The global outlook for hydrogen continues to grow in scale as countries around the world strive to achieve net zero carbon emissions or substantial reductions in shortened timelines.
The number of countries with policies that directly support investment in hydrogen technologies is growing, along with the number of sectors they target.
Australia, with its plentiful resources, economic capacity and established trade connections, is in an ideal position to become a regional hydrogen superpower but it is challenged by the commodity’s high production costs compared to other energy sources.
Still, an expanding list of ASX-listed companies have been getting on board with hydrogen as the pathway to achieving a clean and secure energy future.
What is hydrogen?
Hydrogen is the most abundant chemical in the world and can be produced as a gas, liquid or made part of other materials.
It is present in almost all molecules in living things and can be produced from a variety of resources, such as natural gas, nuclear power, biogas and renewable power sources including solar and wind.
When produced using renewable sources or processes, hydrogen can become a way of storing renewable energy for use at a later time as required.
In gas form, hydrogen can be delivered through existing natural gas pipelines. When converted to a liquid or other material, it can be transported on trucks or ships, making it a tradable commodity to export overseas.
In Australia, hydrogen is mainly used as a raw material for industrial processes.
According to the Australian Renewable Energy Agency (ARENA), hydrogen can help to reduce carbon emissions in those high-temperature industries, as well as some transport sectors.
The growing interest in the use of hydrogen for clean energy systems comes down to two main attributes: it can be produced without direct emissions of air pollutants or greenhouse gases; and it can be made from a range of different low-carbon energy sources, thus contributing to a resilient, sustainable energy future.
It is also hailed for its use in a wide range of new applications as an alternative to current fuels and imports or to complement the greater use of electricity.
The hydrogen colour spectrum
While hydrogen itself is a colourless gas, a rainbow of colours represents the many ways it is produced and not all types are as ‘clean’ as you may presume.
‘Green’ hydrogen is the type receiving the most attention of recent times (and a main focus of this guide) as it refers to hydrogen produced with no harmful greenhouse gas emissions.
It is made using clean electricity from surplus renewable energy sources, such as solar and wind power, to electrolyse water. Without emitting any carbon dioxide in the process, electrolysers use an electrochemical reaction to split water into its two components of hydrogen and oxygen.
Green hydrogen currently only makes up a small percentage of global hydrogen production (about 0.1% according to the International Energy Agency) because production is expensive. However, there is mounting interest in green hydrogen technology and its proportion in the global energy mix is expected to grow as governments execute their various carbon reduction schemes.
‘Blue’ hydrogen is produced by splitting natural gas into hydrogen and carbon dioxide using a process called ‘steam reforming’ or ‘auto thermal reforming’. The carbon dioxide produced as a by-product is then captured and stored to mitigate environmental impacts, known as carbon capture and storage or sequestration (CCS).
Other colours in the spectrum include the most common ‘grey’ hydrogen, which is produced from natural gas or methane using steam reformation but without capturing emissions in the process.
Natural gas is currently the primary source of hydrogen production and accounts for around 70 million tonnes per year or 75% of global dedicated hydrogen production.
‘Pink’ hydrogen (also sometimes classified as ‘red’ or ‘purple’) is generated through electrolysis powered by nuclear energy, and ‘yellow’ through electrolysis using solar.
New entries in the colour charts are ‘white’ hydrogen, a naturally-occurring geological hydrogen found in underground deposits or created through fracking, and ‘turquoise’ which denotes the process of methane pyrolysis to produce hydrogen and solid carbon.
‘Black’ and ‘brown’ hydrogen signify the use of black or brown coal (lignite) in the hydrogen-making process, or hydrogen made from fossil fuels through the process of ‘gasification’. These types are the total opposite to green hydrogen and are the most environmentally damaging. For the purposes of this guide, most information does not relate to this hydrogen category.
History of hydrogen
Hydrogen was first recognised as an element more than 250 years ago by the English physicist Henry Cavendish. Some of its initial uses included an internal combustion engine powered by hydrogen and oxygen, the hydrogen gas blowpipe, hydrogen gas lamps and limelight (stage lighting).
The first hydrogen-filled balloon was invented in the late 1700s and in 1852, Henri Giffard invented the first hydrogen-lifted airship. In the 1900s, regular scheduled flights began on rigid airships lifted by hydrogen known as ‘zeppelins’, which were also used as observation platforms and bombers during World War I.
After the German zeppelin Hindenburg famously exploded mid-air in New Jersey in 1937, killing 36 people, hydrogen’s reputation as a lifting gas was ruined despite later investigations blaming the ignition of the aluminised coating. However, hydrogen is still often used instead of expensive helium for weather balloons.
Liquid hydrogen fuel, together with oxygen oxidiser, was used to power the main engine of NASA’s Space Shuttle from 1981 to 2011. The components were contained within an external tank that was jettisoned about 10 seconds after the main engine cut off and re-entered the Earth’s atmosphere, designed to break up before impact in the ocean.
Current end uses
Nowadays, hydrogen is mainly used as a raw material for industrial processes. It is used in oil refining (removing sulphur from fuels), metal treatment, fertiliser (ammonia) production and food processing (to hydrogenate oils from fats to make products like margarine, for example).
It can replace or supplement natural gas in heating and cooking.
It also has the potential for use in heavy haulage and other large transport solutions with hydrogen-powered fuel cells able to power large vehicles including buses and trucks, maritime vessels and aviation.
Hydrogen fuel cells produce electricity and can power devices as small as laptops and mobile phones, or as large as backup or emergency power in buildings and for military applications.
There is also growing interest in the development of hydrogen-fuelled cars, which usually have an electric motor powered by a hydrogen fuel cell and are believed to be two to three times more efficient than an internal combustion engine running on petrol.
According to the International Energy Agency (IEA) 2019 report titled The Future of Hydrogen, demand for hydrogen has grown more than threefold since 1975 but it is almost entirely supplied from fossil fuels with 6% of global natural gas and 2% of global coal going to hydrogen production.
This means hydrogen production is still responsible for around 830Mt of carbon dioxide each year – the equivalent of the United Kingdom and Indonesia’s carbon emissions combined.
Total global hydrogen demand is currently around 330Mt of oil equivalent per year, which…