Reducing Ship Emissions: a Review of Potential Practical Improvements in the Propulsive Efficiency of Future Ships
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The document reviews methods for reducing ship emissions and improving propulsive efficiency, addressing environmental and economic factors impacting ship design and operation. It highlights that optimizing hull-propeller-rudder interaction and operational strategies like speed and trim can lead to significant power savings. While modifications to hull resistance yield limited improvements, the greatest potential for emission reductions lies in enhanced operational efficiencies and the use of auxiliary renewable energy sources.
Reducing Ship Emissions: a Review of Potential Practical Improvements in the Propulsive Efficiency of Future Ships
- 1. Reducing Ship Emissions: a review of potential practical improvements in the propulsive efficiency of future ships Prof. I Ketut Aria Pria Utama, FRINA KIR-AIPI / ITS
- 2. BACKGROUND • Environmental issues such as the emission of greenhouse gases, pollution, wash and noise are having an increasing impact on the design and operation of ships. • These environmental issues together with economic factors, such as rising fuel costs, all ultimately lead to the need to minimise ship propulsive power. • Various methods and devices for reducing propulsive power are reviewed and discussed. The most favourable methods, from a feasible and practical point of view, are identified and quantified. • It is found that potential reductions in the resistance of existing good hull forms are relatively small, but optimising hull-propeller-rudder interaction offers very promising prospects for improvement. • The biggest potential savings in power arise from optimised operational strategies such as the use of optimum trim, speed and weather routeing.
- 3. CONTENTS • Introduction • Quantifying the Environmental Impact of Ship Propulsion • Powering • Power Savings during Design • Power Savings during Operation • Auxiliary Propulsion Device • Economic and Environmental Issues • Design Procedures • Conclusions
- 4. POWERING • Overall Concept • Components of Powering • Reduction in Propulsive Power REDUCE VESSEL RESISTANCE Hull shape, surface finish Appendages: low drag design Superstructure (air drag): low drag design IMPROVE EFFICIENCY OF PROPULSORS Choice of design parameters, surface finish Adaptation to actual hull wake OPTIMISE HULL/PROPELLER/RUDDER INTERACTION Optimise wake distribution Minimise thrust deduction Upstream flow conditioning Recovery of rotational energy OPTIMISE STRATEGY FOR OPERATIONAL Speed, including slow steaming Trim: monitor/optimise Weather routeing Hull/propeller cleaning TransmissionT R Fuel V Propulsor efficiency PD PS efficiency Main engine efficiency Hull resistancePropeller thrust
- 5. POWER SAVINGS DURING DESIGN • Hull Form • Hull Surface Finish • Appendages • Air Drag • Propulsive Efficiency • Propeller Hull Interaction • Propulsion Machinery and Fuels
- 6. POWER SAVINGS DURING OPERATION • Speed • Effect of Trim on Hull Resistance • Weather Routeing • Hull Propeller Cleaning
- 7. AUXILIARY PROPULSIVE DEVICES • Propulsive power using renewable energy: wind, wave, solar power. • Wind turbines and solar panels, may be used to provide supplementary power to the auxiliary generators.
- 8. ECONOMIC AND ENVIRONMENTAL ISSUES 11.0 11.5 12.0 12.5 13.0 13.5 14.0 EEDI(CO2index) EEDI CO2 Index 24.5 25.0 25.5 26.0 26.5 Requiredfreightrate RFR (fuel cost $300/tonne) 5.0 5.5 6.0 6.5 Annualcapitalcharges($m) Annual capital charges 1.5 2.0 2.5 3.0 5.0 5.5 6.0 6.5 7.0 7.5 8.0 L/B Annualfuelcharges($m) Annual fuel ($300/tonne) Influence of L/B on CO2 index Influence of L/B on Annual Capital Charges Influence of L/B on Required Freigh Rate Influence of L/B on Annual Fuel
- 9. DESIGN PROCEDURES OPERATING ENVIRONMENT AND OWNERS REQUIREMENTS Deadweight, speed, range FEASIBLE TECHNICAL DESIGNS Principal dimensions, masses/capacity, power ESTIMATES OF BUILDING and OPERATING COSTS and REVENUE ECONOMIC EVALUATION OF ALTERNATIVES CHOICE DETAILED DESIGN CONSTRUCTION OPERATING ENVIRONMENT AND OWNERS REQUIREMENTS Deadweight, speed, range FEASIBLE TECHNICAL DESIGNS Principal dimensions, masses/capacity, power ESTIMATES OF BUILDING COSTS, OPERATING COSTS, REVENUE and EMISSIONS ECONOMIC EVALUATION OF ALTERNATIVES CHOICE DETAILED DESIGN CONSTRUCTION ENVIRONMENTAL EVALUATION OF ALTERNATIVES WEIGHTED EVALUATION Overall design flow path Overall design flow path incorporating environmental effects
- 10. CONCLUSIONS • General • Resistance • Propeller Efficiency • Hull-Propeller-Rudder Interaction • Operation • Savings • Economic Viability • Design Procedures