Hydrogen production is classified using color labels to denote the energy source and extraction process.

Gray hydrogen is the most common type produced today. The typical process for gray hydrogen production is steam-methane reforming.

Blue hydrogen takes gray hydrogen one step further by capturing and storing the carbon (CCS) or possibly using it (CCUS).

Turquoise hydrogen uses methane pyrolysis to produce hydrogen and solid carbon and has yet to be proven commercially.

Green hydrogen is produced by water electrolysis, using only renewable energy sources like wind, solar, and hydropower.