In the shipping industry diesel engines are used almost exclusively today. Oceangoing vessels use either heavy fuel oil or marine diesel as fuel, while inland waterway vessels – within the EU for example – use commercial diesel fuel. To date the only relevant alternative drive option for the shipping industry is the use of liquefied natural gas (LNG) or compressed natural gas (CNG) to fuel ships.
As in aviation, fuel cells are currently being tested as energy providers for the on-board power supply. The functional capability of fuel cell modules has been tested successfully under maritime conditions (e4ships 2016). Fuel cells work more efficiently than comparable diesel-generator sets, in the partial load range in particular and through the possibility of combined heat and power generation. Air pollutant and noise emissions in ports can be reduced. In many cases the fuel cells are operated not with hydrogen but with other fuels, including methanol, natural gas or diesel fuel. These offer the advantages of greater availability, lower price and easier storage. They are converted into hydrogen with the aid of internal or external reformers.
The use of hydrogen-powered fuel cells for ship propulsion, by contrast, is still at an early design or trial phase – with applications in smaller passenger ships, ferries or recreational craft. The low- and high-temperature fuel cell (PEMFC) and the solid oxide fuel cell (SOFC) are seen as the most promising fuel cell types for nautical applications (EMSA 2017).
As yet, however, no fuel cells have been scaled for and used on large merchant vessels.
Moreover, in comparison to the efficient, slow-running diesel engine, which runs on heavy fuel oil, the power train and fuel are still far too expensive. In addition, international technical standards still need to be developed in order to use gaseous fuels (such as hydrogen) (Würsig/Marquardt 2016).
Submarines are a niche application of fuel cells. For instance, electrolysers have been used in submarines for some time now to produce oxygen for breathing air. Submarines operated with fuel cells have been developed in the USA and Germany. The submarines developed in Germany use PEM fuel cells and metal hydride hydrogen stores. In terms of submarine applications, fuel cells are characterised by low noise emissions, low operating temperatures and air-independent operation. However, the “market” for submarines is very small, and even in the future it will not grow beyond a niche size.
(source: Shell Hydrogen Study)
EMSA Study on the use of Fuel Cells in Shipping download
EMSA Study on the use of Fuel Cells in Shipping - Tables download
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