Green hydrogen is produced by electrolysis: electricity drives a reaction that separates water into hydrogen and oxygen. When the electricity comes from wind, solar or other qualifying renewable sources, the production step can have much lower greenhouse gas emissions than conventional fossil-fuel routes.
The term describes how hydrogen is made, not a new kind of hydrogen molecule. The product can be used in ammonia plants, refineries, steelmaking or other industries where direct electrification may be difficult. Production requires clean electricity, water, an electrolyser and infrastructure to store or deliver the gas.
Low emissions at the electrolyser do not mean the whole supply chain is emission-free. Equipment manufacture, electricity sourcing, compression, transport and possible leakage all affect the environmental assessment. Definitions and certification requirements also differ across markets.
Compare projects using a documented lifecycle emissions method and a delivered cost, not only the green label. Check whether the renewable power is actually available when the plant runs and whether customers have committed to buy its output.