Blue Economy
Testing to address methane slip in LNG-powered vessels begins
A groundbreaking system designed to tackle one of LNG shipping’s biggest environmental challenges is now undergoing real-world testing aboard an operational vessel.
Addressing a Critical Environmental Challenge
Testing has officially begun on an innovative onboard system designed to address methane slip in LNG-powered vessels. The technology, now installed on an active LNG bunker vessel, targets one of the most significant environmental challenges facing the LNG maritime industry.
Environmental advocates have long highlighted methane slip—the release of unburnt methane during engine operation—as a critical concern, noting that methane ranks among the most potent greenhouse gases, with warming potential significantly higher than CO2 in the short term.
Collaborative Innovation
This technological advancement comes through a collaboration between Mitsubishi Heavy Industries Marine Machinery & Equipment Co. (MHI-MME), Daihatsu Infinearth Mfg. Co., and KEYS Bunkering West Japan.
The partners have developed a methane oxidation catalyst system that showed remarkable promise during initial land-based testing, achieving a verified methane oxidation rate of 70 percent or higher in controlled environments.
From Shore to Ship
Following successful shore-based validation, the system has now been installed on the KEYS Azalea, a 2,352 dwt LNG bunkering vessel built in 2024 by Mitsubishi Shipbuilding.
The KEYS Azalea completed its first bunkering operation in Hiroshima in April 2024 and currently provides:
- Domestic coastal transport of LNG to consumers in the Kyushu and Setouchi areas
- LNG bunkering services for oceangoing vessels calling at ports in the region
How the Technology Works
The catalyst system tackles methane slip through a chemical process called methane oxidation. This reaction converts methane (CH₄) into carbon dioxide (CO₂) and water (H₂O) by facilitating a reaction with oxygen.
While converting methane to CO₂ might seem counterintuitive for emissions reduction, the science is clear: methane has a global warming potential approximately 28-36 times that of CO₂ over a 100-year period (and even higher in shorter timeframes). By converting methane to CO₂, the system significantly reduces the overall climate impact.
Long-Term Testing Phase
The demonstration testing will run continuously for a full year as part of MHI Group’s strategic initiative to strengthen its energy transition business portfolio. This extended testing period will:
- Validate the system’s performance in real-world maritime conditions
- Gather data on long-term reliability and efficiency
- Identify opportunities for further optimization
Industry Context
The LNG industry has emphasized that the newest generation of LNG marine engines already demonstrate improved performance in reducing methane emissions. This catalyst system represents a complementary approach to further minimize LNG’s environmental footprint.
MHI-MME and Mitsubishi Shipbuilding are positioning this technology as a key component of their response to increasing global decarbonization urgency. The companies have stated their commitment to continuing work on reducing greenhouse gas emissions from marine vessels and contributing to improved environmental performance of ships worldwide.
If successful at scale, this technology could significantly strengthen LNG’s position as a transitional fuel in maritime shipping’s journey toward carbon neutrality.