Techno-Economic Analysis of a Solar Calciner for CO2 Emissions Reduction in the Chilean Cement Industry

Abstract

Clinker, constituting approximately 72% of cement's composition, is produced through an energy-intensive process that significantly contributes to CO₂ emissions. This study explores the integration of a solar calciner into the Chilean cement industry, particularly in the Antofagasta region, which is characterized by high solar energy irradiation, with an annual DNI of 3,250 kWh/m². This region also accounts for approximately 30% of the country's cement sector energy consumption. In this context, this study evaluates two Concentrated Solar Thermal (CST) scenarios: the Top of Tower (TT) system and the Beam-down (BD) system, assessing their technical and economic feasibility for reducing CO₂ emissions in the calcination process. The findings suggest that both CST systems could substantially reduce CO₂ emissions in the calciner. However, economic feasibility remains a challenge, primarily due to the low cost of coal, which is the main fuel in the Chilean cement industry. Additionally, the efficiency of the solar calciner is found to be crucial for achieving maximum emission reductions, for the scalability of the technology, and for its future adoption in Chile's cement industry. Although the Levelized Cost of Heat (LCOH) for the proposed plants is currently higher than the coal-fired calciners in which is produced about 90% of current clinker production in Chile, potential reductions in heliostat costs, coupled with an increase in carbon taxes beyond the current value of 5 USD/t_CO2, could significantly improve the economic viability of CST plants in Chile's cement industry.