why diesel is much more expensive than gasoline

The conflict between United States, Israel and Iran has turned the energy industry upside down, leading to an aggressive increase in fuel prices. Diesel has risen so much and so quickly that it is already above the price of 98 gasoline in Spain, the most expensive fuel at the pumps.

The differences. According to data from the Ministry for the Ecological Transition collected According to the Dieselogasolina portal, the accumulated average price of diesel this weekend was around 1.96 euros per liter, before the government measures package to tackle the problem, while 98 gasoline was around 1.97 euros. After the measures, diesel has remained on top, and this may end up being a problem for millions of drivers, transporters and industries that have no alternative.

How we got here. The outbreak of the war in the Middle East on February 28 has acted as a trigger for an increase in prices. Since that date, gasoline has become more expensive by around 18.9%while diesel accumulates an increase of close to 31.1%, according to the Organization of Consumers and Users (OCU).

The problems. Diesel does not only depend on the price of a barrel of oil, but on something more structural. Iran controls the Strait of Hormuz, a key point for maritime oil transit, and any alteration in that area has an immediate impact on international prices. The Government announced last Friday a series of measures in order to alleviate the rise through a reduction in VAT on fuel from 21 to 10%.

Together with its partners from the International Energy Agency, it also authorized the release of up to 11.5 million barrels of oil from strategic reserves, which is equivalent to 12.3 days of national consumption, being the largest release of reserves in the history of the IEA. Prices have dropped from their highs last week, as the chart for the last seven days shows. But diesel is still above 98 gasoline.

Why diesel rises more than gasoline. Every time there is an energy crisis, diesel hits harder than the rest. It makes sense, since the rebound is mainly due to Europe’s dependence on diesel importssince the continent depends on the Middle East for this type of fuel. For this reason, its international price has come to eat up the tax advantage that diesel historically had in Spain.

Added to this is that Europe has spent years closing refining capacity. Well according to data According to the Financial Times, as of 2024 alone the continent has closed about 400,000 barrels per day of refining capacity, a deficit that has been accumulating for years. The process was further accelerated when Russia was sanctioned following the invasion of Ukraine. And Europe depended on Russia for almost half of its total diesel imports. Losing that supply required rebuilding the entire supply chain. And now, without Russia and with the Middle East on fire, Europe’s diesel market is in a bind.

The vehicle fleet is still mainly diesel. If diesel were only the fuel for those who drive on the highway or travel many kilometers, the impact would be limited. But it is not. Of the more than 34 million vehicles which approximately make up the vehicle fleet in Spain, around 57% are diesel vehicles. If we focus only on passenger cars, some 15 million private cars depend on this fuel, which is now ahead of the most expensive gasoline.

And although sales of diesel cars have been collapsing for years (in February 2026 They represented only 4.05% of passenger car registrations) diesel vehicles continue to be the majority in Spain. The renewal of the fleet is slow because new cars are expensive and electric cars have not yet penetrated sufficiently.

The blow to transportation and everything you buy. The problem multiplies when we look beyond conventional tourism. And it is that 93.8% of light commercial vehicles They use diesel, while 98.7% of commercial vehicles use diesel. Trucks, delivery vans, agricultural machinery, buses: almost everything that moves goods in Spain runs on diesel. And approximately one-third of trucking companies’ operating costs are fuel.

In the case of a long-distance heavy truck, the consumption can exceed 4,000 liters per month. The sharp increase in the price of diesel, with increases of more than 30% in a few weeks, is putting pressure on the transport sector. While a private driver can stay at home or take the subway or bus, the truck driver has no alternative. And when transportation costs rise, so do the prices of what you buy at the supermarket.

Cover image | Roberto Rodríguez and engin akyurt

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