Environmental Engineering Reference
In-Depth Information
Table 2.2
Profile of world commercial fleet, number of main engines, and main engine
power
Number
% of
Installed
% of
% of
Number
% of
of main
main
power
total
energy
Ship type
of ships
fleet
engines
engines
(MW)
power
demand
1
Cargo fleet
Container vessels
2 662
2
2 755
2
43 764
10
13
General cargo vessels
23 739
22
31 331
21
72 314
16
22
Tankers
9 098
8
10 258
7
48 386
11
15
Bulk/combined carriers
8 353
8
8 781
6
51 251
11
16
Non-cargo fleet
Passenger
8 370
8
15 646
10
19 523
4
6
Fishing vessels
23 371
22
24 009
16
18 474
4
6
Tugboats
9 348
9
16 000
11
16 116
4
5
Other (research, supply)
3 719
3
7 500
5
10 265
2
3
Registered fleet Total
88 660
82
116 280
77
280 093
62
86
Military vessels2
19 646
18
34 633
23
172 478
38
14
World fleet total
108 306
100
150 913
100
452 571
100
100
Notes:
1.
Percentage of energy demand is not directly proportional to installed power because military vessels
typically use much less than their installed power except during battle. Average military deployment rate
is 50% under way time per year (US Navy, 1996); studies indicate that when under way, naval vessels
operate below 50% power for 90% of the time (NAVSEA, 1994). Energy demand was adjusted to reflect
these facts.
2.
The data upon which military vessel power was based specified the number of engines aboard naval ships.
Sources:
Adapted from Corbett (2004); Corbett and Koehler (2003).
military ships). Other vessels are primarily engaged in extraction of resources (e.g.
shing,
oil or other minerals), or primarily engaged as support vessels (vessel-assist tugs, supply
vessels). Because non-transport ships operate within speci
fi
c regions, often at low power,
to extract the ocean resources, these ships require much less energy than ships engaged in
commercial trade.
To reduce operating expenses, marine engines have been designed to burn the least
costly of petroleum products in high-temperature, high-pressure engines. Residual fuels,
also known as heavy fuel oil (HFO), are a blend of various oils obtained from the highly
viscous residue of distillation or cracking after the lighter (and more valuable) hydrocar-
bon fractions have been removed. Of the two-stroke, low-speed engines, 95 percent use
HFO and 5% are powered by marine distillate oil (MDO). Fuel consumed by 70% of the
four-stroke, medium-speed engines is HFO, with the remainder burning either MDO or
marine gas oil (MGO). Four-stroke, high-speed engines all operate on MDO or MGO.
The remaining engine types are small, high-speed diesel engines all operating on MDO or
MGO, steam turbines powered by boilers fueled by HFO, or gas turbines powered by
MGO. Residual fuels are preferred if ship engines can accommodate their poorer
quality, unless there are other reasons (such as environmental compliance) to use more
expensive fuels.
fi
