Through a memorandum of understanding (MoU) between the two parties, the first set of field demonstrator 3500E marine engines will be deployed in 2026.

A key point in the four-stroke Cat 3500E marine engine platform is the use of dual-fuel technology that leverages proven diesel fuel systems and supports vessels’ low-pressure – below 10 bar – fuel systems. The methanol dual-fuel Cat 3500E engine targets the same performance and durability as the current 3500E diesel engine while meeting emissions standards and delivering 100% power.

“We’re expanding the 3500E platform’s fuel flexibility to provide customers with a wider array of options to navigate the energy transition,” noted Caterpillar Marine global tug segment manager, Andres Perez.

“Fuel flexibility is key to future-proofing assets. This technology will enable owners to adopt their fuel of choice when the conditions are right without having to build a new asset or face cost-prohibitive retrofits,” said Mr Perez.

He highlighted the fuel flexibility and technical features of the methanol dual-fuel platform during a presentation at ITS 2024. A tug built today that is methanol-ready conventional or plug-in hybrid would be able to be retrofit over its 25-30-year lifecycle to meet IMO greenhouse gas emissions targets. By the end of its service life in 2050, the tug would operate with dual-fuel engines that burn e-methanol and renewable biodiesel (HVO), biodiesel (FAME), e-diesel or dimethyl ester (DME), a synthetically produced alternative to diesel. Aftertreatment for IMO Tier III will incorporate formaldehyde abatement.

Tug owners face particular challenges in the decarbonisation journey. While not without its challenges, methanol as a marine fuel offers the advantages of a lower carbon intensity, energy density, liquid storage and multiple production pathways.

“Our dual-fuel Cat 3500E marine engines are optimised to achieve high methanol substitution rates over a wide range of load factors, including the low load ranges that tugs operate in most of the time,” explained Cat Marine global product director, Will Watson. “For example, a 28-m tug transiting at 8 knots requiring only 600 kW of propulsion power would aim to achieve a methanol substitution on an energy basis above 70%. This will enable operators to reduce greenhouse gas emissions while experiencing the power and performance they’re accustomed to,” said Mr Watson.