An ammonia-powered tugboat named NH3 Kraken has completed its maiden voyage as part of a research project designed to reduce carbon emissions from shipping.

Developed by Amogy, NH3 Kraken was originally constructed in 1957 and has been retrofitted with an ammonia-to-electrical power system. The test voyage took place on a tributary of the Hudson River, upstream from New York City.

The huge container ships used to deliver cargo across oceans emit large quantities of air pollutants from their diesel engines, driving climate change and having human health impacts. It has been estimated that maritime shipping accounts for almost 3% of global carbon dioxide (CO2) emissions, and that the industry’s negative impacts on air quality cause about 100,000 premature deaths each year.

Scientists are considering whether switching the global fleet from fossil fuels to ammonia could be a climate solution for the shipping sector.

Traditionally, ammonia is made by stripping hydrogen from natural gas and then...