The times they are a changin'

As the main active ingredient in concrete, cement is essential to the past, present and future of the global construction sector. As well as homes, schools, hospitals, commercial buildings, roads, ports and other facilities, it will be vital to building the new infrastructure that helps the world to deal with climate change. This material will build CO₂ capture, utilisation and storage (CCUS) installations, offshore wind turbines, new water management infrastructure, sea-defences and much more besides.

While becoming more important than ever, cement is also transforming into a far more sustainable product. But what is 'sustainable cement'? A simple answer is: A product that fulfils the current role of cement without its considerable negative environmental impacts.

Chief among the targets for any sustainable cement will be reducing – indeed eliminating – CO₂ emissions from the production process. There are many ways to do this, both on the production side and the utilisation side. These 'standard levers' can be seen in any issue of Global Cement Magazine. There are also novel cement chemistries that do away with the decarbonisation step altogether, those electrifying existing processes, using concentrated solar power and a wide range of alternative production methods that make analagous products with lower emissions.

However, going one step further, we can argue that a 'truly sustainable' cement will also be net zero in terms of Scope 2 and Scope 3 CO₂ emissions. It will also be a net-zero consumer of water, emit no other hazardous pollutants and eliminate – or at least greatly reduce – reliance on virgin natural resources. Biodiversity should be maintained, preferably improved, in areas where virgin resources have been extracted.

While the cement producers that represent the vast bulk of global cement capacity – and many others besides - are now actively working towards these targets – supported in no small part by the sector's international and regional associations – there are many challenges ahead. There are two key obstacles: Firstly, cement specifications are restricted to ‘ingredient-based’ blends in most jurisdictions. This means that cement blends must include a certain amount of clinker to be permitted for use. Novel blends, including those that easily meet (or exceed) their performance are often not allowed. We therefore need a global transition to performance-based standards to fully allow low-CO₂ blends to be used. This is easy on the technical level, but will require huge collaboration, from (supra)-national governments at the top, right down through cement and concrete producer boards, to individual plant staff.

Secondly, every cement association roadmap to net zero uses CCUS to 'mop up' the remaining CO₂ emissions that cannot be removed by other means. We feature numerous CCUS companies in these pages, each keen to reduce emissions ‘on the gigatonne scale.' This is great on the face of it, but it seems that – with some notable exceptions in Europe and North America – there will be very little infrastructure to actually transport collected CO₂ to locations where it can safely be stored once all these systems come online. The CO₂ will have nowhere to go! Governments should already be building trans-continental networks comparable to power generation systems or railways if CO₂ is realistically going to be captured and transported to geological stores. One way to simplify this would be to switch to much larger factories - complete with CCUS facilities - that distribute clinker to many smaller renewably-powered grinding plants. This would make CO₂ networks easier to handle, but require far more government involvement than the sector are used to.

Allied to CO₂ capture and storage, there are also many companies that seek to permanently utilise cement process CO₂ in new products, including building materials. Rapid deployment at scale is a target of many of the companies that we speak with – and for good reason. They are motivated by the increasingly alarming effects of climate change and need to turn a profit too. However, as with the CO₂ network problem, there could be a risk of swapping our current 'clinker glut' for a 'novel materials glut,' should enough start-ups produce at the scales they claim they will.

Whatever solutions end up being widely adopted by the cement/'alternative building materials' sector of the future, they will not come to fruition by adopting a silo mentality. These issues will not be solved without a massive collaborative effort. There are positive signs regarding novel blend standards, but less so regarding CCUS. Ultimately, it is governments that hold the key to industrial strategy. The boldest governments will find that the cement sector is ready, willing and able to take on the decarbonisation challenge. Many of the technical solutions are now proven and conditions seem to finally be set in favour of a period of rapid change for our sector. Global Cement looks forward to providing the commentary....