China's bubble-lubrication system saves large ships 1.1 tons of fuel daily

Summary

China's Shanghai Ship Design and Research Institute reported that its second-generation air lubrication system injects compressed air under the hull of a tanker to reduce seawater friction. In a five-month trial on a 55,000-ton chemical tanker, the system achieved approximately 5% net energy savings. The Institute estimates this equates to saving about 1.1 metric tons of fuel per day; however, this figure is an extrapolation, not a directly measured result.

Why it matters

Global maritime shipping accounts for approximately 3% of CO₂ emissions. Even a modest 5% fuel saving across a large fleet could provide a significant carbon reduction benefit without requiring a switch to new propulsion fuels. The claim that the system is compatible with LNG, methanol, ammonia, and electric propulsion makes it a likely retrofit efficiency layer that operators can adopt alongside their existing fuel transition plans.

Highlights

• The 1.1-ton daily saving is not a directly measured trial value but an estimate based on a 22-ton daily baseline.
• The second-generation system offers real-time energy monitoring and automatic air control based on speed and water depth, compared to the manual prototype from 2022.
• The Institute has not published a detailed breakdown of the five-month trial data, nor has it cited an independent third-party verification source.

Critical take

The headline figure relies on a single five-month trial on a single ship class. The savings figure is explicitly marked as an estimate, and no independent audit or peer-reviewed data has been shared. Until the technology is validated across different hull geometries, routes, and sea conditions, the 5% claim should be viewed as a promising pilot result rather than a fleet-level guarantee.