The role of retrofits in driving efficiency

Lefteris Karaminas, Global Sustainability Manager, ABS talks to DryDock about the latest industry-leading analysis from ABS, Retrofits for Energy and Emissions Improvements, which provides critical insights into the impact of retrofitting, including classification and statutory requirements, as well as best practices for implementation.  

Lefteris Karaminas, Global Sustainability Manager, ABS

Q:   What was the key rationale behind producing the Retrofits for Energy and Emissions Improvements report now?

A:    Regulatory pressure from regional and global air emission legislation is the main catalyst for the increased demand in energy efficiency technologies and onboard carbon capture.

While it is generally easier to apply these to new vessels under construction, the long operational life of a vessel, the potential lack of newbuilding capacity and lack of future demand for second-hand vessels may lead to increased demand for retrofits.

Q:   How is ABS helping clients address their environmental objectives?

A:    Through its Advisories and Guides, ABS provides the industry with a clear understanding of classification and statutory requirements for retrofitting, explores options for improving efficiency, and offers best practices and market insights to support informed decision-making.

ABS has a dedicated team of subject matter experts who work with stakeholders while they evaluate retrofit solutions for their vessels. We help clients address environmental objectives with a range of sustainability services, including assessments of alternative fuels and energy efficiency measures.

In addition, ABS drives awareness of new technologies and measures by engaging the industry with seminars, informative meetings and advisory publications. ABS has supported the industry’s trend toward improving energy efficiency since the beginning.

Q:   How does the rapid development and adoption of new technologies fit in, and how are the risks with using new technology being addressed?

A:    New technologies start as ideas, often undefined and uncertain until they are refined using available tools. The goal is that the product meets the same standards for asset integrity, environmental protection and safety as conventional projects.

As the maritime industry evolves towards a future of more sustainable operations, achieving our desired economic and environmental goals demands a focus on innovation and collaboration as key drivers.

The rapid development and adoption of new technologies have already driven the incorporation of goal-based standards for regulatory compliance into ABS Rules – offering a path to class approval for alternative and novel concepts.

Existing class requirements often prescribe a specific technical solution but since goal-based standards do not dictate specific technical solutions, they are better suited to accommodate and support future technological developments.

Q:   How can the performance of these technologies be evaluated?

A:    Exploring EETs [Energy and Emissions Technologies] means investigating the impact on a vessel’s energy profile without compromising safety. To achieve this, shipowners must take some specific steps when implementing EETs.

These include assessing the present performance of shipboard systems and identifying energy savings from specific improvements based on the vessel’s design and operational characteristics.

Owners must also identify and address potential hazards to the vessel and crew through hazard identification (HAZID) and hazard and operability study (HAZOP) workshops.

It is also important to optimise energy demand by deploying mathematical techniques, such as computational fluid dynamics for a bulbous bow optimisation study or non-heuristic optimisation algorithms for a voyage optimisation study.

Leading retrofit technologies

Q:   What ships are leading the uptake and what are the main technologies being adopted?

A:    EET retrofits, such as ducts, propeller modifications or replacement and air lubrication may increase the efficiency of the vessel, reducing fuel consumption and thus tank-to-wake emissions.

Similarly, wind propulsion technologies (WPTs), such as Flettner rotors, suction wings and rigid sails will also reduce the power required for propulsion, leading to tank-to wake emission reductions.

WPTs are a prime example of robust decarbonisation technology that is effectively independent from sea-trade volumes, as it generates no direct emissions, and which also decouples sustainability efforts from the price of green fuels, which are generally available at a premium accounting for their CO₂ abatement cost.

Q:   Will global shipyard capacity be sufficient to satisfy the rising need for engine retrofits and EET installations?

A:    While shipowners have historically relied on a global network of repair facilities to absorb cyclical peaks, new evidence from market tracking and scenario analysis suggests that yard capacity could become a binding constraint before 2030. Under the right conditions, this could lengthen lead times, raise costs and shift competitive advantage toward those who act early to secure their slots.

For our 2025 publication ‘Beyond the Horizon: Vision Meets Reality’, two retrofit demand scenarios were developed by ABS and Maritime Strategies International (MSI). Scenario 1 – Full Conversion, assumes all eligible oil-fuelled vessels are converted due to escalating oil costs. It would require yard capacity expansion before 2030.

In Scenario 2 – Base Case, which is deemed the more likely, around half of the existing eligible tonnage and 80% of relevant newbuilds are converted. This would place demand within the range of existing and planned capacity, especially if lead times can be reduced from the current 18 months to a target of 14 months.

Figure 1: Retrofit projection — Scenario 1 [MSI, ABS].

Figure 2: Retrofit projection — Scenario 2 [MSI, ABS].

The steepest climb comes in the late 2020s, as regulatory compliance deadlines, fuel-switch strategies and decarbonisation commitments converge.

Comparing total yard demand against the theoretical maximum capacity reveals the crunch point. With only modest capacity growth assumed (+1.5% per year after 2030), the moderate scenario turns negative in 2029, with a 43 million gt-day shortfall, a gap widening to over 400 million by 2031.

In the aggressive retrofitting case, the deficit emerges a year earlier (2028), reaching over 1 billion gt/days by 2030. For owners, this means that the shoulder years just before the deficit (2027 and 2028) will be critical for locking in yard time on favourable terms.

Q:   Do you think the industry’s ambitious emissions targets are likely to be met?

A:    The recent ABS publication – Beyond the Horizon: Vision Meets Reality – makes clear that the maritime industry’s approach to decarbonisation hinges on navigating three critical hurdles: safety, availability and affordability of alternative fuels, challenges that are significant but not insurmountable.

While safety is a non-negotiable prerequisite, the associated risks for alternative fuels are manageable through a combination of engineering and operation. The industry is actively developing the necessary solutions, but this will require a fundamental upskilling of crew and a zero-tolerance approach to operational drift.

The most significant barrier to the energy transition is that sustainable alternative fuels are not yet produced anywhere near the scale required. While fossil LNG has a developed infrastructure, the green versions of methanol, ammonia and hydrogen are still being developed.

Lastly, green fuels are currently far more expensive than conventional fuels, and market forces alone may be insufficient to bridge this gap. The cost disparity is a universal hurdle. Compared to very low sulfur fuel oil (VLSFO), green fuels carry a significant price premium.

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