Colors of Hydrogen

By: Dawn Lima, Vice President of Renewable Energy & Sustainable Technologies, Foss & Company 


Shades of Gray, Blue, Green – Why do we need a color wheel to describe hydrogen and what do the colors mean?

If you have been following the headlines and reading recent articles about the future of energy, you’ve likely read about hydrogen and the many colors used to describe it. Green, blue, gray, yellow, pink, etc. Why does a naturally colorless gas have so many colors?

Hydrogen is a very promising energy source in a decarbonized future as it does not emit carbon dioxide (CO2) when burned. Hydrogen energy could have many uses, particularly to decarbonize heavy vehicle transportation and construction.

What these Colors Mean

So, why are there so many colors to describe hydrogen? The different colors of hydrogen refer to how the hydrogen is made: mainly the source of the hydrogen molecule and the source of the power used to generate the hydrogen. The most common colors include gray, blue and green.

Gray Hydrogen: About 80% of hydrogen produced is currently gray.  To make gray hydrogen, natural gas is burnt in a process called steam methane reform (SMR) and carbon dioxide is released into the atmosphere, not captured and sequestered.  The power to generate the hydrogen is typically the local grid (not necessarily renewable energy) so the source mix will depend on the location of the plant and now decarbonized the grid in the region is.

Blue Hydrogen: Around 1% of hydrogen produced.  Blue hydrogen is slightly less environmentally harmful than gray.  Blue is produced in the same way as gray, but the carbon dioxide is captured and sequestered, not released into the atmosphere.  The power to generate the hydrogen is typically the local grid (not necessarily renewable energy).

Green Hydrogen:  Green hydrogen is also known as clean hydrogen. The source of the hydrogen molecule is water through a process called electrolysis. Power for the plant is from renewable energy sources. This process does not generate carbon, so no carbon dioxide is emitted to the atmosphere.

Brown & Black Hydrogen: Black and brown hydrogen are both produced by during coal, making up nearly 20% of global production. This also makes them the least environmentally friendly.

Interested in learning about white, yellow, pink, aqua or turquoise hydrogen? Check out this article from Fast Company.

Looking to the Future

This diverse array of colors used to describe hydrogen – from gray to blue to green and so on – serves as a visual spectrum illustrating the various methods and environmental impacts associated with its production. As the world explores hydrogen’s potential as a key player in a decarbonized future, understanding these colors becomes crucial. Gray hydrogen, representing the majority of current production, highlights the conventional method where natural gas is utilized, emitting carbon dioxide into the atmosphere. On the other hand, blue hydrogen, though a small percentage, signifies progress by capturing and sequestering the carbon dioxide, mitigating environmental impact. Finally, green hydrogen emerges as the beacon of sustainability, derived from water through electrolysis powered by renewable energy sources, offering a carbon-neutral solution for a cleaner future.

From gray to blue and green, each shade represents a potential new avenue. By understanding and leveraging the diverse methods behind hydrogen production, we can strategically contribute to the growth of environmentally responsible projects. We can embrace the vibrant spectrum of hydrogen possibilities and channel our efforts towards a cleaner, greener energy future.

To learn more about how to get involved in hydrogen, RNG or other renewable energy projects, contact us today.