Substituting fossil fuels in cement production with solar energy to reduce carbon emissions

Cement is responsible for a substantial amount of CO2 emissions, a concern that is growing with rapid rise in the demand for construction materials. This study investigates the decarbonisation potential of solar calcination and photovoltaics-based kiln electrification in clinker production. Optimisation models parametrised by process simulation results were utilised to assess the economic costs and carbon emission reduction performance of the solar driven processes. The findings indicate that the solar driven process can achieve CO2 savings of ∼26 %, through nearly complete replacement of fossil fuels with solar energy. The location dependent analysis of sites in three countries (including the United States, China and Brazil), showed that regions with higher solar energy quality benefit from up to ∼46 % lower costs to implement the proposed retrofitting. Across the analysed sites, the solar calciner achieves cost competitiveness once natural gas price exceeds 30 USD/MWh at the Brazil site and 50 USD/MWh for the other two sites. In contrast, the PV-based kiln electrification costs are significantly higher, undermining its economic viability under current cost assumptions. The results underscore the critical role of local solar energy characteristics in influencing the costs, whilst emphasising the necessity for future cost reduction in renewables-based decarbonisation for clinker production.