1. SeaAsia - Technical Day Singapore, 22 April 2009
Reducing CO2 Emission in Shipping - Some Technical Perspectives
A. K. Seah VP Technology & Business Development

2. IMO CO2 emission reduction strategy
Outcome of MEPC 58 (10 Oct 2008)
Debate on “common but differentiated responsibilities” (CBDR)
GHG Working Group to study:
“Energy Efficiency Design Index” – for new ships
“Energy Efficiency Operational Index” – for all ships
Ship Efficiency Management Plan
Best Practices
Impact on shipping
Market-based measures (e.g. emission trading scheme, FO tax)
To be further debated in depth in MEPC 59

3. Energy Efficiency Indexes
Operational index – voyage specific
Design index – design specific
g of CO2 emitted (based on fuel burnt)
t of cargoes carried * N-M traveled
g of CO2 emitted (based on specific fuel consumption)
Design cargo capacity * Design speed
Various deduction allowed in numerator: e.g.:
innovative technologies that reduces fuel consumption
CO2 capture
Weather factor allowed in denominator – improving hull shape

4. Improving Fuel Efficiency
Improve ship design
Reduce hull resistance: hull form; wave-making resistance; slamming
Reduce skin friction: coating; cleaning; air bubbles….
Improve aerodynamics
Propeller design
Rudder design
Economy of scale
Improve machinery & propulsion
Improve engine efficiency / fuel consumption
Heat recovery; electrical systems
Renewables: sails; Flettner rotors…
Improve operations
Voyage planning; weather routing
Speed
Draft and trims
Shore power…

5. Improving ship design Reduce hull resistance
Low speed ships (tankers, bulk carriers) – Fr ~ 0.15
Skin friction resistance dominant
Strategy: reducing skin friction (polishing, anti-fouling paint…)
Higher speed ships (containerships)
Wave making resistance more dominant
Strategy: reducing wave- making resistance (bulbous bow, trim operation, reduce speed…)
Improve propeller efficiency
Polish the propeller
Improve efficiency: e.g. reduce blade area ratio
Improve wake
Recover propeller energy Fr Fr
Source: Sasaki, ITTC 2008

6. Improving propeller efficiency
Improving the wake
Aframax wake: large bilge vortexes and dead water zones
Use wake-smoothers to accelerate flows in general area: Reaction fins; Wake equalizing duct
Containership wake: wake defect at 12 o’clock position
Use wake smoothers to accelerate flow at that area: Semi-duct, Wake equalizing duct, spoilers
Efficiency improvements: ~3 - 5% (HSVA 2006)
Containership
Aframax Tanker
Wake equalizing duct

7. Improving propeller efficiency
Recovering energy from aft of propeller – various devices
Contra-rotating propellers (CRP)
~15% improvement in efficiency claimed in 19th ITTC report
Hampered by mechanical complexity previously
Now redesigned with pods – available from Wartsila and ABB
Grim wheel
Mounted aft of propeller and rotates freely
More blades than propeller; inner part of the Grim wheels acts as a turbine blade and outer part acts as propeller
6~12% improvement in efficiency claimed in 19th ITTC report
Additional thrust fins
Developed and patented by IHI 1984
For right-handed propeller, stbd fin is upward inclined and port fin is downward inclined; both act as aerofoil with lift forces providing additional thrusts
4~8% improvement in efficiency claimed in 19th ITTC report

8. Improving propeller efficiency
Kawasaki Rudder-bulb fins
IHI Additional Thrusting Fins
Wake-equalizing duct
Asymmetrical stern
Mitsui OSK Propeller boss cap fins
Contracted Tip propellers
Gruthues spoilers
Stern tunnel
Stern flap
Modern contra rotating propellers
Hitachi Zosen nozzle
Mitsui integrated ducted propeller
Reaction fins
Takekuma
Grim wheel

9. Improving propeller efficiency
Improvement strategy: e.g. if wake has little defect, then no wake-improvement device; try aft of propeller energy recovery
Quantify % of different propeller energy loss
Example strategy:
Friction loss > axial loss > rotational loss at design operating condition
priority could be recovering friction loss first, then axial loss, then rotational loss
Design operation range
Source: HSVA
J = advance coefficient = V/(n*D)

10. Improving Engine Fuel Efficiency
Fuel efficiency of prime movers  10MW
Low Speed Diesel Engines: 49-50%
Medium Speed Diesel Engines: 48-49%
High Speed Diesel Engines: 42-43%
Steam Turbines: 27-32%
Reheat Steam Turbines: 34-38%
Gas Turbines: 30-35%
Historical improvements in 2-stroke diesel

11. Improving waste heat recovery
Thermal efficiency of engine < 50%; exhaust gas heat loss < 30%
Waste heat recovery
Both MAN and Wartsila have similar proposal: turbo or/and steam generators
Energy recovery (electric power) up to 11%
Turbo Gen & Steam Turbine
Steam Turbine
Power Turbine
Source: Wartsila

12. BIMCO study: fuel consumption trends
-16%
-19%
-13%
-28%
Source: WMTC 2009

13. BIMCO study: fuel consumption trends
-26%
-35%
Sealand SL TEU built MW steam turbine - 31 kts g CO2/TEU*NM
Emma Maersk 12,000TEU built MW diesel kts g CO2/TEU*NM
Slow steaming for 8000TEU speed 25kts reduced to 20 kts (20%) - fuel saving 260t/d to 128 t/d (51%)
Source: WMTC 2009

14. BIMCO study: container ship slow steaming
Scenario: move 10 million TEU 5,000NM within 1 year (250 sailing days)
Slow steaming will result in reduced CO2 emission, despite increase in number of ships employed.
At which point this becomes uneconomical?
Source: WMTC 2009

15. Natural Gas as fuel
Extensive studies made comparing gas v. HFO as fuel for LNG carriers
Energy consumption: DFDE comparable to 2-stroke diesel
CO2 emission: DFDE can reduce by ~20%
IMO - t of CO2 / t of fuel, HFO v. NG: v (13.5% credit for NG)
Gas
Gas
Gas
Gas
HFO
Gas
Gas
DF-Electric155,000 cbm LNG Carrier; Total 40MW
Source: Wartsila Dual Fuel LNGCs – Gastech 08

16. The Renewables Wind Energy Solar Energy Wartsila’s concepts
Wing shaped sails of composite material installed on deck – possible efficiency gain of ~20%
Flettner rotors installed on deck – provides thrusts in driection perpendicular to wind
Source:
Skysails - Weather and route dependent
On trial for 2 feeder-size ships Michel A and Beluga Skysails
Towing force example: model SKS320 – 16t with 25-kt wind; 133m MPP vessel propeller thrust 23t
Annual fuel saving: 10~30% claimed
Source:
Solar Energy
NYK’s PCC Auriga Leader - 200m x 32m x 34m; 6200 cars; 18,700 dwt
328 solar panels, USD 1.68m, 40 kW, ~0.3% of installed power
Source:

17. The Renewables Biofuels Potential net CO2 saving but various drawbacks
2nd generation biofuels based on Fischer Tropsch (FT) biomass to liquid (BTL) process hold more promise
Marine application concerns:
Less calorific value than fossil fuel – engine derating required
Currently lack worldwide marine biofuel standard – premixed or blending on board
Regarded as “noxious liquid” under Annex II; regulatory uncertainty
Other: shelf life, dedicated system and switching between fuels…
Ref: IEA: Transition from 1st to 2nd Generation Boifuel Technologies 2008

18. The Game Changer… The scrubber….removing SOx & NOx & CO2 ?
Source: Ecospec press conference 16 Jan 2009

19. The shape of things to come?
Super Eco-Ship by NMRI
Source: ISOPE 2005 – Y Minami et al, National Maritime Research Institute, Japan

20. The shape of things to come?
Wallenius Wilhelmsen’s
Environmentally-Sound Ship Orcelle
Source: Wallenius Wilhelmsen Green Flagship
Photovoltaic panels
Sails
No ballast water – pentamaran hull, no stern propeller and no rudder
No emission – only renewables: wind, wave, current, fuel cell and hydrogen
Target: 2025
Fins to harness wave energy

21. w w w . e a g l e . o r g