Make With Mouser IoT Design Contest - SupaCap Maritime Transport

Background
Maritime being in high demand in logistics activity with having high volume cargo in one voyage. As the biggest role in logistic industry, sustainable and energy conserving in maritime transport will bring a big change in its aspects and a plus role to the climate change. Thus, through the technology of Maxim MAX38888EVKIT Continua™ Regulator Evaluation Kit with the ability of charging and discharging current, this could apply to the maritime transport which able to adjust its power between the ship to go over its load and high waves by the sea. Include the smart system to lowered and high its usage of power which also able to be applied during the port in and port out which high density energy needed.

Problem Statement
According US academic research, fuel resulting from air release from maritime transport - sulphur, particulate matter and nitrogen dioxide. Maritime transport contributes 3.5% to 4% in climate change emissions which primarily carbon dioxide.

Methodology

Supercapacitor


1619173604629.png


These results show that the hybrid system could improve system performance by overcoming individual limitations (disadvantages) and enabling synergistic effects. In other words, LIBs, which are the most common battery types, have a high energy density. However, their power densities are low compared to that of an SC of the same size. Also, LIBs have a short life cycle compared to an SC, which has an approximately 1000×longer life cycle than LIBs


Conventional System

Table 2.
Comparison of power demands between a conventional and the proposed system.

1619173620612.png


1619173640635.png

Figure 1. Layout of a conventional power system.


The simple layout of a conventional power system is shown in Figure 1. Even though three gensets are installed as power sources, the number of gensets in operation is different depending on the power required for each operation mode. Primarily, only one genset is in operation in the normal seagoing mode with about 54.3% load factor (Table 2). The second generator is only used for the port in/out operations or the crane operations, and the last one is installed for redundancy.

1619173650242.png

Figure 2. Docking/undocking procedure of a ship in a conventional system.

The steps for one voyage cycle in a conventional system are shown in Figure 2. Step 3 includes not only deck crane operation for cargo handling but also simply staying at a harbour. In this study, it was assumed that three (3) of four (4) deck cranes were in operation during cargo handling, because safety risks would be increased if all cranes were in operation simultaneously.

Fuel Consumption and CO2 Emissions
The fuel consumption of a genset varies depending on the load factor, as shown in Figure 3, and the lowest fuel consumption is between 70%–85%. In this study, this graph was used to calculate the fuel consumption of the gensets. The emissions from fuels can be calculated by multiplying the fuel consumption of the onboard engine with the emission factor (Ef). This Ef varies according to the engine type (main and auxiliary engines, auxiliary boilers), engine rating, engine speed, type of fuel.

Total emissions (kg) = Fuel consumption × Ef. (10)

1619173658953.png

Figure 3. Example of a genset fuel consumption graph.

For CO2 emissions, the Ef for each fuel type was based on IMO guidelines. The Ef of HFO was
3.114 based on its lower calorific value of 40,200 kJ/kg and carbon content of 0.8493. The Ef of MGO was 3.206 based on its low calorific value of 42,700 kJ/kg and carbon content of 0.8744. And, the Ef of SOX emissions was calculated by multiplying 0.02 with the sulfur content S (%) present in the fuel. In the case of MGO, S (%) did not exceed 0.1 %, whereas the average value of HFO was 2.7%. The Ef used for NOX emissions was the suggested value for Tier I ships without the use of a scrubber system. These emission factors are summarized in Table 3. Based on the emission factors, the emissions from onboard gensets for the conventional power system were calculated as shown in Table 4, and those for the proposed power system were calculated as shown in Table 5.

Table 3. Emission factors for different pollutant types.

Fuel
Emission factors
CO2 (g·CO2/g·fuel)SOX (g·SOX/g·fuel)NOX (g·NOX/g·fuel)
Heavy Fuel Oil (HFO)3.1140.0540.057
Marine Gas Oil (MGO)3.2060.0020.057
Table 4. Emissions from onboard gensets for each mode (conventional system).

Electric Power Fuel Efficiency Emissions (kg)

Mode Time (h) Fuel (kg)


Demand (kW)(g/kWh)CO2SOXNOX
Normal seagoing (10 days)380 24019517,784.055,379.38960.341013.69
Excluding winch loads​
Port in/out Winch (Port-in)
500 2
29.25 kWh
198198.0
5.8
634.79
18.59
0.40
0.01
11.29
0.33
Winch (Port-out)41.75 kWh8.326.610.020.47
Excluding crane loads​
Cargo loading/unloading
Crane loads (3 cranes)​
550 120 1
1.01 kWh × 3 each ×
1800 cycle 2
19212,672.0
1047.2
40,626.43
3357.32
25.34
2.09
722.30
59.69
Harbor​
250 482132556.08194.545.11145.69
Total
-
34,271.3108,237.66993.311953.46
1 Assuming crane operators work in shifts of 6 h (120 h = 6 h × 20 turns). 2 Assuming each crane was operated for 15 cycles per hour (1800 cycles = 120 h × 15 cycles).

Table 5. Emissions from onboard gensets for each mode (proposed system)

Electric Power Fuel Efficiency Emissions (kg) Mode Time (h) Fuel (kg)

Demand (kW)(g/kWh)CO2SOXNOX
Ship power (AMP)Ship loads
Normal seagoing
LIB Charging
(10 d)
(After port-out)
380 240
80 kWh × (85%–40.1%)
191
191
17,419.2
6.8
54,243.39
21.18
940.64
0.37
992.89
0.39
Port in/out (Excluding winch loads)500 2192192.0615.550.3810.94
Total
-
17,618.054,880.12941.391004.23

Even though the ESS did not generate harmful emissions directly at a port, the emissions were generated indirectly, because it had to be recharged using the AMP; shore power was originally transferred from land-based power plants. Thus, the generated emissions from the used shore power were calculated as shown in Table 15. In this study, emission factors that generated 1 kWh of electricity were assumed to be 151 g·CO2/kWh, 0.03 g·SOX/kWh, and 0.16 g·NOX/kWh based on a European electricity company . This value changed depending on the country. For example, in Denmark where the dominant electricity power source is from wind power plants (about 44%, 2016), the total CO2 emission factor is 75 g/kWh, whereas the world average is 507 g/kWh .

Table 6. Emissions from shore charging (proposed system).

Emissions (kg) Mode Electric Power Demand (kW) Time (h)

CO2SOXNOX
Shore power (AMP)Cargo loading/unloadingExcluding crane loads Crane loads (SC charging)550 120
1.54 kWh × 3 each × (97.4%–67.7%) × 1800 cycle
9966.00
372.95
1.98
0.07
10.56
0.40
HarborLIB charging (After port-in) Harbor loads80 kWh × (90%–49.3 %)
250 48
4.92
1812.00
0.00
0.36
0.01
1.92
Total
80,502.41 kWh12,155.862.4212.88

Emissions (kg) Mode Electric Power Demand (kW) Time (h)

CO2SOXNOX
Shore power (AMP)Cargo loading/unloadingExcluding crane loads Crane loads (SC charging)550 120
1.54 kWh × 3 each × (97.4%–67.7%) × 1800 cycle
9966.00
372.95
1.98
0.07
10.56
0.40
HarborLIB charging (After port-in) Harbor loads80 kWh × (90%–49.3 %)
250 48
4.92
1812.00
0.00
0.36
0.01
1.92
Total
80,502.41 kWh12,155.862.4212.88

Overall, the proposed system could reduce CO2, SOX, and NOX emissions, especially in the cargo handling and harbor modes at a port . There was about a 77% reduction for CO2, about a 93% reduction for SOX, and a 99% reduction for NOX. On the contrary, the emission reduction rates for the normal seagoing mode and the port in/out mode (Figure 11b) were not high (under 10%).
In addition, the emission reduction rate varied depending on the ship’s schedule. As shown in Table 16, when the cargo handling time was 60 h, the emission reduction rate was approximately 28% for CO2, 4% for SOx, and 35% for NOx, but this increased to 45%, 6%, and 56% each for 180 h of long cargo handling operations. And, as shown in Table 17, when the sailing time was 20 d, the emission reduction rate was approximately 26% for CO2, 4% for SOx, and 32% for NOx, but this increased to 50%, 8%, and 64% each for 5 d of short sailing time. Therefore, the proposed system is more eco-friendly if a ship has a long cargo handling time or visits many ports with a short-term sailing time.



Solution


1619173688860.png

Figure 3. Layout of the proposed power system.

In the proposed system, one of the onboard gensets was replaced with two kinds of ESSs (LIB and SC). The LIB and SC were used as a power source during port operations. Also, one of the remaining gensets was downsized from 700 kW to 500 kW to obtain a higher fuel efficiency in the normal seagoing mode. The layout of the proposed power system is shown in Figure 3.


Figure 4. Docking/undocking procedure of a ship in the proposed system.

The reason for adopting two different ESSs was that each has different characteristics as an energy storage system. In the case of port in/out operations, high load demand occurred only twice (port-in and port-out). Thus, the LIB was more suitable because of its high energy density. On the other hand, the SC was more suitable for highly repetitive deck crane operations because of its long life cycle capacity and high power density. Therefore, the number of gensets in operation in each mode was changed, as shown in Table 2, and it was shown that load factors of the onboard gensets increased to above 70% even in the normal seagoing mode and port in/out mode. In the proposed system, two steps were added for one voyage cycle, as shown in Figure 4, because of the AMP connection/disconnection processes for shore power.

Blog entry information

Author
salihanazley
Views
52
Last update

More entries in Design Contest

Share this entry

Top