Air lubrication has been known for decades, but the power required to make and deliver air remains a challenge. Conventional systems need dedicated compressors, electrical drives, and complex operating regimes.
Engine-supported air lubrication tries to improve this by using scavenge air from the main engine instead of relying on separate electrically driven compressors.
The compression work still exists, and the ship must pay the marginal penalty somewhere in the engine and turbocharger system.
However, the reported scale of the claim is part of why the concept is credible; Everllence's engine-supported approach has been described as delivering estimated net fuel savings of about 3.5%.
This modest number is large enough to matter on ships with high fuel bills, rising carbon exposure and expensive future low-carbon fuel options.
Air lubrication itself is not a science project anymore; Silverstream has passed well beyond the conference-slide stage.
The key question remains: after the ship has spent energy compressing, moving and controlling the air, is there still a net fuel saving?
Practical engineering challenges remain, but the concept is worth paying attention to for its potential to improve maritime sustainability.
The concept is clever, but not free; compression work still exists and imposes a penalty on the engine and turbocharger system.
