A practical advice on the widely discussed alternative fuels: Biofuels, Liquefied Natural Gas, Methanol, Ammonia, and Hydrogen.
An examination for each of these alternative fuel types will focus on good practices in storage, handling, bunkering, safety and emergency response.
As informed, LNG is currently taking the lead as a transitional fuel. However, several zero-emission fuels such as methanol and hydrogen are also on the rise.
It is uncertain which fuel will be the preferred choice of the future, and it is likely that a variety of alternative fuels will be required to meet future demand. Shipowners must conduct due diligence as part of their decision-making process, involving a comprehensive identification and risk assessment. This assessment requires consulting various stakeholders, including the engine maker, fuel supplier, classification society, H&M insurers and the ship’s flag state.
Key considerations
- Suitability and impact on the onboard engines: Consult the engine maker to determine if the selected alternative fuel is suitable for on board engineers or if retrofitting is required.
- Fuel management: Properly train the crew to handle alternative fuels, considering the operational hazards they may pose compared to fossil fuels.
- Health, safety and environment (HSE): While the alternative fuels may have their obvious environmental benefits, they may come with some increased safety risks. Therefore, any alternative fuel should be accompanied by a thorough assessment of its HSE risks, and this should form the basis of the on-board safety measures for handling the fuel.
- Quality: With the current lack of international standardisation, clear and detailed bunker specification needs to be developed by the shipowner to ensure suitable fuel is delivered.
FATTY ACID METHYL ESTERS
Fatty acid methyl ester (FAME) is a form of bio diesel made from renewable fats, oils and greases. It is usually blended with a petroleum diesel fuel to make up a percentage of the fuel. A 100% biofuel or neat biofuel would be represented as B100 – ‘B’ For biofuel and 100 for the percentage. Most marine fuels will use a B7, but there is an increase in the market as higher percentage blends are being brought into use. Although it is widely used, it does present certain challenges when stored and used as a fuel on board a ship. Most blends below 20% are manageable but blends above this percentage level may require careful consideration when used on board a ship.
Storage
FAME is highly susceptible to oxidisation and in neat condition, serves as an effective solvent. It also has a lower cloud point and increases in viscosity in cold
conditions, leading to freezing or gelling. Therefore, it will be necessary to take the following precautions when using FAME:
- AVOID storage duration of over 6 months to minimise the risk of oxidisation
- IMPLEMENT a fuel condition monitoring programme, periodically drawing samples sent to an onshore laboratory to ensure the fuels acid number and oxidation stability meet specification
- REGULARLY DRAIN storage tanks to prevent microbial bacterial growth
- MAINTAIN the fuel temperature at least 10°C above the pour point and store it in tanks located away from cold temperatures, potentially requiring the use of heating coils on board
- STORE FAME only in clean tanks, as its solvency can result in deposits within the tank, which may then be present in filters and engine components
Bunkering
The bunkering framework as diesel fuels. However, care must be taken during supply to ensure the fuel is not loaded into a tank containing non-compatible fuels
Handling
When using FAME in higher concentrations, it is imperative to ensure compatibility with the engine, and at a minimum, the following steps should be taken:
- Ensure a sufficient quantity of FAME is bunkered, considering its 14% lower calorific value compared to petroleum-based fuel
- Check with the engine manufacturer that the engines NOx compliance is not compromised due to operating parameters
- Be aware that FAME fuel blends may cause damage to materials such as Teflon, Viton, fluorinated plastics and nylon, potentially contaminating and corroding fuel systems. Therefore, operators will have to ensure that the fuel system and any tank coatings can withstand the solubility used
- Inspect, change or clean fuel filters as required
- Drain water from the fuel tanks regularly
- Prevent water ingress into the fuel
- Flush the fuel system when not in use and conduct additional fuel filter services based on the blend percentage and feedstock used.
Safety
FAME is free of hazardous materials and is generally considered safe for use. If heated the vapours could irritate the mucous membranes and cause irritation, dizziness, eye irritation and nausea. Prolonged or repeated contact is not known to cause significant skin irritation, and no hazards are expected from incidental ingestion. However, safety precautions and equipment for storing and handling FAME and diesel blends should be put in place. When handling the fuel blend, always wear personal protective equipment, including gloves, and wash exposed skin with soapy water. Ensure the relevant Safety Data Sheet (SDS or MSDS) is
reviewed for recommendations on safe handling, type of gloves, and related procedures before beginning work with FAME and biodiesel blends.
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