Calcined clay kiln projects have been announced on every continent, according to new analysis, though the technology still accounts for a small fraction of global cement output.
The data, compiled by the Leadership Group for Industry Transition (LeadIT), shows commercial-scale calcined clay projects are now more widely distributed than carbon capture, utilisation and storage (CCUS) schemes, which remain concentrated almost exclusively in advanced economies.
Analysts attribute the wider adoption of calcined clay to its technical simplicity and significantly lower cost compared with CCUS.
Clay has been used in cementitious materials for centuries, predating the invention of Ordinary Portland Cement (OPC). Conventional cement production is responsible for roughly 6% of direct CO2 emissions from energy use and industrial processes worldwide, making the sector a priority for decarbonisation efforts.
The largest operational calcined clay plants are concentrated in emerging markets and developing economies, particularly in Africa, Latin America and Asia, where the majority of future construction activity is projected to take place.
Calcined clay, derived from kaolin, occurs in greater quantities in humid tropical regions. Ghana has emerged as a frontrunner in commercial production, hosting two of the world’s largest facilities.
According to the analysis, more than 72% of tracked calcined clay projects have been announced at commercial – rather than pilot or demonstration – scale, and 70% of those commercial-scale projects are already operational.
Based on current and announced projects, calcined clay could unlock 26m metric tons per year of lower-carbon cement capacity. Even at an optimistic 35% blend ratio, however, this represents less than 1% of the 4bn metric tons of cement produced globally each year.
Few new projects were announced in 2025, but LeadIT’s analysis identifies at least six additional projects due to be commissioned in 2026 – four in Africa and two in Europe. A longer-term pipeline shows 15 active projects across Africa, Europe and the Americas. Replacing a share of clinker with calcined clay can reduce emissions by up to 40% compared with OPC, though the overall contribution to global cement capacity is expected to remain marginal.
Perez Yeptho, analyst at LeadIT, said: “Our analysis underlines the need for faster implementation. Delivering significant emissions reductions in the cement industry will require an accelerated and more extensive scaling not just of calcined clay projects but also other low-carbon technologies in the future.”
OPC relies on clinker, produced by heating a mixture of limestone and clay to around 1,500C – a highly emissions-intensive process, both through fuel combustion and the chemical transformation of limestone itself.
Calcining clay at much lower temperatures and using it to replace part of the clinker content can significantly cut these emissions. Limestone calcined clay cement (LC3), the most prevalent form currently in production, typically blends 15% limestone with 30% calcined clay.
Further emissions reductions could come from electrified calcination technologies, such as electric arc calciners or electrified linear calcination conveyors, which replace fossil fuels with electricity – offering additional savings when paired with renewable power sources.
The findings form part of LeadIT’s Green Cement Technology Tracker, which also covers CCUS projects; a companion analysis on carbon capture technologies was published in May 2026. The full dataset is available on the LeadIT website.
LeadIT was established by the governments of India and Sweden in 2019 to drive public and private sector action on industrial decarbonisation. It brings together 19 countries and 33 companies working towards a just transition to net-zero emissions in heavy industry, with its secretariat hosted by the Stockholm Environment Institute (SEI).
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