Fuel Cells
Fact Sheet N 8
Edition I - October 2024
Key Facts
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For newbuilt and retrofit
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Requires fuel of high purity
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Technical requirements in ES-TRIN available
Funded by the Horizon Europe Programme of the European Union under grant agreement No 101096809
Funded by the Horizon Europe guarantee of the United Kingdom, under project No 10068310
Funded by the Swiss State Secretariat for Education, Research and Innovation
Catalogue of
Greening Technologies
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Fuel Cells
FACT SHEET N 8
Introduction
This fact sheet offers insight into various applications of fuel cells for propulsion and auxiliary power in inland ships. Hydrogen storage options and alternative energy carriers are presented with their pros and cons in brief. Information ranges from relevant regulations, technical concepts including benefits and downsides to recommendations for further reading.
Facts
Fuel cells are energy converters that continuously convert the chemical energy of the fuel, such as hydrogen, natural gas or methanol, into electrical energy and thermal energy (heat losses) using an oxidant such as oxygen. The fuel cell can supply electricity as long as suitable fuel is available. The basic working principle can be seen in Figure 1.
The principle of the fuel cell was invented in 1838, however the first commercial use of fuel cells came more than a century later in NASA space programs to generate power for satellites and space capsules. Since then, the improvement of the fuel cell began and nowadays they are used in many other applications, e. g. for primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. The second most important application for fuel cells is as a power source for vehicles of all kinds.
With fuel cells local emission-free power generation is possible. The comparison of a fuel cell with a conventional internal combustion engine shows that no mechanical stress on components takes place because no fuel is burned. This results in no wear, vibration, or generation of noise.
Emissions
When talking about emissions, there are initially different ways of looking at them: On the one hand, a distinction is made between toxic and climate-impacting emissions. On the other hand, a distinction is made between local and global emissions. Examples of toxic emissions are nitrogen oxides, particulates, formaldehyde, etc., while climate-impacting emissions include CO2, methane, laughing gas, etc. Local emissions have effects on the immediate surroundings of the source, such as toxicity. The effects of global emissions are not limited locally; they can be climate-impacting substances, for example, or the now banned CFC, which damages the ozone layer or sulphur emissions from the seagoing sector.
Figure 1: Basic working principle of a PEM fuel cell
If the emissions caused by a propulsion technology or an energy source are to be assessed, there are again various approaches. The most common are the well-to-wake and the tank-to-wake approach. In the well-to-wake approach, the emissions from the entire upstream chain required for the production and supply of an energy carrier are considered. For an engine, a fuel cell or a battery this approach is called Life-Cycle-Analysis. The tank-to-wake approach looks at the emissions generated by the ship during use. Everything that happened before the energy carrier, storage system or energy converter came on board is excluded. These two definitions can produce very different results in the assessment of the technologies. For example, when considering the overall chain, the choice of a methanol combustion engine could be better than that of a battery-electric drive. This is the case if the production of the battery causes more emissions than the combustion of methanol. It is important to note that this type of consideration is also different for each ship and depends on its operating time and energy requirements. The following table shows the relevant emissions for this fact sheet.
Emission compared to conventional diesel
The global GHG emissions are dependent on the hydrogen source.
better
Regulations
The technical requirements for fuel cells are included in ES-TRIN 2023, Chapter 30, Annex 8, Section 3.1. The technical requirements for the storage of hydrogen are foreseen in ES-TRIN 2027 Chapter 30, Annex 8, Sections 2.3 and 3.4
For seagoing vessels, the IMO circular 1647 from 15 June 2022 (Interim guidelines for the safety of ships using fuel cell power) applies.
Technical Concept
Basic Working Principle of Fuel Cells
All fuel cells consist of two electrodes - the anode and the cathode. These are separated by an electrolyte with an ion-permeable membrane. After the fuel has been supplied to the anode, it is divided into electrons and protons. The free electrons flow into an outer circuit between the anode and cathode to be used as an electric current. The protons spread through the electrolyte to the cathode. At the cathode, the oxygen from the air combines with the electrons from the outer circuit and protons from the electrolyte. This results in water and heat.
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Several fuel cells in a row make up a fuel cell stack. The number of individual cells that are connected in series can be used to variegate the performance of the stack and adapt it to the respective requirements.
All fuel cell types are based on the reaction of a fuel with oxygen. The electrochemical reaction generates basically electricity, heat and water. From the fuel cell, the electricity is provided as direct current (DC). If alternating current (AC) is required for further use, DC from the fuel cell is routed to an inverter is converted there to AC.
Classification of Fuel Cells
Basically, fuel cells are classified according to their operating temperature and the type of electrolyte used in the fuel cell. The following fuel cells are particularly interesting for inland waterway vessels:
- Low Temperature Proton Exchange Membrane Fuel Cell (LT-PEMFC)
- High Temperature Proton Exchange Membrane Fuel Cell (HT-PEMFC)
- Solid Oxid Fuel Cell (SOFC)
PEMFC uses a water-based polymer membrane as electrolyte, H2 as fuel and O
2 as oxidant. The operating temperature is < 100°C. Due to the low temperature, only pure hydrogen can be used in PEMFC. The byproducts besides electricity are water and heat. The fuel cell can be started cold without pre-heating to the operating temperature.
If the operating temperature is significantly exceeding than 100°C, PEMFC is used. These can reach up to 200°C and used mineral acid electrolyte instead of a water based one. The fuel cell must first be brought to operating temperature before it functions properly.
SOFC contains a solid electrolyte. From an operating temperature of approx. 650°C, this so-called oxide ceramic conducts the hydrogen ions through it. Some devices reach a temperature of 1,000°C. SOFC is one of the high-temperature fuel cells. An internal reforming of natural gas to hydrogen takes place in SOFC itself.
Propulsion Concept
Components on Board
The fuel cell system as a propulsion system for a ship often consists of several components. These include the fuel cell, an electric motor, accumulators and partly a reformer. A negative property of the fuel cell is its own inertia to react. This inertia is balanced by an accumulator. It must also be taken into account that a fuel cell needs some time to reach operating temperature, this time difference is also compensated by the accumulator. The fuel cell supplies direct current, the energy produced is transmitted to an electric motor for propulsion. This electric motor, for example, generates the rotary motion for the propeller shaft. The energy requirements for all electrical equipment on board a ship can be supplied directly from the fuel cell or accumulator without detours.
Methanol System for a HT-PEMFC
From the methanol tank (1) the fuel is taken to the reformer unit (3) to extract the hydrogen from it. The process needs heat which is produced by burning an amount of methanol in the heater (2).
The pure hydrogen is then fed into the fuel cell (4). Some of the reaction heat in the fuel cell is fed back in the reformer. The remaining heat is emitted in a separate heat exchanger system (6).
The voltage of the electric current produced is transformed into the usual on-board voltage by the voltage transformer (5).
The hydrogen’s high pressure in the tank (1) is lowered to a for the fuel cell suitable amount in the pressure reduction unit (2). From there it is fed into the fuel cell.
The voltage of the electric current produced is transformed into the usual on-board voltage by the voltage transformer (4).
The reaction heat is emitted in a separate heat exchanger system (5).
Hydrogen System for a HT-PEMFC
0
The arrangement of the fuel cell and the accumulator can be either parallel or in series. The following diagram shows the basic conversion process in a fuel cell using the example of hydrogen as a fuel.
- Check valves
- Refueling receptacles, etc.
- H2 Tanks
- Double-walled pipes, if necessary
- Thermal pressure relief devices
- Control valves
- Pressure reduction system
- Vent system
- Purge system
Equipment
The equipment for the H2 storage and distribution system on board consists of:
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Tank System for Compressed Hydrogen
The tanks are typically stored on deck in a safe location; storage under deck might also be possible. From a safety point of view placing the H2 tank-system on deck is the safest solution since ventilation and dilution are the most important safety measures.
The hydrogen tank system typically consists of several individual cylinders, which are combined in a multiple element gas container (MEGC) that is connected to the ship via one fitting.
Figure 2: 500 bar H2 Tank-Tainer with 500 kg of H2
As hydrogen refuelling infrastructure in harbours is not existing, it might be favourable to use swappable hydrogen tank solution for larger volumes. Filling the MEGC with high-pressure hydrogen takes several hours, blocking the ship at the port. The regulatory aspects to enable the use of one tank-system on several ships are still being worked out. A 20 Feet Container with 500 kg of usable hydrogen with ADR/ADN-certification is on the market (see Figure 2). Currently there are two pressure levels favoured by the industry: 350 and 500 bar.
Source: Argo-Anleg
For smaller ships needing smaller quantities of H2, a fixed tank system that can be refuelled with a small mobile refuelling station might be a favourable option.
Fuel Purity
When hydrogen is used in the PEMFC, attention must be paid to hydrogen purity. In principle, any hydrogen contamination can impair the performance and service life of the fuel cell system. The required purity is particularly difficult to achieve during the reforming process from natural gas or methanol. The hydrogen purity should be above 99.99 Vol.-%. The requested hydrogen for fuel cell is defined in the Norm EN 17124:2018.
Special Safety & Other Requirements
The primary hazards and issues associated with hydrogen systems can be categorised and prioritised as follows:
- Flammability:
- Pressure effects
- Easy ignitability of mixtures with oxidant
- Small size of the molecule:
- Low viscosity
- High diffusion rate
- High buoyancy
- Interactions with materials (embrittlement of certain metals)
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Asphyxiation hazard if oxygen is replaced
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Hazards associated with the storage procedure:
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Elevated storage pressure for gas
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Low temperature for cryogenic liquid
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Others for other methods, such as metal hydrides
ES-TRIN 2023 Article 30.04 states that “a risk assessment shall be conducted to ensure that risks arising from the use of fuels with a flashpoint equal to or lower than 55 °C affecting people on board including passengers, the environment, the structural strength and the integrity of the craft, are addressed.”
A HAZID study may cover the following areas (as applicable):
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General arrangement of vessels
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H2 fuel-storage arrangement and details
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H2 fuel supply and vapour-handling system, from fuel storage to machinery spaces
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H2 fuel arrangement in fuel handling room and engine room
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General arrangement of the fuel-handling and engine rooms, including their ventilation
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Main engine safety concepts and vessel integration
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Hazardous area classification plans
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Ventilation and vents for stored H2 fuel, fuel-supply system, machinery space and hydrogen consumer
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H2 fuel-bunkering arrangement
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Safety systems
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Gas detection and firefighting arrangement
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Arrangements to purge or make H2 inert
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Cargo storage and its impact
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Bunkering
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Emergency Escape and Rescue
Very good forced or natural ventilation of the areas with hydrogen is necessary. It must also be ensured that EX zones are formed around installation locations and ventilation outlets.
Crew Skills
As of today, there is no official certificate for training personnel on the hydrogen. Nonetheless, the crew must be trained and certified to be able to use the hydrogen system on bord, be familiar with the detection of leaks and the partial system shutdown procedures. Especially also for the swapping process of hydrogen tank systems on ships. Currently, the manufacturer of the hydrogen tank-system must propose a dedicated training to the crew. However, CESNI has developed guidelines (recommendations) concerning competences required for operation of craft using methanol as a fuel and for operation of craft with an electrical power supply for propulsion. Similar recommendations are currently being developed for operation of craft using hydrogen as a fuel.
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Fuel Cells
FACT SHEET N 8
Crew training procedures or H2Barge2 and Antonie were composed by the following chapters:
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Familiarity with physical and chemical properties of fuels aboard ships subject to the ESTRIN and IGF Code.
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Operate the controls of fuel related to propulsion plant and engineering systems, services and safety devices on ships subject to the ESTRIN and IGF Code.
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Plan and monitor safe bunkering, stowage and securing of the fuel on board ships subject to the ESTRIN and IGF Code.
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Take precautions to prevent pollution of the environment from the release of fuels found on ships subject to the ESTRIN and IGF Code.
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Monitor and control compliance with legislative requirements.
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Take precautions to prevent hazards.
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Apply occupational health and safety precautions and measures on board a ship subject to the ESTRIN and IGF Code
Bunkering & Infrastructure
No bunker infrastructure for hydrogen is currently available in harbours. Depending on the size of the future facility, the Directive 2012/18/EU (Seveso III) specifies requirements: Hydrogen is listed in Annex 1, Part 2 of this Directive, with threshold values of 5 t for "lower-tier establishments" and 50 t for "upper-tier establishments".
Bunkering larger volumes of H2 not only demands standardised bunkering procedures on the ship, but also demands special regulations to the port. The bunkering process itself is complex and must be approved for each individual H2
tank-system. As there is no standardisation yet each H2 tank-system will have its own dedicated refuelling process. On the shore side, large infrastructure would have to be installed to bunker H2. It may be that only a certain amount of hydrogen is permitted to be stored in one place without a special authorisation procedure. To be able to quickly refill H2 tank-systems space for the technical components is needed. These large areas are not always possible to find in harbours.
Taking away the complexity of bunkering hydrogen in harbours is an argument for swappable hydrogen tanks. They could be refilled outside the harbour in a restricted area or directly at hydrogen production site. This would merely make the bunkering a logistics task.
For any bunker strategy it is necessary to check for availability and possible fuelling locations at the beginning of the project.
Economics
The investment and operating costs are highly dependent on the individual ship and its operational profile. Nevertheless, there are key figures for some components. These are linked to a database so that they are updated as soon as new information is available.
Investment Costs
The investment for the hydrogen engines is between 500€ and 600€ per kW. For the H2 storage 800€/kg is a guiding value.
Operational Costs
Currently, the price for Hydrogen is between 10€ and 16€ per kg. A level to get near the diesel price would be between 4.5 €/kg and 6 €/kg.
Deployment Example
Vessel type
| Inland container vessel
ENI
| 02323207
Vessel Size
| 110m x 11.45m
Year Built
| 1997
Propulsion
| PEM Fuel Cell system – three fuel cell units (3x 275kW)
Hydrogen Capacity
| 2 x 500kg in swappable containers
H2barge1
Source: Future Proof Shipping
Fuel Cells
FACT SHEET N 8
Argo-Anleg GmbH (DE)
FPS – Future Proof Shipping (NL)
Mercurius Shipbuilding BV (NL)
ZES – Zero Emission Services (NL)
Compagnie Fluviale de Transport (FR)
Sogestran (FR)
Koedood Diesel Service BV (NL)
CMB – Revolve Technologies Ltd. (UK)
SPB – Stichting Projecten Binnenvaart (NL)
Scandinaos AB (SE)
MARIN – Maritime Research Institute Netherlands (NL)
viadonau – Österreichische Wasserstraßen-GmbH (AT)
TTS – Transport Trade Services GmbH (AT)
ZT Büro Anzböck Richard (AT)
EUFRAK – Euroconsults Berlin GmbH (DE)
CRS – Hrvatski Registar Brodova (HR)
OST – Ostschweizer Fachhochschule (CH)
Project Coordinator
DST - Development Centre for Ship Technology and Transport Systems
Partners
Disclaimer
The content of the publication herein is the sole responsibility of the publishers and it does not necessarily represent the views expressed by the European Commission or its services. While the information contained in the document is believed to be accurate, the author(s) or any other participant in the SYNERGETICS consortium make no warranty of any kind with regard to this material including, but not limited to the implied warranties of merchantability and fitness for a particular purpose. Neither the SYNERGETICS Consortium nor any of its members, their officers, employees or agents shall be responsible or liable in negligence or otherwise howsoever in respect of any inaccuracy or omission herein.
