Since the outbreak of the Iran war, higher road fuel prices have added an estimated €53 billion to transport costs across the European Union, according to a report published on Wednesday by the Brussels-based environmental group Transport & Environment (T&E). The bulk of that burden—€40 billion—comes from diesel, which has become the continent's most expensive fuel problem.
T&E calculates that higher road fuel prices are now costing the EU an average of €270 million a day, with diesel alone accounting for €203 million of that daily figure. The remaining €67 million is attributed to petrol. These estimates compare costs during the war with the same period last year, adjusted for inflation, and cover the 28 weeks up to 6 September.
Why diesel is the weak spot
Europe's heavy reliance on diesel is a structural vulnerability. Diesel and gasoil make up about 43% of the oil products used in the EU by volume—roughly 16 percentage points above the global average and about twice the share in the United States. Nearly four in ten passenger cars on EU roads ran on diesel in 2024, and road transport consumed 77% of the EU's diesel and gasoil that year. Cars take the largest slice, followed by heavy trucks and buses, then vans.
The price surge is hitting ordinary drivers hard. T&E estimates that the average EU diesel car driver paid about €142 more over the period studied than in the comparable period last year. By 14 September, filling a 50-litre diesel tank cost about €30 more than before the war. For businesses, the numbers are starker: an average German long-haul diesel truck incurred roughly €6,000 in extra fuel costs over the period, equivalent to €236 a week. That example, based on a German truck rather than an EU-wide average, illustrates the pressure on logistics firms across the bloc.
What's driving diesel prices up
Crude oil prices have risen sharply since the war began, but diesel has climbed even faster. The conflict has disrupted fuel production and exports from the Middle East, while attacks on Russian refineries have further squeezed global supply. T&E notes that diesel and gasoil exports from the Middle East and Russia together fell by almost 75% in August compared with a year earlier. The gap between crude oil and wholesale diesel exceeded $100 a barrel in early September, against a typical range of $10 to $30—a clear sign of a shortage of refined diesel, not just more expensive crude.
The weighted average EU diesel price reached €2.159 a litre on 14 September, the highest in the European Commission's series dating back to 2005. ECB experts told Euronews Business last week that, based on fuel futures at the time, diesel refining margins were expected to peak in October—though that forecast concerned margins, not pump prices.
Supply could tighten further this autumn as demand for heating oil, farm machinery and freight rises while refineries carry out seasonal maintenance. The United States is also considering a full or partial ban on diesel exports. President Donald Trump said on Tuesday that he supported the idea, though no ban has been announced. Such a move could make it harder for Europe to secure supplies, adding to the pressure on already strained markets.
What can be done
T&E points to measures that could cut diesel demand from cars by 15% in the short term, drawing on recommendations from the International Energy Agency. These include increased working from home where possible—T&E calculates that three additional remote working days per week could reduce a driver's fuel bills by up to 20%—as well as lowering motorway speed limits, investing in better public transport, and providing advice on fuel-saving driving, such as maintaining tyre pressure.
In the longer term, the group argues that electric vehicles would reduce Europe's exposure to oil price shocks. It estimates that nearly eight million electric cars in the EU avoided the use of about 46 million barrels of oil in 2025, saving €2.9 billion in oil imports. That shift, however, will take time, and for now the continent remains acutely vulnerable to diesel price spikes.
Some governments are already responding. Czechia has capped fuel margins and trimmed diesel duty to ease the burden on consumers, while French diesel has topped €2.41 a litre, highlighting the regional variation in prices. The broader picture is one of a continent paying a heavy price for its diesel dependence—a cost that shows no sign of easing soon.
