Sources: AP-42, Kimble
150,000 DWT tankers. Fuel consumption for tankers also varies with tanker speed and ocean conditions. Data from several sources (ARB 1990) indicate that the fuel consumption for a modern tanker is about 1.8 kg/1000 ton-mi. This fuel consumption is based on a round trip, carrying ballast on the return trip.
Tanker ships also produce emissions while in port. Auxiliary engines operate to produce electric power and tugboat maneuver the tanker into port or to the oil unloading platform. In port time for tanker ships is generally as short as possible in order to maximize use of the tanker. In port operation time and fuel consumption were estimated from information included in and ARB workshop on marine emissions. Tugboat fuel consumption is estimated from hours of tugboat operation and tugboat fuel consumption curves. NOx emission factors are lower for port operations than those for at sea operations because the engines operate at lower load, use lighter diesel oil, and a different mix of engines.
Table 4-12 shows the distances traveled by tanker ships. The capacity of the tanker in gallons of product per DWT is also shown. Tankers carry about 95 percent of their weight capacity as cargo with the balance being consumables and ballast. Thus 95 percent of a short ton results in 288 gal of methanol per DWT (2000 lb/ton/6.6 lb/gal 0.95 capacity.
Table 4-12: Overview of Waterway Transportation
Route to Los Angeles
One Way Distance (naut. mi)a
aNautical Mile = 1.136 mile = 2,000 yards.