Since the Ukraine invasion began in late February, European leaders have hesitated to ban Russian energy imports, as the region still heavily depends on the country for coal, oil and gas. In 2020, Russia accounted for over 40% of Europe’s natural gas imports, 35.5% of its oil imports, and almost 20% of its coal imports, according to EU data.

However, after evidence emerged last week suggesting that Russian troops massacre civilians in Bucha while retreating from Kyiv, some European leaders have grown convinced that stronger measures against Russia may be necessary.

“These atrocities cannot and will not be left unanswered,” European Commission President Ursula von der Leyen—the head of the EU’s governing body—said on Tuesday. Von der Leyen proposed the ban on Russian coal imports and other sanctions Tuesday. EU ambassadors will debate the sanctions package in a meeting on Wednesday.

Energy continues to be a lifeline for Russia’s increasingly isolated economy, providing a channel of funds that could help pay for imports or fuel the war effort. Russia may earn over $320 billion from its energy trade this year, an increase of over a third from last year, according to Bloomberg.

Russia is even starting to leverage its stranglehold over European energy supplies by demanding that gas importers pay for shipments in rubles rather than in other currencies, to help prop up the Russian currency.

While debates over energy sanctions have typically paid more attention to Russia’s exports of oil and gas, the country is also a major coal exporter. According to data from the International Energy Agency (IEA), Russia was the third-largest source of thermal coal in 2020, following Indonesia and Australia.

Bruegel, a Brussels-based think tank, says roughly 70% of European thermal coal imports, come from Russia. Germany was the largest European importer of Russian coal by tonnage in 2020, importing 12.8 million tonnes, making up about 67% of the country’s total coal imports. About 81% of Poland’s imported coal came from Russia in 2020.

Coal makes up about 15% of Europe’s energy mix in 2021, though the region has attempted to shift away from using coal for power generation due to carbon emission concerns. Several European countries, including France, Italy, and the Netherlands have pledged to phase out coal by 2030. Some countries, like Belgium, have already phased out coal. 

But as Europe reduces its use of coal overall, “the share that comes from Russia has massively increased,” Fabian Rønningen at Rystad Energy told Bloomberg. Many EU states also increased coal purchases to help offset scorching gas prices as the bloc endures a bruising energy crunch.

By eliminating Russian coal, European countries will be forced to compete for replacements on the international market, and the cost of securing energy supplies will likely flame higher.