Ammonia: grey, blue and green

Ammonia (NH₃) is the base of nearly all synthetic nitrogen fertilizer, made by combining hydrogen with nitrogen from the air in the Haber-Bosch process. The color follows the hydrogen: grey ammonia uses hydrogen from unabated natural gas; blue ammonia captures and stores the CO₂ from that step; green ammonia uses hydrogen from electrolysis on renewable power.

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Related terms

Hydrogen and ammonia

• Blue hydrogen
• Capture rate
• Carbon capture and storage
• Electrolysis
• Green hydrogen
• Grey hydrogen
• High-temperature electrolysis
• kg CO₂e/kg H₂
• Make-up hydrogen
• Methane leakage
• Nm³
• Steam methane reforming