Evaluate emissions for an Asia—Europe route and a feeder route serving the UK market

The second alternative includes a modified deep-sea service (by skipping Felixstowe port) and a feeder service between Felixstowe and Rotterdam. In this scenario, the total ССЬ emissions from shipping are composed of two parts. The First part is incurred by a container ship in the modified deep- sea service during a round-trip. The second part is incurred by the feeder ship sailing between Felixstowe and Rotterdam. As the deep-sea service is a weekly service, the second part should be calculated over one-week period. In addition, extra container handling activities are required at Rotterdam because of the transhipment, which incurs electricity consumption and implies extra CO2 emissions for electricity generation.

We call the modified deep-sea service as the main service and assume that a single feeder ship is deployed between Felixstowe and Rotterdam sailing twice a week to meet the market demand in the UK. The sailing schedule and port distance (in nautical miles) for the main service are largely the same as the original deep-sea service in Table 7.10, except that the ship will sail directly from Rotterdam to Tanjung Pelepas, the distance between which is 8,296 nautical miles. The sailing schedule and port distance (in nautical miles) for the feeder service are given in Table 7.12.

In this second alternative, Rotterdam port is treated as a transhipment port to connect to Felixstowe port. Hence, all demands designated to Felixstowe via the main service have to be unloaded at Rotterdam and then loaded on the feeder vessel to be carried to Felixstowe. Similarly, all demands departed from Felixstowe have to be carried by the feeder vessel to be unloaded at Rotterdam first, and then are loaded onto a vessel in the main service. In addition, note that Felixstowe is a surplus port (i.e. imports are more than exports), the empty containers that are to be repositioned to Asia ports will

Table 7.12 Schedule and distance of the feeder service (based on Song and Xu 2012b)

Port

Transit time (days)

Distance (nautical miles)

Rotterdam

0

118

Felixstowe

1.75

118

Rotterdam

1.75

118

Felixstowe

1.75

118

Rotterdam

1.75

118

also be first moved by the feeder ship to Rotterdam, then transferred to the main service.

Because the feeder ship sails twice a week and the main service is a weekly service, the demand volume to Felixstowe by the deep-sea ship will be halved and served by the feeder ship twice a week. The capacity of the feeder ship is determined by the actual load with the assumption of 90% vessel utilisation, which gives rise to the feeder capacity ranging from 583 TEU to 777 TEU. The maximum sailing speed of the feeder ship is assumed to be 21 knots. Since the vessel in the feeder service (less than 800 TEU) is much smaller than that in the deep-sea main service (i.e. 6,600 TEU), we assume that the handling rate for the feeder service is one-third of the handling rate for the main service.

For the second alternative, the ССЬ emissions consist of three parts, namely the emissions of the ship in the main service (in a single round-trip), the emissions of the feeder ship in the feeder service (in two round-trips), and the emissions from the additional electricity consumption due to double handling of transhipments. Note that almost all container cranes are AC drive and it has been reported that the average electricity usage per container for the AC quay crane is 3.91 kWhour (Tran et al. 2008). To calculate the CO2 emissions from electricity generation, the electricity conversion factor has to be selected. DEFRA (2010) provides conversion factors based on UK GHG inventory in 2008 according to the amount of ССЬ emitted from major power stations per unit of electricity. The ССЬ emission factor for electricity consumed (including electricity generated and electricity losses) in DEFRA (2010) is 541.6 grams per kWhour in 2008. We use this value in our calculation of the implied ССЬ emissions from the additional electricity consumption.

Since there are three parts of ССЬ emissions in the second alternative, we define an aggregated Cl to facilitate the comparison with the first alternative. The aggregated Cl is defined as the sum of the three parts of ССЬ emissions divided by the sum of transport work carried by the main deep-sea service and the feeder service (in TEU*km). Table 7.13 gives the ССЬ emissions (in tonnes) for both services and the additional electricity consumption and the aggregated Cl for the second alternative with different scenarios.

From Table 7.13, it can be observed that the results of the deep-sea main service are similar to the First alternative in Table 7.11. For the feeder service, the ССЬ emissions of the feeder vessel are much more sensitive to the demands in the UK market when the handling rate is low, e.g. in the —40% level. The incurred ССЬ emissions from extra electricity consumption are increasing as the demand in the UK market increases, which is in line with intuition. Similar to the first alternative, the Cl is increasing as the demand in the UK market increases, and decreasing as the port handling rate increases. We can also observe the disproportionality of the impact of the port handling rate on the aggregated Cl.

Table 7.13 ССЬ emissions (tonnes) and aggregated Cl (g/TEU x km) for the second alternative with different scenarios (based on Song and Xu 2012b)

Handling rate level (%)

Demand

toFEL

(TEU)

Main

service CO2 (tonnes)

Feeder CO2 (tonnes)

Electricity

co2

(tonnes)

Aggregated Cl (g/TEU*kni)

1,050

17,994

63

9

90.33

1,120

18,634

71

9

92.90

-40

1,190

19,294

83

10

95.55

1,260

19,975

100

11

98.30

1,330

20,677

131

11

101.17

1,400

21,401

189

12

104.24

1,050

16,704

41

9

83.77

1,120

17,269

43

9

85.98

0

1,190

17,851

44

10

88.25

1,260

18,450

46

11

90.57

1,330

19,066

48

11

92.94

1,400

19,698

51

12

95.36

1,050

16,231

36

9

81.38

1,120

16,768

37

9

83.47

40

1,190

17,320

38

10

85.61

1,260

17,888

40

11

87.79

1,330

18,470

41

11

90.01

1,400

19,069

42

12

92.28

 
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