Alternative fuel momentum hits the brakes

Have we reached peak alternative fuel momentum? Engineers at Rolls-Royce think so – for now.

Seawork exhibitor Rolls-Royce believes the maritime industry's enthusiasm for alternative fuels has peaked, as shipowners confront uncertainty over fuel availability, infrastructure, economics and which technologies will ultimately prevail.

Lukas Köhler, Senior Vice President Global Marine & Mining, says the industry has lost some of the decarbonisation momentum it built five years ago. While methanol remains an option, he says the short-to-medium-term reality is diesel, prompting Rolls-Royce to continue investing heavily in combustion-engine technology.

“The conversations are still there,” says Phil Kordic, Senior Expert Commercial Marine Business. "But with biofuels and HVO offering solutions that can be used today, customers are increasingly looking at flexible vessel architectures that can accommodate future technologies without committing to equipment prematurely."

Methanol's biggest hurdle is now supply rather than engine capability. Rolls-Royce has secured DNV certification for methanol readiness on its mtu Series 4000 marine engines, but Köhler says green methanol production and availability in ports remain limited.

The company also sees a role for batteries, but not as a universal solution for commercial vessels. Instead, combustion engines and battery-electric propulsion can increasingly work together, with engines providing backup, range or peak power.

That is the thinking behind Rolls-Royce's new variable-speed mtu Series 2000 generator sets, covering approximately 650–1,850 kWe. Unlike fixed-speed gensets, the engines can adjust their speed to match electrical demand, operating more slowly and efficiently at low loads before increasing speed when higher power is required. Rolls-Royce says the technology can cut fuel consumption and CO₂ emissions by up to 15%, while reducing operating noise by around 6dB.

Power density is another advantage. A 16V2000-based genset can deliver up to about 1.8MW for some vessel applications while weighing as little as seven tonnes. That compact footprint is particularly relevant to hybrid vessels, where battery systems already add significant weight.

For now, Rolls-Royce's message is pragmatic: optimise what exists, use biofuels where possible, and design vessels with the flexibility to accommodate whatever comes next.

Read the full interview with Maritime Journal editor Debbie Mason on the MJ website here.

Image; Lukas Köhler, Senior Vice President Global Marine & Mining

Exhibitor; Rolls-Royce Solutions