Slow Steaming Savings

Compare fuel and CO₂ for a voyage at two speeds. Holds distance constant, scales main-engine fuel by V^n and adds aux consumption that rises with extra voyage hours.

VoyageSlow steaming

Voyage

Distancenm

Reference speed

Reference speedknMain-engine fuel rate at referencet/day

Slow-steaming case

Slow-steaming speedknSpeed exponent–Auxiliary fuel rate (constant)t/day

Fuel Cf

Fuel

Reference fuel

800.0t

400 h

Slow-steaming fuel

542.5t

500 h

Fuel saved

257.5t

32.2 %

CO₂ saved

801.9t

Formula, assumptions, and limits

$$F_\text{slow} = \left(\text{ME}_\text{ref} \cdot \left(\tfrac{V_\text{slow}}{V_\text{ref}}\right)^n + \text{AE}\right) \cdot \frac{D / V_\text{slow}}{24}$$

Main-engine daily rate scales as V^n, so lower speed burns less per day AND takes more days. Net saving is positive while n > 1 and auxiliary share is below the saving margin. Boiler and tank-heating fuel behave like aux - add to the AE term.

Spotted an error in this calculation? . We acknowledge editorial corrections within two working days.