What is the Hydrogen Rainbow?

Although hydrogen is a colorless gas, the various forms of technology used to produce hydrogen reveal a rainbow of colors. The colors that make up the rainbow help us learn each type of hydrogen’s production process and the potential impacts it can have on our planet.

Green hydrogen

Produced through electrolysis of water using only electricity from renewable sources such as hydropower, wind, and solar. Production does not cause any greenhouse emissions meaning there is no carbon dioxide produced, only hydrogen and oxygen. Green hydrogen is more expensive and only a small percentage of overall hydrogen. This type of hydrogen is key to reducing carbon emissions and working towards a greener, sustainable future.

Blue hydrogen

Uses the process of steam methane reforming; however, the carbon dioxide is captured and sequestered underground. This type of hydrogen is a source of clean hydrogen, the closest thing to green hydrogen, and is sometimes referred to as “low-carbon hydrogen.”

Turquoise hydrogen

Produced by a process called methane pyrolysis. This is a potential low-emission solution that has hydrogen and solid carbon as its primary outputs.

Brown/Black hydrogen

The most environmentally damaging type of hydrogen. Production relies on the gasification of coal which releases harmful carbon emissions that have long lasting impact on our planet.

Grey hydrogen

The most common form and is created from natural gas through steam methane reformation. Throughout this process the greenhouse gases are not captured and released into the atmosphere.

Pink hydrogen

The type generated through nuclear energy to fuel electrolysis. This type can also be referred to as purple or red hydrogen. The elevated temperatures produce steam that can be utilized in other hydrogen productions for more efficient electrolysis.

Yellow hydrogen

A new term that identifies hydrogen made through electrolysis using solar power.

White hydrogen

Naturally occurring found underground in deposits.