Research Trends and Results

Basic Analysis of Energy-saving Domestic Marine
Unit Load Transportation
SASAKI Tomoko, Senior Researcher
WATANABE Tomihiro, HeadPort Systems Division, Port and Harbor Department(Key words) domestic marine unit load transportation, fuel consumption, energy saving

1. Introduction
Response to global warming has become an
important issue, and the need for unit loadtransportation using containers, chassis, etc. are also
great.
In order to contribute to the design of policies for
future freight transportation, we conducted aquestionnaire survey of shipping companies which
operate ferries, RORO ships and container ships used
for domestic marine unit load transportation. We also
introduce the results of analysis conducted to grasp thestate of actual transportation by every ship type andthe state of measures taken by shipping companies toreduce energy consumed by transportation.
2. The outline of the questionnaire survey
The questionnaire form related to energy-savingtransportation was created separately for ferries,
RORO ships, and container ships, and it was mailed toshipping companies in July, 2012.
The recovery results are shown in the table.
Table. Questionnaire vote recovery resultTotal of all ship
types

Ferry
RORO ship
Container ship
Number of shipping
companies
29 (94%)11 (100%)
10 (91%)
12 (86%)(Recovery rate)
Number of ships
55 (90%)22 (100%)
17 (89%)16 (80%)(Recovery rate)
Note: Because the questionnaire survey of more than one type of ship may have been
conducted in the same shipping company, the sum of the number of shipping
companies of all ship types and the number of shipping companies of each ship type
do not match.

3. Analysis of the questionnaire survey result(1) Actual state of domestic marine unit loadtransportation
Based on the questionnaire, the results of analysis ofoperation speed for every route section, and fuelconsumption per distance and per ton-kilometer are
shown in figure 1.
Operation speed is shown in the upper row of figure
1. The average value of the operation speed for everyroute section of ferries was the largest, revealing acharacteristic of passenger ferries.
Moreover, all types of ships sailed an average of
between 80% and 90% of their service speeds.
Fuel consumption is shown in the lower row of

Figure-1. The average actual fuel consumption per
distance differed between ship types, with that offerries the largest. However the average value of
actual fuel consumption per ton-kilometer differedlittle between ship types.
This is because the load factor of container ships
was low and that of ferries was high. So fuelconsumption per ton-kilometer of container ships washigh.
When the average value of estimated fuelconsumption per ton-kilometers when fully loaded
was compared with the actual average value, it turned
out that the average value of fuel consumption per
ton-kilometers of ferries decreases about twenty
percent, RORO ships decreases about 60 percent, andcontainer ships decreases about 70 percent.
Operation speed and fuel consumption analysis
results
Figure 1. Results of analysis of operation speed andfuel consumption
Ship type(Actual value)

Ferry(Average 5,083t)

RORO ship(Average 5,367t)

Container ship
(Average 2,357t)

Operation speed(Actual value)

Average 37.1
[km/h]

Average 34.6
[km/h]

Average 19.8
[km/h]

Cruising rate/speed(Actual value)

Average 86.3%

Average 88.5%

Average 85.3%

Average 67[kg/km]Average 44[kg/km]Average 15[km/km](Average loadfactor 76%)

(Average loadfactor 66%)

(Average loadfactor 45%)

Average
0.026 (kg/t/km)

Average0.023 [kg/t/km]

Average0.023 [kg/t/km]

Approx.
20%
reduction

Approx.
60%
reduction

Approx.
70%
reduction

Average0.020 [kg/t/km]

Average0.009 [kg/t/km]

Average
0.007 [kg/t/km]

Per unit
distance
Fuelconsumption(Actual value)

When fully
loadedFuelconsumption(Estimatedvalue)

Per tonkilometer(2) State of measures to save energy in transportation
The questionnaire results are shown in figure-2.
Most shipping companies carried out slowdown
operation (97%). Many shipping companies carriedout energy-saving transportation measures which do
not require much investment in plant and equipment.
The number of shipping companies which carriedout each energy-saving transportation measureFigure 2. Number of shipping companies which tookeach energy-saving transportation measure
00社

1010社

2020社

29社
29Slowdown 減速運航
operation
Drag reduction on the surface
of a ship's bottom
船底表面の抵抗低減
Use of an ocean 海流や風の利用
current or a windImprovement
in load factor
積載効率の向上
Shorteningof a route
航路の短縮Thermal insulation,
heat barrier
断熱・遮熱対策
Improvement of a propulsive
mechanism
推進装置の改良High efficiency 主機の高効率化
of a main engine
Utilize heat of exhaust discharged froma mechanism
機関排熱の利用
Energy saving of auxiliarymachinery
補機の省エネ化
Energy saving船内設備の省エネ化
of inboard equipment
船体重量の低減
Reductionof hull weight
抵抗の少ない船体形状
Hull form
with little resistance
太陽エネルギーの利用
Utilizationof solar energy
Utilization of風力の利用
wind power
陸上電力の停泊時使用
Utilization of land electric power
during anchorage

0%

50%

100%

4. Conclusion
I would like to utilize the analysis results as data to
analyze the influence which environment and modal
shift policies have had on the cost of transport andoperation speed of domestic marine ships, etc.
[Source]TECHNICAL NOTE of NILIM NO. 716
http://www.nilim.go.jp/lab/bcg/siryou/tnn/tnn0716.htm