By Jonathan Butler
Platinum group metals (PGMs) and hydrogen are virtually synonymous – wherever hydrogen is produced, distributed, or consumed in industrial applications, PGMs are usually involved.
These metals, therefore, hold tremendous promise as the world addresses the triple challenges of decarbonisation while ensuring energy security and developing the next generation of high-value manufacturing.
The unique chemical and physical properties of platinum, iridium and ruthenium in particular makes them ideally suited to catalysing the reactions involved in the generation of low carbon hydrogen, moving it at scale, and transforming the hydrogen back into energy for a wide range of end-uses.
In order to limit climate change and bring CO2 emissions to net zero by 2050, the International Renewable Energy Agency (IRENA) has estimated that there will need to be an increase in global renewable energy deployments by around 3.5 times current levels by the end of this decade. In short, this means a lot more renewable electricity the energy mix.
Since renewables are intermittent, sometimes electricity demand exceeds supply. As we know from the South African context, this can lead to grid instability and mitigating measures such as load shedding.
This is where grid balancing comes in – an electrolyser can be used to split water into hydrogen and oxygen using renewable electricity in times of abundance. The resulting renewable or green hydrogen can then be stored and utilised when the grid needs extra supplies – simply by combining the hydrogen with oxygen in a fuel cell to generate electricity again.
PGM-containing PEM water electrolysis is a superior technology for balancing renewables at scale. Platinum and iridium coatings used on the cathode and anodes respectively enable the electrolyser to start up and shut down rapidly, offer high durability, and can be scaled up to the multi-Gigawatt scale.
Green hydrogen produced from renewable-powered electrolysis can also be used as a zero carbon transport fuel – which is especially relevant for those hard to decarbonise sectors such as heavy duty trucks which are not suited to batteries, and marine and aviation which present unique challenges due to their need for energy dense fuels.
Hydrogen can also be used to create zero carbon heat and power, for example from stationary fuel cells, and produce zero carbon hydrogen as a feedstock for other hard to decarbonise sectors such as steelmaking and ammonia.
And perhaps most importantly in the longer term, when green hydrogen is combined with CO2 captured from carbon-intensive industries, we have the building blocks for the entire chemical value chain. Manufacturing zero carbon petrochemicals therefore presents a huge opportunity for PGMs both in green hydrogen production and as catalysis for many other value-added products.
Large-scale production of green hydrogen using PGMs is already getting underway: the Hydrogen Council, an industry body, has recently shown that as of January 2023 around 25 million tonnes of renewable hydrogen projects were in the pipeline for 2030. With the US government recently announcing a tax credit of $3 (R53) for every kg of low carbon hydrogen produced, the ramp up of green hydrogen production should accelerate even further and start to approach the 75 million tonne mark, which the Hydrogen Council has said is needed to put us on a track to net zero by the end of this decade.
It is not only in the production of hydrogen that PGMs can make a major contribution. Green hydrogen needs to be stored and distributed. Some of the most promising ways of doing this at scale involve using PGM catalysts to store the hydrogen in conventional, widely used chemicals including organic solvents and ammonia before releasing the hydrogen where it is needed. Companies like Hydrogenious, Chiyoda and Amogy are leading the way in these novel hydrogen storage solutions, which employ PGMs.
The ‘holy grail’ for PGM demand, and one that has been widely trailed for many years, is of course platinum (and ruthenium’s) use in fuel cells, primarily in vehicles but also in stationary power generation. Real commercial traction is already happening in fuel cell heavy duty trucks, niche transport such as forklifts and in increasing deployments of passenger cars, bringing material volumes of platinum demand.
According to Mitsubishi’s own forecasts, there will be close to a million ounces of PGM used annually in all the various hydrogen applications by 2030. This will help push the platinum, iridium and ruthenium markets into substantial deficits in future.
So the challenge for PGMs and hydrogen, if they are to contribute to our societal goals of net zero and energy security, is to ensure adequate metal availability. This can be met by a combination of improved recycling, reduction of catalyst loadings per unit, re-engineering the catalysts to include cheaper PGMs, ring-fencing supply, and risk-hedging metal prices.
With this we can build a new long-term sustainable demand base for the PGM industry and realise the important role PGMs and hydrogen have to play in decarbonisation and value creation.
Dr Jonathan Butler is Head of Business Development in Mitsubishi Corporation’s precious metals division, specialising in the use of PGMs in hydrogen.
BUSINESS REPORT