Russia’s oil processing has fallen just 3% this year despite Ukraine’s biggest drone attacks to date as refineries averted a steep decline in fuel production by leveraging spare capacity to offset damage from the strikes, sources said and data showed.

Ukraine has ramped up drone attacks deep inside Russia, aiming to knock out oil refineries, depots and pipelines and cripple Moscow's biggest source of funding for the war in Ukraine.

Most of the attacks occurred at the start of 2025 then resumed from August. Ukrainian drones struck at least 17 major refineries in total, forcing Russia, the world's second-largest crude exporter, to curb fuel exports and order extra drone defences.

At the height of the second wave of strikes between August and October, attacks and planned maintenance took 20% of Russia's refinery capacity offline, according to the Reuters calculations based on information from three Russian industry sources.

But that only resulted in a 6% drop in total Russian refining volumes to around 5.1 million barrels per day - a reduction of some 300,000 bpd compared to the same period last year - the sources said and data showed.

More broadly, from January to October, oil processing fell to around 220 million metric tons (5.2 million bpd), down 3% from last year.

The sources spoke on condition of anonymity due to the sensitivity of the issue. Russia no longer publishes data on oil refining. Russia's energy ministry declined to comment.

The breakdown between planned and unplanned maintenance was not available.

RUSSIA LEVERAGES SPARE CAPACITY, KYIV LAUDS DRONE SUCCESS

The three industry sources told Reuters that Russian refineries were running well below full capacity before the attacks and were able to mitigate their impact by restarting spare units at both damaged and unaffected plants as well as putting back into operation the attacked units after repairs.

Russia has total refining capacity of around 6.6 million bpd, but industry sources say it is rarely fully utilised.

Kyiv says its drone offensive aims to disrupt fuel supplies to Russian troops in Ukraine and deprive Moscow of oil revenues.

The International Energy Agency said that Russian revenue from crude oil and oil products sales declined in August to one of the lowest levels seen since the start of the war in 2022.

Ukraine's President Volodymyr Zelenskiy said last month that the long-range strikes may have reduced gasoline supplies in Russia by up to a fifth.

The Kremlin, however, says that the fuel market is stable, and Russian President Vladimir Putin has said that Moscow will never bow to pressure from abroad.

UKRAINE STRIKES DEEP INSIDE RUSSIA

While Russian refineries may be coping for now, the drone attacks have not been without impact.

In the first quarter of the year, Ukraine hit six major refineries, including Ryazan, Volgograd, Saratov, Tuapse and Ufa and Astrakhan.

And since the start of August, it has launched at least 58 attacks on key Russian energy sites, sending drones as far as 2,000 km (1,200 miles) into Russian territory, according to data compiled by UK-based non-profit group Open Source Centre.

Ukrainian drones have damaged plants, including those in Novokuibyshevsk, Kirishi, Salavat, since early August.

Western sanctions, meanwhile, have complicated Russia's efforts to obtain spare parts from the Western companies that have helped upgrade the majority of its refineries over the past 30 years.

Russian firms have said they have found ways to produce equipment domestically or import from China, which remains a strategic ally of Moscow. And repairs have ensured distillation units get back online within weeks in most cases, industry sources said.

But they are costly and sometimes require more time to complete, making it unclear how long Russia can resort to spare capacity if Ukrainian drone attacks continue.