Potential of diesel electric system for fuel saving in fishing vessels: a case study on a bottom longline fleet of Brazil

Figures & data

Table 1. Summary of performance data for the bottom longliner fishing fleet.

						Time (h) spent on each stage
Vessel	Length (m)	Days Ocean	Effective fishing days	N° Launch/Day	Total fuel consumption (L)	Going	Setting	Waiting	Hauling	Return
1	14.00	14.5	12	3	3294	18	54	54	108	18
2	14.00	20.5	16	2	3059	30	64	32	96	10
3	13.65	22	19	2	4118	48	44	49	152	48
4	13.50	17	15	2	2000	42	48	44	87	26
5	16.30	18	17	3	2706	26	77	9	111	10
6	16.27	23	19	3	4118	24	74	23	139	22
7	17.00	18	16	3	2941	12	108	14	120	12
8	16.00	17.5	13	3	2500	12	88	26	98	12
9	22.00	20	17	3	4706	48	77	77	204	48
10	13.70	25	20	2	2800	36	53	60	160	24
11	15.00	25	20	4	6471	84	140	53	240	36
12	13.88	22	18	3	2588	36	79	22	79	36
13	12.50	16	11	2	2941	18	55	220	132	15
14	13.70	18	14	3	3294	7	56	21	105	13
15	14.08	25	20	3	4412	15	120	30	180	5
16	14.50	20	15	3	3529	24	101	14	113	84
17	14.00	20	16	3	2200	10	96	24	128	10
Average		20	16	2.76	3393	29	78	45	132	25

Figure 1. Main diesel-electric components.

Table 2. Definitions of the main parameters of ship propulsion.

(1) Effective power (Pe)	= power required to tow the ship at the required speed = total resistance × ship speed = Rt × Vs
(2) Thrust power (Pt)	= propeller thrust × speed past propeller = T × Va
(3) Delivered power (Pd)	$\begin{array}{l}=powerrequiredtobedeliveredto\\ thepropulsionunit\left(atthetailshaft\right)\end{array}={\displaystyle \frac{P_{\mathrm{t}}}{{\eta }_{\mathrm{rr}}.{\eta }_{\mathrm{o}}}}$
(4) Quasi-propulsive coefficient (QPC) (ηd)	${\displaystyle \frac{=\text{effective power}}{\text{delivered power}}}={\displaystyle \frac{P_{\mathrm{e}}}{P_{\mathrm{d}}}}=\eta h\cdot \eta rr\cdot \eta o$
(5) Transmission Efficiency (ηt)	${\displaystyle \frac{=\text{delivered power}}{\text{power required at engine}}}$
(6) Installed power (Pi)	$=Pe/\left({\eta }_{\mathrm{d}}\cdot {\eta }_{\mathrm{t}}\right)$ + margin (roughness, fouling and weather)

Table 3. Main features of the vessel.

Total Length (m)	14
Beam (m)	3.53
Draft (m)	1.5
Service speed (kn)	6

Table 4. Limits of applicability for Holtrop and Mennen.

Parameter	Minimum	Maximum
Lwl/B	3.9	15
B/T	2.1	4
Fn	0.05	1

Figure 2. Fuel consumption relationship for longliners.

Table 5. Comparison of estimated fuel with consumption obtained in the field research, in litres.

Consumption (l) / Stages	Average consumption-Research field	Average consumptionMethod 1	Average consumptionMethod 2	Average consumptionMethod 3
Going	-	609	577	208
Return	-	437	483	177
Total Access to the fishing grounds	-	1047	1060	385
Setting	-	1082	1549	567
Waiting	-	91	427	163
Hauling	-	1113	2629	956
Total Capture	-	2286	4605	1687
Total Fishing Trip	3393	3333	5665	2072
MAPE (%)		55	64	40

Table 6. Optimum results for selected propellers.

	Diameters (m)
Parameters	0.6	0.65	0.7	0.75	0.8	0.85
Z (n°blades)	4	4	4	4	3	3
BAR	0.4	0.4	0.4	0.4	0.45	0.45
P/D	0.8	0.8	0.8	0.9	0.8	0.8
ηo	48%	50%	53%	55%	57%	59%
ηd	41%	43%	46%	48%	50%	51%

Table 7. Electrical Balance of the consumer groups for each operating condition.

		At sea
Group Classification		Essential (kW)	Normal (kW)	Fishing – Setting and Hauling (kW)	Fishing – Waiting (kW)
1-	Engine Room (continuous service)	0.03	0.13	0.13	0.13
2-	Engine Room (intermittent service)	0.0	0.43	0.0	0.0
3-	Engine Room (miscellaneous)	0.0	0.05	0.06	0.06
4-	Air Conditioning / Ventilation / Heating	0.01	1.56	0.01	0.01
5-	Refrigeration of provisions (equipment)	0.20	0.20	0.20	0.20
6-	Deck machinery	0.0	0.0	0.65	0.0
7-	Kitchen/Pantry	0.31	0.69	0.31	0.31
8-	Laundry	0.0	0.25	0.0	0.0
9-	Factories	0.0	0.1	0.0	0.0
10-	Lighting	0.85	2.25	2.03	2.03
11-	Nautical and Navigation Equipment	3.28	4.76	4.00	2.29
Total Groups		4.7	10.4	7.7	5

Table 8. Selected marine generator set features.

Model	Electrical Power (kW)	Engine RPM	Frequency (Hz)
Cummins: 27.5 MDKBT	27.5	1800	60
Fuel Consumption (l/h)
1/4 load	1/2 load	3/4 load	Full load
3.7	5.1	6.7	9.2

Source: (Cummins Onan 2017).

Figure 3. Percentage of power used by generators in each stage of fishing.

Table 9. Calculation of consumption by stages on a typical fishing trip.

Consumption (l) /Steps	Estimated average consumption: ‘Conventional’ diesel system – 72.4 hp engine	Estimated average consumption (l) – Diesel-electric system
Going	342	387
Return	300	339
Total Access to the fishing grounds	642	726
Setting	607	518
Waiting	84	40
Hauling	524	309
Total Capture	1215	867
Total Fishing trip	1857	1593

Table 10. Estimated investment cost for the two propulsion systems.

Components (US$)	Diesel System	Diesel-Electric System
Installed Power	39900	45418
Power Eletronics	-	14990
Investment Cost	39900	60408

Table 11. Total diesel consumption and cost of a typical trip for the two propulsion systems.

Propulsion system	Diesel consumption (l): typical trip	Cost per trip (US$)	Anual cost (US$)
Diesel	1857 l	1931	23,175
Diesel-electric	1593 l	1657	19,881

Figure 4. Breakeven for additional investment cost of diesel-electric system compared to diesel system.

Table 12. GHG emissions by steps for a fishing trip.

Steps of fishing trip	CO2e (kg) – Diesel system – typical vessel	CO2e (kg) – Diesel electric system – typical vessel
Going	1023	1158
Setting	1817	1550
Waiting	251	120
Hauling	1567	923
Return	896	1014
Total	5554	4765

Table A1. Characteristics of the engines used to estimate the SFC.

Engine - Vessels	Power (hp)	Maximum rpm	Engine - Curves SFC used	Power (hp)	Maximum rpm
Mercedes	160	2000	Mercedes OM-366 A	178	2400
Mercedes 366 - 16/20 - powered	208	2600
Mercedes 366	140	2000	Mercedes OM-352	128	2800
Mercedes 352	120	4000
Scania 240	240	2000	Scania DI 09 070M	250	1800
Scania 240	240	2500
Scania 290	290	2000	Scania DI 13 080M	300	1800
Scania	190	2700	Scania DI 13 081M	220	1800
Scania 110	110	2000
Cummins - c serie - 220	220	2000	Cummins QSB 5.9	225	2600
Cummins 360	360	2000	Cummins QSM 11	350	1800
MWM 229	95	2500	MWM D-229-06	108.5	2500
MWM 229 6 cylinders	120	2500
MWM 6 cylinders – 10 serie	180	2500	MWM 6.10 TCA	192	2500
MWM 229 6 cylinders	180	2500
MWM 6 cylinders – 10 serie	220	2500	MWM 10 serie	215	2500
MWM 229	290	2500	MWM 12 serie	286	2500
Average	198	2400	-	223	2273

Table A2. Parameters used to estimate the fuel consumption of the fishing trip.

Engines/Stages			Going		Setting		Waiting		Hauling		Return
Vessel	Engine power (hp)	Maximum engine rpm	RPM	SFC	RPM	SFC	RPM	SFC	RPM	SFC	RPM	SFC
1	160	2000	1600	0.182	1200	0.193	800	0.193	1200	0.193	1600	0.182
2	140	2000	1700	0.191	1700	0.191	0	0	1500	0.191	1700	0.191
3	208	2600	1500	0.182	1500	0.182	1000	0.193	1100	0.193	1500	0.182
4	120	4000	3000	0.204	2250	0.196	1500	0.191	1500	0.191	3000	0.204
5	240	2000	1250	0.178	1200	0.178	0	0	800	0.184	1200	0.178
6	290	2000	1500	0.177	1500	0.177	700	0.180	1100	0.174	1500	0.177
7	190	2700	2000	0.199	1150	0.175	0	0	950	0.173	2000	0.199
8	240	2500	1800	0.177	1150	0.186	800	0.184	950	0.182	1800	0.177
9	110	2000	1650	0.179	1400	0.178	1200	0.177	1350	0.192	1550	0.182
10	220	2000	1475	0.231	1500	0.231	500	0.412	850	0.412	1500	0.231
11	360	2000	1600	0.185	1600	0.185	5	0.194	1300	0.190	1600	0.185
12	95	2500	1800	0.199	1700	0.198	700	0.202	1500	0.200	1800	0.199
13	180	2500	1400	0.175	1700	0.171	0	0	1250	0.184	1600	0.172
14	290	2500	1400	0.179	1400	0.179	800	0.211	1200	0.192	1800	0.178
15	180	2500	1550	0.173	1300	0.179	800	0.184	1450	0.175	1200	0.184
16	220	2500	1200	0.222	1150	0.222	500	0.222	950	0.222	1200	0.222
17	120	2500	1500	0.200	1500	0.200	0	0	850	0.202	1500	0.200
Average	198	2400	1643	0.190	1465	0.189	547	0.205	1194	0.203	1650	0.191

Onan C. 2017. Folha de Especificações: Marine generator set Quiet DieselTM Series 22.5/27.5 QD Model MDKBT. [accessed 2017 January 22]. Available from: http://www.cumminsonan.com.br/maritimo_modelo_gerador_27-5.asp.

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