Renewable Hydrogen for Sustainable Ammonia Production

More than half of all produced hydrogen is consumed in ammonia plants. Ammonia’s potential as a carbon-free fuel, hydrogen carrier, and energy store represents an opportunity for renewable hydrogen technologies to be deployed at an even greater scale.

The Haber-Bosch process reacts atmospheric nitrogen with hydrogen to produce ammonia (NH₃), which is 17.8% hydrogen by weight. Ammonia is the precursor to most modern nitrogen-based fertilizers. More than half of all the hydrogen produced around the world today is consumed in ammonia plants — in fact, ammonia production represents 55% of total global hydrogen use (1).

Hydrogen is typically produced on-site at ammonia plants from a fossil fuel feedstock. The most common feedstock is natural gas, which feeds a steam methane reforming (SMR) unit. Coal can also be used to produce ammonia via a partial oxidation (POX) process. Different regions favor different feedstocks. For example, some ammonia producers use naphtha, petroleum coke, or even heavy fuel oil as their hydrogen source.

Ammonia is the second-most synthesized chemical on the planet (behind sulfuric acid), with a global production in 2018 of around 170 million metric tons (m.t.) (2). Thirty million m.t. per year of hydrogen is produced in the SMR and POX units of ammonia plants around the world. But this hydrogen is captive: All of the 30 million m.t. of hydrogen produced each year in SMR and POX units is consumed in the production of ammonia, and none is available for sale as a hydrogen product. It is easy, therefore, to overlook the ammonia industry when considering the hydrogen industry. However, in the context of scaling up hydrogen, it is crucial to understand the role that ammonia will play.

Today’s ammonia producers have more operational know-how regarding hydrogen production than all other hydrogen-producing industry segments combined. In competitive commodity markets, that knowledge is the difference between profit and loss.

However, ammonia producers are beginning to demand a different kind of hydrogen — decarbonized, renewable, sustainable hydrogen — and they will require huge quantities of it. In the long term, there will be many large markets for renewable hydrogen; but in the near term, renewable fertilizers represent a feasible, early market opportunity that is orders of magnitude greater in scale than other existing markets.