by Peter Majewski, Future Industries Institute, University of South Australia.
Hydrogen
Hydrogen is the most abundant element in the universe. Using it for the production of energy appears to be a no-brainer. However, on earth, hydrogen rarely occurs as pure hydrogen, but it is bonded to predominately oxygen forming water. The bond between the oxygen atom and the two hydrogen atoms in water is very strong, so, a lot of energy is needed to split hydrogen from oxygen.
To split water, either electrolysis and or chemical reactions are used. Electrolysis uses electric power to split water in H2 and O2. The chemical reaction process generally uses coal and steam. While H2 is set free oxygen forms a new bond with carbon, forming CO and CO2. The other chemical reaction process oxidises natural gas releasing H2 and forming CO2. Methane is the predominant source of hydrogen production, accounting for about 65 per cent of the total hydrogen production of about 70 million tons per year, followed by coal. Electrolysis accounts only for a very small fraction of H2 production.
But this is about to change drastically.
The use of hydrogen to decarbonise power production, mobility, and a number of industrial processes, like steel, cement, lime, alumina, and fertiliser production, has been at the forefront of developments to reduce CO2 emissions and address climate change. The war in Ukraine brought another significant geopolitical aspect to this development, i.e. the realisation of the European Union that it needs to become independent of gas and oil from Russia by replacing it with green hydrogen.
The colours of hydrogen
The current way to label hydrogen from the various production processes is applying a colour code.
Green hydrogen is produced from water using electrolysis run solely by wind and solar energy or hydropower. Blue hydrogen is based on methane and uses carbon capture and storage to reduce CO2 emissions. Grey hydrogen is also using methane, but without carbon capture and storage, while turquoise hydrogen also uses methane, but the process forms solid graphite as a by-product, not CO2. Pink hydrogen uses nuclear power to split water. Black hydrogen uses black coal, while brown hydrogen applies brown coal. Finally, there is natural gold hydrogen formed through geological processes within the earth’s crust which are not linked to oil and natural gas formation, but a reaction of water with iron oxide in the rocks at high temperatures and pressures.
Of all these types of hydrogen, green hydrogen production appears the only truly sustainable process which is free from greenhouse gas emissions or other by-products, apart from – of course – oxygen. Gold hydrogen is also free of any by-products, but as it is mined, it doesn’t fall under the ‘sustainable’ banner.
However, to produce the current hydrogen output using electrolysis and electricity about the total annual electric power generation of the European Union is needed. In order to have green hydrogen, this amount of electric power needs to be solely produced from renewable energy sources.
Currently, it is most important to reduce the cost for green energy to reduce the cost of green hydrogen from currently about USD 5 down to USD 2 per kg to be cost competitive against blue and grey hydrogen. However, future carbon pricing will most likely considerably increase their price.
Electrolyser producers are ramping up production, as they realize the rise of hydrogen in future. There are two main types of electrolyser available, alkaline electrolysers and Proton-Exchange-Membrane (PEM) electrolysers. While PEM electrolysers have higher efficiency of more than 80 per cent, they are more expensive due to the use of noble metals for the process and the membrane is subject to degradation over time. Alkaline electrolysers are a well established technology which has been used for many decades, but their efficiency is in the 70 per cent range.
To reduce costs green hydrogen producers want to have high efficiency for the process, which not necessarily means just having the most efficient electrolyser, but importantly having long periods of sunshine and/or wind to produce the green energy needed for running the electrolysers and producing pure water form wastewater or seawater for the electrolysis.
How does Australia come into play?
South Australia is behind Denmark, world leading in the generation of renewable energy, due to the significant investments into renewable energy in the state, but also due to the fact that there is plenty of sunshine and, when the sun is not shining, there is plenty of wind. Over several days in the past year, all of South Australia’s electricity demand was satisfied by renewable energy generated in the state and renewable energy was even exported to the eastern states. Similar optimal conditions can be found in Western Australia and lesser in the eastern states, while Tasmania has significant capacity of hydro power for producing green hydrogen.
Nevertheless, in order to provide sufficient green energy for the production of green hydrogen in Australia, the entire current green energy generation in Australia, which is about 32.5 per cent of the total energy production, needs to be doubled. While this appears very demanding, it sounds less scary when considering that Australia already doubled the renewable energy output between 2017 and 2022. And according to the Clean Energy Council, by early 2022, 131 renewable energy projects were under construction or have reached financial close totalling $25.5 billion in capital investments and providing more than 17GW in renewable energy output.
Most recently, the Asian Renewable Energy Hub in the Pilbara started and will generate up to 26GW of wind and solar capacity to produce 1.6 million tonnes of green hydrogen per year at a total estimated investment of about $ 36 billion. In addition, Fortescue Future Industries has struck a potential $50 billion green hydrogen agreement with German energy giant E.ON to produce and ship to Germany up to five million tonnes of green hydrogen per year from 2030 on. This project will require 60GW to 70GW of renewable energy.
But we are not alone. Morocco, Namibia, Spain, Chile, Tunisia are also ramping up green hydrogen production.
Skills development
Initiatives have commenced to build a skilled workforce for the hydrogen industry.
Australia and Germany started the HyGATE initiative with the objective to strengthen Australian-German R&D cooperation on green hydrogen production and to stimulate innovation. CSIRO and the Australian Hydrogen Research Network are working together to establish collaborations across the research and broader hydrogen communities, domestically and internationally. The Corporate Research Centre on Heavy Industry Low Carbon Transition, or HILT CRC, led by the University of Adelaide is aiming at providing R&D solutions for the decarbonisation of the production of steel, cement, and alumina using hydrogen. Currently, the University of Adelaide is also leading an initiative aiming at establishing a Corporate Research Centre on Scaling Green Hydrogen, or Hydrogen CRC. This initiative has already attracted participation of 15 Australian universities and significant interest from leading international and domestic industry of the hydrogen sector.
Time will tell whether green hydrogen will provide the necessary decarbonisation of industry and mobility. Nevertheless, hydrogen technology will be very disruptive for many industries and it is easy to imagine that by 2050 things such as a petrol or diesel engine will be a subject of the past like a steam engine today.
