The cement industry is one of the largest emitters of CO₂ globally. A 2022 paper commissioned by the European Cement Industry Research Association (ECRA) investigates different technologies and their impact on energy demand and CO₂ emissions for the sector on its transition towards net-zero CO₂ by 2050.
Among the 48 technologies studied, the use of renewable biofuel from Hydrothermal Carbonization (HTC) and Torrefaction of biomass has proven to be particularly effective and economical. Thus, up to 40 kg CO₂ emissions per ton of cement are avoided at abatement costs of 75-150 EUR per ton CO₂ in case 20% of current fossil fuels are being replaced.
Since waste materials such as sewage sludge can be utilized for Hydrothermal Carbonization, a cement plant additionally generates income from disposal fees when implementing this process. Thus, the conversion to climate-friendly energy sources through HTC is cost-neutral or even generates additional profits.
Table 1 summarizes the calculation data of the study and lists the technologies in order of their CO₂-abatement costs. Taking into account moderate disposal fees as additional income source, HTC turns out to be the most economical technology with relevant CO₂ abatement potential, even reaching negative CO₂-abatement cost up to 180 EUR per ton CO₂.