What kind of fuel cells will be used?
The project will use solid-oxide fuel cells (SOFC) that operate at temperatures in the range of 500-1000°C, at high efficiency. SOFC technology is used mainly in land-based power plants with electrical capacities up to 10 MW, and as residential combined heat and power systems using natural gas fuel. The ShipFC will develop a compact SOFC system specifically for maritime use.
Why is green ammonia a good alternative to traditional fuels?
As ammonia contains no carbon, it does not emit CO2. It has the potential to be a zero-emission fuel, but this depends on the production method: whether we make grey, blue, or green ammonia. Grey ammonia is produced using energy from fossil fuels, thus emitting large amounts of carbon. Blue ammonia is produced using the same method, but emissions are reduced by carbon capture and storage (CCS). Green ammonia is the only zero-emissions alternative. When making green ammonia, hydrogen is produced using renewable, zero-emissions energy.
Project partner Yara has several ongoing projects for green ammonia production, for example using hydropower at the plant in Porsgrunn, Norway, wind power in Sluiskil, Netherlands, and solar power in Pilbara, Australia.
What are the emissions from the use of ammonia in the ShipFC-project?
The process of generating electricity from ammonia is similar to that of a hydrogen-based power plant. Ammonia (NH3) is fed into the fuel cell anode. The air is fed into the fuel cell cathode, allowing the ammonia to be oxidized and form water and nitrogen at the anode side. This produces electrical energy. The gas stream leaving the anode contains water, nitrogen, a minor amount of hydrogen, and possibly a negligible amount of unconverted ammonia.
This residue is then fed into the catalytic converter developed by Fraunhofer IMM. Here, the air is introduced, and the residue comes into contact with a catalyst layer deposited onto the internal surface of the reactor. This triggers a chemical reaction. Ultimately, the only end products are water and nitrogen. An optimal reaction process will produce no or only negligible amounts of environmentally harmful nitrogen oxides.