Why don’t all fuels react the same to rising oil prices?

When the Brent crude price moves, not all fuels at the pump follow the same path. Diesel, SP95, SP98, E10 and LPGc react differently to changes in crude oil. Why? Detailed explanations below.

More or less direct dependence on crude oil

The Brent price, quoted in US dollars, is a global benchmark that directly influences the purchase cost of crude. But crude has to be refined, transported and distributed… and not all fuels require the same processes or import volumes.

Diesel and gasolines such as SP95 or SP98 come from the same crude, but their refinery yields differ: producing diesel is more or less costly depending on crude quality, and yields also vary with seasonal demand.

See also: Real-time Brent price

Taxes: a decisive factor in price reactions

In France, pump prices are heavily influenced by taxes, especially the excise duty and VAT. These taxes are not proportional to crude prices:

• Excise is fixed per litre (about €0.67 for gasoline, €0.607 for diesel).
• VAT is proportional, but applied after excise.

Result: a 5% change in Brent does not lead to 5% at the pump, but roughly 1.5%.

Different demand patterns by fuel

Seasonal demand also matters:

• In winter, diesel rises due to heating oil demand.
• In summer, gasoline rises with holiday travel.

This explains why SP95 may fall while diesel rises at the same time.

Distinct supply chains

SP95-E10, LPGc and E85 are alternative or blended fuels:

• SP95-E10 contains 10% ethanol.
• LPG depends on propane/butane, less tied to Brent.
• E85 is largely agricultural (sugar beet, corn).

The EUR/USD exchange rate matters

Oil is priced in US dollars, but you pay in euros at the pump:

• If the euro weakens, oil costs more.
• If the euro strengthens, it can offset a Brent increase.

On prix-carburant.eu, we factor both effects into our forecasts. Track Brent and fuel curves in our tool: Price simulation