A shortage of fuel oil used in ships and power plants looms in the third quarter as refiners, increasingly squeezed by wars that have disrupted both crude processing and tanker traffic, prioritise output of diesel and other products at its expense.

While crude oil avoided major price spikes in recent months, refined product prices have soared as strikes damage refineries in Russia and the Middle East and curbs on ship traffic choke flows. China has also cut refining capacity and exports to avoid burning stocks.

Tightening supply threatens to further raise costs for shipowners and power generators already dealing with war-related disruptions. Higher bunker fuel costs could also in turn feed into shipping rates.

Asia will be hardest-hit, as it is most reliant on Gulf flows disrupted by the Iran war, with Singapore, the world’s largest bunker hub, importing more than half of its nearly 1 million barrels a day of demand, according to import data from Kpler. Consultancy Rystad has a similar outlook.

The deficit is expected to hit 218,000 barrels per day (bpd) in the third quarter, consultancy Energy Aspects has forecast, the first shortfall it has estimated since the third quarter of 2025, when it was a marginal 6,000 bpd.

“Due to the protracted supply disruption in the Middle East, we expect fuel oil supply to remain critically tight in the third quarter,” Rystad analyst Valerie Panopio told Reuters.

Fuel oil joins gasoline, diesel and jet fuel among the refined products struggling to keep up with demand. US diesel prices hit record highs on Friday as renewed US-Iran hostilities and Ukrainian attacks on Russian refineries increased supply disruptions.

Refiners opting to produce some of those other products to tap fatter profits have meant fuel oil has been hit harder.

Nigeria’s 650,000-barrel-per-day Dangote refinery, for example, has ramped up diesel, gasoline and jet fuel exports, while its fuel oil exports have dropped, according to Kpler.

Dangote and other refineries can use fuel oil as feedstock in secondary refining units to make other fuels.

“Record-low gasoline and diesel inventories will incentivise refiners globally to maximise secondary unit runs with more fuel oil feedstock barrels, in turn tightening fuel oil balances,” Energy Aspects analyst Royston Huan said.

Gasoline stocks independently held in the Amsterdam-Rotterdam-Antwerp hub hit their lowest level in nearly five years on August 27. US East Coast distillate inventories, which include diesel, fell to a record low in the week to August 28.

Price up 76pc in top hub Singapore

Fuel oil storage levels and prices already reflect the pressure.

Stocks are some 30 per cent below three-year seasonal averages in top hubs Singapore, Amsterdam-Rotterdam-Antwerp and Fujairah, data compiled by Reuters showed.

Ships sailing longer routes to avoid key oil chokepoints, the Bab el-Mandeb strait or the Red Sea altogether due to threats by Houthi militants also increase demand, Panopio noted.

The price of the main shipping fuel, very low sulphur fuel oil, is up 76% since the Iran war started to just under $825 a metric ton, or $130 a barrel, in Singapore as of September 1, data from bunker price platform ZeroNorth shows.

That outstrips a 40pc rise in benchmark Brent crude oil in the same period.

Hits to Russia, Middle East output

Ukrainian drone attacks have affected Russia’s refinery output, with its fuel oil exports in August hitting a record low of 591,000 bpd, down from an average of over 860,000 bpd in 2025, according to Kpler data going back to 2017.

Middle East fuel oil exports were down by 45pc year on year to an average of 447,000 barrels per day in March-August, Kpler data showed.

Refinery outages in the Middle East have included the Al-Zour refinery in Kuwait, a top fuel oil exporter, which has only exported one 26,000 bpd cargo since March, versus around 191,000 bpd in January-February, according to the data.