Steel is the backbone of our civilization, but it is also the largest single cause of global warming, through its massive greenhouse gas emissions (about 7% of all global CO₂ emissions). YAN MA introduces here a novel approach to deploy intermittent renewable energy in the form of green ammonia and use it for an unprecedented ironmaking process, i.e., ammonia-based direct reduction. Bypassing ammonia cracking (splitting it into hydrogen and nitrogen), the research demonstrates how using ammonia to produce direct reduced iron brings significant and heretofore unrecognized advantages. This novel approach sheds light on future sustainable ironmaking. Further work will look to vary different aspects of the process so that it can be used on an industrial scale.