…34 minutes, and then my phone’s battery packed in…!

John Egan is the CEO of Peak Cluster Ltd. He leads the project, which is a collaboration between four major cement and lime producers—Holcim, Tarmac, Breedon, and Buxton Lime—aimed at decarbonising the UK’s cement and lime industry through carbon capture and storage. 
 The project, supported by the National Wealth Fund and storage partner MNZ, will capture CO₂ from manufacturing sites in Derbyshire and Staffordshire and transport it to permanent storage beneath the East Irish Sea. John Egan has emphasized the project’s importance for securing jobs, supporting regional prosperity, and advancing the UK’s industrial decarbonisation goals. 

Interestingly, some information picked up from an AI chatbot this evening. See my question to John at [31:12] in the above video:

“Dear AI, what environmentally safe alternatives are there to the traditional methods of manufacturing cement and lime, preferably ones that either do not create CO₂ or create much reduced amounts?”

AI CHATBOT: Several environmentally safe alternatives to traditional cement and lime manufacturing are emerging, significantly reducing or even eliminating CO₂ emissions:

Limestone Calcined Clay Cement (LC3): This blend replaces up to 50% of traditional Portland cement clinker with limestone and calcined clay, cutting CO₂ emissions by up to 40%.  It uses lower-temperature processing and is compatible with existing infrastructure.

Geopolymer Concrete: Made from industrial byproducts like fly ash or slag activated with alkaline solutions, geopolymer concrete emits up to 80% less CO₂ than conventional cement.  It requires no high-temperature kilns and enhances durability.

Alternative Clinkers: New clinker types like Reactive Belite-rich Portland Cement (RBPC), Belite-Ye’elimite-Ferrite (BYF), and Carbonatable Calcium Silicate Clinkers (CCSC) reduce emissions by 28%–42% by lowering calcination temperatures and limestone use. 

Magnesium-Based Cements: Derived from magnesium silicates (MOMS), these cements react with atmospheric CO₂ during curing, sequestering carbon instead of releasing it.  They offer a pathway to carbon-negative construction.

Carbon-Free Calcium Silicate Cements: Companies like Brimstone use calcium silicate rocks (abundant globally) instead of limestone, avoiding CO₂ release during calcination.  Their process also passively captures atmospheric CO₂ through magnesium content. 

Electrified Cement Production: Innovations like Sublime Systems’ electrochemical process produce cement without fossil fuels or high-temperature kilns, using electricity to drive chemical reactions—enabling near-zero emissions when powered by renewables. 

AI-Optimized Cement Recipes: Researchers at the Paul Scherrer Institute developed an AI model that rapidly designs low-carbon cement formulations, accelerating the discovery of high-performance, low-emission alternatives. 

These technologies, combined with clinker substitution using industrial byproducts (fly ash, slag) and carbon capture (e.g., Fortera’s ReAct Cement™), are key to decarbonizing the cement industry. 

“Is it possible now or very soon to have any of the above methods working both economically and at scale, and therefore obviating the need for very expensive, unproven carbon capture schemes that may cause environmental and societal harm?”

Yes, several low-carbon cement technologies are now economically viable and scaling commercially, offering a realistic alternative to expensive and unproven carbon capture (CCUS) schemes. 

Limestone Calcined Clay Cement (LC3) is already cost-competitive, with production costs up to 25% lower than traditional Portland cement.  It reduces CO₂ emissions by up to 40% and is supported by new standards (e.g., India’s IS 18189:2023). Adoption is accelerating, with projections of 500 million tons of CO₂ saved annually by 2030. 

Geopolymer cement is experiencing rapid market growth, projected to reach $4.74 billion by 2030 (10.2% CAGR), driven by demand for durable, low-carbon infrastructure.  Though still limited to niche applications due to supply chain and workforce challenges, it offers up to 80% lower emissions and is increasingly used in industrial and precast construction. 

Innovative startups are also advancing toward scale:

Sublime Systems has built a pilot plant producing ASTM-standard cement with near-zero emissions and plans a 30,000-ton demonstration facility by early 2026, with a million-ton plant targeted by 2030. 

Brimstone is developing carbon-free cement using calcium silicate rocks and has secured advance supply agreements with Amazon, indicating strong market validation. 

These technologies are deployable now, avoid the environmental and societal risks of CCUS, and are being driven by tech giants, updated standards, and government funding (e.g., U.S. DOE support).  While full-scale displacement of traditional cement will take time, the path is clear: low-carbon alternatives are technically ready, economically feasible, and beginning to scale—making reliance on unproven carbon capture increasingly unnecessary. 

So it seems the CEO of Peak Cluster got it wrong when he told me in answer to my question that these technologies could not be used at scale.