What is hydrogen?

25.01.21 By
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Hydrogen is becoming an increasingly common term in the energy sector, often described as being ‘renewable’, ‘green’—or more recently ‘clean’. While a hydrogen-fuelled economy presents many opportunities for Australia, it’s only the variety of hydrogen generated with renewables, termed ‘green hydrogen‘, that belongs in our zero emissions future.

The increasingly used ‘clean hydrogen’ is potentially misleading since it describes hydrogen generated either from renewables or from fossil fuels associated with a carbon capture and storage technology.

Key points:


When the term ‘hydrogen’ is used in the energy sector, it refers to a simple molecule of two hydrogen atoms: H2. Creating hydrogen uses a lot of energy, and splitting it apart releases that energy again. This means that generating hydrogen, then using it, works a little like charging and discharging a battery.

It isn’t possible for hydrogen to outperform a conventional battery in many areas. That said, there is huge potential for hydrogen to replace fossil fuels in areas that are especially energy-intensive or where other zero emissions solutions are unavailable, like steel-making and long-range transport. Hydrogen can be used in many other sectors as well, from fertiliser production to simple energy storage to powering fuel cells in cars and ships.

Different types of energy can be used to produce different types of hydrogen:

A graph explaining the different types of hydrogen energy.

Brown, black, grey and blue hydrogen all result in significant greenhouse gas emissions and so contribute to climate change when produced at scale.


The recently coined term ‘clean hydrogen’ can be misleading, as proponents of fossil-fuelled hydrogen have used this to describe fossil fuel hydrogen linked to carbon capture and storage (CCS),  as well as renewably-sourced hydrogen.

Carbon capture is, and will always be, incapable of providing a zero emissions energy supply when attached to fossil fuels. This includes its use in the production of blue hydrogen. Carbon capture can only reduce the emissions intensity of the fossil fuel and frequently does so by very small amounts. Developing a blue hydrogen industry would result in a massive new and unnecessary source of greenhouse gas emissions at a time where the world is already moving away from existing sources. Producing hydrogen with fossil fuels will only push global temperatures higher and further exacerbate climate impacts such as deadly bushfires.

While ‘hydrogen’ may be referred to as ‘the fuel of the future’, it is only ‘green hydrogen‘—the type of hydrogen produced using renewable sources—that can play a role in our zero emissions future.


Today, Australia is one of the world’s largest coal exporters and the largest liquefied gas exporter. Both are polluting fossil fuels, and Australia is paying a high cost for that with more severe and frequent extreme weather events like bushfires, heatwaves, and drought. In the long term, these exports must end.

Renewable hydrogen, or green hydrogen, has the potential to not only completely replace coal and gas exports, but to do so while increasing the total value to our economy and providing jobs for Australians where they need them most.

Already, major economies like Germany and Japan are trying to cash-in on Australia’s renewable hydrogen export potential. Both countries, along with Australia’s other major trading partners, have a net zero emissions target and are only interested in importing ‘green’ hydrogen produced with renewable energy. There is no export market for polluting hydrogen produced with coal, gas, or carbon capture and storage.

This past summer of devastating bushfires, drought, extreme heat and floods, and more recently the third mass bleaching on the Great Barrier Reef in five years, demonstrate why it is critical that Australia pursues technologies that get us to zero greenhouse gas emissions as soon as possible.