Exclusive-Russia restoring oil refining capacity knocked out by drones

The logo of Taneco are seen on tanks at its refinery complex, which is part of Russia's oil producer Tatneft group of companies, in Nizhnekamskin

MOSCOW (Reuters) - Russia has been able to swiftly repair some of key oil refineries hit by Ukrainian drones, reducing capacity idled by the attacks to about 10% from almost 14% at the end of March, Reuters calculations showed.

Ukraine stepped up drone attacks on Russian energy infrastructure since the start of the year, hitting some major oil refineries across the world's second largest oil exporter in attacks that sent up oil prices.

Russia says the drone attacks amount to terrorism. Ukraine says its drone attacks on Russia are justified because it is fighting for survival as Russia has made "massive retaliatory" strikes on Ukrainian energy infrastructure.

There have been no reports of successful attacks on Russian large refineries since the Taneco plant was hit on April 2.

Russia is repairing its refineries fast, despite difficulties in obtaining Western know-how.

That includes Rosneft-owned Ryazan plant, which put back he CDU-4 and main CDU-6 primary oil refining units into operation, as well as Kuibyshev refinery repairing CDU-4 and Syzran's CDU-5 and previously idled for maintenance CDU-6.

According to Reuters calculations, total Russian primary oil refining capacity, idled by drones, was reduced to 90,500 metric tons per day (660,000 barrels per day) from around 123,800 tons per day (907,000 bpd) previously.

However, in total, Russia's cumulative primary oil refining capacity, put offline due to various outages and maintenances, is expected at 4.4 million tons in April, up from 4.1 million tons in March.

The respite in Ukraine's strikes comes after criticism from the United States, the world's top energy consumer, where high fuel prices is high up on the agenda in the run up to presidential election on Nov. 5.

Replying to Republican U.S. Senator Tom Cotton on why Joe Biden administration was discouraging Ukrainians from the attacks on Russia's "war-making capabilities", Defence Secretary Lloyd Austin told the Senate Armed Services committee last week that the attacks could harm global energy markets.

"Certainly, those attacks could have a knock-on effect in terms of the global energy situation, and ... but quite frankly, I think Ukraine is better served by going after tactical and operational targets that can directly influence the current fight," he said.

(Reporting by Reuters; writing by Vladimir Soldatkin; editing by Guy Faulconbridge and David Evans)