VLSFO — What It Is, Why It Costs What It Does, and Why the Price Never Sits Still

§1 — What VLSFO Is (and What It Is Not)

VLSFO stands for Very Low Sulphur Fuel Oil. The “very low” refers to sulphur content: VLSFO must contain no more than 0.50% sulphur by mass, down from the 3.50% permitted under the old High Sulphur Fuel Oil (HSFO) standard. The IMO 2020 global sulphur cap, which entered force on January 1, 2020, made VLSFO the default compliance fuel for ocean-going vessels above 400 gross tonnes operating outside Emission Control Areas.

Before 2020, VLSFO barely existed as a commercial product. The marine fuel market ran almost entirely on HSFO — a thick, viscous, high-sulphur residual oil that is essentially the bottom of the refining barrel. VLSFO had to be invented. What refiners did was blend: mixing residual fuel streams with lighter distillate fractions to hit the 0.50% sulphur ceiling. The result is not a standardised product. Different refineries produce VLSFO from different blend combinations. Different ports receive VLSFO from different regional suppliers. The fuel has the same name and the same sulphur limit, but what is actually in it — its viscosity, its stability, its compatibility with other batches — varies.

This blending variability is not an academic concern. VLSFO compatibility problems have caused filter blockages, pumping failures, and engine damage on vessels that mixed incompatible batches. The industry calls this the “cat fines” and compatibility risk problem. Unlike craft beer, where variation is the point, VLSFO variation is a liability. Operators now routinely test bunker samples before loading and maintain separate tanks to avoid mixing batches from different ports or suppliers.

§2 — Three Fuels, Three Economics

The 2020 sulphur cap created three compliance pathways, and three fuel economics now run in parallel.

The first pathway is VLSFO — switch fuel, no hardware changes, no capital outlay. This is what roughly 80% of the global fleet did. It is the simplest solution. The cost is the higher fuel price: VLSFO runs about $200 to $250 per tonne more expensive than HSFO in normal market conditions, because it requires blending work that HSFO does not.

The second pathway is scrubbers — exhaust gas cleaning systems that strip sulphur oxides from the exhaust before it leaves the funnel, allowing the ship to continue burning cheaper HSFO. About 5,000 vessels have taken this route. The economics depend entirely on the Hi-5 spread: the price difference between HSFO and VLSFO. When the Hi-5 spread is wide, scrubbers pay back their capital cost quickly. When the spread collapses, scrubbers are a stranded investment. In mid-June 2026, the spread sits at approximately $157 per tonne — comfortably above the $100-per-tonne level that most operators use as the scrubber breakeven threshold. At this spread, a scrubber-fitted Capesize burning 50 tonnes a day saves roughly $7,850 daily versus a VLSFO-burning equivalent.

The third pathway is Marine Gas Oil (MGO) — a distillate fuel with a 0.10% sulphur limit, used in Emission Control Areas (ECAs) where the 0.50% VLSFO limit is not sufficient. MGO is the cleanest and most expensive of the three. In Singapore as of late June 2026, MGO trades at approximately $937 per tonne — $225 more than VLSFO. Ships operating in the North Sea ECA, Baltic ECA, or North American ECA must switch to MGO (or use a scrubber) when entering the 200-nautical-mile zone.

§3 — Why the Price Never Sits Still

VLSFO prices are more volatile than crude oil, which is itself a volatile benchmark. The reason is that four independent forces act on the price simultaneously, each on its own timeline.

The first force is crude oil. VLSFO is made from crude, so Brent movements transmit into bunker prices. But the relationship is not linear. Blending a residual fuel stream to hit the 0.50% sulphur limit requires distillate fractions — lighter products that have their own demand cycle and their own pricing. Ship & Bunker data from June 23 shows VLSFO at Singapore trading at roughly 25.8% above the Brent crude price — a blending premium that fluctuates with the distillate market.

The second force is refinery run rates and output priorities. Refineries optimise for high-margin products first: gasoline in summer, diesel in winter, jet fuel year-round. VLSFO is not a refinery priority product — it is made from what is left after the higher-value cuts are taken. When refinery runs are high and product demand is strong, VLSFO supply can tighten even when crude is plentiful.

The third force is geopolitics. Hormuz is the clearest current example. In June 2026, the Fujairah VLSFO price stands at $1,082 per tonne — $477 above Rotterdam on the same day, against a normal historical spread of $10 to $20. The premium reflects disrupted barge logistics, elevated war risk for supply vessels, and diverted regional supply chains. This is not a crude oil movement — Brent has not risen 79% relative to Rotterdam. It is a port-specific supply shock.

The fourth force is regional supply logistics. Bunkering infrastructure — barges, storage terminals, pipeline access — varies enormously by port. Singapore has deep, liquid supply. Rotterdam has multiple competing suppliers. Smaller ports may have one or two bunker suppliers, making prices less competitive. A barge shortage in Singapore does not propagate to Rotterdam, and vice versa. Port-level supply tightness creates local premiums that can persist for weeks.

§4 — Reading the Data Hub

Bunker price data is useful only when you read the spreads, not the headline numbers. The Fairway ETA Data Hub shows four G4 benchmark ports updated weekly. As of June 23, 2026, VLSFO prices are: Singapore $712/tonne, Rotterdam $605/tonne, Fujairah $1,082/tonne, Houston $612/tonne.

The headline that matters is not the Singapore number — it is the Fujairah premium. Rotterdam and Singapore typically trade within $10 to $20 of each other. Houston is slightly higher due to US Gulf logistics. Fujairah should be marginally above Singapore, reflecting its position as a transshipment hub for Gulf crude exports. In normal conditions, the Fujairah-Rotterdam spread is $20 to $40.

The current $477 spread is not normal. It reflects the Hormuz disruption: constrained barge movements in the Gulf, war risk premiums on supply logistics, and diverted tanker traffic. Any charterer routing a vessel through the Gulf and planning to bunker at Fujairah is facing a voyage fuel cost calculation that is fundamentally different from what the Rotterdam number suggests.

The Hi-5 spread — currently around $157 per tonne globally — is the second critical read. At this spread, a scrubber-fitted vessel burning HSFO rather than VLSFO saves $157 per tonne. A large tanker or bulk carrier consuming 60 to 80 tonnes per day at sea saves $9,400 to $12,600 daily. Over a 30-day voyage, that is $280,000 to $380,000 in fuel savings — against a scrubber installation cost of $2 to $5 million. Payback periods at this spread run under two years.

The MGO-VLSFO spread — currently around $225 per tonne in Singapore — is the ECA compliance cost read. Every time a vessel enters a designated ECA and must switch from VLSFO to MGO, it pays this premium on the distillate volume consumed inside the zone. For a ship making regular North Sea or Baltic transits, this cost is a predictable standing item in voyage economics.

§5 — What Comes Next for VLSFO

VLSFO was designed as a compliance solution, not as a long-term fuel strategy. The IMO 2020 sulphur cap was always the first regulatory step — with deeper decarbonisation to follow. The question the fuel market has been trying to price is: how long does VLSFO's dominance last?

The IMO's Net Zero Framework — which would introduce both a global fuel standard and a carbon pricing mechanism for shipping — was approved in principle at MEPC 83 in April 2025. But its formal adoption was adjourned at the Extraordinary MEPC session in October 2025, after Saudi Arabia called a vote to delay by one year. The motion passed 57 to 49, with 21 abstentions, following intense US opposition. The reconsideration is now scheduled for autumn 2026. If adopted then, the earliest entry into force would be 2028. The delay removes near-term regulatory pressure that would have accelerated the transition away from fossil marine fuels. For now, VLSFO remains the path of least resistance.

The market numbers support that. The global marine fuel market — dominated by VLSFO — was valued at approximately $42.6 billion in 2025 and is projected to reach $74.8 billion by 2034, driven by fleet growth and rising fuel prices rather than volume reduction. VLSFO demand is not expected to peak before 2030 on any mainstream scenario.

But the carbon cost layer is already live. Under EU ETS, every tonne of VLSFO burned on EU-linked voyages generates approximately 3.15 tonnes of CO₂, now priced at €65 to €85 per tonne of CO₂ — adding €205 to €268 per tonne of fuel in carbon cost alone. The UK ETS extends a parallel obligation from July 1, 2026, at £30 to £55 per tonne of CO₂ — adding £95 to £173 per tonne of fuel for qualifying UK voyages and in-port operations.

The operational consequence is that the true cost of a tonne of VLSFO in 2026 is not $605 or $712 or $1,082. It is the fuel price plus the carbon cost plus the ECA premium when applicable. For a ship making regular EU and UK port calls, the carbon cost can add $150 to $250 per tonne of VLSFO equivalent — closing the gap with alternative fuels faster than headline bunker prices suggest.