Navigator Holdings has won approval in principle from classification society DNV for an ammonia-fuelled LPG carrier.
The US-listed shipowner said subsidiary Navigator Gas has been developing the design with an industry-wide consortium, including MAN Energy Solutions, Babcock International and the Norwegian Maritime Authority (NMA).
Approval has been granted under the special features notation (GF NH3) of DNV's new rules for the use of ammonia as fuel in gas carriers.
DNV, alongside the NMA, reviewed the design and relevant documentation and found no potential "showstoppers" to its realisation, Navigator said.
Navigator's head of fleet and technical operations, Paul Flaherty, said the approval is the first step in preparing the company to lower greenhouse gas emissions.
"In the longer term, using ammonia ... is one of [the] alternative fuels options we are pursuing, along with carbon capture and storage," he added.
The company will also use carbon offsetting and improved vessel optimisation.
"If our industry is going to continue to play a central role in the global economy, we need to be exploring all options that can get us further towards decarbonisation," said Torgeir Sterri, DNV's regional manager for western Europe.
Decision of the decade
"At the same time, we recognise that for our customers, how to tackle the decarbonisation challenge is going to be most challenging and significant decision they are likely to make this decade."
The new class notations and guidelines are aimed at giving shipowners the flexibility to find the path that fits their operations and business, DNV said.
Andrew Scott, business development director at systems maker Babcock LGE, said his company has experience of how ammonia is carried on gas carriers.
"Specific issues occurring when utilising ammonia as a fuel are well understood, resulting in an inherently safe design," he added.
Thomas Hansen, head of promotion & customer support at MAN Energy Solutions, described ammonia as of "especial interest."
"Since large quantities of ammonia are already transported around the world, it is a well-established commodity and using it to power ships would be a natural step," he added.
MAN Energy already plans to have a dual-fuel, two-stroke ammonia engine commercially available for large ocean-going ships by 2024.
A retrofit package for existing ships is targeted for 2025.
