Caledonian Maritime Assets Ltd (CMAL) is exploring hybrid ferry options to reduce emissions and operating costs on aging ferries. CMAL owns 24 harbors and operates 30 ferries with an average age of 22 years. Hybrid ferries could reduce fuel consumption and emissions by at least 20% through the use of lithium-ion batteries and more efficient propulsion systems. CMAL is also investigating the feasibility of hydrogen fuel cells to enable zero emission ferries in the future as fuel cell technology advances. A consortium led by CMAL is studying the technical and commercial viability of hydrogen fuel cells for ferries.
3. Port Ellen - Islay
Caledonian
Maritime
Assets
Ltd
Owns or
operates 24
• old ferries, some over 40 years harbours
• ageing infrastructure
• economic uncertainty
•Environmental challenges
MV Eigg built in 1974
30 ferries –
average age
22yrs
7. The Future - Hybrid Ferries
Reasons for Hybrid Propulsion System
•Reducing Emissions
•Possibly zero emissions in harbour as vessel will be powered by batteries or shore
supply while in harbour mode
•Energy Savings
•Fuel Savings, on existing vessels there are periods of low load running, which can
increase SFOC by 5-10%
•Reduced Operating Costs
•Reduced noise when operating on batteries
•Flexible and efficient operation, excellent redundancy
•Less Installed Power by optimising machinery selection
•The batteries onboard the vessel could be charged overnight from a shore supply,
could be a wind turbine or from a source of renewable power (Hydro or Wind Farm).
10. Model Tests
Service Speed 9.0 kts
Required power and Propeller Revolutions at
Design Draught:
Trial Conditions, BF2
Draught (m) PD (kW) N (rpm)
1.60m 258.7 87.4
11. DAILY DUTY CYCLE
Sconser - Raasay Route
Daily Average Duty Cycle
24%
Percentage of day at Power Range
13% 12%
9% 10% 11% 9%
5%
3% 3%
0% 0% 1% 0% 0% 0% 0% 0% 0% 0%
Percentage of Available Power
Hybrid Ferries Project
12. FUEL CALCULATIONS – DIESEL ELECTRIC
Diesel Electric 3 x 360kW Engines
Max Propulsion
9 knots MAN PORT OVERNIGHT
Power
DAILY HOURS 25% 2.5% 15.5% 57%
DAILY HOURS 6.0 h 0.6 h 3.7 h 13.7 h
SHAFT POWER 750 kW 267.5 kW 120 kW 72 kW
kWh
MAIN ENGINE
360 kW 360 kW 360 kW 360 kW
POWER (MCR)
NUMBER
3 1 1 1
CONNECTED
TOTAL INSTALLED
1080 kW 360 kW 360 kW 360 kW
ME POWER (MCR)
TOTAL ME POWER
848 kW 322 kW 144 kW 87 kW
DEMAND
MAIN ENGINE Total
79% 89 % 40 % 24 %
LOAD
FUEL
CONSUMPTION 434 litres/day 23litres/day 85 litres/day
(litres/day)
Estimated Total Daily Fuel Consumption 542 litres/day
Hybrid Ferries Project
13. TIMETABLE : SCONSER – RAASAY ROUTE
Transit Time: 20mins Manoeuvring Time: 2mins At Slip: 8-23mins
Timetable
30 March 2012 to 20 October 2012
RAASAY
SCONSER - RAASAY
SCONSER RAASAY RAASAY SCONSER
Time from Dep - Time from Time from Dep - Time from Dep -
Depart Arrive Transit Man At Slip Total Depart Arrive Transit Man At Slip Total
Arr Dep - Dep Arr Dep
MON-SAT - - - - - - - - 07:55 08:20 00:25 20 2 8 30 00:30
08:25 08:50 00:25 20 2 8 30 00:30:00 08:55 09:20 00:25 20 2 8 30 00:30
A On Sat only, will dep Sconser 09:25 09:50 00:25 20 2 8 30 00:30:00 09:55 10:20 00:25 20 2 8 30 00:30
at 1830 arrive Raasay 1855 10:25 10:50 00:25 20 2 8 30 00:30:00 10:55 11:20 00:25 20 2 13 35 00:35
B Saturdays only 11:30 11:55 00:25 20 2 23 45 00:45:00 12:15 12:40 00:25 20 2 23 45 00:45
13:00 13:25 00:25 20 2 8 30 01:30:00 14:30 14:55 00:25 20 2 8 30 00:30
15:00 15:25 00:25 20 2 8 30 00:30:00 15:30 15:55 00:25 20 2 23 45 00:45
16:15 16:40 00:25 20 2 23 45 00:45:00 17:00 17:25 00:25 20 2 13 35 00:35
17:35 18:40 01:05 20 2 8 30 00:30:00 18:05 18:30 00:25 20 2 18 40 00:40
18:45 19:10 00:25 20 2 8 30 01:45:00 20:30 20:55 00:25 0 0 0 0 00:30
21:00 21:25 00:25 0 0 0 0 - - - - - - - - -
180 18 102 180 18 122
14. TIMETABLE - kWh
Timetable
30 March 2012 to 20 October 2012 Transit : 2124 kWh/day
RAASAY
SCONSER - RAASAY Manoeuvring : 91 kWh/day
Load Estimates
mins Hrs kW
At Slip: 388 kWh/day
Transit Total/Day 360 6.00 Transit 353.92
Man Total/Day 36 0.60 Manoeuvre 152
At Slip Total/Day 224 3.73 At Slip 104
Total : 2603 kWh/day
At Pier 0 0.00 0
Overnight/Day 820 13.67
Total/Day 1440 24.00 Estimated Loads
(including losses)
Mins Hrs/Day kWh/day Hrs/Year
Transit total 360 6.00 2123.52 2190.00
Man Total
At Slip Total
36
224
0.60
3.73
91.20
388.27
219.00
1362.67
Transit 354 kW
At Pier
Total for Operational
Day 620 10.33 479.47 3771.67
Manoeuvre 152 kW
Overnight 820 13.67 4988.33
Total 1440 24.00 2602.99 8760.00
At Slip 104 kW
36.13% of operational day at slip
36% of Operational Day at Slipway
15. HYBRID MACHINERY ARRANGEMENT
Voith
Propeller
Fwd Engine Fwd Prop
Room Room
Prop Genset x 1 Genset x 2 Prop
Motor Motor
VSD
Battery Battery
Compt Compt
Prop Main
Motor Swbd Prop
VSD Motor
Aft Prop Aft Engine
Room Room Voith
Propeller
16. SERIAL HYBRID SYSTEM
Ship's
Shore
Shore
3 x 330kW G1 G2 G3 Service
Supply
Supply
Generators
400V, 50Hz, 3ph
Cos Ø = 0.9
Ships Ships Emer
Service Service Swbd
Variable
Battery DC Link Speed DC Link
Battery
Bank Drives Bank
350kWh 350kWh
Solid State Solid State
Generator Generator
375 kW 375 kW
0 – 015 RPM M1
M
M M2
M
0 – 65 RPM
375 kW M
PROP1
Prop 1 M
PROP2
Prop 2
375 kW
17. PROPULSION MACHINERY OPTIONS
)
Generator
Shore
Hotel
Supply
Mode 1 - Generator
Mode 2 - Generator + Battery
AC
Mode 3 - Battery
Mode 4 - Battery charging
Variable DC
Speed Battery
Rating of Shore Power: Drive DC
400V 3ph 50Hz, 125A
AC
Propulsion
Motor
Hybrid Ferries Project
18. INNOVATIVE SHIP POWER DISTRIBUTION NETWORK
Plug -in for
Lithium Ion Batteries directly Lithium Ion Batteries Overnight Charging
connected to DC Link.
No additional electronics or
voltage conversions required.
Variable
Speed
Drives
Voith Schneider Propulsion
Propulsion Units Electric Motors Lithium Ion Batteries Main Switchboard Generators 330kW
19. GENERATING SETS
Volvo Penta Marine Generating Set:
Quantity - 3
Engine Type D13 MG
SFOC 191 g/kWh
Rated Power 360 kWm
Alternator Type Stamford HCM534D
400V, 3ph, 50Hz
332 kWe
368 kVA
0.9 Power Factor
Weight 3185 kg
Hybrid Ferries Project
20. VOITH SCHNEIDER PROPULSION UNITS
Voith Schneider Propulsion Units:
Quantity - 2
Type: 16 R5 EC/90-1
No of Blades - 5
Blade Length – 900mm
Rated Power 375 kW
Weight 6700 kg
Input Speed – 605 RPM
C:Usersjanderson.CMALDOMD
esktopiVSPVoithSchneiderPropell
erProgramm3.exe
Hybrid Ferries Project
22. BATTERY COMPARISON
Lead Acid Lithium Ion
Depth of Discharge 50% 80%
Cycle life at 50% Depth 8000
1000
of Discharge >3000 @ 80% DoD
Energy Density 20 Wh/kg 100 Wh/kg
Charge Efficiency 60% 95-99%
Maintenance Maintenance required Maintenance Free
Hybrid Ferries Project
24. LITHIUM ION BATTERY STRING
108 Batteries, 54 in series, 2 sets in parallel
Hybrid Ferries Project
25. INNOVATIVE SHIP POWER DISTRIBUTION NETWORK
The hybrid diesel electric propulsion system will use at least
20% less fuel than a diesel mechanical propulsion system
operating at design speed and with the vessel fully loaded,
resulting in at least a 20% reduction in CO2 emitted by the
Vessel.
At lower speeds and light loaded conditions; greater fuel
savings can be achieved and a greater reduction in CO2
emissions.
On days with reduced numbers of crossings it will be
possible to operated on batteries only for some crossings.
In port the vessel is capable of operating on batteries only,
zero emissions.
Hybrid Ferries Project
27. RULES & REGULATIONS
In new class B, C and D and existing class B ships, and new ships
constructed on or after 1 January 2003 with a length of 24
metres and above, a double bottom shall be fitted extending
from the forepeak bulkhead to the afterpeak bulkhead as far as
this is practicable and compatible with the design and proper
working of the ship.
Double Bottom
760mm High
Hydrogen Ferries Feasibility Project
28. Caledonian Maritime Assets Ltd - HYBRID FERRIES
Now Future?
Lithium Ion Batteries Fuel Cells?
Launch Date 17th December 2012
Ferguson Ship Builders – Port Glasgow
20% reduction 100% reduction
in emissions in emissions
29. Hybrid Ferry
Other Energy Efficiency Measures
Alternative Fuels (Biodiesel, LNG)
Energy Saving Lighting
Speed Control for Main Pumps and Ventilation Fans
Optimised Hull Design
Improved Hull Coatings
Lightweight Construction (Aluminium and other composite materials)
Improved Insulation Materials
Solar Panels
Fuel Cells (marine commercial units under development)
30. Feasibility Study
CMAL have been commissioned to carry out a feasibility study for
Scottish Enterprise to evaluate the technical and commercial
possibilities of using hydrogen fuel cells to enable the development of
zero emission ferries
Consortium, CMAL, Logan Energy, St Andrews University and SHFCA
31. FUEL CELL
Capacity 125 – 150 kW Units
Quantity?
Size 1530mm x 871mm x 495mm each
Weight 404 kg each
Type of Fuel?
Lifetime?
Cost of fuel cell, tanks, integration etc?
Location on ship?
32. FUEL
Availability?
Cost?
Storage Tank Size?
Storage Tank Pressure?
Quantity of Fuel required?
33. Thank you for you attention
Andrew Flockhart
Andrew.flockhart@cmassets.co.uk
Editor's Notes
We carried out a duty cycle and power study on one of our existing vessels: the Loch Striven which operates between Sconser and Raasay. This bar chart shows the percentage loading on the main propulsion engines at various operating modes through a typical day. e.g. 24% of the day the vessel was using between 6 & 10% of the available power.As you can see 40% (3% + 24% +13%) of the operational day was spent with power levels less than 15% of the vessels available power and only 4% was spent at power levels above 45% of the vessel’s available power. Overall only 22% of the vessels available energy production capacity being utilised during the course of the day.In conclusion it was evident that the diesel engines are not operating at their optimum efficiency.We could not change the type of propulsion units or change the hull form or speed.So had to consider other ways to reduce fuel consumption and emissions. To overcome this problem when low power levels are required most of the time; a diesel electric system is best suited, where the supply of power can be provided more in balance with the power demand.
These are the fuel calculations for a Diesel electric system, including max electrical losses and vessel operating at design draught.The optimum configuration is 3 electrical generating sets, each at 360kW and again the same max propulsion power of 750kW.The estimated loading on the gensets are 89% during transit, 40% during manoeuvring and 24% in port. For the 9 knot condition only 1 generator is in operation. the other 2 generators are only required when max propulsion power is needed for when holding station in adverse weather conditions.The total fuel consumption is estimated at 542 litres/day.
So how will we operate this system?We envisage that there will be 4 modes of operation, each will be easily selected by a switch at the wheelhouse conning position. An automatic battery and power management system will control the starting and stopping and load sharing between the generators and the batteries.The system will also be capable of manual operation.So looking at the modes of operationMODE 1 - GENERATORS ONLY The generators will supply the power for the propulsion motors and the auxiliary load. This is the conventional diesel electric configuration without the need for batteries and does not restrict the vessels operations.Mode 2 – GENERATORS AND BATTERIES Generators and Batteries operating at the same time. The batteries providing a minimum 20% of the energy required.Mode 3 – BATTERIES ONLYWhen the vessel is at the slipway,it will be possible to stop the generators with the batteries providing all the required power giving zero emissions.MODE 4 – BATTERY CHARGINGThe batteries will be charged overnight using the front end of Variable speed drives and therefore separate battery chargers are not required. .
The planned propulsion for these vessels will be Vertical Cycloidal Propellers, this system is used on many of the current small ferries and has the following main advantages. generates thrust in any direction quick and precise reactioncombines propulsion and steering in one unitYou can find the following interactive program on the Voith Schneider website which shows the operation of these units.This programme shows how the voith Schneider propeller operates by adjusting the revolutions, driving pitch and rudder pitch. It is also possible to select the type of control system and view the hydrodynamic forces.
We have considered two kinds of batteries. Lead acid and Lithium ion, for each of which there are several different types and chemistries.When specifying a battery, there are many factors to take into account:DEPTH OF DISCHARGE This is the percentage amount of energy that can be extracted from the battery . CYCLE LIFEThis the number of times the battery can be discharged and recharged. ENERGY DENSITYThis the ratio of the energy available to the weight of the battery.CHARGE EFFICIENCYthis is how much energy you get out for the amount of energy you put in.Although Lithium ion is typically 3 times more expensive than an equivalent lead acid battery. Lithium ion has the benefits of being smaller, lighter, more efficient and has a cycle life 3 times greater than lead acid and therefore works out to be no more expensive in the long term.The estimated total weight of the batteries is 6800kg.