Rapidly growing interest in hydrogen in Australia has shone a light on the element’s versatile application as we move toward a net-zero world, but also the complexity of the way the fuel is classified.
As outlined in ANZ’s latest report, The ANZ Hydrogen Handbook – AH2, hydrogen has a variety of applications.
It is an excellent carrier of energy, with each kilogram of hydrogen containing about 2.4 times as much energy as natural gas. This energy can be released as heat through combustion or as electricity using a fuel cell.
The different methods of producing hydrogen are classed by colour. Our handy table outlines each classification below. You can read more by downloading the report.
Main types of hydrogen energy
Main types of hydrogen energyGreen
 | - Produced through electrolysis of water using a renewable power source
- Zero carbon emissions in production and combustion
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Blue
 | - Same production process as brown or grey hydrogen
- Carbon emissions are captured
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Grey
 | - Produced from methane or natural gas through steam methane reforming
- Material carbon emissions released during production
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Brown
 | - Produced from coal through gasification
- Material carbon emissions released during production
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Other types of hydrogen energy
Other types of hydrogen energyTurquoise
 | - Produced when natural gas is broken down with the help of methane pyrolysis (as opposed to steam methane reforming) into hydrogen and solid carbon. The difference is that the process is driven by heat produced with electricity, rather than through the combustion of fossil fuels.
- The output of carbon in solid form (rather than CO2) means there is no requirement for CCS and the carbon can even be used in other applications, such as a soil improver or the manufacturing of certain goods such as tyres. Where the electricity driving the pyrolysis is renewable, the process is zerocarbon, or even carbon negative if the feedstock is bio-methane rather than fossil methane (natural gas).
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Pink (also Purple or Red)
 | - Produced by electrolysis using nuclear power.
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Yellow
 | - Produced by electrolysis using grid electricity.
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White
 | - A naturally-occurring geological hydrogen found in underground deposits and created through fracking.
- There are no strategies to exploit this hydrogen at present.
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The ANZ Hydrogen Handbook – AH2 provides up-to-date and practical information on the commercialisation of hydrogen and helping customers explore the emerging opportunities. Download the report now.
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A guide to the colours of hydrogen
Staff Writer
ANZ Insights
2022-02-10
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