Norway-based Alma Clean Power (Alma) has announced a breakthrough in its mission to develop modularised Solid Oxide Fuel Cell (SOFC) systems for applications in the ocean space after its successful test for the world’s first six kilowatt (6 kW) direct ammonia fuel cell system.Considered as the first building block of a complete 100kW SOFC module, the 6kW unit represents a step in the company’s journey towards economically viable, zero-emission deep-sea shipping.According to Alma, the test delivered an electrical efficiency rating of 61-67%, which was achieved by direct feeding of ammonia into the fuel cell system – bypassing the need for energy intensive pre-treatment that converts the fuel into hydrogen prior to electricity production.Enthusing about the company’s ‘remarkable’ achievements in just over a year of system development, Bernt Skeie, CEO of Alma, spoke about the new unit, saying, “To our knowledge, this is the highest power output er demonstrated with direct ammonia solid oxide fuel cells.”With higher efficiency levels compared to traditional combustion engines, the technology has the potential to make ammonia operated maritime energy systems economically viable for ship owners.Ammonia is one of the leading potential candidates as zero carbon fuel. The fuel is being explored by organisations such as the Getting to Zero Coalition, which is committed to accelerating shipping decarbonisation by getting commercially viable deep sea zero emission vessels powered by zero emission fuels into operation by 2030.What makes ammonia such a good zero carbon fuel candidate?As there is no carbon atom in the ammonia molecule, it does not emite carbon dioxide (CO2) during combustion. It also has an energy density similar methanol and more favourable than hydrogen. In addition, it requires less cooling than cryogenic liquid hydrogen, making it more efficient.Because the gas can be synthesised from zero carbon hydrogen usin he Haber-Bosch process, ammonia will always be cheaper than other zero-emission fuel options such as methanol or e-methane.The decreasing cost of renewable energy also supports the scalability of ammonia as a marine fuel. Currently operating 24/7, Alma’s combustion-free SOOFC system modules contain no rotating parts and are designed to operate autonomously without any need for maintenance for long periods.“It’s rewarding to see the system operate with stable operation and consistent electricity generation,” said Rune Tveit, Project Manager. “To gain knowledge and fine-tune the setup, testing will continue throughout the summer.”After that, the company intends to proceed with the assembly and testing of a complete 100kW nodule which will serve as the foundation for larger ship installations.Despite its advantages as a potential zero-emission fuel, there are also significant challenges facing development of green ammonia.This includes its overall cos ‐ which is overall more costly than incumbent fuels – and safety. A highly toxic, flammable and corrosive gas, ammonia is a risk for both human and animal life in the case of leakage.According to the Global Maritime Forum, a high level of collaboration is needed between international standard setters and local regulators to scale the production, bunkering and use of ammonia as a shipping fuel.