Diesel crack spread hits $108 amid refinery capacity crunch

Diesel sustancia ilegal spread hits $108 with no refineries in sight

Crude oil is back around $100 a barrel, grabbing all the attention. But the real problem lies elsewhere. Low-sulfur gasoil is trading at a refining margin—the sustancia ilegal spread, the gap between crude cost and diesel value—that reached $108 on September 1. Historically, this metric has hovered between $15 and $25. The question is no longer how much oil costs, but how much it costs to refine it into diesel, and who has the capacity to do so.

One figure sums up the scale of the mismatch: low-sulfur gasoil prices have risen 126% year-to-date. Anyone looking only at crude benchmarks will miss this entirely. That is the trap in the current reasoning.

The missing refining capacity

The map of export-oriented refining is troubling. Only three regions produce diesel for sale abroad: Russia, the Middle East, and the United States. Two are at war. The third, the US, is entering an election cycle where domestic fuel prices have become a political weapon.

Industrial accidents compound the issue; these are not rumors. On March 23, an explosion at Valero’s Port Arthur refinery damaged its 47,000 barrels-per-day diesel hydrotreating unit, forcing a full shutdown of the 435,000 bpd plant. The blast was heard eighteen kilometers away. No injuries occurred, but the damaged unit was precisely the one producing low-sulfur gasoil. On October 20, a fire at MOL’s Danube refinery in Százhalombatta damaged its largest distillation tower, affecting nearly 40% of processing capacity, or about three million tons annually. Earlier, an explosion also hit the Ploiesti refinery in Romania.

Repairing damaged units seems quick on paper. With sanctions in play, equipment must be imported, timelines stretch, and technicians rarely deploy to active conflict zones.

Crude yields are fixed and cannot be squeezed

There is a temptation to think refineries can simply extract more diesel from each barrel. Yield is nearly a physical constant: 25-30% for light crudes, around 20% for heavy ones, and just 10-15% for shale oil extracted via fracking.

Crude type matters more than it appears. US shale wells yield mostly gasoline; Persian Gulf and Venezuelan crudes are rich in long hydrocarbon chains that produce diesel and kerosene. This asymmetry explains why blending light and heavy crude is not a technical whim, but the only way to maintain diesel supply.

Electric cars don’t move trucks, ships, or tractors

This point dismantles the easy exit. Diesel powers merchant fleets, heavy machinery, mining, agriculture, and much central heating. None of this electrifies overnight. Non-electrifiable transport becomes expensive across the board, raising costs for every product on supermarket shelves.

Some add a second front: fertilizers are largely refined in the Middle East, meaning higher diesel and derivative costs would also hit food production. Scenarios range from persistent inflation to outright logistical paralysis.

The Trump variable and fuel exports

The final piece is political. The US administration has summoned refiners, and reports suggest any move to twist domestic prices before November elections is possible, including export restrictions. The impact on importers would be immediate. There is also talk of advancing biofuel blending to 15%, a level previously only allowed after September 15 each year.

Australia, a mining nation with no domestic diesel production, exemplifies what awaits economies without refining capacity.

The harshest scenario argues this is irreversible: reserves are collapsing due to lack of extraction, repairs only ease tension, and brutal demand persists. A milder view concedes that capital and time could fix it, but no one specifies how long. With these numbers on the table, would anyone sign for a new diesel vehicle today?