At the start of January 2025 –the number of in-service ships (above 100 gt) with energy efficiency technologies (EETs) onboard totalled 11,497, an increase of 12.6% from January 2024. According to data from Clarksons, some 41% of total in-service tonnage is now equipped with innovative emissions- reducing and fuel-saving technologies.
The volume of EETs installations, including onshore power supply facilities has grown every year since 2018, up 89% from 2019 to 2025 in terms of the number of ships. Currently scheduled plans for 2025 suggest that a further 2% of GT will be retrofitted with EETs.
There are around 30 different types of ESDs/EETs in use, falling into hull, propeller, solar, wind or engine-based categories. The most popular technologies being fitted or pending fall into the hull and propeller categories (existing fleet and orderbook).
Under the hull category, air lubrication (635 ships), bow enhancement (4,014 ships) and hull fins (1,484 ships) are the most popular.
Under the propeller category, propeller boss cap fins (3,044 ships), propeller ducts (3,510 ships), rudder bulbs (5,573 ships), stator fins (3,695 ships) and wake ducts (430 ships) are the most favoured.
By comparison, under wind, Flettner rotors (54 ships), rigid sails (39 ships) and suction wings (54 ships) are the most prevalent, while 193 ships have been fitted with waste heat recovery systems. 168 ships have been fitted with solar panels.
Air lubrication, which reduces frictional resistance between the hull and the water, enabling ships to burn less fuel and thereby reducing their emissions, is a key technology commanding industry attention. It has enjoyed mainstream acceptance and uptake in the past decade after some hit and miss trials during the late noughties.
However, convincing shipowners about the cost and environmental savings of installing air lubrication systems means that suppliers like Silverstream must support understanding across a business on how installing its technology will impact the vessel and the subsequent performance benefits.
“We need to manage expectations across multiple stakeholders within an organisation. Questions will depend largely on their role and sometimes we will get the same questions again but with a different emphasis depending on the person asking the question,” says Simon Pearson, Silverstream’s Head of Application Engineering.
“For example, the initial inquires will focus on the impact of the technology on the vessel itself as there are always precedents on how these things are done. People will want to understand what changes to expect during the build or install. Once the vessel has been delivered, there is greater attention to performance verification. There is a lot of data available and getting alignment around the key data points and building a shared understanding of how to analyse these is also complex.”
Pearson adds that it’s also worth noting that ALS is the only hydrodynamic EET that can be turned on and off. This, he says, is advantageous in that ALS can demonstrate on-and-off performance in real-world full-scale scenarios. However, it can make measuring performance in the real world at full scale is incredibly challenging due to the external variables being managed at any one time.
According to ABS, the Houston-headquartered classification society, energy optimisation is being more vigorously pursued by stakeholders than ever before as the dynamically changing environment requires ongoing vessel optimisation at technical and operational levels. Owners, charterers, and builders all face unique, evolving challenges in ensuring vessels operate efficiently across a wide range of scenarios, not just the ‘design point’. Furthermore, MEPC 83 was a pivotal session with forthcoming regulations that will trigger a greater need for energy efficiency technologies (EETs).
These factors mean timely and informed decisions need to be made, says Stergios Stamopoulos, ABS Director of Global Sustainability. Class has a key role in supporting shipping stakeholders navigate the plethora of energy efficiency technologies on offer and the challenges for shipowners vary at different stages. Before selecting EETs, owners must ensure that everything else has been done to enhance performance. Class can assist by carrying out performance modelling, assessment, and remote energy audits, to identify and quantify operational degradation and areas for improvement.
Once solutions are selected, class can help predict the savings for the anticipated operating profile by evaluating specific performance characteristics of the technology under consideration and carrying out performance modelling and simulation at vessel level for the operating profile (route-based and AIS-based simulations) and identifying and addressing any potential hazards on vessel and crew, Stamopoulos adds.
Furthermore, class can help evaluate the savings based on in-service measurements using the vessel’s performance model to analyse measurements and derive the statistical saving as well as optimising the energy demand.
According to Stamopoulos, the scene is set for an even greater reduction of the global energy footprint through stronger CII targets with owners already trying to benchmark their performance against IMO trajectories and peer vessels. They are also assessing energy improvements on both operational and technical fronts.
“Whilst the GFI push for alternative fuels with much lower GHG intensity cannot be readily achieved, due to insufficient availability at mass scale, the cost of traditional fuel shows no signs of reduction, so owners and charterers are more readily evaluating the viability and impact of EETs than before. As some EET solutions require drydock space or time for ordering and manufacturing to a specification, advance project planning becomes essential, and this is a key area where class can help.”