Ship carrying Russian gas docks in Spain

STORY: Despite the cascade of Western sanctions on Russia in response to its invasion of Ukraine, one thing hasn't been affected so far are flows of Russian gas to Europe and the funds to pay for it.

Europe remains heavily dependent on Russian gas, which supplies around 40% of its needs, and is now worried that Russian President Vladimir Putin could use it to retaliate against sanctions.

But Russia, which pumps gas through pipelines that cross Ukraine and other eastern European nations, requires the revenue, perhaps now more than ever.

So far there has not been any interruption of gas supplies.