Updated 24 November 2025.
In today’s marked there is a collective strive towards zero emissions. It is therefore not surprising that many are exploring how to build vessels, or optimize existing vessels, so they run on green energy sources.
However, investing in systems that use green energy such as batteries, is not the only option when creating a more sustainable vessel. What often gets overlooked is the importance of optimizing the energy-consumption.
In this article, we will dive deeper into this topic and look at ways you can achieve a greener operation, regardless of the energy source used.
Energy Efficiency is Key
Choosing a greener energy source is a meaningful step, but if your vessel uses more energy than necessary, you are limiting the potential of any system.
Just as you would insulate your home before buying a larger heating system, vessels need an efficient platform before electrification or alternative fuels can deliver their full benefit.
Key benefits of increased energy efficiency
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Lower emissions: Using less energy directly reduces CO₂, NOₓ and particle emissions. Efficiency improvements alone can cut emissions from shipping by 20–30% in typical operations.
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Reduced operating costs: Fuel remains one of the largest cost drivers for most operators. Even a 5–10% reduction makes a measurable impact.
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Extended range for electric/hybrid vessels: Less energy consumption means more time between charging cycles or less required battery capacity.
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Reduced need for new power installations: A more efficient vessel often requires a smaller engine, less installed battery capacity, or lighter auxiliary systems.
In short: the cheapest and fastest way to reduce emissions is to use less energy.
Read more: Why Twist Your Rudder
Three Key Areas That Determine Vessel Energy Efficiency
Energy efficiency is about eliminating waste, using less energy to perform the same mission without compromising safety or operational capability. Below are the primary areas with the highest improvement potential.
1. Weight Optimization
Weight is one of the most influential factors affecting energy consumption. Any unnecessary mass increases draught, resistance and propulsion load.
How to reduce vessel weight effectively
- Replace outdated or overly robust components with modern lightweight alternatives
- Review onboard equipment for redundancy or seldom-used systems
- Consider structural optimization or use of advanced materials where feasible
- Optimize battery or fuel storage layouts to avoid unnecessary structural reinforcement
Even moderate weight reductions can generate significant savings over the vessel’s lifetime.
2. Reducing Hull Resistance
Hull design and surface quality directly affect hydrodynamic resistance, especially at higher speeds.
Improvement opportunities
- Hull shape optimization or retrofitting (e.g., bulb modifications, stern refinement)
- Regular hull cleaning and propeller polishing
- High-performance antifouling coatings
- Minimizing appendage drag
- Utilizing CFD modeling to identify flow inefficiencies
3. Optimizing the Complete Propulsion Line
A propulsion system is only as efficient as its weakest link. Real gains come from looking at the entire propulsion line, not individual components.
This includes:
- Engine or electric motor
- Gearbox
- Shafting
- Brackets and struts
- Rudder
- Propeller or combined propulsor systems
A highly efficient propulsor allows operators to install smaller engines or reduce battery capacity without sacrificing performance. Servogear’s own experience across high-speed vessels shows that an optimized propulsion package can improve system efficiency by up to 20–25%, depending on vessel type.
Read more: Efficient Propulsion in a Green Environment, What are the Options?
Conclusion
Energy is a limited and valuable resource. Whether your vessel is powered by diesel, hybrid or full electric systems, optimizing efficiency is the most effective way to reduce operational costs and environmental impact.
Before investing in new energy sources, evaluate how your vessel uses energy today. Improving efficiency is the most immediate, scalable and cost-effective path toward sustainable maritime operations.
