05/23/2025
The hydrogen rainbow isn't just colorful for fun – it's a shorthand for understanding production methods and their environmental impact. Here’s the deal:
Gray Hydrogen: Currently dominating 95% of total global hydrogen production, gray hydrogen is made via steam methane reforming (SMR) of natural gas without capturing CO₂ emissions. For every ton of hydrogen produced, approximately 10 tons of CO₂ are released into the atmosphere.
Blue Hydrogen: Using the same SMR process, blue hydrogen captures and stores the resulting carbon emissions (CCUS). While not completely carbon-free, it reduces emissions by 60-90% compared to gray hydrogen and represents a significant stepping stone in the transition.
Green Hydrogen: Green hydrogen is produced by splitting water through electrolysis powered by renewable electricity. No carbon emissions are produced during generation, making it truly zero-emission when renewable energy is used.
Pink/Purple Hydrogen: Generated through electrolysis powered by nuclear energy, this offers another low-carbon pathway with stable baseload power.
Turquoise Hydrogen: Emerging through methane pyrolysis, this process splits natural gas into hydrogen and solid carbon, avoiding direct CO₂ emissions. The carbon can potentially be used in materials applications.
White Hydrogen: Naturally occurring geological hydrogen found in underground deposits, this emerging frontier could potentially provide zero-carbon hydrogen without electrolysis energy requirements.
While these color classifications provide convenient shorthand, what ultimately matters is carbon intensity – the total emissions per kilogram of hydrogen produced. We’re focused on technological innovations that will transform electrolytic production methods and hope to make sustainable hydrogen production accessible to the world.