How do alternative fuels like LNG, hydrogen, and ammonia compare in terms of efficiency and emissions?

Large American ports, ie Los Angeles, it seems to be seeing LNG as the fuel of the past and no longer consider it part of the port development. Interestingly enough LNG is not even being counted as a potential transitional option to something cleaner.

The outlined challenges for hydrogen can be resolved by implementing onsite production of the fuel. This reduces liquefaction, storage, and transportation costs. It can be generated at the place where it is needed by the water electrolysis process, instead of generating it in centralized SMR plants and liquefying it for transport in large trailers. This method is proven to be carbon-free and cost-effective (5.1-7.5 $/kg-H2) at a BMW manufacturing plant. (Felgenhauer, Markus & Hamacher, Thomas. (2015). State-of-the-art of commercial electrolyzers and on-site hydrogen generation for logistic vehicles in South Carolina. International Journal of Hydrogen Energy. 40. 2084-2090. 10.1016/j.ijhydene.2014.12.043).

There is a clear opportunity for hydrogen to play a role in maritime shipping. However it is important to recognise that it will not be a direct replacement for HFO or MDO, but a part of a suite of solutions that includes overall efficiency of vessel operation. The low hanging fruit will be in short sea shipping and return to base vessels, a prime example being ferries and offshore wind O&M vessels.

I believe that a new build Disney ship has been planned for the year 2028 that is fueled by Ammonia - MAN engines. I honestly think that this type of fuel is for now a good substitute to power ships

In the realm of alternative fuels, LNG, hydrogen, & ammonia present a diverse efficiency & emissions profiles:- LNG - The Queen Mary 2, a transatlantic ocean liner, utilises LNG, cutting sulphur emissions by 99% & nitrogen oxides by 85%, though its greenhouse gas reduction is less pronounced Hydrogen - Germany's rail operator, Deutsche Bahn, runs hydrogen-powered trains that emit only water vapour, showcasing hydrogen's high energy efficiency & zero carbon emissions, but with current challenges in production & storage. Ammonia - A pilot project in Norway is exploring ammonia-powered ferries. Ammonia, while carbon-free, requires careful handling due to its toxicity but promises significant emissions reductions

I believe that ammonia produces toxic emissions due to its poor combustion characteristics, like low laminar flame speed and high auto-ignition temperatures. To overcome this, it can be decomposed into hydrogen by means of a catalyst (ruthenium is proven to have a high efficiency of hydrogen yield for decomposition). This onsite generation of hydrogen can increase combustion characteristics and generate low NOx emissions on a tank-to-wheel basis. It can be used as a secondary fuel in ICE or can be coupled with fuel cell applications.