The prices of so-called bunkers in Europe have surged this year to such an extent that they’re more expensive than diesel, gasoline and jet fuel – at least in barrel terms, the unit that refineries use to calculate their processing margins.

The reason for the rally is because the fuel in question just fundamentally changed. On Jan. 1, it became mandatory for most of the world’s merchant fleet to consume fuel containing no more than 0.5 percent sulfur. Until Dec. 31, a 3.5-percent upper limit existed in most parts of the world.