Portugal's Minister for the Environment and Energy, Maria da Graça Carvalho, has a plan for the country's fuel prices: carpool, drive slower, and use public transport when possible. She delivered this counsel on September 23rd, reassuring citizens that reserves are fine and no shortage is coming, even as diesel and petrol consumption climbed 4 to 6 percent over last year despite record prices at the pump.

What her advice does not mention is the government's own hand in that price. Roughly 47 percent of what a driver pays for a liter of gasoline in Portugal is tax — the special consumption tax (ISP), a carbon surcharge on top of it, and VAT layered over both. Diesel runs a similarly heavy 41 percent. Adjusted for purchasing power, Portugal now carries the third-highest gasoline tax burden and the sixth-highest diesel tax burden in the European Union. None of that is imported inflation, OPEC supply discipline, or a refinery outage. It is a rate the Council of Ministers sets and can lower by decree.

Instead, the government's chosen instrument has been a temporary ISP discount — roughly €1 billion spent so far in 2026, projected to reach €1.3 billion by year's end — dialed up or down at will depending on which fuel is politically louder that week. That is not a tax cut. It is a subsidy that borrows against future budgets to soften a tax the state could simply reduce permanently, and it can be switched off the moment the news cycle moves on.

So the citizen gets two offers from the same government in the same month: a rebate sized by ministerial discretion, and an appeal to personal virtue — share the ride, ease off the accelerator, take the bus. Both cost the treasury nothing it didn't already plan to spend, and neither touches the structural 47 percent that will still be sitting on every liter after the discount lapses.

There is a version of this crisis where the state actually gives something up. It would look like a permanent reduction in the ISP rate, published in the Diário da República, not a rolling discount recalculated every few weeks. It would look less like advice and more like an admission that Lisbon built its own fuel bill.

Carpooling is fine advice for a commuter. It is a strange centerpiece for an energy minister's response to a national price shock, unless the point is to make the citizen manage the government's tax policy for it, one shared ride at a time.