Ammonia

Ammonia is a colorless, pungent-smelling compound of nitrogen and hydrogen, chemical formula NH3, produced overwhelmingly today for fertilizer but increasingly explored as a carbon-free energy carrier. Because it liquefies at a far less extreme temperature and pressure than hydrogen, ammonia is markedly easier to store and transport, and its volumetric energy density of about 11.5 megajoules per liter is nearly double that of liquid hydrogen. Experiments with ammonia as a vehicle fuel date back at least to an 1871 ammonia-gas-engine streetcar demonstrated in New Orleans, but its current momentum is in shipping: the International Energy Agency projects ammonia could meet around 45 percent of shipping fuel demand by 2050, shipbuilders DSME and MAN Energy Solutions announced an ammonia-fueled ship design in 2020 aimed at commercialization by 2025, and Saudi Arabia shipped the first international cargo of fuel-grade blue ammonia, made from natural gas with captured carbon dioxide, to Japan that same year. Renewable green ammonia, made using electrolysis powered by renewable electricity, is the pathway producers are pursuing to make the fuel genuinely carbon-free.