(SINGAPORE) — 2025 was another challenging year for global marine fuel quality, as decarbonization legislation took numerous twists and turns, increasing demands on shipowners and operators across the world. Alongside this, the traditional fossil fuels also raised numerous quality issues.
The International Maritime Organization (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 United States 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 carbon intensity indicator (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 Emission Control Area (ECA) entered into force in May 25, while the Canadian Arctic, Norwegian Sea and northeast Atlantic ECAs are approaching. Meanwhile, European Union (EU) emissions regulation sees the phase-in of the EU Emissions Trading System (ETS) continuing, with a further step-up due in January, while FuelEU Maritime entered into force on 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 percent of the fleet is set to be alternative-fuel capable.
Veritas Petroleum Services (VPS) tested 1.2 million MT of biofuels delivered to ships in 2025, a 50 percent 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 newbuild 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 percent of fleet GT), “eco” engines (36 percent) and energy saving technologies (44 percent).
From a fossil fuel perspective, VPS issued 37 bunker alerts over 2025, an increase of 37 percent over 2024, with very low sulfur fuel oils (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 62 ppm to 176 ppm across East Coast U.S., 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 flashpoint issues, which were in the main related to distillate fuels, but also VLSFOs and high sulfur fuel oils (HSFOs) suffered from this problem.
In addition, VPS identified, via its 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 percent of the fuels used, followed by 34.4 percent HSFO, 14.4 percent marine gasoil (MGO), 1.9 percent fiofuels and 1.8 percent ultra-low sulfur fuel oil (ULSFO). Regarding biofuels usage, the samples tested by VPS equated to an increase from 805,808 MT in 2024 to 1,203,760 MT in 2025 (a 50 percent increase).
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 percent 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 percent 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 percent), 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 0.5 percent sulfur fuels or 0.1 percent sulfur fuels, accounts for only 26 percent 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 percent. The 2025 bunker alerts included all the marine fossil fuel grades of VLSFO (27) being the most problematic fuel, followed by HSFO (eight), MGO (one) and ULSFO (one). The bunker alerts covered nine different test parameters: cat-fines (13), flashpoint (eight), TSP (four), density (four), seawater (three), sulfur (two), sodium, potassium, and used lubricating oil (ULO).
Singapore accounted for 46 percent of the bunker alerts issued in 2025, which is an unusually high level, while China did not require any bunker alerts during the course of the year.
– Veritas Petroleum Services
