The International Maritime Organization (IMO) has issued IBIA’s new Shipboard Biofuel Blend Checklist for FAME-based biofuels as an annex to MEPC 85/INF.10. Developed to support vessels using biofuel blends for the first time, the checklist covers fuel assessment, compatibility, tank preparation, water management, bunkering, storage, fuel treatment, and machinery monitoring, providing operators with practical guidance for managing FAME-containing marine fuels safely and effectively.
London, UK | September 16, 2026 – The International Maritime Organization (IMO) has formally brought a new shipboard biofuel checklist into its official documentation, publishing it as an annex to MEPC 85/INF.10. Developed by the International Bunker Industry Association (IBIA) Technical Working Group, the checklist provides vessel operators with a practical, end-to-end framework for managing fatty acid methyl ester (FAME)-based marine biofuel blends safely and effectively.
Dated September 3, 2026, the submission was made ahead of the 85th session of the Marine Environment Protection Committee (MEPC 85), scheduled for November 30 to December 3. While the submission is informational, asking the Committee simply to note the information rather than imposing a new mandatory fuel standard, it places detailed, high-level bunker-management guidance directly within the IMO framework.
The checklist forms part of the ongoing update of the IBIA/BIMCO Shipmaster’s Bunkering Manual and is designed specifically for vessel operators preparing to bunker and consume biofuel blends for the first time.
From Fuel Specification to Machinery Operation
The checklist is deliberately operational. Rather than treating biofuel as simply another line item on a bunker specification sheet, it takes operators through a strict sequence of decisions covering the fuel itself, the ship’s fuel system, tank condition, water management, bunkering procedures, fuel treatment, storage, and machinery performance.
This approach reflects IBIA’s central warning: increasing the use of biofuel blends introduces different or additional operational risks, particularly during a vessel’s first-time usage. The guidance is built upon CIMAC Guideline 04|2024 (Marine fuels containing FAME: A guideline for shipowners & operators).
For non-FAME bio-based products, IBIA explicitly advises consulting original equipment manufacturers (OEMs) and recognized organizations to verify product suitability. The distinction is vital: the checklist is not a universal approval for every bio-derived marine fuel; its scope is specifically FAME-based biofuel blends.
The 9-Part Operational Framework
1. Pre-Bunkering Preparation and Route Assessment
The first section places the emphasis on preparation rather than troubleshooting. Before ordering or bunkering, operators must confirm that the intended biofuel blend meets the agreed fuel specification and consult the OEMs for main equipment, including:
- Main and auxiliary engines
- Fuel separators
- Boilers
- Other relevant auxiliary equipment
OEM consultations establish approved blend limits and operational recommendations. Operators must also verify requirements with the vessel’s flag administration and classification society, complete a vessel-specific risk assessment, and ensure crews are briefed on handling, storage, and operational characteristics.
Fuel characteristics vs. the voyage: Operators must review fuel specifications, blend ratios, density, viscosity, heating values, and cold-flow properties, specifically Cloud Point (CP), Cold Filter Plugging Point (CFPP), and Pour Point (PP). Route planning is crucial here, as a blend suitable in one climate may require different consideration in significantly lower ambient temperatures.
2. System Compatibility Beyond the Engine
The second section addresses fuel-system compatibility. The checklist calls for confirmation that the intended biofuel blend is compatible with the ship’s:
- Seals and gaskets
- Elastomers
- Hoses
- Pumps
- Valves
- Piping systems
- Fuel-treatment equipment
Tank coatings also come under scrutiny. Operators are instructed to verify the compatibility of tank coatings, paint systems and protective coatings with the biofuel blend. For vessels fitted with selective catalytic reduction (SCR) systems, the guidance recommends consulting the SCR supplier regarding operation on biofuel blends.
This broad equipment focus is significant because the introduction of a new fuel affects considerably more than the combustion process itself. The fuel comes into contact with the storage, transfer, treatment and injection infrastructure before reaching the engine.
3. Rigorous Tank Preparation at First Loading
The checklist takes a notably conservative approach to the condition of bunker tanks before a vessel’s first biofuel loading. Operators are advised to strip bunker tanks before loading biofuel blends and to minimise inventories in settling and service tanks before introducing the new fuel.
The tanks should be inspected for:
- Sludge
- Sediments
- Residues from previous fuel batches
- Heating-coil leakage
- Water ingress
The guidance specifically highlights the possibility of water entering from ballast tanks, cargo tanks or hull defects. It also recommends avoiding unnecessary commingling of different fuel batches. That emphasis reflects a broader fuel-management principle: introducing a new blend into a poorly prepared or contaminated fuel system can turn an otherwise acceptable fuel into an operational problem.
4. Continuous Water Management
Water receives its own section in the checklist. Operators are instructed to drain free water before loading and during storage, while tank bottoms should be monitored regularly for accumulation.
- Free water must be drained before loading and throughout storage, with tank bottoms monitored regularly.
- Crews must watch actively for signs of microbiological contamination and ensure fuel separators are correctly configured for efficient water removal.
For operators, the message is straightforward: water management cannot be treated as a one-off bunkering task. It remains part of the ongoing management of FAME-containing fuel onboard.
5. Tighter Documentation and Bunkering Controls
At the point of bunkering, the checklist calls for verification of the Bunker Delivery Note (BDN) alongside the relevant fuel and biofuel specifications. Crews should verify:
- The fuel specification
- The biofuel specification
- The declared blend ratio
- Sustainability documentation, where applicable
Representative bunker samples should be obtained in accordance with the company’s procedures. Operators should also record tank allocation and fuel-segregation arrangements.
The focus on the blend ratio is particularly relevant as the market moves towards higher-volume and more varied biofuel blending. The blend being delivered is a central part of the fuel’s operational identity and needs to be reconciled with the specification agreed for the vessel.
6. Heightened Monitoring During Initial Consumption
One of the checklist’s most practical warnings concerns the initial consumption period. IBIA calls for increased monitoring when the vessel begins consuming a biofuel blend, particularly with regard to filters and separators. Crews should closely monitor:
- Fuel filters for clogging
- Separator performance
- Fuel-transfer pumps
- Booster pumps
The vessel should also carry adequate stocks of filter elements, separator spares and other consumables. The reason given in the checklist is particularly relevant for vessels moving from conventional fuels: biofuel blends may loosen accumulated deposits in tanks and fuel systems.
Those deposits can subsequently move through the fuel system and increase filter loading during the initial period of operation.
For an operator, this creates a very practical implication. The first days or weeks of consuming a new blend may require more attention than steady-state operation once the fuel system has stabilised.
7. Active Fuel Treatment and Separation Settings
Fuel treatment and separation receives a dedicated section. Operators are told to verify that separator settings are suitable for the density and characteristics of the fuel being used.
- That includes checking the correct gravity-disc selection, or ensuring that automated separator settings are appropriate.
- Where applicable, operators are also encouraged to consult the separator OEM about software updates or dedicated biofuel operating modes.
- The checklist calls for monitoring of sludge-discharge frequency and sludge characteristics, together with attention to automatic water-detection systems and any abnormal alarms.
This gives separators a central role in the transition to FAME blends. The guidance effectively treats fuel treatment as an active operating parameter rather than a fixed setting.
8. Proactive Storage and Shelf-Life Management
The checklist also addresses what happens when biofuel is not consumed quickly. Its preferred approach is to avoid prolonged storage wherever possible and to use a first-in, first-out (FIFO) fuel-management strategy. Where fuel must be stored, operators are advised to keep tanks as full as practicable to minimise condensation while avoiding excessive heating.
During storage, the checklist calls for regular monitoring for:
- Water accumulation
- Oxidation and fuel degradation
- Sediment and gum formation
- Increased acidity
- Microbial contamination
- Corrosion
Water should be drained regularly from tanks and low points. If storage exceeds six months, IBIA’s checklist says operators should consider retesting fuel quality. Storage duration should also remain within the fuel supplier’s recommendations.
Before consuming fuel that has been stored for an extended period, the operator should assess its condition and investigate any signs of instability or contamination. The message is particularly relevant to ships whose trading patterns, tank-management practices or bunker purchasing strategies result in relatively long residence times for fuel onboard.
9. Machinery Performance and Voyage Fuel Planning
The final section turns to machinery performance and fuel planning. Following a fuel changeover, operators are instructed to monitor engine performance and fuel consumption.
The checklist specifically highlights the lower energy content of biofuel blends as a factor that needs to be incorporated into voyage fuel planning. That means operators should not simply assume that an identical volume of a biofuel blend will provide identical energy availability to a conventional marine fuel.
The checklist consequently asks crews to verify that sufficient quantities are onboard to complete the intended voyage. Lubricating-oil condition and contamination levels should also be monitored, with operators instructed to follow the relevant OEM lubrication and maintenance recommendations.
A Bridge Between Fuel Supply and Shipboard Reality
The checklist illustrates how the maritime biofuel discussion is moving beyond availability and emissions accounting toward the practical realities of shipboard fuel management.
For the bunker buyer, questions begin with specification and blend ratio. For the chief engineer, they extend into compatibility, filtration, separation, and water management. For the master, implications include risk assessment, crew readiness, and voyage planning. The IBIA checklist brings these elements into a single cohesive workflow.
Biofuel’s Operational Learning Curve
FAME-based blends have become an increasingly visible component of the marine fuel market as shipowners seek to reduce lifecycle greenhouse-gas intensity without immediately replacing conventional liquid-fuel infrastructure.
However, alternative fuels still have to operate inside real ships, with real tanks, pumps, separators, and engines under fluctuating environmental conditions. For vessels making their first transition, this document provides a vital roadmap.
What Ship Operators Should Take from the Checklist
For operators preparing a vessel for its first FAME-based blend, the core takeaway is simple: treat the fuel change as a controlled operational transition, not just another bunker stem.
- Before delivery: Secure correct specifications, OEM input, risk assessments, and crew training.
- Before loading: Ensure tanks and fuel systems are meticulously prepared.
- During bunkering: Control documentation, blend verification, and segregation.
- During initial consumption: Maintain heightened watch over filters, separators, and pumps.
- During storage: Proactively manage water, contamination, and residence time.
- Throughout voyage: Monitor machinery performance and energy density requirements.
Checklist at a Glance
Scope: FAME-based marine biofuel blends
Primary users: Vessel operators and crews, particularly first-time users
Guidance basis: CIMAC Guideline 04|2024, Marine fuels containing FAME
Key areas covered:
- Pre-ordering and pre-bunkering regulatory and technical review
- Fuel and system compatibility
- Tank preparation
- Water management
- Bunkering operations and documentation
- Initial consumption and increased monitoring
- Fuel treatment and separation
- Storage management
- Machinery performance and voyage fuel planning
IMO Status: Annex to MEPC 85/INF.10 (submitted for the Committee to note). Click Here to Download Biofuel Checklist
About the International Bunker Industry Association (IBIA)
Established in 1993, IBIA serves as the recognized global voice of the marine energy value chain. Representing a diverse cross-section of fuel suppliers, traders, shipowners, brokers, surveyors, port authorities, and maritime experts spanning more than 70 countries, the association champions transparency, operational quality, and high safety standards. Alongside advocating at the IMO, IBIA continues to guide the maritime sector through both operational challenges and its broader transition toward sustainable, low- and zero-carbon marine fuels.
Source: IBIA