London CNN Business  — 

Russia’s increasingly aggressive actions against its European gas customers are taking a toll. The country’s natural gas exports have tumbled by more than a quarter since January. But surging prices have kept Russia’s coffers bulging as it continues to cut off deliveries.

Moscow’s gas exports to countries outside of its Commonwealth of Independent States, which includes 11 countries in Central Asia and Eastern Europe, fell nearly 28% in the first five months of 2022, Russian state energy giant Gazprom (GZPFY) said on Wednesday.

So far, Gazprom has cut off at least 20 billion cubic meters of its annual gas supplies to customers in six European countries — Poland, Bulgaria, Finland, Denmark, Germany and the Netherlands — because they failed to make payments in rubles, a demand President Vladimir Putin made back in March.

That amounts to nearly 13% of the European Union’s total annual gas imports from Russia, according to data from the International Energy Agency.

But James Huckstepp, head of EMEA gas analytics at S&P Global Commodity Insights, told CNN Business that gas prices have risen to an average of €96 per megawatt hour ($102) in 2022 from last year.

As a result, “it is unlikely that [Russia] will see significantly less revenue until further cuts are made,” Huckstepp said.

Since Putin’s ultimatum, Gazprom has offered customers a workaround. Buyers could make euro or dollar payments into an account at Russia’s Gazprombank, which would then convert the funds into rubles and transfer them to a second account from which the payment to Russia would be made.

Many large customers have taken up Gazprom on its offer to keep gas flowing. But others have resisted. On Tuesday, Shell (SHLX) Energy said it had “not agreed to new payment terms,” which resulted in Gazprom shutting off flows to its German customers. The Netherlands’ GasTerra similarly said in a Monday statement that it would not comply with Gazprom’s “one-sided payment requirements.”

The EU is moving quickly to reduce its dependence on Moscow anyway, ramping up imports of liquefied natural gas (LNG) and pledging to slash consumption of its Russian gas by 66% before the end of the year.

Countries are also racing to fill up their gas storage facilities ahead of the winter to avoid potentially disastrous supply shocks. The bloc has set a target for member states’ underground stores to be at least 80% full by November.

Germany, the bloc’s biggest economy, is particularly reliant on Russia’s gas to power its homes and heavy industry, but has managed to whittle Moscow’s share of its imports down to 35% from 55% before the start of the war in Ukraine.

Russia may not feel the impact just yet. While the EU is its biggest buyer of gas, according to data from the US Energy Information Administration, soaring oil and natural gas prices have ballooned Moscow’s revenues.

EU fossil fuel imports from the country generated $47 billion in the two months after Russia invaded Ukraine, double the value for the same period in 2021, according to a report by the Centre for Research on Energy and Clean Air.

And some of Europe’s biggest energy companies have started the process of opening new accounts with Gazprombank to keep the gas flowing, despite insistence by EU officials that such a move would fall foul of its sanctions against Russia.

But as Europe turns further away from Russia’s gas in the months to come, Moscow will find it harder to find alternate buyers — as it has done for its oil — because its gas exports are mainly delivered via pipelines, which can take years to build.

Robert North contributed reporting.