that proposes ship owners and operators implement new practices and technologies when optimizing the operational performance of a ship. It provides guidelines for the development of a SEEMPS, which consists of three parts:

Part I: Ship management plan to improve energy efficiency

Part II: Ship fuel oil consumption data collection plan

Part III: Ship operational carbon intensity plan. ³⁹

The Energy Efficiency Existing Ship Index (EEXI) promotes continuous improvements in the energy efficiency of existing ships by comparing current EEXI benchmarks with required EEXI benchmarks for ensuring compliance with a minimum standard of energy efficiency .⁴⁰
The Carbon Intensity Indicator (CII) establishes a necessary annual reduction factor to ensure the ongoing enhancement of a ship’s operational carbon intensity. The attained yearly operational CII must be recorded and validated against the obligatory annual operational CII. This process allows the determination of the operational carbon intensity rating.⁴¹

4.1.2 Technological drivers

There are readily available technologies that could help to reduce the GHG from international shipping by 82% and even 95%, considering the current GHG projections until 2035. ⁴²

As already described in section 3 there are many sustainable technologies like wind propulsion, air lubrication, smart shipping, and the use of alternative fuels.

4.1.3 Economic drivers

The following economic factors influence the transition to sustainable shipping.

Readily available technologies can lead not only to energy efficiency improvements and emission reductions, but also these technologies have payback periods that are often manageable, which make them cost-effective. The cost effectiveness depends of some factors such as the price development of the fuel prices as already mentioned in the section 3. Energy efficiency improvements, which results in money savings, can also be achieved by increasing ship capacity and the practice of slow steaming.⁴³, ⁴²

4.1.4 Environmental drivers

Climate change is the biggest driver for achieving sustainability in the sector over the past years. Annual GHG emissions from shipping increased by 9.6% in 2018 compared to 2012.⁴² As mentioned before, shipping is one of the biggest global emitters of CO2. Around 30% of the transported goods by shipping are fossil fuels, which makes shipping one of the main facilitators of the continued use of fossil fuels. ⁴² For this reason, it is imperative to change, as soon as possible, how shipping is doing to ensure the achievement of the Paris Agreement’s goals and IMO’s goals. According to the actual estimations, should the ongoing pattern of escalating greenhouse gas emissions persist, there is a high probability that the Earth’s average temperature will elevate by 1.5°C by the beginning of the 2030s.⁴⁴

4.2 Barriers

There are various barriers to becoming more sustainable. These barriers are technological, political, legal, economic, and environmental. A holistic approach is needed to reduce the shipping industry’s environmental impact. ⁴⁵

4.2.1 Political and Legal Barriers

Some barriers impede the international regulations created by IMO that are applied globally. The sector is marked by extensive misuse of national flags to evade local or national rules in accordance with the IMO regulations. These practices include tax avoidance through the utilization of tax havens. Additionally, deficiencies in legal enforcement by Port State Controls are also prevalent and susceptible to misuse.⁴⁶

Another barrier is the timeline between the development and implementation new regulations.⁴⁶ A rapid implementation of the regulations is needed considering the urgency of climate change.

4.2.2 Technological barriers

There are barriers to the implementation of these new technologies. For example:

• Limited availability of alternative fuels at scale

Uncertainty surrounding the availability of LNG bunkering facilities (infrastructure) presents obstacles for shipowners interested in investing in ships powered by LNG.⁴³

• Access to new technologies

• Renewable energy production

• Lack of on-shore infrastructure to implement new technologies.⁴²

Best practices: CMA CGM and Maersk have overcome technical barriers such as the access to technologies and the limited availability of alternative fuels which are internal and external barriers. CMA CGM In 2020, the company CMA CGM launched the first 23,000 TEU LNG-fueled container ship. To develop this ship they have overcome internal as well as external obstacles such as to tank able to transport LNG in its liquefied form. To achieve it was not easy due to the characteristics of LNG, for example, to be liquefied it needs to be in very low temperatures. (-163 degrees Celsius) but they have overcome this and other technological barriers to be able to use LNG in container ships for the very first time in the sector. ⁴⁷ Maersk The limited availability of alternative fuels is an internal challenge that Maersk has overcome in trying to become more sustainable. To ensure the viability of green fuels, Maersk has created 9 new strategic collaborations incentivizing scale-up and availability of alternative fuels around the globe.⁴⁸

4.2.3 Economic barriers

The development or establishment of zero-emission technologies depends upon a secure demand. Carbon pricing or taxes can incentivize the market to transition to new technologies and alternative fuels.⁴³, ⁴⁹

A considerable obstacle to achieving carbon emission reduction in maritime transport lies in the limited profitability of zero-emission vessels. The difference in cost between traditional and zero-emission ship fuels obstructs the implementation of established and accessible technological remedies. As a result, there exists a barrier that restricts the integration of zero-emission energy sources for ships due to the risk of stranded assets.⁴⁹

4.2.4 Environmental barriers

In the past, the fuels required to ship goods worldwide were nearly 100% fossil fuels. The sector consumes 300 million tons per year and, giving rise to about 2.5% of anthropogenic CO2 emissions, and is expected to continue rising. For this reason, the continued use of fossil fuels is one of the most significant barriers. It is necessary to increase the use of alternative fuels or decrease the use of fossil fuels to achieve the targets of IMO. ⁵⁰, ⁵¹, ⁴⁵

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28
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29
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1
Zhou, Y., et al. Sustainable Shipping: A critical review for a unified framework and future research agenda,
Science Direct https://www.sciencedirect.com/science/article/abs/pii/S0308597X23000052 (2023).
2
Fang, X., Adrift, Alone, and Far from Home: The Human Side of the Global Maritime Industry, Harvard International Review https://hir.harvard.edu/global-maritime-industry/ (2020).
3
European Commission, Employment and working conditions [Online] available under: https://transport.ec.europa.eu/transport-modes/maritime/seafarers/employment-and-working-conditions_en (2023).
4
Bundeszentrale für politische Bildung Das Lexikon der Wirtschaft, Sozialdumping https://www.bpb.de/kurzknapp/lexika/lexikon-der-wirtschaft/20640/sozialdumping/ (2016).
5
International Labour Organisation, ILO body adopts new minimum monthly wage for seafarers
https://www.ilo.org/global/about-the-ilo/newsroom/news/WCMS_845493/lang–en/index.htm#:~:text=The%20meeting%20agreed%20to%20raise,as%20of%201%20January%202025. (2023).
6
Salomon, M., at al. Handbook on Marine Environment Protection https://link.springer.com/book/10.1007/978-3-319-60156-4 (2018).
7
NABU, Schiffsabgase schädigen Menschen und Natur https://www.nabu.de/umwelt-und-ressourcen/verkehr/schifffahrt/16641.html (2023).
8
Möller, S., Die Bremischen Häfen in der Globalen Politischen Ökonomie https://blogs.uni-bremen.de/hafenblog/2020/06/02/die-weltweiten-emissionen-der-schifffahrt/ (2020).
9
Hiltscher, L., CO2 – neutral bis 2050 – gelingt das?, Tagesschau https://www.tagesschau.de/wirtschaft/unternehmen/schifffahrt-klimaziele-co2-ausstoss-101.html (2022).
10
Umweltbundesamt, Seeverkehr – Luftschadstoffe, Energieeffizienz und Klimaschutz https://www.umweltbundesamt.de/themen/verkehr/emissionsstandards/seeverkehr-luftschadstoffe-energieeffizienz#luftverunreinigung-durch-seeschiffe (2022).
11
[1] Koundouri, P., The Ocean of Tomorrow https://link.springer.com/chapter/10.1007/978-3-030-56847-4_10 (2020).
12
Bayrischer Rundfunk, Traibhausgase und Lärm: Wie die Schiffahrt die Umwelt belastet https://www.br.de/nachrichten/wissen/treibhausgase-und-laerm-wie-die-schifffahrt-die-umwelt-belastet,ShkGVmR (2021).
13
Lorange, P. Innovations in Shipping. 2 The Shipping Industry: A Status Report. (eds. Lorange, P.) 9-32. (Cambridge University Press, 2020).
14
Ariffin, N. I. B. & Hannan, M. A. Wingsail technology as a sustainable alternative to fossil fuel. IOP Con-ference Series: Materials Science and Engineering 788, 012062 (2020).
15
Seddiek, I. & Ammar, N. Harnessing wind energy on merchant ships: case study Flettner rotors onboard bulk carriers. Environmental Science and Pollution Research 28, 32695–32707 (2021).
16
Anemoi. Rotor Sail Technology Anemoi Marine https://anemoimarine.com/rotor-sail-technology/ (2023).
17
GloMEEP. Flettner Rotors Global maritime energy eﬀiciency partnerships https://glomeep.imo.org/technology/flettner-rotors/ (2017).
18
Menon, A. Flettner Rotor For Ships – Uses, History And Problems Marine Insight https://www.marineinsight.com/naval-architecture/flettner-rotor-for-ships-uses-history-and-problems/ (2021).
19
Wallenius Wilhelmsen. Wallenius WilhelmsenWorld’s first wind-powered RoRo vessel secures EUR 9M in EU funding Wallenius Wilhelmsen https://www.walleniuswilhelmsen.com/news/worlds-first-wind-powered-roro-vessel-secures-eur-9m-in-eu-funding (2023).
20
Kim, Y. & Steen, S. Potential energy savings of air lubrication technology on merchant ships. International Journal of Naval Architecture and Ocean Engineering Volume 15, 100530 (2023).
21
Wärtsilä. Air Lubrication System Wärtsilä.com https://www.wartsila.com/marine/products/propulsors-and-gears/energy-saving-technology/air-lubrication-system (2023).
22
Alop, A. The Main Challenges and Barriers to the Successful “Smart Shipping”. the International Journal on Marine Navigation and Safety of Sea Transportation Volume 13, Number 3 521-528 (2019).
23
Kumar, R. 5 Benefits Of Digital Twin In The Shipping Industry Marine Digital https://marine-digital.com/article_5benefits_of_digital_twin (2023).
24
DNV GL. DIGITAL TWIN REPORT FOR DMA Digital Twins for Blue Denmark. (2018).
25
Foretich, A., Zaimes, G., Hawkins, T., Newes, E. Challenges and opportunities for alternative fuels in the maritime sector. Science Direct, Maritime Transport Research 2, 100033 (2021).
26
Wan, Z., Zhu, M., Chen, S. & Sperling, D., Pollution: Three steps to a green shipping industry. Nature 530, 275-277 (2016).
27
Genc, R. Sustainability in Cruise Ship Management. International Journal of Social Science Studies 4(6), 76-83 (2016).
28
Aasness, M. & Odeck, J. The increase of electric vehicle usage in Norway—incentives and adverse effects. European Transport Research Review 7, 34 (2015).
29
Sæther, S. & Moe, E. A green maritime shift: Lessons from the electrification of ferries in Norway. Energy Research & Social Science 81, 102282 (2021).
30
Siemens Energy. Decarbonizing maritime transport – A study on the electrification of the European Ferry Fleet. (2022).
31
Prevljak, N. World’s first all-electric fast ferry named in Norway. Offshore Energy.biz https://www.offshore-energy.biz/worlds-first-all-electric-fast-ferry-named-in-norway/ (2022).
32
Wärtsilä. MS Medstraum – the worlds first zero emission fast ferry Wärtsilä.com https://www.wartsila.com/insights/article/introducing-the-ms-medstraum-the-worlds-first-zero-emission-fast-ferry (2022).
33
Statista. Number of ocean cruise passengers worldwide 2009-2027 Statista https://www.statista.com/statistics/385445/number-of-passengers-of-the-cruise-industry-worldwide/ (2023).
34
Szondy, D. All-electric Sea Zero concept ship promises zero-carbon cruising New Atlas.com https://newatlas.com/marine/all-electric-sea-zero-concept-ship-promises-zero-carbon-cruising/ (2023).
35
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36
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39
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41
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42
International Transport, Forum. Carbon Pricing in Shipping, OECD Publishing https://www.itf-oecd.org/sites/default/files/docs/carbon-pricing-shipping.pdf (2022).
43
OECD/ITF. Navigating Towards Cleaner Maritime Shipping: Lessons from the Nordic Region https://www.itf-oecd.org/sites/default/files/docs/navigating-cleaner-maritime-shipping.pdf (2020).
44
Lee, J.-Y., et al. Future Global Climate: Scenario-Based Projections and Near-Term Information. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (2023).
45
Bouman, E. A., Lindstad, E., Rialland, A.I. S, AH. State-of-the-art technologies, measures, and potential for reducing GHG emissions from shipping – A review https://www.sciencedirect.com/science/article/pii/S1361920916307015. Transportation Research Part D: Transport and Environment 52, 408-421 (2017).
46
Parviainen, T., Lehikoinen, A. Kuikka, S. Haapasaari, P. How can stakeholders promote environmental and social responsibility in the shipping industry https://link.springer.com/article/10.1007/s13437-017-0134-z. WMU Journal of Maritime Affairs 17, 49–70 (2018).
47
CMA CGM. Our History cmacgm-group.com/ https://www.cmacgm-group.com/en/group-and-vision/Our-history. (2023).
48
Maersk. Sustainability report 2022. https://www.maersk.com/sustainability/reports-and-resources. (2023).
49
OECD. International Transport, Forum. Carbon Pricing in Shipping, OECD Publishing https://www.itf-oecd.org/sites/default/files/docs/carbon-pricing-shipping.pdf (2022).
50
IMO. Initial IMO GHG Strategy IMO.org https://www.imo.org/en/MediaCentre/HotTopics/Pages/Reducing-greenhouse-gas-emissions-from-ships.aspx. (2023).
51
International Energy Agency. International Shipping, Why is shipping important? Iea.org https://www.iea.org/energy-system/transport/international-shipping. (2023).