*5.3. 40 k DWT Bulk Carrier*

The 40 k DWT bulk carrier uses the following operating modes during operations: Normal seagoing, port in/out, loading (shore crane), loading (deck crane), and harboring. To perform the test bed experiments, the scale of the values obtained as a result of the electric load analysis was adjusted according to the output of each operating mode of an actual ship. As shown in Figure 15, the hybrid power source was used in the load scenarios. Normal seagoing was a fuel cell operation interval. Port in/out was a fuel cell + battery + diesel generator operation interval. Port in/out (with thruster) was a fuel cell + battery + diesel generator operation interval. Loading (shore crane) was a fuel cell + battery operation interval. Loading (deck crane) was a fuel cell + battery + diesel generator operation interval. Harboring was a fuel cell interval. The scale-adjusted electric load analysis was applied to the test bed before the output tests were performed.

**Figure 15.** Operating modes of the 40 k DWT bulk carrier.

Figure 16 compares the fuel consumption during each operating mode of this ship. The fuel consumption was at maximum during the loading (deck crane) mode and at minimum during the harboring mode. The fuel consumption increased as the load increased, and decreased as the load decreased. However, on observing the CO2 emission reduction rates shown in Figure 17, it can be seen that the CO2 emission reduction rate of the loading (shore crane) mode was as high as 85% even though this operation consumed more fuel than during normal seagoing operations.

**Figure 16.** Fuel consumption in each operating mode of the 40 k DWT bulk carrier.

**Figure 17.** Comparison of CO2 emissions and CO2 emission reduction rate in each operating mode of the 40 k DWT bulk carrier.

#### *5.4. 130 k DWT LNG Carrier*

The 130 k DWT LNG carrier uses the following operating modes during its operations: Normal seagoing, port in/out, port discharging, port loading, and port idle gas free. The test bed experiments were conducted by adjusting the scale of the values obtained from the electric load analysis based on the output of each operating mode of an actual ship. As shown in Figure 18, the hybrid power source was used in the load scenarios of this ship. Normal seagoing was a fuel cell operation interval. Port in/out, port discharging, and port loading were fuel cell + battery + diesel generator operation intervals. Port idle gas free was a fuel cell operation interval. The scale-adjusted electric load analysis was applied to the test bed, and the output tests were performed.

**Figure 18.** Operating modes of the 130 k DWT LNG carrier.

Figure 19 compares the fuel consumption during each operating mode of this ship. The maximum amount of fuel was consumed during the port discharging mode, whereas it reached a minimum during the port idle gas free mode. The fuel consumption increased and decreased as the load increased and decreased, respectively. However, on examining the CO2 emission reduction rates shown in Figure 20, it can be seen that the CO2 emission reduction rate of the normal seagoing mode was as high as 83%, even though the fuel consumption in this mode exceeded that in the port idle gas free mode.

**Figure 19.** Fuel consumption in each operation mode of the 13 0k DWT LNG carrier.

**Figure 20.** Comparison of CO2 emissions and CO2 emission reduction rate in each operating mode of the 130 k DWT LNG carrier.

## *5.5. 300 k DWT Very Large Crude Oil Carrier (VLCC)*

The 300 k DWT VLCC uses the following operating modes during operations: Normal seagoing, with an inert gas supply system (IGS) topping up, tank cleaning, port in/out, and load/unload. An adjustment was made to the scale of the values of the electric load analysis of the output of each operating mode of an actual ship to perform the test bed experiments. As shown in Figure 21, the hybrid power source was used in the load scenarios of this ship. Normal seagoing was a fuel cell operation interval. With IGS topping up was a fuel cell + battery operation interval. Tank cleaning, port in/out, and load/unload were fuel cell + battery + diesel generator operation intervals. The scale-adjusted electric load analysis was applied to the test bed, and the output tests were performed.

**Figure 21.** Operating modes of the 300 k DWT VLCC.

Figure 22 compares the fuel consumption during each operating mode of this ship. The fuel consumption was at maximum during the port in/out mode and at minimum during the normal seagoing mode. The fuel consumption increased as the load increased and decreased as the load decreased. However, on observing the CO2 emission reduction rates shown in Figure 23, it can be seen that the CO2 emission reduction rate in the IGS topping up mode was as high as 85%, even though the fuel consumption in this mode was higher than in normal seagoing mode.

**Figure 22.** Fuel consumption in each operating mode of the 300 k DWT VLCC.

**Figure 23.** Comparison of CO2 emissions and CO2 emission reduction rate in each operating mode of the 300 k DWT VLCC.

Operating profile scenarios for each type of ship were developed, and the five developed load scenarios were applied to the test bed. The results are presented in Table 15.


**Table 15.** Cumulative CO2 emissions and reductions at load scenario.
