Hydrogen was first recognised as an element more than 250 years ago by the English physicist Henry Cavendish. For the purposes of this guide, most information does not relate to this hydrogen category. These types are the total opposite to green hydrogen and are the most environmentally damaging. ‘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’. 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. ‘Pink’ hydrogen (also sometimes classified as ‘red’ or ‘purple’) is generated through electrolysis powered by nuclear energy, and ‘yellow’ through electrolysis using solar. 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. 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.

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). ‘Blue’ hydrogen is produced by splitting natural gas into hydrogen and carbon dioxide using a process called ‘steam reforming’ or ‘auto thermal reforming’. 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.

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. Without emitting any carbon dioxide in the process, electrolysers use an electrochemical reaction to split water into its two components of hydrogen and oxygen. It is made using clean electricity from surplus renewable energy sources, such as solar and wind power, to electrolyse water. ‘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. 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. 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 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. In Australia, hydrogen is mainly used as a raw material for industrial processes.Īccording 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. 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 gas form, hydrogen can be delivered through existing natural gas pipelines. Hydrogen is the most abundant element in the universe, accounting for around 70% of all matter. When produced using renewable sources or processes, hydrogen can become a way of storing renewable energy for use at a later time as required. It is present in almost all molecules in living things and can be generated from a variety of resources, such as natural gas, nuclear power, biogas and renewable power sources including solar and wind. Hydrogen is the most abundant chemical in the universe and can be produced as a gas, liquid or made part of other materials.

Australia, with its plentiful resources, economic capacity and established trade connections, is in an ideal position to become a regional hydrogen superpower, provided it can resolve the commodity’s high production costs compared to other energy sources.

Hydrogen fuel cell stocks