GUEST COLUMN:
Dr Andrea Folli
University Research Fellow in Electrocatalysis
Cardiff University Net Zero Innovation Institute
Some of the most important materials for modern technology are not always found where people expect them. At Aberthaw, they may be present in a material that has historically been treated as a by-product of power generation: pulverised fuel ash.
Pulverised fuel ash, or PFA, is the fine ash produced when pulverised coal is burned in a power station. At the former Aberthaw Power Station, there is an estimated 18 million tonnes of it, held in a 50-metre-high mound across the site. It is easy to think first about established uses, particularly in cement and concrete, where fly ash has long been used as a supplementary cementitious material. That is an important part of the discussion, but it should not be the only one.
My interest is in what else this material could make possible. My background is in photoelectrochemistry, and I am also part of the management team of Cardiff University’s Net Zero Innovation Institute, where we look at how technologies and innovation can support the transition to net zero. Through that work, I have been discussing the Aberthaw ash with CCR Energy, which now owns the site, for a number of years, particularly around whether it could be used as a source of valuable materials.
Initial analysis has identified a range of elements in the ash, including rare earth elements. These are not abstract scientific curiosities. Rare earth elements are used in advanced electronics, magnetic materials, telecommunications and defence technologies. They sit at the centre of many of the technologies that modern economies rely on.
They also raise a wider strategic question. Europe does not have easy access to large domestic sources of rare earths, and global supply chains are increasingly shaped by geopolitical pressure. For that reason, there is a strong argument for looking at how these elements can be recovered from materials that are already on our own territory, rather than relying only on traditional extraction from new mineral deposits.
That is where the ash at Aberthaw becomes particularly interesting. The cement and concrete route is already well understood, but the presence of valuable elements suggests that other forms of value may also be present. The challenge is how to recover those elements in a way that does not destroy the remaining material or make it unusable for other applications.
Many established extraction processes rely on strong acids. That can be effective in separating valuable elements, but it creates another problem. If the process damages the remaining ash, then we may lose the opportunity to use it afterwards as a cementitious material or in other applications. In trying to recover one form of value, we could accidentally remove another.
My research interest is in whether electrochemical techniques could provide a different route. Instead of relying on harsh acid processes, there may be ways to use more benign solvents and electricity to separate elements selectively from the ash. This is very early-stage work, at what we would call technology readiness levels zero to two. It is fundamental research, not a commercial process ready to be rolled out tomorrow.
The mature use of ash in cementitious materials can create value now, whereas the extraction of rare earth elements using alternative techniques may take much longer to develop. But those two routes should not be seen as competing with each other. The real opportunity may be in finding the right combination of technologies, so that established uses can generate income while also helping to support further research into higher-value possibilities.
This is where circular economy thinking has to include the economy as well as the material. It is not enough to say that everything should be reused. There also has to be cash flow, investment and a commercial structure which allows early value to support later innovation. Revenue from applications that are already available could help subsidise research into technologies that are further from market but potentially significant in the long term.
Public funding will also be important, particularly for the lowest technology readiness levels. It is difficult to expect smaller companies to fund very early-stage, blue-sky research unless there is a clear route to market. Large corporates may sometimes be able to invest in that kind of work, but for many organisations the risk is too high. Public funding can help bridge that gap, especially where the research has a real-world application and a clear connection to future economic needs.
The broader opportunity for South Wales is not only about extracting more financial value from a mound of ash – it is also about skills, jobs and industrial capability. If Aberthaw becomes a place where mature markets, demonstrators and early-stage research sit alongside each other, it could help build expertise in circular materials, electrochemical processing and net zero technologies.
The practical route should start with what can be done now, while keeping space for what could be developed next. Aberthaw’s PFA may have immediate uses in established markets, but it could also become a platform for testing technologies that help us think differently about industrial by-products, material security and the resources needed for net zero.
