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# Green, Blue and Grey Hydrogen: What the Colours Actually Mean
- URL: https://www.energyinsider.io/green-blue-and-grey-hydrogen-what-the-colours-actually-mean/
- Published: 2026-10-12T11:26:06.000Z
- Updated: 2026-10-12T11:26:06.000Z
- Description: Hydrogen is only as clean as the way it is made. Grey, blue and green describe very different production methods with very different emissions, costs and investment cases. Here is what the colours actually mean, and why it matters.
- Author: Louise Mitchell
- Tags: Insider+ Knowledge, Hydrogen

Hydrogen is often described as a clean fuel, but that description hides an important truth: hydrogen is only as clean as the way it is made. The industry uses an informal colour code to distinguish production methods, and those colours carry very different implications for emissions, cost and the investment case. Understanding them is essential to making sense of the hydrogen sector, because the same molecule can be nearly carbon-free or highly carbon-intensive depending on its origin.

## Grey hydrogen

Grey hydrogen is the incumbent, and today it accounts for the overwhelming majority of global production. It is made from natural gas through a process called steam methane reforming, which strips hydrogen from methane and releases carbon dioxide as a by-product. It is the cheapest way to make hydrogen and underpins existing industrial uses such as fertiliser and refining. Its drawback is straightforward: it is carbon-intensive, with the emissions vented to the atmosphere. When people note that most hydrogen is not clean today, grey hydrogen is what they mean.

### Blue hydrogen

Blue hydrogen uses the same natural-gas-based process as grey, but adds carbon capture and storage (CCS) to trap most of the carbon dioxide that would otherwise be released. The result is lower-carbon hydrogen at a cost higher than grey but generally below green. Blue hydrogen is frequently framed as a transitional or bridge option: it can decarbonise existing production at large scale using established technology, while green capacity is built out. Its critics point to two issues: capture is not complete, so some emissions remain, and upstream methane leakage can erode the climate benefit if not tightly controlled.

### Green hydrogen

Green hydrogen is the version that gives the sector its clean reputation. It is made by electrolysis, using electricity to split water into hydrogen and oxygen, with the electricity supplied by renewables such as wind or solar. Done this way, production is essentially carbon-free. The obstacle is cost: green hydrogen is currently the most expensive to produce, dependent on the price of renewable electricity and the capital cost of electrolysers. Bringing that cost down, through cheaper renewable power and cheaper, larger electrolysers, is the central challenge on which much of the sector's future rests.

### Why the distinction matters for investors

The colours map onto quite different parts of the listed hydrogen universe. Established industrial-gas majors are profitable today largely on grey and blue hydrogen, giving them steady, lower-risk exposure. Electrolyser manufacturers are the pure green-hydrogen play, but many remain loss-making, dependent on cost reduction, renewable-power prices, demand growth and policy support such as production incentives and government tenders. The pace at which green displaces grey and blue is therefore the key variable, and it has so far moved more slowly than optimists once hoped, as several high-profile setbacks in the electrolyser industry have shown.

Other colours occasionally appear, including pink hydrogen made by electrolysis powered by nuclear electricity, and turquoise hydrogen from methane pyrolysis, but grey, blue and green are the three that dominate discussion.

### The bottom line

Hydrogen's climate value is entirely a function of how it is produced. Grey is cheap and dirty, green is clean but costly, and blue sits in between as a lower-carbon bridge that depends on effective carbon capture. Any serious assessment of a hydrogen project or company should start with a simple question: which colour, and at what cost?