Aberthaw Ash Should Be Treated as a National Resource

There are some industrial materials which would be treated very differently if they were discovered today, detached from the history that produced them. The pulverised fuel ash at Aberthaw is one of them.

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. Because it is associated with coal-fired generation, it is easy for people to see it only as a legacy issue. In my view, that is the wrong starting point.

If a geologist found a finite deposit of aluminosilicate spheres with properties that could be used beneficially in cementitious materials, we would be talking about safeguarding it. We would recognise it as a resource. We would ask how to use it properly and how to make sure it was not wasted. The fact that this material came from a power station should not prevent us from taking the same view.

I have worked with fly ash for many years, including in the cement industry and through the UK Quality Ash Association. Over that time, I have seen fly ash processed, commercialised and used successfully in cementitious and non-cementitious markets. That experience makes me cautious about claims which are not proven at scale, but it also makes me very clear about the opportunity that exists when the material is understood and handled properly.

For me, Aberthaw should be seen as part of a national resource. Once this material is gone, it is gone. Coal-fired power stations are not going to produce more of it. That means decisions about its future should not be made as though it were simply something to clear away. It has to be assessed as a finite material with potential value for construction, carbon reduction and industrial supply.

The UK has only a limited number of major single-use fly ash deposits of this kind. In terms of scale, Aberthaw is one of the few that could make a meaningful contribution to the cementitious market for many years. That is significant because there is potential demand for several million tonnes of secondary cementitious materials in the UK. Aberthaw cannot meet all of that demand, but it could make a valuable contribution.

The reason this matters commercially is that the cementitious route is not speculative. Fly ash has been used for many years as a supplementary cementitious material. Technologies exist to dry material, remove carbon and produce a good cementitious product. There are also markets in blocks and other construction products, from simpler applications through to more sophisticated products such as autoclaved aerated concrete blocks.

That does not mean every question has been answered. At Aberthaw, the key technical issue I would want to understand is chloride content.

We know from previous experience that the ash has the potential to work well. We know the broad mineral content and we know processing technologies are available. But chlorides can affect where material can be used, particularly in reinforced concrete and related applications.

Getting that result would allow much more informed conversations with potential partners and investors.

That is an important distinction. There is no shortage of interesting ideas around fly ash, including rare earth extraction, geopolymers and other novel uses. Some may prove valuable, and it is right that CCR Energy is looking broadly at the options rather than becoming fixed on one route too early. But there is also value in momentum. A clear technical result, followed by focused discussions with credible partners, can turn a general opportunity into something much more practical.

The carbon case is also strong. Work we have done, albeit at benchtop level, suggests that every tonne of processed stockpile fly ash replacing a tonne of cement can save around 760kg of CO2. Processing has its own footprint, particularly drying, but if renewable energy can be used for that stage, the overall benefit becomes more significant. That creates both a commercial and a societal argument for making good use of the material.

There is also a wider discussion about the best commercial model. If the public sector simply sells the material too cheaply, it may lose long-term value. If it prices it too high, it may limit the market. A partnership or equity-based approach could allow value to be shared over time, particularly if the material increases in importance as demand for secondary cementitious materials grows.

I am not dismissive of the more innovative possibilities. Rare earth elements are clearly of strategic interest, and other countries have looked at fly ash through that lens. But any extraction route has to be judged carefully. Some processes use strong acids, and if they render the remaining material useless, then one potential value stream may be gained at the expense of another. The best approach is to look at all options, but to test them against what is commercially proven, scalable and capable of preserving value.

That is why I keep returning to the idea of Aberthaw as a national resource. It is not only a site issue for South Wales, nor only a legacy of coal-fired generation. It is a finite material which could support the UK’s need for lower-carbon construction products, reduce reliance on primary materials and create a platform for further innovation.

The next step should be practical. Establish the key technical facts, particularly around chloride content. Use those facts to engage serious partners. Build momentum through routes that can generate cash flow, while allowing more innovative work to continue in parallel.

Aberthaw’s ash should not be treated as a liability to be disposed of, but as a resource whose value needs to be protected, proven and put to use.