Steve Bee, Group Marketing and Strategic Projects Director of marine fuels testing company VPS, on Monday (26 January) covered a detailed review of 2025 Marine Fuel Quality including marine fuel off-specifications, fuel contamination issues as well as methanol and ethanol:
Introduction
2025 saw another challenging year for global marine fuel quality, as decarbonization legislation took numerous twists and turns, increasing demands upon ship owners and operators across the world. Alongside this, the traditional fossil fuels also raised numerous quality issues.
The IMO delayed the vote on the adoption of the Net Zero Framework (NZF) for one year after strong lobbying against the measures, especially from the USA and Saudi Arabia. This has made the next steps for shipping emissions regulation uncertain with re-negotiation now needed in order to overcome the now apparent entrenched split between countries’ positions.
However, other areas of decarbonization regulation continue to progress, with a review of CII ratings ongoing at the IMO and annual reduction factors to 2030 agreed upon, but still much to be discussed in the upcoming phase 2. The Mediterranean ECA entered into force in May-25, while the Canadian Arctic, Norwegian Sea and NE Atlantic ECAs are approaching. Meanwhile, EU emissions regulation sees the phase-in of the EU ETS continuing, with a further step-up due in Jan-26, while FuelEU Maritime entered into force in Jan-25, with standards scheduled to tighten over the coming years.
The uptake of alternative fuels continued to rise, with alternative fuel capable vessels accounting for over half of orderbook in investment terms. Its estimated by 2030 nearly 20% of the fleet is set to be alternative fuel capable.
VPS tested 1.2million mt of biofuels delivered to ships in 2025, a 50% increase on 2024 levels. Plus methanol testing and ethanol testing demand also increased.
The delay to the IMO NZF vote extends regulatory uncertainty for shipping and could have some bearing on fueling choices in the short-term, with a lack of a clear signal needed to drive more significant investment in ‘green’ technologies.
However, ‘green’ fleet renewal remains a key factor supporting new-build appetite in some sectors (notably containers) and is expected to remain a general underlying theme, driving investment decisions against the backdrop of an ageing fleet and industry efforts to reduce emissions.
Flexibility and optionality are current key themes, with continuing progress in the uptake of scrubbers (fitted on 30% of fleet GT), ‘Eco’ engines (36%) and Energy Saving Technologies (44%).
From a fossil fuel perspective, VPS issued 37 bunker alerts over 2025, an increase of 37% over 2024, with VLSFOs being the fuel type requiring the highest number of alerts and Singapore being the most frequent port/region providing potentially problematic fuels. VPS witnessed a pandemic of high cat-fine levels in VLSFOs during August, resulting in seven bunker alerts being released for cat-fine levels ranging from 62ppm-176ppm across East Coast USA, Singapore, Algeciras ARA and Port Louis. This issue highlighted the importance of employing fuel system check services to provide elevated protection and risk mitigation for vessels. In addition VPS witnessed numerous flash point issues, which were in the main related to distillate fuels, but also VLSFOs and HSFOs suffered from this problem.
In addition, VPS identified, via our new advanced chemical screening service, the contamination of residual-based fossil fuels, by cashew nut shell liquid (CNSL). This non-volatile organic compound, if undetected pre-burn, can cause issues with fuel pumps and exhaust systems and SCR units.
The 2025 Marine Fuel Mix
Across 2025, the fuel mix with respect to samples received for testing in VPS laboratories, equated to more than 63 million MT, which averages at 5.25 million MT of marine fuels per month. VLSFO was the most popular marine fuel with 47.6% of the fuels used, followed by 34.4% HSFO, 14.4% MGO, 1.9% Biofuels and 1.8% ULSFO. Regarding biofuels usage, the samples tested by VPS equated to an increase from 805,808 MT in 2024 to 1,203,760MT in 2025 (+50%).

Testing to ISO8217
Despite the introduction of the latest and seventh revision of the International Marine Fuel Quality Standard, ISO8217 in May 2024, VPS has seen little take-up of fuel being purchased against this latest revision, at around 0.3% of samples received. In fact, those samples we have received purchased against the latest standard have been for biofuels only.
It is surprising that just over 8% of samples received by VPS for testing in 2025, are still being purchased against ISO8217:2005. This revision is over 20 years old and bears little resemblance to today’s fuel. Therefore, vessels purchasing fuel to this standard are at greater risk of damages and environmental non-compliance.
The majority of marine fuel is still being purchased to ISO8217:2010/12 revisions, (65.4%), which are themselves around 15 years old and offering reduced protection for vessels versus the latest revision. Even the 8 year old 2017 specification, which offers no specification for 0.50%-sulphur fuels, or 0.10%-sulphur fuels, accounts for only 26% of the fuels received for testing.

VPS Bunker Alerts
Bunker Alerts highlight short term quality fuel quality issues identified by VPS, for a specific test parameter of a specific fuel grade/type in a specific port. The service provides valuable information to customers, to assist in avoiding potentially problematic fuel types in a highlighted port or region, to further protect the customer’s asset and crew.
Across 2025, VPS issued 37 bunker alerts, compared to only 27 alerts in 2024, an increase of 37%.
The 2025 Bunker Alerts included all the marine fossil fuel grades of VLSFO (27), being the most problematic fuel, followed by HSFO (8), MGO (1) and ULSFO (1).
The Bunker Alerts covered 9 different test parameters, Cat-fines (13), Flash Point (8), TSP (4), Density (4), Seawater (3), Sulphur (2), Sodium, Potassium, ULO.

Singapore accounted for 46% of the Bunker Alerts issued in 2025, which is an unusually high level. Whilst China did not require any Bunker Alerts during the course of the year.

2025 Marine Fuel Off-Specifications
Whilst VPS issued 37% more Bunker Alerts in 2025 versus 2024, the overall off-specifications by fuel grade actually improved against 2024 levels for HSFOs, VLSFOs, ULSFOs, MGO and Biofuels. The greatest improvement was shown by HSFOs going from 10.7% in 2024 to 7.2% in 2025.

In terms of region, Europe continues to be the area providing the highest level of off-specification fuel, even though the level of off-specs improved in 2025 versus 2024, going from 12.2% to 10.3%. However, Singapore’s off-specification rate increased from 5.9% in 2024 to 7.6% in 2025.

VLSFO Fuel Quality
As the most used marine fuel type, VLSFO accounts for almost half of the fuels tested by VPS. In terms of quality, VLSFO had an off-specification rate of 5.2% in 2025. Of the 5.2% VLSFO off-specifications, Europe provided the highest level of off-specification VLSFOs in both 2025 (13.3%) and 2024 (11.9%). Africa, as a specific region, provided the next highest level of off-specification VLSFO with 4.8% of fuels tested exhibiting at least one off-specification parameter in 2025 compared to 5.8% in 2024. North America had the third highest VLSFO off-specification rate with 4.3% off-specs versus 7% in 2024.

Note: The full review by VPS can be found here.
Photo credit: VPS
Published: 27 January, 2026