The Global Centre for Maritime Decarbonisation (GCMD) has released a new report completing its three-pillar assurance framework by establishing a practical approach to marine biofuel quantity and renewable content verification. Drawing from real-world commercial trials, the guidelines help shipowners navigate mass flow meter viscosity challenges and distinguish normal measurement variances from under-blending. Ultimately, the framework protects commercial value, ensures regulatory compliance, and builds market confidence as marine biofuel adoption scales.
Singapore | August 27, 2026 – As the maritime industry accelerates its adoption of alternative marine fuels to meet stringent decarbonization targets, ensuring that buyers get exactly what they pay for has become a critical operational hurdle. Addressing this pressing industry challenge, the Global Centre for Maritime Decarbonisation (GCMD) has released its landmark report, Quantity assurance in marine biofuel supply chains.
The comprehensive framework outlines a practical, evidence-backed approach to help shipowners verify both the total delivered volume and the exact renewable fraction of marine biofuels. Drawing directly from GCMD’s extensive end-to-end supply chain trials conducted under real-world commercial operating conditions, the publication marks the completion of the organization’s foundational three-pillar biofuels assurance framework.
Closing the Verification Gap in Biofuel Transactions
Unlike conventional marine fuels, biofuels are procured not only for their physical energy content, but also for the environmental attributes they represent: renewable content and certified greenhouse gas (GHG) emissions reductions.
The renewable fraction directly dictates the green premium paid by shipowners, underpins accurate GHG accounting, and ensures strict regulatory compliance. However, current industry practices present a vulnerability: blend ratios, such as B24 or B30, are traditionally supplier-declared rather than independently verified.
GCMD’s new report aims to close this verification gap, boosting market transparency and strengthening commercial trust as marine biofuel trade scales globally.
Ensuring Reliable Measurement of Total Volume Transferred
While Mass Flow Meters (MFMs) have widely emerged as the gold standard for custody transfer by offering a transparent and auditable mechanism for fuel measurement, introducing biofuels introduces complex physical variables:
- Viscosity Challenges: Blending fatty acid methyl ester (FAME) with conventional marine fuels like Very Low Sulphur Fuel Oil (VLSFO) or High Sulphur Fuel Oil (HSFO) alters fluid dynamics. This can reduce the final blend’s viscosity, potentially pushing it outside the validated operating range of the MFM installed on a bunker barge.
- Operational Solutions: To protect measurement integrity, GCMD stresses that the viscosity of the final fuel blend must be rigorously assessed under actual transfer conditions against the applicable MFM operating range. Operators can manage this effectively through precise transfer-temperature control or by deploying MFMs specifically validated for broader operational ranges.
Navigating the Complexities of Verifying the Renewable Fraction
Verifying the actual renewable content within a delivered bunker blend requires sophisticated analytical methodologies, which vary depending on the feedstock:
- FAME-Based Blends: Can be effectively verified through standard compositional analysis.
- HVO-Based Blends: Require advanced radiocarbon analysis, as renewable and fossil hydrocarbons are molecularly identical and cannot be distinguished via simple compositional testing.
However, interpreting these laboratory results requires careful nuance. Neat FAME can naturally contain up to 3.5% non-ester material, meaning the measurable FAME content of a finished blend (e.g., a BXX mixture) may not precisely match its nominal, supplier-declared blend ratio.
Furthermore, because all laboratory methods carry finite measurement precision, minor discrepancies between measured results and declared blend ratios do not automatically point to incorrect blending, commercial foul play, or under-delivery. GCMD’s approach provides a practical framework to distinguish normal measurement variation from potential, malicious under-blending.
Completing GCMD’s Three-Pillar Biofuels Assurance Framework
With the release of this latest study, GCMD officially finalizes its comprehensive three-pillar assurance framework, addressing the core vectors of marine biofuel trading:
- Quality: Ensuring the fuel is fit for safe use in ship engines.
- GHG Emissions Abatement: Confirming that the fuel delivers its claimed emissions reductions.
- Quantity & Content: Guaranteeing that the transaction contains the precise physical fuel quantity and contracted renewable fraction.
“Buyers need confidence that they have received both the fuel and the renewable content they paid for. This report provides a practical, evidence-backed basis for verifying renewable fuel claims, protecting commercial value and supporting credible GHG accounting as marine biofuel use scales.” stated, Professor Lynn Loo, CEO of GCMD
Access the Full Report
Industry stakeholders, shipowners, bunker suppliers, and maritime executives can access and download the complete Quantity assurance in marine biofuel supply chains report directly through the GCMD official platform.
About the Global Centre for Maritime Decarbonisation
The Global Centre for Maritime Decarbonisation (GCMD) is an international, independent action tank established on August 1, 2021, to help international shipping decarbonize through pilots and trials. Its mission is to support decarbonization across four pillars: shaping standards, deploying solutions, financing projects, and fostering collaboration across sectors.
GCMD was founded with the support of industry partners, alongside funding from the Maritime and Port Authority of Singapore (MPA) for qualifying research and development programs. Since its founding, GCMD has expanded its ecosystem to include more than 130 centre- and project-level partners contributing funds, expertise, and in-kind support to pilot, accelerate the deployment of, and scale the adoption of decarbonization solutions.
GCMD has launched four key initiatives to close technical and operational gaps in:
- Enabling ammonia as a marine fuel;
- Developing an assurance framework for drop-in green fuels;
- Unlocking the carbon value chain through onboard carbon capture and articulating the value chain of captured carbon dioxide; and
- Closing the data-financing gap to scale the adoption of energy efficiency technologies.
GCMD is strategically located in Singapore, the world’s largest bunkering hub and busiest transshipment port.
Source: GCMD