The average U.S. diesel price reached $6.50 a gallon on Friday, up from $5.62 a month earlier and just below the record $6.53 set earlier this week, AAA said. European Central Bank Vice President Boris Vujcic warned that energy prices, particularly diesel, could remain high for an extended period because global refining capacity is unlikely to return soon to pre-conflict levels. Global refinery throughput was 81 million barrels per day in July, nearly 5 million barrels below a year earlier, while U.S. refining capacity had fallen about 1% to 18.2 million barrels per calendar day as of Jan. 1, 2026. Damage to Russian refineries, a Russian diesel export ban and the closure of the Strait of Hormuz have further tightened global supply. The disruption has boosted earnings for major U.S. refiners and prompted the Trump administration and Republican lawmakers to consider diesel-export restrictions before the midterm elections, although Energy Secretary Chris Wright warned that such a move could reduce refining and raise gasoline and jet-fuel prices. Europe is also vulnerable because years of refinery closures have increased its reliance on imported fuel, NATO Secretary General Mark Rutte said. The outlook could change if Hormuz reopens: Iranian Foreign Minister Abbas Araghchi said Iran had sent the U.S. a Qatar-delivered plan that could reopen the waterway within seven days if conditions were met, but the Wall Street Journal reported that President Donald Trump rejected it. Ark Invest CEO Cathie Wood expects oil to fall sharply after a reopening and said prices could return toward $30 to $35 a barrel over the next few years. Lower crude prices may provide limited relief at the diesel pump while refining capacity remains constrained.