While crude oil grabs the headlines during conflict, it is diesel, the fuel powering trucks, farms, factories and hospitals, that quietly determines how much a war actually costs the world economy
When conflict flares in the Middle East, most people watch the price of crude oil. They are watching the wrong number. Diesel, the fuel that moves freight, powers farm machinery, keeps hospital generators running and drives industrial production, faces more pressure than any other petroleum product during geopolitical shocks, and that pressure translates directly into higher costs across nearly every sector of the global economy, according to a media report.
The reason matters well beyond fuel pumps. Diesel’s unusual vulnerability means that even when crude prices calm down after a crisis, the economic pain from a conflict can linger for months longer than headlines suggest.
Diesel’s importance stems from how deeply embedded it is in the physical machinery of the global economy. It powers lorries, trains, buses and boats, along with vehicles central to the military, farming and construction sectors. Diesel-powered generators also serve as critical backup power at factories, hospitals and large buildings, as well as in remote areas with limited grid access, the report noted. Few other fuels touch so many different industries simultaneously.
A fuel with no global price tag
Unlike Brent crude or West Texas Intermediate, both of which trade on recognised global benchmarks, diesel has no single worldwide exchange price. Its cost instead varies enormously by region, shaped by local supply and demand conditions, logistical costs, and taxation, according to the report.
That regional variation becomes dramatic once conflict escalates. Bridget Payne, head of energy forecasting at Oxford Economics, described diesel as both the most affected fuel and the most important for the macroeconomic outlook during the current disruption.
Its supply is being squeezed simultaneously by lower Middle Eastern refinery output and the loss of Russian exports, she said, while its central role in freight, agriculture and industry means that higher prices feed rapidly into transport, production and distribution costs, ultimately reaching consumers.
The scale of regional price differences is striking even in ordinary times. As of last week, the global average price of diesel stood at roughly 1.47 dollars a litre, according to industry tracker data cited in the report. But the gap between the cheapest and the most expensive is enormous.
Venezuela, holder of the world’s largest crude reserves, prices diesel at just 0.004 dollars a litre, while Hong Kong charges 4.379 dollars for the same amount. Only 31 countries maintain diesel prices below 1 dollar a litre, a group that includes Egypt, Lebanon, Syria, Iran and the Gulf states. Petrol prices show a similarly wide range, from 0.023 dollars in Libya to 4.062 dollars in Hong Kong, with a global average matching diesel’s at 1.47 dollars.
Why crude oil’s recovery didn’t bring diesel down with it
One of the clearest signs of diesel’s unique vulnerability emerged in early July, when the United States and Iran signed a 60-day framework agreement. By that point, Brent crude had slid roughly 40 per cent from its wartime peak, returning close to prewar levels. Diesel told a very different story, falling by only 15 per cent and remaining substantially elevated, Payne said.
The explanation lies in how refining actually works. The recovery in crude exports did not immediately translate into higher supplies of refined fuel, since refiners secure crude and set their operating plans several weeks in advance. Supply of crude oil itself returned faster than refiners could raise purchases and adjust their run rates, Payne explained, which temporarily weighed on Brent prices even though that additional crude could not be quickly converted into diesel, jet fuel or gasoline.
This lag is a structural feature of the fuel market, not a temporary glitch. Petrol is composed of a mix of alkanes and cycloalkanes with relatively short carbon chains and a boiling point between 40 and 205 degrees Celsius, according to the European Automobile Manufacturers Association, cited in the report.
Diesel, by contrast, is made of alkanes containing 12 or more carbon atoms and boils at a much higher range, between 250 and 350 degrees Celsius. These are genuinely different products requiring different refining processes, which is part of why crude oil recovery does not automatically translate into equivalent relief for diesel buyers.
Refining bottlenecks, not crude supply, drive the real cost
According to the International Energy Agency, refined product cracks and margins surged to four-year highs in early July, as increased crude supplies pushed oil prices sharply lower while product markets remained tight. Renewed hostilities between the United States and Iran then drove both Brent and WTI up by almost 16 per cent every week, yet refined fuels remained what one analysis called the real inflation story.
Ole Hansen, head of commodity strategy at Denmark’s Saxo Bank, explained the distinction plainly. If crude oil tells only part of the story, he said, refined products continue to paint a much tighter picture. Unlike crude oil, refined products face far fewer mitigation options, since several Middle Eastern refineries remain affected by the ongoing conflict while Russia’s diesel export restrictions continue to constrain global availability.
Global refining capacity itself remains relatively limited, Hansen noted, which prevents increases in crude supply from quickly translating into additional diesel and gasoline production. As a result, refining margins have expanded sharply.
For consumers and industry alike, he said, it is refined fuel prices, not crude oil itself, that ultimately determine the economic impact of an energy shock. This distinction carries real weight, since elevated diesel and gasoline prices feed directly into freight costs, manufacturing, agriculture and broader inflation, potentially creating a more persistent drag on economic activity than crude prices alone would suggest.
A vulnerability with no easy fix in sight
How the underlying conflict will ultimately play out remains uncertain. But Oxford Economics has been clear about what it would take to bring diesel prices meaningfully lower: a sustained recovery built on a genuine improvement in transit through the Strait of Hormuz combined with the restoration of refinery throughput. Absent that combination, relief is likely to remain partial and slow.
The analysis also flagged a growing tail risk of acute diesel shortages, which could constrain freight movement, agricultural output and industrial production if conditions worsen rather than improve. Hansen echoed that concern, noting that elevated diesel prices, along with petrol and natural gas, have the potential to slow economic growth, squeeze corporate margins and weaken consumer spending well beyond the immediate region affected by conflict.
That is ultimately what makes diesel such a distinctive vulnerability in any geopolitical shock.
Crude oil prices can spike dramatically and then retreat just as quickly once tensions ease, offering a visible, headline-friendly measure of crisis and recovery. Diesel behaves differently, dragged down by refining bottlenecks, regional supply constraints and structural limits on how quickly crude can become usable fuel.
For truckers moving freight, farmers running machinery, and hospitals relying on backup generators, that slower, stickier recovery is what actually determines how long a geopolitical shock continues to be felt, long after the crude oil charts have returned to normal.
