How to Improve Energy Efficiency of Ships

How to Improve Energy Efficiency of Ships?

Energy efficiency has become a prime cause of concern across all industries in the world, and shipping is no exception. The terms ‘sustainability’ and ‘green ships’ are heard more and more frequently today, as the core principles of ship and boat building are being transformed due to these influences.

The concepts of energy efficiency and its need in everyday shipping have filtered down from the realm of the abstract to ground reality and are making their presence felt in the day-to-day functioning of shipping organizations.

In general terms, the energy efficiency of boats and ships by design, as defined by the Energy Efficiency Design Index, is the ratio of carbon dioxide the ship would emit, per ton-mile of the work done by the ship.

The best ways to optimize and maintain the energy efficiency of the ship are planned and implemented using the Ship Energy Efficiency Management Plan. SEEMP delineates all the best practices that need to be practiced on board and within the organization to ensure smooth sailing and maximum efficiency of the ship.

Finally, a critical analysis of whether or not these measures are useful, the return on investment they’re offering, and the modifications required in the process to make it better can be done using the Energy Efficiency Operation Index (EEOI). The main difference between the EEDI and the EEOI here is that the former measures how well a ship is built while the latter measures how well it is operated.

Having cleared these basic terminologies, let us move on to see why energy efficiency is so important in ships.

Why is Energy Efficiency Important in Ships?

Shipping remains the primary form of transport for cargo and heavy goods, as it is the least expensive when it comes to cost by volume. As an industry, shipping accounts for nearly 3% of the greenhouse gas emissions in the world. To put that in perspective, if shipping were a country, it would be the 6th-largest producer of carbon dioxide, in the world. That is serious.

The high amount of emissions is a consequence of inefficient ship design, and lack of planning and optimum utilization of resources. Furthermore, as the transport sector continues to expand, the pressure for a greener and cleaner shipping industry increases even more. Hence, volatile fuel prices, the increased need for environmental regulations, and the pressure for reduced fuel consumption are the main drivers for necessitating energy efficiency in ships.

Understanding the fact that shipping needs to improve as a whole, not just in pockets of the sector, the International Maritime Organization has laid down several rules and regulations to increase green standards in shipping. Here is a look at some of these.

The Role of the IMO in Promoting Ship Energy Efficiency

The most important role of the IMO in increasing ship efficiency is that it helps standardize the efforts. Every organization in shipping is endeavouring on its own to increase its efficiency, but the IMO helps coordinate these efforts and give them a proper direction without which every company would be going their own way.

The IMO has issued several edicts and created several smaller organizations to help delineate the work towards increasing ship efficiency. It has adopted a two-fold approach to reduce the greenhouse gas emissions of ships and hence promote ship efficiency; first, through regulatory work, and second, through capacity building initiatives.

The Marine Environment Protection Committee outlined its vision to reduce GHG emissions and phase them out by the end of this century, in April 2018. Furthermore, it has adopted mandatory energy efficiency measures for ships, under Annex VI of IMO’s pollution prevention treaty (MARPOL). Amidst the slew of resolutions made, the most well-known ones are the sulphur cap by 2020 and the aim to reduce carbon emissions by at least 50% by 2050, as compared to 2008.

The IMO has set stringent emission caps for shipping companies, based on the region of travel. For instance, in the SECAs (Sulphur Emission Control Areas), the sulphur limit is 0.10% m/m, while outside the SECAs, the limit is less than 0.50% from January 1, 2020. Ships being built currently and in the future are expected to adopt these specifications from the start and increase efficiency by a massive 30% by 2025.

As seen above, the EEDI and the SEEMP are now made mandatory for every ship traveling the seas. Under these energy-efficiency regulations, every ship is now expected to have an energy-efficiency management plan, improved voyage planning, regular cleaning and maintenance of the propeller and other parts of the ship, and installation of energy-efficient waste heat recovery systems.

One of the biggest initiatives the IMO has taken towards the successful implementation of these programs is the Global Maritime Energy Efficiency Partnership (GloMEEP) Project. GloMEEP aims at increasing the knowledge and technical know-how of shipping companies across the world to drive the maritime world towards a low-carbon future.

Another initiative is the Global MTCC Network Project, funded by the European Union, which aims to connect developing and underdeveloped shipping countries with the more technologically advanced nations, which can help them benefit from the technical know-how of the latter.

Technologies to Improve Energy Efficiency in Ships

The areas of focus while improving energy-efficiency include ship design, shoreside electricity, fuels and consumption, and operational measures on the vessel. Various technologies and methods of operation have been developed with these areas in mind, so as to achieve maximum efficiency of existing and future vessels.

  • Ship design to improve energy-efficiency

Ship design plays a crucial role in ship efficiency, as it becomes the foundation for operational and transit efficiency. Technical measures that reduce fuel consumption include highly efficient marine engines and power trains, optimized flow profiles around hull, rudder, and propeller, and innovations such as the bulbous bow.

In addition to the fuel-saving potential of technical measures related to hull and propeller geometry, hull construction, propulsion machinery, auxiliary machinery and equipment,  heat recovery, cargo handling, and alternative energy sources, there is now a need to develop efficiency by understanding how these systems affect one another.

  • Alternative fuels as a resource for green ships

LNG is the fuel of choice today when it comes to replacing conventional fuels in shipping, as it has a comparatively lower amount of sulphur and nitrogen oxide emissions. However, the larger storage spaces required for LNG fuels deter its widespread use at the moment.

This has led to the exploration of non-conventional sources of energy for use in futuristic ships. Technology for the effective harnessing of solar and wind power is under the lens. Additionally, synthetic fuels and other alternative fuels like methanol, dimethyl ether, etc. are being researched for their fuel-efficiency potential.

  • Operational measures to increase operational efficiency

A successful and sustainable reduction in the amount of fuel used in ships and an overall increase in operational efficiency can be obtained by implementing a variety of operational methods. These include slow-speed operation planning, higher capacity and resource utilization, and precise communication between shipping entities for efficient route planning.

Reducing the turnaround time in ports is another way of increasing ship efficiency. A study by Johnson and Styhre (2013) showed that the two largest sources of unproductive time in port are waiting time at berth when the port is closed, and waiting time at berth due to early arrival. With one to four hours of decreased time per port call, the potential for increased energy efficiency was 2%-8%.


It can be seen from the study above that increasing ship efficiency is a combination of multiple factors, each of which plays an important role in its own way. With lofty targets in place, there has been a consistent rise in the incentives and regulations for improving ship energy efficiency.

The IMO has become a strong force driving this change in the shipping industry as a whole and encouraging shipping and boat manufacturing companies across the world to come up with innovative solutions to meet ship efficiency standards.

At present, we can see that there is great potential in the measures being implemented for better ship efficiency. However, the actual results still remain to be seen. What are your thoughts about the various practices for increasing ship efficiency? Any insights on how you ensure increased efficiency in your own organization? Drop a comment to let us know!

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