… For decades, hydrogen has been hailed as a potentially revolutionary alternative to fossil fuels …
Green hydrogen - Made by using clean electricity from renewable energy technologies to electrolyse water (H2O), separating the hydrogen atom within it from its molecular twin oxygen. Currently very expensive.
Blue hydrogen - Produced using natural gas but with carbon emissions being captured and stored, or reused. Negligible amounts in production due to a lack of capture projects.
Grey hydrogen - This is the most common form of hydrogen production. It comes from natural gas via steam methane reformation but without emissions capture.
Brown hydrogen - The cheapest way to make hydrogen but also the most environmentally damaging due to the use of thermal coal in the production process.
Turquoise hydrogen - Uses a process called methane pyrolysis to produce hydrogen and solid carbon. Not proven at scale. Concerns around methane leakage.