Improving the energy efficiency of ships

Improvement of the energy efficiency of the vessels will require increasing attention with time, owing to the CII rating thresholds getting increasingly stringent every year, and the regional regulations like EU ETS. The enhanced GHG emission reduction targets from the adoption of the 2023 IMO strategy, will further intensify this need.

While certain alternate means for GHG emissions reduction may get increasingly adopted, maximizing fuel efficiency will still be essential for minimizing the operational costs which are inherently high for solutions like biofuels and carbon capture. At OSM Thome, we have focussed on both the design and the operational efficiency improvement measures.

In the years 2022 and 2023, while preparing for compliance with EEXI and CII regulations, the vessels have been assessed for the requirement and the potential for implementation of energy-saving devices, to minimise the power limitations required to be imposed through EPL and SHAPOLI. Many vessels were fitted with pre-swirl and post-swirl propulsion improvement devices (like propeller ducts, stators, finned propeller caps, rudder bulbs etc.), and high-performance hull coatings.

A strong focus has also been maintained on the optimization of the auxiliary power utilization, through solutions like variable frequency drives, LED lights, etc. Digital solutions have also been promoted for voyage optimization, weather-based routeing, and telemetry data acquisition and utilization, for performance evaluation and improvement, for both propulsion and auxiliary power.

It is well acknowledged that diligent and timely maintenance of all equipment, including the engines and the boilers, is vital for the best energy efficiency. Besides, we realize the essentiality of close monitoring and analysis of the operational data. Viewing this, a central vessel performance team and Operations Hub have been established to ensure that data and performance indicators are obtained with maximum accuracy, compared with appropriate benchmarks (from sea trial or shop test reports, peer or sister vessels’ performance etc.), and the deficiencies are picked up timely.

A structured approach ensures that the corrective actions are identified and discussed with not only the ship staff and the vessel managers, but also the owners and the charterers, for timely adjustment to vessels’ trading profile and speed, or for engaging in hull maintenance activities, for meeting the targeted CII.


By Rajiv Malhotra, Head of Technical Support