Despite comprehensive EU sanctions imposed on Russia in response to its full-scale invasion of Ukraine in February 2022, Russian oil still floods into the European Union, much of it with obscured provenance.

Indeed fossil fuel exports pumped an estimated €4.47 billion ($4.85 billion) per week into the Russian economy in mid-October, €350 million of which came from the EU.

Gas purchases from Russia, although still well below the 150 billion cubic meters (bcm) registered in 2021, started to creep up again in late 2023.

EU Energy Commissioner Kadri Simson recently expressed her "deep concern" over these increases, telling a mid-October EU Energy Council meeting: "We must remain vigilant that this does not become a structural trend."

But some EU member states aren't even trying to curb their addiction.

High costs

In Central Europe, where dependence on Russian energy is traditionally heaviest, the likes of Austria, Hungary and Slovakia remain reliant on Russia for around 80% of their gas.

Given this high dependence and the challenge of annulling long-term contracts, it's certainly a tougher task for those in the region to switch to what are often more expensive alternatives.

The Czech Republic (Czechia) has managed, largely switching to buying liquefied natural gas (LNG) via the Netherlands and Germany. However, it has found weaning itself off Russian oil harder.

Simson's tone suggests Brussels is becoming impatient.

"We must remember," she said, "that the costs of dealing with Russia are not just measured in the price of gas, but also in the lives lost in Ukraine."

Political strategy

In Hungary, however, Prime Minister Viktor Orban appears determined to deepen his country's dependence on Russian energy.

Having already grown the volume of Russian gas it buys since Russia's invasion of Ukraine, Budapest is discussing a further increase, Foreign Minister Peter Szijjarto recently announced. Szijjarto has also declared that his country has "no option" but to rely on Russian oil.

Eighteen months ago, the EU granted Hungary, Czechia and Slovakia temporary exemptions to its embargo on Russian crude to allow them to arrange alternatives, but Budapest has rejected diversification options.

That fits with Orban's habit of supporting geopolitical rivals of the EU and NATO, including complicating the EU's efforts to help Ukraine directly.

It also reflects a longstanding domestic strategy of buying political support by providing cheap energy to Hungarian households, notes Martin Jirusek, an expert in geopolitics and energy security at Czechia's Masaryk University.

Slovakia's nationalist-populist premier Robert Fico is another leader who says Russian energy is vital for his country and that Brussels should seek friendship with Moscow rather than leveling sanctions.

Turning off the tap

However, there's a major new challenge on the horizon for some of the countries that are holding out.

Ukraine operates one of two remaining pipelines carrying Russian gas into the EU, shipping 15 bcm of the 25 bcm that arrived in the bloc last year, but it plans to halt the flow when its contract with Gazprom expires at the end of the year.

Fico, whose country earns vital income transporting this gas on to Austria, appears to be struggling to persuade Kyiv to continue to work with the aggressor.

Stakeholders, including Kyiv, Moscow and other interested states, are reportedly mulling a variety of scenarios to keep Ukraine's pipelines — which could become a target for Russian missiles — filled with gas.

Russia could sell gas at its border, leaving customers to arrange transit across Ukraine themselves. Alternatively, Azerbaijan could send supplies under a deal agreed with the EU in 2022. However, any arrangement would require Russian cooperation.

Political will

Hungary, which is largely fed by Russian gas arriving via the Turk Stream pipeline running beneath the Black Sea, would face little change in the event of a halt. Slovakia and Austria, on the other hand, would be forced to act.

However, neither is likely to be shivering due to a January cut-off. In the event of shortages, they'd be able to tap EU storage facilities, which Brussels says are 95% full.

They should also be able to arrange alternative supplies. Norway is now the EU's largest gas supplier, while EU networks would also allow deliveries of US and North African LNG via terminals in Germany, Poland and Italy.

"The goal to halt all Russian imports is realistic," Jirusek told DW. "All EU states have the physical capacity to do so. There are routes to get non-Russian oil and gas to Hungary and Slovakia. The question is only whether the political will exists."

Rising pressure

The uncertainty over the Ukrainian transit route is helping to exert pressure on the hold-outs.

Analysts at the Bruegel think tank note that the likely Ukraine shutdown has finally pushed Austria into action, with work on infrastructure now underway.

Still, questions remain over the legal challenges of annulling the long-term contract with Gazprom, while the election success of Austria's Russia-friendly Freedom Party could make things tricky.

At the same time, the struggles of even Ukraine's staunchest allies in the region illustrate the complexities of diverting from decades of energy flows from the east.

Czechia's Russian oil imports have spiked this year as PKN Orlen, the Polish state company that controls the country's refineries, has chased profits.

Nevertheless, Prague has pledged to abandon its exemption on Russian oil once expansion of a pipeline carrying crude from Italy is completed at the end of the year.

'Dangerous choice'

The coming year could also see the EU raise the pressure following a six-month lull during Hungary's presidency of the European Council.

Poland will take over the rotating presidency in January, and Ukraine's Sanctions Commissioner Vladyslav Vlasiuk recently expressed "high hopes" for its ally's stint at the helm of the bloc.

Reports suggest that a new sanctions package focusing mainly on energy is in the works, although a European Commission spokeswoman refused to confirm or deny that to DW.

However, Commissioner Simson has highlighted Brussels' anger with those countries that are dragging their feet — Hungary in particular.

"If member states prefer to continue importing Russian gas, and they do it even beyond contracted capacity, or if they wish to sign new agreements for new capacities, I want to be clear: This is not a necessity," she said. "It is a political choice, and a dangerous one."

Edited by: Aingeal Flanagan