A new study from UCL Energy Institute questions the idea that LNG and methanol function as “transition fuels” on the path toward ammonia in shipping. According to the researchers, they may instead create lock-in effects where shipping companies become stuck with technologies that soon fail to meet climate requirements.

It is often said that LNG and methanol are transition fuels, or stepping stones, toward green ammonia. But is that really the case? According to the study “When is a stepping stone a dead-end?” published last Thursday by the UCL Energy Institute, the answer is no. Rather than serving as stepping stones, there is a significant risk that these fuels become sinks that push the shipping sector into an even deeper dependence on fossil fuels.

“There is a real danger of confusing short-term movement with long-term progress. Our findings, based on interviews, document analysis, including patent data, and econometric analysis, show that investments in LNG and methanol can easily become dead ends if they lock capital, infrastructure, and expectations into pathways that do not lead to zero emission shipping,” says Pinar Langer of the UCL Energy Institute, one of the researchers behind the study.

According to the study, LNG has some potential as a transition fuel, but only if strong policy measures are introduced. Ships must be developed to be “truly ammonia-ready,” and ports and bunkering systems need to be adapted for ammonia in ways that allow cost-effective reuse. Without such policies, LNG investments risk competing with—rather than enabling—green ammonia.

Methanol is assessed as having even weaker overlap with ammonia. Tanks, storage systems, and bunkering pipelines designed for methanol simply have too little compatibility with ammonia systems. According to the researchers, this means that investments being made today are unlikely to support a later transition.

The researchers are also not fully convinced that the dual-fuel engines being built today will actually run on ammonia in the future. In theory, they can be converted to operate on different fuels, but doing so requires extensive modifications to other ship systems. In practice, this means that converting a vessel from methanol to ammonia later on could be almost as costly as rebuilding a conventional ship from scratch.

The study urges policymakers to do two things. First, they must make the targets genuinely meaningful. This requires building long-term credibility around emission-reduction goals so that shipping companies and investors actually factor in the value of real ammonia readiness when ordering new vessels.

Second, a faster rollout of ammonia is needed through targeted investments in research and development, demonstration projects, and robust safety standards. The goal must be to establish the fuel commercially already within this decade.