Green ammonia is made in two chemical stages: first, hydrogen is split from water using renewable electricity; second, that hydrogen is reacted with nitrogen taken from the air in the Haber-Bosch process to form ammonia. The inputs are simple—renewable power, water, and air—but the payoff is significant. Because the process avoids the fossil-fuel-based hydrogen that dominates conventional ammonia manufacturing, it offers a low-carbon route to fertilizer and an emerging zero-carbon fuel for deep-sea shipping.
What Is Green Ammonia?
Ammonia itself is not new. The molecule, NH₃, has been synthesized at industrial scale for a century, and agriculture remains its largest market. What is new is the energy and feedstock mix behind it. The Royal Society describes one route to green ammonia as using hydrogen from water electrolysis and nitrogen separated from the air, fed into the Haber process, with the whole chain powered by sustainable electricity.
The distinction matters because conventional production is carbon-intensive. Ammonia is most commonly made from methane, water, and air, using steam methane reforming (SMR) to produce the hydrogen before the Haber process runs; roughly 90% of the carbon dioxide produced comes from the SMR step, according to the Royal Society. Green ammonia keeps the same synthesis chemistry but swaps the fossil-derived hydrogen for electrolytic hydrogen and powers everything with renewables. As Stargate Hydrogen's Fernando Camargo puts it, the underlying synthesis reaction is unchanged—the difference lies in the hydrogen source.
