Hanwha Power Systems: deploying ammonia gas turbines onboard vessels

Retrofitting LNG carriers

Hanwha Power Systems and GasLog will explore the retrofit of existing LNG carriers to be powered by ammonia gas turbines. Hanwha Power Systems and Hanwha Ocean (in collaboration with GasLog) have already completed preliminary engineering and economic feasibility studies, with the partners now set to develop a comprehensive demonstration plan. GasLog currently owns and operates a fleet of twenty-four large LNG carriers, ranging between 145,000 – 180,000 m³ cargo capacity, with another fourteen carriers operated by partner organisations.

If the demonstration of ammonia gas turbines for ship propulsion is successful, it will be a major turning point in the global shipbuilding and shipping industry paving the way for eco-friendly fuel propulsion in vessels.

Justin Lee, CEO of Hanwha Power Systems in his organisation’s official press release, 19 Sept 2024

Hanwha Power Systems’ move is attracting a lot of attention from shipowners who currently lack suitable alternatives for carbon reduction. Ongoing discussions are also taking place with some major ship owners. In particular, ship owners point out that ammonia gas turbines do not require pilot oil during normal operation, whereas engines typically use pilot oil at all operating points. For a gas turbine using ammonia fuel it is possible to operate completely carbon-free, or operators can freely mix ammonia and natural gas so that they can respond flexibly and economically to future regulations. The gas turbine will generate a negligible amount of methane slip, even if natural gas is used as fuel. Feasibility studies are ongoing for other potential fuels that could be used.

Potential benefits of ammonia gas turbines on vessels, detailed by Hanwha Power Systems in its official press release, 19 Sept 2024

Naval vessels in the 1940s, civilian vessels in the 1950s

Gas turbines have been deployed onboard vessels since the mid twentieth century. Although conventionally-fueled engines are preferred at sea for efficient sailing at consistent, lower speeds, gas turbines offer the potential of fast acceleration and maneuvering, plus a high power-to-weight ratio for the installed equipment. It is for this reason that naval ships were the first to apply gas turbine propulsion, and the British Royal Navy’s motor gunboat MGB 2009 was converted in 1947. Since then the German, Danish, Finnish, Swedish, USSR, Canadian and US navies have all commissioned and sailed turbine-propelled warships. Rolls Royce claims the current highest-rated, in-service marine gas turbine: the 36-40 MW MT30 (aboard the US navy’s Littoral Class combat ships). GE’s LM2500 is the most widely-deployed naval gas turbine.

For civilian maritime applications – which do not have the same operational demands as naval – uptake was understandably slower. The first small tanker was not retrofitted until 1951. Ex-naval vessels, container ships and passenger ferries were all demonstrated over the ensuing decades. More recently, cruise ships have combined steam and gas turbines to provide fuel flexibility and enhanced reliability.