The European Union has announced a ban on Russian coal. Squeezing Russia’s energy exports is seen as the way to bring Vladimir Putin to his knees and withdraw from Ukraine. But global sales of oil and gas — not coal — are the real contributors to Russia’s coffers. Marco Werman speaks with Simone Tagliapietra of the Brussels-based economics think tank Bruegel to get a reality check on the impact sanctions have had on Russia’s energy exports so far.