Electric Kilns

cement · lime · calcination

Electric heat can remove the fuel emissions from a cement kiln. About 60% of the CO2 comes from the limestone, so electrification alone gets less than half way.

About 60% of a cement plant's CO2 comes from limestone during calcination and about 40% from fuel burned for heat; electric heat removes the fuel share, while the limestone share needs capture or new chemistry. Precalciners run at 900 to 1,050 degrees C and rotary kilns at 1,400 to 1,500 degrees; Coolbrook claims its electric RotoDynamic Heater reaches 1,700 degrees; Sublime Systems' electrochemical process runs at ambient temperature. WHERE A CEMENT PLANT'S CO2 COMES FROM ~60% limestone (calcination) ~40% fuel for heat Electric heat removes this partNeeds capture or new chemistry KILN TEMPERATURES AND ELECTRIC ROUTES Precalciner 900-1,050 °C Rotary kiln 1,400-1,500 °C Coolbrook RDH (claimed) to 1,700 °C Sublime electrochemical ambient
CO2 from rock
~60%
Kiln temp
~1,450 °C
Sublime plant
30 kt/yr
Companies tracked
10, 1 Chinese
Hub
Industry

Finding

An electric kiln can remove the fuel emissions, but most of cement's CO2 comes out of the rock

Cement and lime kilns emit about 0.6-0.9 metric tons of CO2 per metric ton of cement. Roughly 60% is released by limestone itself as it decomposes in the kiln; only about 40% comes from the fuel. Replacing the flame with electric heat cuts the second part, and leaves a purer CO2 stream that is easier to capture.

That makes cement the slowest of the heavy industries to electrify. The heat is the hardest to supply - clinker forms at about 1,450 °C in a rotating kiln built around a flame - and success still leaves most of the emissions. Electric kilns have run at research scale (VTT's 12-meter Decarbonate kiln in Finland), and Coolbrook has signed agreements with Cemex and UltraTech to pilot its RotoDynamic Heater, which it says reaches 1,700 °C, but no full-size electric clinker kiln operates yet.

The alternative is to change the chemistry. Sublime Systems makes cement electrochemically at room temperature from calcium silicate rock instead of limestone, avoiding both the fuel and the process CO2; its first commercial plant, in Holyoke, Massachusetts, is sized at 30,000 metric tons a year, against about a million metric tons for a conventional plant. Clay calcination, which runs cooler, is another route being electrified (FLSmidth's ECoClay). China makes about half the world's cement, so the economics will be decided there.

Vendors

Electric kiln and alternative cement developers

Most rows are pilots: electric heat for existing kilns, heat batteries that feed them, and chemistries that skip the kiln. Active companies first, then pilots, research groups and companies that exited.

Electric kiln and calciner developers
CompanyProductsHQTechnologyReference sitesStatus
FLSmidthElectric clay calcination (ECoClay); cement plant equipmentDenmarkElectric calciner for clayactive
Rondo EnergyHeat batteries supplying kiln and process heatUSResistive-heated brick storageSCG cement plant, Thailandactive
Sinoma International EngineeringCement plant engineering and kiln linesChinaConventional kilns; electric routes at research stageactive: CNBM group; world's largest cement plant contractor
thyssenkrupp PolysiusActivated clay calcining and cement kiln equipmentGermanyCalcined clay; oxyfuel-ready kilnsactive
Calix (Leilac)Indirectly heated calciner that separates process CO2; electric heating optionAustraliaIndirect calcinationLeilac-2 with Heidelberg Materials, Hannoverpilot
CoolbrookRotoDynamic Heater for kilns and calcinersFinlandRotodynamic electric heating to about 1,700 °CCemex and UltraTech pilot agreementspilot
Electrified Thermal SolutionsJoule Hive firebrick heat batteries for kiln and process heatUSElectrically conductive firebrick to about 1,800 °Cpilot
Alternative cement chemistries
CompanyProductsHQTechnologyReference sitesStatus
BrimstoneCarbonate-free portland cement processUSCalcium silicate feedstockpilot
ForteraReAct recarbonated cementUSCaptures kiln CO2 into the productpilot
Sublime SystemsElectrochemical cement from calcium silicate rockUSRoom-temperature electrochemistryHolyoke, Massachusetts plant (30,000 t/yr)pilot

Routes

Four routes to lower-carbon cement

Cement decarbonization routes
RouteHowCO2 addressedStatus
Electric rotary or calciner heatingResistive, plasma or rotodynamic heat replaces fuel~40% (fuel share)Pilots
Hydrogen-fired calcinerH2 burners replace coal or gas~40%Trials; H2 cost
Electrified kiln + carbon capturePure CO2 stream captured and storedUp to ~100%Capture doubles plant energy use
Electrochemical cementNo limestone, no kilnUp to ~100%First commercial plant, 30 kt/yr

Sources

Sources and scope

Scope
Electric Kilns for Cement and Lime
Sources
Global Cement; Coolbrook, Cemex and UltraTech announcements; VTT Decarbonate project; Sublime Systems
Updated
October 2026