The most energy efficient way to move things around the world is stick something in a 40 by 8 foot foot shipping container that is hauled to port by an 18 wheel truck and loaded on a gigantic container ship. These ships piled high with goods from all over the world can be as large as 400 by 59 meters and can carry up to 9000 of these 40 foot shipping containers at a time.
These ships are often designed to burn the dirtiest type of fuel, which is the residual sludge left over after oil distillation that is called heavy fuel oil. This sludge is so viscous that it has to be heated just to pump it into the ship engines to be burned. Most large ships operating today use a type of fuel known as intermediate fuel oil, which is a mixture of heavy fuel oil which has a viscosity up to 700 mm2 per second and marine gas oil, which is No. 2 distillate with a viscosity between 1.5 and 6 mm2/sec. This intermediate fuel oil is generally sold as IFO180 or IFO360, meaning it has a viscosity of 180 mm2/sec or 360 mm2/sec.