Introduction: the carbon footprint of shipping


The shipping industry currently emits 3% of all global greenhouse gases. Therefore, it is obvious that the shipping industry needs to decarbonise in order to reduce their carbon footprint.

In order to have a better understanding of the challenges the shipping industry has to face, it might be useful to give a description of the actual situation:

  • The current merchant fleet emits approximately 1 billion tons  C02 each year
  • Insofar no action is undertaken in the shipping industry, the global share of  the emissions of greenhouse gasses, produced by shipping, may reach 17% in 2050
  • The International Maritime Organisation (IMO)  has set a 50% reduction target of the emissions of greenhouse gasses by maritime transport in 2050, and it has the ambition to reach the full decarbonisation by 2100.
  • Maritime shipping takes care of 75% of the external trade of the European Union and 30% of the intra-European transport of goods.
  • Insofar Short Sea shipping is concerned, this mode of maritime transport represents 59%  of the total sea transport of goods from and to European ports.  Short Sea shipping will play an important role in the global and European supply chains. The decarbonisation of the SSS is therefore very important.
  • Vessels have long operational lifetimes  and are only replaced after 30/40 years

Therefore, considering this situation it is necessary that the shipping industry in Europe starts to invest in decarbonisation, searching for zero emission fuels. The family of the zero emission fuels consists of different members, including the category of biofuels, batteries and different hydrogen-based fuels, like ammonia, hydrogen and methanol. Green hydrogen, fuel cells and batteries will become important tools in order to realise the reduction of the carbon footprint of the maritime transport.

Nevertheless there are several barriers for zero-carbon fuels on board of the vessels:

  • Limited levels of new built ships per year- limited incentives to retrofit or to build new ships
  • Limited knowledge in the effectiveness of alternative propulsion technologies
  • Lack of fuelling infrastructures
  • Lack of bunkering procedures and standards
  • Lack of fuel quality standards
  • Lack of auxiliary equipment
  • Limited knowledge about thermodynamics and fluid dynamics
  • Lack of knowledge about onboard storage of some of these fuels
  • Lack of conversion equipment
  • Price-setting of the new fuels versus the traditional carbon fuels (lack of competitiveness of the new fuels)
  • Availability of new fuels
  • Lack of certification of different types of vessels, utilising the new types of fuels
  • Lack of legal framework for both maritime transport as bunkering
  • The supply chain of the new fuels is not mature
  • Lack of acceptability of the new fuels by the different stakeholders, including political level, sponsored by the traditional oil and gas companies.

In order to tackle some of these obstacles, the ISHY project will investigate the following working-fields:

  • Testing of the effectiveness of low carbon propulsion technologies
  • Demonstrating the feasibility of the H2 bunkering facilities in a port
  • Prepare tools to support the transition to low-carbon propulsion systems for both retrofitting and the building of new ships.

1. Zero-emission shipping

Shipping is responsible for sustainable emissions of greenhouse gasses and air pollutants. Insofar that the current regulations are not altered, shipping emissions are expected to increase in an unsustainable way, with associated climate change impacts and damage to human health.

The decision of the IMO (international maritime organisation) to set a reduction of 50% of the greenhouse gasses emissions from maritime transport by 2050 (in comparison to the level from 2008) is an important step on the way to full decarbonisation.

The commitment to zero-emission shipping does not only imply major benefits by offering cleaner air and lesser damage to the health, but it also offers economic and commercial opportunities to our economies at the North Sea: the zero-emission shipping will require a wide-scale adoption of low-emission technologies and fuels.

In order to have a better understanding of zero-emission shipping, it might be important to give an overview of the different technologies and fuels that are considered by this concept. In order to make a selection, only those technologies and fuels are considered that effectively can make a contribution to the reduction of the shipping emissions and that have the potential to be cost-effective:

a) The fuel production technologies:

  • Hydrogen production technologies
  • Methanol production technologies
  • Ammonia production technologies
  • Bio-LNG technologies

b) The Non-fuel technologies:

  • Low carbon shore power
  • Onboard hydrogen production and storage technology
  • Batteries for electricity storage onboard
  • Electric engines
  • Air lubricants
  • Wind propulsion
  • Exhaust Gas Recirculation and Selective Catalytic Reduction (EGR/SCR)

2. Zero-emission technologies

a) The fuel production technologies

  • Hydrogen production technologies:
    • Hydrogen can be produced by different industrial procedures. In this context, electrolysis, utilising green energy, and steam methane reformation, including carbon capture, are most evident
    • The level of reduction of greenhouse gases is high
    • Today, the cost of the production of green hydrogen is still very high, but this might change in the near future, considering the developing technologies
  • Methanol production technologies
    • Methanol can be produced from synthetic gas, combined with carbon capture storage, or from green hydrogen that is combined with CO2 sources (waste/atmospheric)
    • The level of reduction of greenhouse gases is high
    • The production cost of methanol is rather competitive, in comparison with the price of the tradition fuels, insofar that the methanol is produced from fossil sources. When the methanol is produced on the basis of green hydrogen, then the price will be much higher
  • Ammonia production technologies
    • Ammonia is produced from combining hydrogen with nitrogen
    • The level of reduction of greenhouse gases is high
    • The production cost of ammonia is high due to the green hydrogen component
  • Bio-LNG production technologies
    • Bio-LNG refers to the liquified methane from biomass. This concerns both harvested biomass and the biomass from the organic fraction of different sources of waste (e.g. manure)
    • The level of reduction of greenhouse gases is high
    • Today, bio-LNG is more expensive than LNG, but it can become more competitive with other fossil fuels in the near future

b) The non-fuel technologies

  • Low carbon shore power
    • Low carbon shore power enables the vessels in the port to avoid the use of their engines in order to run their onboard generators
    • The level of reduction of greenhouse gases is high
    • In this case, the electricity price needs to be compared with the price of fossil fuels. The electricity price might go down, insofar that a reduction of the renewable energy production cost is to be expected
  • Onboard hydrogen technologies
    • Hydrogen can be produced, stored and used on the vessel, but this requires specialist equipment, including hydrogen storage tanks and fuel cells, to convert hydrogen into electricity
    • The level of reduction of greenhouse gases is high
    • Considering that special materials are needed for the storage of hydrogen, the cost is much higher than for the storage of fossil fuels. As to hydrogen fuel cells, they are quite expensive today, but a cost reduction is to be expected considering the upscaling of the technology
  • Batteries for electricity storage onboard
    • Batteries provide energy for the propulsion of the vessel
    • The level of reduction of greenhouse gases can be high
    • The cost is very high due to the low energy density. This solution is interesting for smaller vessels. The cost will go down in function considering the expected improvements in the performance of the batteries
  • Electric engines
    • Electric propulsion systems substitute the combustion engine in the vessel with an electric motor
    • The level of reduction of greenhouse gases can be high
    • The electric engine is more expensive than the combustion engine but also more efficient
  • Air lubricants
    • The use of air to reduce the frictional resistance of the hull of a vessel in the water
    • The level of reduction of greenhouse gases is medium
    • This system might be cost-effective for vessels with very high fuel consumption
  • Wind propulsion
    • This consists of the onboard use of sails, rotors, kites and others as an auxiliary propulsion source.
    • The level of reduction of greenhouse gases is medium
    • This system might be cost-effective for certain types of vessels as long as there is enough deck space available. These vessels can operate on routes with suitable wind speeds and directions
    • This technology is used to reduce the nitrogen oxides in the exhaust of the vessels
    • The reduction of greenhouse gases is low
    • This technology brings a high extra cost, but there are improvements to be expected

Next to the different levels of development of each of these zero-emission technologies, one should also consider the complications related to the organisation of the supply chain. For example, low-carbon hydrogen can be produced from natural gas or green electricity through the electrolysis of water. This hydrogen needs to be stored. For maritime applications, hydrogen is stored as liquid hydrogen to achieve the highest energy density. This storage requires specific materials and technology. Hydrogen can also be stored by other methods: in a compressed form or by conversion to carrier fuels, such as ammonia. Once the green hydrogen is stored, it can be used in a combustion engine, which is tailored for hydrogen injection and combustion, or in a fuel cell, in order to produce electricity. If the green hydrogen is used in a fuel cell, the electricity that is produced can be used to power an electric motor for propulsion or for auxiliary systems onboard the vessel.

3. Challenges for Zero-Emission Ships

In order to develop the market of the Zero-Emissions Ships, five major challenges can be identified:

  • Regulations and community: development and acceptance of regulations for the bunkering of hydrogen-powered systems
  • Infrastructure: development of suitable transport and storage technology on land and on board the vessels.
  • Green hydrogen: large scale production of green hydrogen from renewable energy sources in a cost-efficient way
  • Cost factor: is there a will to cover the extra cost for hydrogen fuel and technology, knowing that the cost of fuel cells does not include the environmental and health costs
  • Capacity: the maritime sector needs megawatt applications insofar as fuel cell power installations on board the vessels are concerned. They need to have robustness, long life and a mature safety concept within a maritime environment

4. Zero-emissions ships and ports

Ports will play a major role in the implementation of the hydrogen strategy.  Many ports are linked with onshore and offshore wind power production sites and with the electricity interconnectors, which enables them to feed large electrolysers for green hydrogen production. Often, the ports are also the basis for large industrial clusters which are in need of hydrogen in order to reduce their carbon emissions. Moreover, ports are also mobility hubs, and in this way, a synergy can be created between hydrogen production, storage and supply and the use of hydrogen in land and maritime transport. Port regions will therefore become the first movers in the creation of the hydrogen valleys.

For inland waterways and short sea shipping, hydrogen will become one of the alternative low-emission fuels. Hydrogen is also a key stepping stone in the production of ammonia or electro-fuels with a higher energy density, which are required for longer distance shipping. The EU Hydrogen roadmap predicts that shipping applications will be of major importance in stage 2 of the roadmap, which runs from 2024 to 2030. Price support schemes are likely to be required for some time in the maritime sector.

Within this Hydrogen roadmap, the EU commission foresees as well the revision of the Alternative Fuels Infrastructure directive and the Trans-European Transport Network, whereby a strategy needs to be worked out in order to set up a network of hydrogen refuelling stations for shipping. Also in this field, the ports will play a major role in the near future.

Finally, port facilities are needed to import and export hydrogen by ship and to transport the hydrogen to the hinterland of these ports. Port facilities will include liquid hydrogen terminals, liquid hydrogen storage tanks, liquid hydrogen truck loading, evaporation units, liquid organic hydrogen carrier terminals, dehydrogenation plants, ammonia terminals, ammonia storage tanks and ammonia cracking installations.

On the basis of assumptions, an estimation has been made by Hydrogen Europe for the investments that need to be made in major hydrogen ports:

  • Liquid hydrogen terminal and storage: 1 billion euro
  • Ammonia terminal, storage and cracking installation: 300 million euro
  • Liquid Organic Hydrogen carrier terminal, storage and dehydrogenation plant: 200 million euro
  • Port pipeline infrastructure for hydrogen, ammonia, bunkering facilities and multimodal logistic centres: 1 billion euro

The overall investment costs are thus estimated at approximately 2,5 billion euro.

5. Zero-Emission Shipping and ISHY

Considering the future developments of the maritime sector, 15 partners from the UK, France, the Netherlands and Flanders have been working together in order to design a pragmatic cross-border project related to the introduction of Zero-Emission Technologies in the maritime sector.

The overall objectives of the ISHY project are:

  • Development of tools for implementation of hybrid & hydrogen technologies in vessels and ports
  • Demonstration of hybrid and hydrogen technologies in newly built and retrofitted vessels.
  • Establishment of a hydrogen bunkering station at the Port of Oostende
  • Increase the acceptance of low or zero-carbon technologies with high impact potential and cost-effectiveness on the longer term


Partner Working-theme
Port of Oostende BE Lead partner, Hydrogen Bunkering station to be installed at the port
Impulse Zeeland NL Application and demonstration of hybrid systems in various retrofitted vessels
Solent University UK R&D, feasibility studies and tests of low carbon propulsion technologies
WaterstofNet BENL Developing various concepts for H2 bunkering in ports
Zilvermeeuw BV NL Design, develop and build a new passenger ship with Hybrid propulsion
T.U. Delft NL Multi-objective optimization tool
University Polytechnique Hauts-de-France FR Development of optimal energy management in simulation
GEO Aqua BE Develop and build a Crew Transfer Vessel (CTV) with hybrid propulsion
Yerseke Engine Services NL Retrofit of breakbulk barge, with a hybrid propulsion system
Hybrid Marine Ltd UK Multimode hybrid development, hybrid commercial barge analysis
Zepp Solutions NL Development of a H2-fuel cell module to be used in various vessels
Lloyds Register UK Risk Assessment of proposed Low Carbon Technologies
Vives University BE Implementing hydrogen injection for a diesel engine
Vera Cruz Shipping BE Retrofit of breakbulk barge, with a hybrid propulsion system
Parkwind NV BE Develop/realize a Hydrogen bunkering facility for CTVs in Port of Ostend

Therefore, the following concrete actions will be taken:

  • Hybrid configuration in a small inspection craft
  • Retrofitting of a CTV
  • Inland barge with a hydrogen-based hybrid propulsion system
  • New river cruise vessel with an electric propulsion system
  • The development of an H2 fuel cell module, to be used in vessels
  • The development and installation of an H2 bunkering station for vessels at the port of Oostende

This will be supported by:

  • The development of business cases related to the retrofitting of existing vessels and the building of new vessels
  • Tool for certification of vessels, integrating low-carbon propulsion technologies
  • Testing and monitoring in real-life circumstances

6. ISHY and the pilot projects


B. Inland barge (VERACRUZ)

C. River cruise Vessel (Zilvermeeuw)


D. Hybrid configuration for commercial vessels (Hybrid Marine) – case of the Natalia

E. H2 Fuel Cell module (ZEPP Solutions BV)

F. Bunkering station at the port of Oostende (Parkwind NV)