Russia's pipeline exports of natural gas to China are expected to have risen by a quarter this year, a source familiar with the data has told Reuters.
It comes as Moscow ramps up sales to Asia and cements ties with the world's largest energy consumer.
However, calculations indicate this will not offset the fall in revenue from the loss of the European gas market.
Russia has re-routed most of its oil to India and China since the start of the war in Ukraine in 2022 as Moscow and Europe - once its main commodity export market and source of revenue - cut ties.
It's proven harder to divert gas flows eastwards and painstaking talks to bring more Russian gas to China have yielded limited results.
The source, who spoke on condition of anonymity as he was not authorised to talk to media, told Reuters that Russian energy giant Gazprom expected gas exports to China via the Power of Siberia Pipeline to reach around 38.6-38.7 billion cubic metres this year, up from 31 bcm in 2024 and exceeding the pipeline's planned annual capacity of 38 bcm.
Gazprom has not responded to a request for comment.
During Vladimir Putin's visit to China in September, the countries agreed to increase annual volumes on the route by an additional 6 bcm, to 44 bcm, a year. Russia and China also gave their blessing to the Power of Siberia 2 pipeline, which could one day deliver an additional 50 bcm of Russian gas per year through Mongolia from the Arctic gas fields of Yamal.
However, the main obstacle to implementing the project, the price of Russian gas, remains unresolved.
Russia's economy ministry estimates that revenue from gas exports to China will be 30%-40% lower than the value of exports to Europe in 2025-2028.
The only operational route for Russian gas supplies to Europe is via the TurkStream pipeline under the Black Sea. Deliveries via Ukraine - which amounted to around 12-15 bcm in recent years - were halted at the start of the year as Moscow and Kyiv failed to extend a transit deal.
According to Russian finance ministry data, gas exports generated around 420 billion roubles (£3.93bn) for the state budget in January - November.
China is an ally of Russia and has been accused of helping its war in Ukraine, though Beijing has repeatedly denied allegations that it has supplied Kremlin forces with weapons.