In a search for alternatives to fuel oil for ships, only LNG has yet made any real progress. For some niche vessels, methanol and ethane have also proved to have a place and in recent years energy storage systems have proved a good way to make the most of power that would have otherwise have gone to waste.
Fuel cells – once considered the best option for the future – dropped out of the picture after just one or two installations and companies that had been pioneers put the idea on the back burner. However, interest in the idea never went away entirely and in November last year ABB made an announcement that indicates a revival of fuel cell projects could be on the cards.
The new project involves ABB and Royal Caribbean International vessel and will be the first fuel cell system to provide an energy source for a luxury cruise ship. “This pilot installation demonstrates that fuel cell technology is now firmly in sight of the cruise industry,” said Juha Koskela, Managing Director, ABB Marine & Ports. “Fuel cells have been the next big thing for 25 years, but now they are reality.”
The pilot installation, including control, converter and transformer technology from ABB, will generate 100 kW of energy, and has been fully developed, marinized, assembled and tested by ABB Marine & Ports. ABB selected an FCvelocity proton exchange membrane (PEM) pure hydrogen fuel cell engine from Ballard Power Systems for its pilot system.
The output of the fuel cell at 100kW is not a major contribution to a cruise ship’s power demand and it is considerably smaller than the 330kW fuel cell system installed in 2009 on the offshore vessel Viking Lady. Information available on the Ballard Power Systems website indicates that the fuel cell selected for the new project is considerably smaller than that in the earlier project with a size of around 0.5m3 and weighing 285kg but it also requires two other modules – one for coolant and the other for air – which add to the size and weight.
Liquid hydrogen makes its debut
A much larger fuel cell system will be needed if another ambition announced last year is to be realised. Some weeks before ABB’s announcement, Viking Line – operator of the first international LNG-fuelled ferry Viking Grace – revealed that it was hoping to build a 230m, 900-passenger ferry powered by hydrogen fuel cells.
The hydrogen would be carried in liquid form which means a system capable of maintaining the fuel at -253°C – considerably colder than the temperature needed for LNG. At present, liquid hydrogen is not produced on a large scale in Europe, but Viking Line is apparently in dialogue with Statoil in order to find a solution based on a Norwegian refinery.
The alternative to using fuel-cells is to burn liquid hydrogen in an internal combustion engine. This has its problems for as well as the need for a liquid hydrogen fuel system, hydrogen can cause metals to become brittle and because of the small size of molecules readily diffuses through many materials.
In December, Hydroville – a 14m catamaran passenger shuttle became the first LR classed vessel to use hydrogen to power a diesel engine. Hydroville is owned by Belgian operator CMB and is a showcase for the use of clean fuels and is primarily a project to test hydrogen technology for applications on larger vessels. CMB has plans for a hydrogen-powered auxiliary engine on an ice-classed feeder container ship.
The engines in the vessel are a pair of H2ICED units with a combined total shaft power of 441kW. The engines are modified common rail Ford diesel automotive engines which have been used in several prototype road vehicles and other applications. They can run on hydrogen or standard diesel fuel. The fuel system for Hydroville comprises 12 hydrogen tanks (205 litre @ 200bar) and 2 diesel fuel tanks (2×265 litre) as pilot/backup fuel.
Hydrogen is undoubtedly a clean fuel but to produce it requires more energy than the fuel itself holds. That means that any polluting effect is merely pushed back up the line unless the production facility receives its power from sources such as hydroelectricity, nuclear or some renewable source.