Awake at the Wheel

Pick your poison: Sierra Club ranks the oil suppliers.

These companies are among the largest and most powerful enterprises on the planet. The complexity of their organization and activities, the vastness of their reach, and the huge number of variables involved make objective ranking difficult. That said, it is possible to lump them into three general categories, as Sierra editorial interns Robynne Boyd and Sarah Ives do below: the “bottom of the barrel” (ExxonMobil and ConocoPhillips), the “middle of the barrel” (Royal Dutch Shell, Chevron, Valero Energy Corporation, and Citgo), and the “top of the barrel” (BP and Sunoco).