The paper industry is one of the five most energy-intensive industries in Germany. Large quantities of process steam in the temperature range of 100 to 200 °C are required especially for drying moist paper webs. Usually this process steam is provided by the combustion of fossil fuels (natural gas, coal, fuel oil). Since optimizing the energy efficiency of the paper manufacturing process is increasingly reaching its physical and economic limits, innovative approaches such as renewable heat are needed to further reduce CO2 emissions. This problem can also be found in other branches of industry – for example in the chemical industry.
The dilemma of the heat transition in German industry lies in the lack of usability of many renewable energies for the production of renewable heat at the required temperature level. In principle, biogas or biomass combustion systems, renewable gases (hydrogen or EE-methane), solar thermal systems, geothermal energy or power-to-heat (heat pumps or electric heating systems) would be suitable. However, none of these technologies has yet achieved widespread use – whether for cost reasons, lack of supply or lack of consistency. Although heat accounts for 70 to 75 % of the final energy consumption of German industry, renewable heat contributes only 4.3 % of final energy consumption.
Geothermal energy in particular has the potential to cover a larger share of the heat demand due to its base load capacity. The focus of the project is particularly on the temperature range up to 200 °C, which accounts for around 30 % of industrial process heat requirements. However, geological sites with sufficiently high temperatures for direct process steam generation of sufficient quality for industrial processes are rare in Germany. Therefore, processes are necessary to upgrade the thermal water or the generated steam. In the course of the UMSICHT sub-project, possible process routes are being developed and analyzed for this purpose and evaluated for the pilot site Kabel Premium Pulp & Paper (KPPP) in Hagen.