During the 2025 GREEN4SEA Singapore Forum, Capt. Satinder Singh Virdi, Principal Consultant, Head, Research and Development, Maritime Advisory (Singapore/Asia-Pac), AFNI, FRINA, DNV, delivered a presentation on the role of energy efficiency measures in achieving decarbonization and emission compliance within the maritime industry.
Regulatory and stakeholder pressures
Within the IMO framework, ongoing and upcoming discussions will shape the direction of future requirements. In addition to regulatory pressure, there is increasing scrutiny from cargo owners and financial institutions. These stakeholders expect clear strategies for decarbonization. Ships without a concrete plan may begin to experience pressure to act, especially as a significant number of vessels have yet to initiate any meaningful changes.
Pathways to net zero by 2050
The path to net zero emissions by 2050 involves implementing a range of strategies, including the use of low- and zero-carbon fuels, biofuels, energy efficiency technologies, and operational measures. These options can be combined in ship-specific and route-specific ways, creating a customizable approach. While not every measure works in all scenarios, a variety of tools are available. The confidence in adopting alternative fuels depends on ease of implementation, operational cost, and required competencies.
Principles of energy efficiency
Energy efficiency improvements can be achieved by applying fundamental principles of engineering and physics, such as reducing drag on the propulsion system. This includes both operational practices and design enhancements. Measures range from optimizing crew operations to implementing propulsion and hull design improvements.
Upgrading onboard systems
Advancements in onboard machinery and energy optimization can also play a key role. Systems installed a decade ago can still be upgraded. Additionally, energy harvesting technologies such as wind propulsion are becoming more available.
However, there remains a notable resistance to adoption. Overcoming this resistance is critical for future compliance. Class societies, including ours, have issued guidance documents offering high-level estimates on the efficiency gains possible through various measures. Each improvement contributes to fuel savings, greenhouse gas reductions, and enhanced compliance with regulations.
Propulsion and hull optimization
Popular propulsion and hull-related measures include propeller retrofits. Often, the operational speed of a ship does not align with its design speed, leading to inefficiencies. For example, a new tanker rated for 15 knots may operate at 12 knots due to charterer requirements. This mismatch results in daily fuel loss. Shipowners are sometimes advised to retrofit even relatively new vessels.
Low-friction coatings and regular hull cleaning are other effective measures. However, they are not consistently practiced, and cleaning services may not be available in all regions. Improvements to propeller flow and water streamlining using current technologies can also enhance efficiency. Measures such as installing a shaft generator, where feasible, can yield significant savings, potentially reducing oil consumption by 5 to 10 tons per day.
Moreover, waste heat recovery and better maintenance of machinery, generators, auxiliary engines, and boilers are also key to improving operational efficiency.
The rise of energy harvesting technologies
Energy harvesting measures like wind propulsion are gaining traction and could become a game changer, particularly for vessels operating on routes with consistent wind patterns. Historically, ships navigated the globe using wind power alone, underscoring its proven viability.
Underutilized operational measures
Operational measures such as just-in-time arrival and autopilot optimization also offer potential. However, in practice, many of these are underutilized. For example, although crew members may claim proficiency in using autopilot systems, adjustments are rarely made. Often, manuals are only consulted when systems fail in poor weather. Just-in-time practices are being adopted in some ports, but they must be paired with fuel-efficient speed adjustments to be effective.
The question of cost and Return of Investment
Operators and stakeholders are often concerned with the financial aspect of these decisions and whether they are cost-effective. To answer some of these questions, DNV’s “Energy Efficiency Measures and Technologies” report provides an overview of the available solutions as well as calculations surrounding costs and their potential pay-off.
Adoption trends, fuel options and workforce competency
Adoption remains uneven. Most attention has focused on propeller-related measures due to their immediate return on investment. However, many other viable strategies have yet to be fully leveraged.
Several fuels are now available, but their successful integration requires thoughtful planning, competency development, and operational adjustments. Alas, a frequently overlooked issue is the competency of shore-based staff. While much focus has been on training ship crews, those onshore, who coordinate with shipyards for deliveries, also require adequate understanding, even if they have never sailed themselves. Coordinated, long-term planning is essential.
Final recommendations
In conclusion, energy efficiency measures can gradually enhance compliance with emissions regulations. It is vital first to understand the specifics of one’s fleet and then establish a dedicated team to explore available options.
Measures should be evaluated on a case-by-case basis. It is not sufficient to ask how many ships of a particular category have adopted a specific technology. Suitability depends on factors such as operational regions and ship type. For example, the adoption of wind propulsion should be considered based on whether a vessel operates in regions with consistent wind patterns.
Thus, a key point to consider is that for these technologies to truly work, a customized approach is essential.
Above article has been edited from Capt. Satinder Singh Virdi’s presentation during the 2025 GREEN4SEA Singapore Forum.
Explore more by watching his video presentation here below
The views presented are only those of the authors and do not necessarily reflect those of SAFETY4SEA and are for information sharing and discussion purposes only.
