Everllence and Partners Complete S90 Methanol Engine Retrofit

Everllence has announced the world’s first conversion of an Everllence B&W S90 two-stroke engine to dual-fuel methanol running following the successful sea-trials of COSCO Shipping Lines’ 20,000+ TEU container vessel, COSCO Shipping Libra.

The vessel’s 11S90ME-C engine was retrofitted to an 11S90ME-LGIM (-Liquid Gas Injection Methanol) unit.

Everllence PrimeServ – Everllence’s after-sales division – partnered with COSCO Shipping Heavy Industry from concept to execution in delivering the world’s first S90 methanol engine retrofit, a full-scope project covering engineering, project management, installation, commissioning, and sea-trials.

As part of the process, Everllence invested in a dedicated 4S90 testbed engine in Japan that was commissioned in early 2025. The testbed validated the S90 engine’s methanol performance under real operating conditions, accelerating its readiness for this first large-bore milestone.

Everllence believes that the potential for further large-bore retrofits is substantial with over 300 vessels worldwide currently equipped with S90-class engines and therefore potential candidates for similar retrofits.

Michael Petersen, Senior Vice President and Head of Everllence PrimeServ, Denmark, said: “With 26 dual-fuel conversions already completed and an even larger pipeline across various alternative fuels, shipowners can trust Everllence to deliver retrofit solutions at scale."

Petersen added: “While the journey toward full decarbonisation will require collaboration across the industry, this achievement demonstrates that large-scale conversions are both technically proven and commercially viable. This opens a practical pathway towards accelerating the maritime energy transition together with our customers.”