DNV has analysed more than 180 bow-retrofit projects, and the evidence from that dataset set the tone at the classification society's second Energy Efficiency & Technologies Forum: shipowners should commit capital on the back of measured fuel savings, not vendor projections.

The forum gathered shipowners, technology providers, academics and DNV experts to test the practical readiness of the full decarbonisation toolkit — hydrodynamic retrofits, wind-assisted propulsion, LNG and biomethane, shore power, emissions-data management, onboard carbon capture and nuclear propulsion.

Why does efficiency still outrank alternative fuels?

Jason Stefanatos, Global Decarbonization Director at DNV Maritime, opened the event by framing the commercial hierarchy plainly. He said:

"While alternative fuels will play a critical role in decarbonization, improving energy efficiency remains one of the most immediately and commercially attractive opportunities available to shipowners today. The challenge is to understand which solutions deliver measurable value under real operating conditions and how they can be implemented at scale."

That argument carries weight for operators weighing capital allocation. Efficiency retrofits pay back in fuel saved today, while alternative-fuel bets hinge on uncertain fuel availability and price. A single fuel or technology will not deliver the transition, participants repeatedly stressed.

What does the operational evidence show?

André Kauffeldt, Principal Engineer at DNV's Ship Performance Center, presented findings drawn from the 180-plus bow-retrofit projects. Katerina Prifti, HSQE Director/DPA/Vetting at Laskaridis Shipping, added real-world results from the company's evaluation of wind-assisted propulsion.

Both presentations pointed to the same caution: fuel savings and payback periods vary significantly depending on vessel design, operating profile and trading pattern. A retrofit that performs on one trade may underdeliver on another — which is why the forum's recurring demand was that investment decisions rest on measured operational performance rather than theoretical potential.

How do fuel choices and compliance economics interact?

George Kriezis, Technical Director at Neptune Group of Companies, examined LNG and biomethane within long-term decarbonisation strategies. His analysis highlighted three variables shaping fleet economics: fuel availability, lifecycle emissions and FuelEU Maritime compliance considerations. For owners planning newbuilds or conversions, the regulatory penalty-versus-benefit calculation under FuelEU Maritime now sits at the centre of the fuel decision, not at the margin.

Shore power drew a more sober assessment. Lefteris Koukoulopoulos, Regional Decarbonization Specialist at DNV Maritime, noted that uptake is increasing in some vessel segments, but access to shore-power connections remains limited in many ports — an infrastructure constraint that continues to cap adoption regardless of shipboard readiness.

What role does verified data play?

Trusted emissions data emerged as a second pillar of the discussions. Konstantinos Kordas, Performance Engineer at Navarone S.A., outlined the company's fleet-level energy-efficiency strategy. Vasileios Petousis of Seanergy Maritime Holdings, together with Mette Rønning Raabel and Lars Nyflot from DNV Maritime, argued that verified emissions data underpins three functions at once: regulatory reporting, performance monitoring and operational decision-making.

The message for operators: without a trusted performance baseline, neither compliance reporting nor technology payback can be proven.

Which technologies remain on the horizon?

Earlier-stage options also took the floor. Dimitris Koutsaftis, CCS Technical Product Manager at ERMA FIRST, and Chara Georgopoulou, Head of Maritime R&D and Advisory Greece at DNV Maritime, reviewed the opportunities and challenges of onboard carbon capture. Closing the event, Professor George Dimopoulos of the National Technical University of Athens laid out the conditions under which nuclear propulsion could become relevant for selected shipping applications.

What should owners do next?

Koukoulopoulos summarised the forum's conclusion:

"Across the sessions, one conclusion was consistent: maritime decarbonization will not be delivered by a single fuel or technology. For shipowners, the immediate task is to establish an accurate performance baseline, select measures suited to each vessel and trade, test the less mature solutions, and verify results before moving from individual projects to fleet-wide implementation."

The roadmap, then, is sequential: baseline first, vessel-specific measures second, pilots of immature technologies third, fleet-wide rollout only after verification. With FuelEU Maritime already biting and efficiency retrofits offering the fastest documented payback in DNV's 180-project dataset, expect owners to channel near-term capex into hydrodynamic and wind-assisted measures while carbon capture and nuclear stay in the trial phase.