A key area of action for CO2 reduction in the cement industry is the fuels chosen to cover thermal energy requirements. The table below provides an overview of the development of fuel input in cement manufacture in Germany. It shows that the proportion of coal and lignite in the total thermal energy requirement has dropped from around 87 per cent in 1987 to around 62 per cent in 2000, and then to around 28 per cent in 2018, through increased use of alternative fuels.
Development of the specific fuel energy demand
Increasing the proportion of alternative fuels in the sector is one of the most important measures for reducing CO2 emissions. First of all, this is due to the low carbon content as compared with coal. In addition, some alternative fuels are of plant or animal origin, i.e. they do not lead to any increase in concentration of CO2 in the atmosphere – meaning that they are considered climate-neutral. Furthermore, the use of alternative fuels for energy in cement production offers two particular advantages as compared with other processes:
First, the materials are dried in the cement works' rotary kilns as part of the process. This leads to an increase in energy efficiency, as there is no need to use any upstream drying apparatus. Second, a special feature of use of alternative materials in clinker burning is that both the energy content and the material components in the resulting ash can be almost completely used as product components.
Fuel energy consumption classified by energy sources
|Consumption (million GJ/a)||2014||2015||2016||2017||2018|
|Heyvy fuel oil||0.2||0.3||0.6||0.5||0.2|
|Natural gas and other gases||0.5||0.4||0.5||0.5||0.6|
|Other fossil fuels||0.0||0.3||<0.1||<0.1||<0.1|
|Total thermal energy||92.5||89.5||91.2||96.8||96.0|