Part one, which focused on the characteristics of biofuels and blends, can be read here
Sustainability
When it comes to sustainability, not all biofuels are created equally, and their production may introduce unintended consequences regarding the environment.
Sustainability credentials may be damaged if the biofuel was derived from crops that would have been used for food or has led to a change in land use or resulted in deforestation.
Biofuels should be certified to an international standard, evidenced by a Proof of Sustainability Certificate (POS) or an equivalent document.
Emissions Factors
Greenhouse gas (GHG) emissions from shipping, and in the case of biofuels we are primarily concerned with carbon dioxide (CO2), can be measured two ways: Tank-to-Wake and Well-to-Wake. Tank-to-Wake (TtW) concerns only the combustion of the fuel, while Well-to-Wake (WtW) also considers its sourcing, production and transportation.
An important measure for shipowners and charterers is the fuel’s emissions factor. The emissions factor is used to calculate estimated emissions for every tonne of fuel burnt on board. However, this depends on which regulatory requirement is being satisfied.
On an international level, the IMO’s guidance on the use of biofuels assigns a ‘CO2 Emission Conversion Factor’ (Cf). This is to be used under the Carbon Intensity Indicator (CII) regulations and when reporting fuel consumption to the IMO Data Collection System (IMO DCS), where emissions are recorded on a tank-to-wake basis. Biofuels and blends that have accredited sustainability certification (e.g., the ISCC or RSB schemes) and fulfil the certain life cycle emissions criteria, could be assigned a lower Cf. However, biofuels that have not been certified sustainable or not met the criteria, are assigned a Cf equal to its fossil fuel equivalent.
In the European Union (EU), its emissions trading system (EU ETS) is concerned only with tank-to-wake emissions. The emissions factor for biofuels is specified by Commission Delegated Regulation (EU) 2023/2776, Annex I. For biofuel blends, each component is considered separately.
FuelEU Maritime considers well-to-wake emissions, with the well-to-tank (WtT) and tank-to-wake phases considered separately. The regulation provides default WtT and TtW emission factors for all fuels, including biofuels, which allows the WtW GHG intensity to be calculated. If the biofuel is derived from food or feed crops and therefore is not certified according to the EU Renewable Energy Directive (RED II), it will be assigned the same emissions factor as the equivalent fossil fuel.
Charterparty Performance Warranties
Fatty Acid Methyl Esters (FAME) biofuels have a lower calorific value in comparison to traditional fossil fuels. This literally means you are getting less bang for your buck. The higher the FAME content in the blend, the more fuel is required to obtain the same power. According to CIMAC, a vessel burning 100% FAME (B100), fuel consumption could be 13% higher than if burning a traditional marine fuel.
This could in theory have an appreciable impact on any agreed performance warranties in a charterparty. Owners should revisit their charterparty performance warranties and vessel descriptions if transitioning to burn biofuels.
As noted earlier, the 2024 edition of ISO 8217 provides the most up to date consideration of FAME biofuels and would therefore be the most suitable version of the standard to be referenced in the charterparty if looking to burn FAME biofuels or its blends.
As illustrated with the recent issues with Cashew Nut Shell Oil in part one, Owners should be very clear on the specification of biofuels if the time charterer is obliged to provide bunkers in the charterparty.
Achieving widespread FAME isn’t easy
In their report ‘Fuel for Thought – Biofuels’, Lloyd’s Register highlights a potential barrier to the large-scale delivery of FAME biofuels to vessel requiring bunkers. Biofuels with a FAME content greater than 25% (bearing in mind that the biggest demand for a biofuel product is currently B30) must be carried in bunker supply vessels that comply with MARPOL Annex II (Noxious Liquid Substances in Bulk) and the IBC Code.
As such, the vast majority of bunker vessels and bunker barges, which comply only with MARPOL Annex I (oil) regulations, cannot carry biofuels above the B25 limit. This presents a potential bottleneck in the supply chain to those vessels opting for biofuels and blends.
Submissions to the IMO have been made to attempt to find a solution to this problem.
Pollution Risk
The pollution and spill advisory organisation ITOPF has issued guidance on the pollution risk of biofuels in their report: ‘FATE, BEHAVIOUR AND POTENTIAL DAMAGES & LIABILITIES ARISING FROM A SPILL OF BIOFUELS INTO THE MARINE ENVIRONMENT’.
They note that in the initial stages of a spill into the marine environment, FAME will float and spread on the water, forming a slick on the surface, essentially behaving like conventional diesel oil.
However, any similarities with a conventional diesel oil spill are limited. Unlike conventional diesel oils, FAME will not mix with water. Furthermore, 100% FAME (B100) will not evaporate and will therefore remain on the sea surface for a longer period in comparison to conventional diesel oil. With FAME blends, the rate of evaporation increases with the increasing percentage of fossil fuel in the product.
The temperature of the water and the biofuel’s pour point will determine its fate and behaviour when spilled. If spilled in warm water (>10 °C), it is likely that both FAME and hydrotreated vegetable oils (HVO) will spread over a large area to form a thin slick on the water’s surface under the influence of weather and sea conditions. If spilled in cold water conditions (<10 °C), the viscosity of HVO would likely increase, reducing its spread on the sea surface. If FAME were to be spilled in cold water, its viscosity would significantly increase and could begin to solidify.
ITOPF also warns that 100% biofuels carried as bunkers are not specifically addressed in any international convention. They state that the current wording within the International Convention on Civil Liability for Bunker Oil Pollution Damage, 2001 (2001 Bunkers Convention) does not include biofuels under the definition of oil, referencing only “mineral oil”. As such, any legal liabilities in the event of a spill are likely to fall under the relevant national legislation.
Recommended Reading
ITOPF_Biofuels_-_Fate__Behaviour__Damage_and_Liability_Report.pdf
CIMAC_Guideline_Marine-fuels_containing_FAME_04-2024.pdf
Fuel for thought Biofuel report | LR
Bio-diesel | Fuel Pathways | Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping