Cement Decarbonization Is a Harder Problem

Cement is arguably harder to decarbonize than steel: ~60% of its CO₂ emissions are process-inherent (calcination of limestone releases CO₂ regardless of energy source), meaning electrification alone cannot solve the problem. The credible pathways are: (1) supplementary cementitious materials (SCMs) like calcined clay and fly ash replacing clinker — deployable now, commercially proven; (2) alternative binders (Brimstone, Sublime Systems' electrochemical process) that bypass calcination — early stage but technically compelling; (3) CCUS integrated at kiln exhaust — capital-intensive and geography-dependent. Near-term capital should focus on SCM-based cement producers and the SCM supply chain, particularly calcined clay given fly ash scarcity as coal plants retire. Avoid speculative alternative binder plays without a >10,000 tonne production reference.