Maritime power. What are the advantages and disadvantages of diesel engine, lng and electricity?

Direct propulsion of diesel engine is the mainstream at present, which has the advantages of wide fuel sources, low price (even worse than oil), high single-machine power and high efficiency, but the disadvantages are environmental pollution, poor starting performance of low-speed engine in cold start (warm-up is needed for standby), poor acceleration performance (under normal circumstances, it takes 1-2 hours from starting to sending out full power), poor maneuverability and poor reversing performance when equipped with fixed-pitch propeller and variable-pitch propeller.

LNG is a kind of fuel, which can be used for dual-fuel diesel engine or gas turbine at present. The advantage of LNG is clean (no pollution from sulfur oxides, nitrogen oxides, particulate matter, etc.), but the disadvantage is that the storage and gasification supply device is complex in technology and high in price.

Electric propulsion is a way of propulsion, and the power source can be provided by prime movers with synchronous generators such as diesel engines (medium and high speed machines), gas turbines and steam turbines. The advantage of electric propulsion is that the power can be large (increasing the number of generators). At present, this scheme is mostly adopted by passenger ships, with simple engine room layout, high ship speed and good maneuverability, but the disadvantage is low efficiency.