Daphne Technology and Maran Gas, part of the Angelicoussis Group, said their joint pilot project has completed the first commercial deployment of a plasma-catalytic methane slip aftertreatment system on an operating liquefied natural gas carrier. The trial, carried out aboard the Maran Gas Chios, recorded reductions in methane slip of up to 4 ± 2 grams per kilowatt-hour, marking a notable step toward managing an emissions source that has proved difficult to control on ships.

Methane slip refers to unburned methane that escapes from engines, vents or other fuel-system paths and enters the atmosphere. Because methane traps far more heat per molecule than carbon dioxide over short timescales, reducing slip is increasingly regarded as essential to near-term climate mitigation, particularly for vessels that carry and use natural gas as fuel. The Daphne-Maran pilot is reported as the first demonstration that a plasma-catalytic approach can function in the operational environment of a commercial LNG carrier.

Plasma-catalytic systems use an electrical discharge to activate methane molecules and generate reactive species that a downstream catalyst can more readily oxidize to carbon dioxide and water. That combination aims to achieve meaningful conversion at temperatures and flow conditions typical of marine engine exhaust, where conventional catalytic oxidation is often inefficient. Daphne’s SlipPure™ system was evaluated alongside the company’s PureMetrics™ emissions monitoring platform, allowing the partners to quantify performance and emissions in situ during normal ship operations.

The pilot’s measured reduction — described by the developers as "up to 4 ± 2 g/kWh" — provides an initial benchmark for what plasma-assisted abatement can accomplish on board. Daphne Technology emphasized that SlipPure™ and PureMetrics™ continue to be developed to offer scalable solutions both for marine vessels and for land-based gas engines that face similar methane oxidation challenges. Maran Gas’s participation under the Angelicoussis Group banner illustrates a growing willingness among shipowners to trial novel emissions-control technologies as regulators and charterers press for lower greenhouse-gas intensity.

Industry analysts say practical, verifiable methane abatement will be a key component of maritime decarbonization, complementing fuel-switching, energy-efficiency measures and alternative fuels. The ability to monitor reductions reliably at sea is equally important for compliance and corporate reporting; the integration of an aftertreatment device with an emissions-monitoring platform addresses both requirements.

Looking ahead, the technology will need additional validation over longer voyages, across broader engine operating ranges and through certification processes required by classification societies and regulators. Retrofitability, power draw, maintenance intervals and lifetime catalyst performance under marine conditions will also determine commercial viability.

For now, the Daphne–Maran pilot offers the sector a concrete proof of concept: plasma-catalytic methane abatement can be implemented on a working LNG carrier and measured in real operating conditions. If the approach scales and is adopted widely, it could become a practical tool to slash one of the more stubborn sources of shipping’s greenhouse-gas footprint.