Green Fuel Certification Needs Chemical Fingerprinting to Curb Feedstock Fraud, NTU Study Says

A new study from Singapore’s Nanyang Technological University (NTU) has called for chemical “fingerprinting” of biofuels to strengthen certification systems and prevent fraudulent claims about feedstocks as the International Maritime Organization (IMO) develops rules for sustainable marine fuels.

The study, commissioned by US climate campaign group Pacific Environment and conducted by NTU’s Maritime Energy and Sustainable Development (MESD) centre of excellence, examines existing fuel certification frameworks and identifies weaknesses that could undermine the credibility of low-carbon fuels used in shipping.

The Maritime and Port Authority of Singapore (MPA) reviewed the study before its publication.

Why Biofuel Feedstock Fraud Is a Concern

The report points to recent cases in which virgin crop oils were reportedly certified as waste-based feedstocks, including used cooking oil (UCO) and palm oil mill effluent (POME). Such discrepancies were detected only after the volumes being declared became difficult to reconcile with plausible supply levels.

According to the study, reliance on documentation and conventional chain-of-custody checks may therefore be insufficient as international shipping increases its use of alternative fuels.

The researchers recommend introducing chemical testing, or “fingerprinting”, to establish the actual origin of a fuel independently of its accompanying documentation. The approach would require further methodological development and a cost-benefit assessment before wider implementation.

Singapore has already developed a fingerprinting method using methanol as a case study, according to the report.

IMO Sustainable Fuel Rules Could Draw on Existing Schemes

The NTU study assesses several existing certification systems that could provide models for the framework being developed by the IMO as part of its Net-Zero Framework.

These include the International Sustainability and Carbon Certification (ISCC) and Roundtable on Sustainable Biomaterials (RSB) schemes, which are used in connection with the European Union’s Renewable Energy Directive and the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA).

The report also examines Brazil’s RenovaBio, California’s Low Carbon Fuel Standard and the US Renewable Fuel Standard.

Among the systems reviewed, ISCC appears to have the largest market presence. The study says more than 90% of biofuels in the UK are ISCC-certified, while 7,546 ISCC certificates were issued in 2024 compared with 72 issued by RSB.

The researchers suggest that the scale of ISCC’s certification infrastructure could make it an important reference point as the IMO develops its own requirements.

Central Database Recommended for Fuel Traceability

In addition to chemical verification, the study recommends establishing a central database that records fuel transactions throughout the supply chain.

Such a system could help prevent double counting by ensuring that the same batch of fuel cannot be presented as a qualifying green fuel more than once.

The report identifies the European Union’s Union Database as a potential model for such a system.

Pacific Environment’s Singapore climate specialist Lim Jie Ying said that as shipping scales up the use of these fuels, certification systems need to be robust enough to guard against fraud and unsustainable production, while also being practical and workable across complex international supply chains.

ILUC Emerges as a Key Difference Between Certification Schemes

The treatment of indirect land-use change (ILUC) is identified by the study as the largest difference among the certification systems examined.

ILUC refers to emissions that can arise when land used for food production is displaced by energy crops, potentially resulting in agricultural expansion or deforestation elsewhere.

The study notes that CORSIA and the two US schemes examined account for ILUC, while the EU certification systems reviewed do not apply the same treatment.

The researchers recommend a hybrid policy approach that uses quantitative ILUC values to increase the carbon-intensity assessment of crop-based biofuels while continuing to permit their use under defined conditions.

The approach could be combined with usage limits or an eventual phase-out of feedstocks considered to carry particularly high environmental risks.

The issue is already part of discussions at the IMO. The United States has proposed regional ILUC risk rules in submission ISWG-GHG 21/3/21.

Singapore Could Expand Auditor Capacity

For Singapore, the report recommends increasing the number of trained sustainability auditors alongside the adoption of fuel fingerprinting techniques.

The measures are intended to strengthen oversight of sustainable fuel supply chains as the city-state expands its role in maritime alternative fuels.

Dr Yeoh Keat Ping, the study’s lead researcher and research lead at MESD, said strengthening the traceability of sustainable fuels through continued research and innovation will be critical in supporting the maritime energy transition.

What Happens Next for the IMO Net-Zero Framework?

The certification recommendations are being developed against the backdrop of continuing negotiations over the IMO’s Net-Zero Framework.

The framework failed to secure adoption during an extraordinary session held last October. It is scheduled to return to the Marine Environment Protection Committee (MEPC) on November 30, with a resumed adoption session pencilled in for December 4.

The eventual IMO certification requirements will determine how sustainable marine fuels are verified, traced and accounted for across international supply chains.

For shipping companies, fuel suppliers and regulators, the development of reliable verification systems will therefore be closely linked to the credibility of emissions reductions attributed to alternative marine fuels.