Diesel to Climb 9.5 Cents and Petrol 6 Cents on Monday 4 May as Brent Tops $110 on Strait of Hormuz Closure — DGEG Forecast Pushes Pump Prices to €2.05/L Diesel and €1.99/L Gasoline

Portuguese drivers face the steepest weekly fuel-price jump of the year on Monday 4 May 2026. Modelling based on Direção-Geral de Energia e Geologia (DGEG) data points to diesel rising 9.5 cents per litre to an average of €2.050/L — back above the €2.00 threshold for the first time in three weeks — and gasoline 95 simples climbing 6 cents to €1.988/L. The forecast covers the week running 4 to 10 May.

The trigger is straightforward: Brent crude has marched from $72 a barrel before the Israel-Iran conflict to $110 at the close of last week, peaking at $126 on Tuesday — the highest reading since the immediate aftermath of Russia's 2022 invasion of Ukraine. The closure of the Strait of Hormuz, through which roughly twenty percent of seaborne crude transits, is the single largest input into refiner margin assumptions for May.

What is moving

• Diesel (gasóleo simples): €1.958/L average across the week of 27 April-3 May, projected €2.050/L for 4-10 May.
• Gasoline 95 simples: €1.927/L last week, projected €1.988/L for 4-10 May.
• GPL auto: Holding at €1.026/L; LPG remains the only mainstream fuel insulated from the Brent shock because of its longer-dated contracting cycle.

The Ministério das Finanças is partly cushioning the move by leaving the extraordinary ISP discount in place — but only just. The diesel ISP cut has been reduced to 6 cents per litre for the new week (down from a peak of 13 cents during the worst of the spring volatility), while the gasoline discount is held flat at 4.58 cents. Without the ISP cushion, the projected pump price for diesel would already be sitting near €2.11/L.

The wider market read

This is the third significant Brent shock since the conflict began. The first two waves were absorbed by Galp and Repsol largely through margin compression and the running-down of pre-conflict refining inventories. Those buffers are now exhausted: Galp's Q1 results released Wednesday confirmed upstream and refining margins benefiting from elevated Brent, and the integrated player has signalled that ex-refinery prices for May reflect the full Mediterranean wholesale tape rather than the smoothed pricing of March and April.

The Brent-to-pump pass-through in Portugal is now running at about 70 percent within one to two weeks. With Iranian and Iraqi cargoes off the market and the Ras Tanura-Houston-Rotterdam shipping arc disrupted, ENMC inventory data published mid-week shows national diesel stocks down 4 percent month-on-month, sitting just inside the 90-day strategic cover.

What This Means for Expats

• Refuel Sunday, not Monday: Posted prices at most stations update between Sunday night and Monday morning. The €2.00/L diesel threshold is a real psychological and budget marker; topping up before 23:59 on Sunday 3 May saves roughly €5 on a 50-litre fill.
• Algarve summer driving: If you are renting cars or driving distances around the south for the May long weekend, factor in fuel that is now 25-30 percent above the pre-conflict baseline. A round trip from Lisbon to Faro now costs €70-80 in diesel against €55-60 in early March.
• Highway tolls and scappy: Combined with the toll increases that took effect on the A22 and A28 in January, total cost-per-kilometre on premium-route motorways is now at a five-year high.
• Fleet-card holders: If you have a Galp Frota, Repsol Solred, BP Plus or Cepsa Star card, the fuel-card discount remains the cleanest cushion against the spike. The Continente combustível 5-cent discount applies on top, capped at 60 litres per fortnight.
• Watch the next ISP decision: Finance is reviewing the petroleum-tax discount weekly. If Brent stays above $115 into mid-May, expect the 6-cent diesel cushion to be reinstated to 9 or 10 cents to keep the pump price below €2.10/L. The next Council of Ministers is on Thursday 8 May.

The DGEG publishes the new statutory weekly average on Monday morning — that becomes the reference for benchmark consumer-price indices and informs the Banco de Portugal's energy-cost panel released on the 15th.