Future environmental impacts of cement production in Germany and the effects on downstream consumers

Being responsible for more than 9 % of the greenhouse gas emissions of German industry, the cement industry needs to undergo a drastic transformation to enable climate neutrality by 2050. Industrial emissions can be reduced through efficiency improvements, fuel switch, or new production technologies. As cement is used as an input material into numerous industries, e.g., the construction sector, changes in the cement production also influence environmental performances of other industries and products. The same applies for metal and electricity supply, which are often the environmental hotspots of downstream production processes. In this study, we first investigate how the environmental impacts of cement production in Germany will change assuming that the cement industry will undergo a decarbonization until 2050. Secondly, we assess how a decarbonization of the cement industry in combination with an electricity transition and metal supply developments might influence the environmental performances of other products at the example of wind and hydropower plants. Taking into account innovative technologies and different production routes we model decarbonization pathways for the German cement industry using normative scenarios. These scenarios consider seven different variables: a shift to Best-Available-Technologies, efficiency improvements, clinker substitution, shifting to alternative fuels, electrifying the precalciner and Carbon Capture Storage (CCS). The environmental implications of each scenario variable are assessed using prospective Life Cycle Assessment (LCA) and the approach of background scenarios. This means that processes within the background database of ecoinvent 3.6 are adapted according to our cement scenarios using Brightway2. In addition to the cement scenarios, we incorporate background scenarios from recent studies into ecoinvent. These are metal supply scenarios for copper, nickel, lead and zinc, as well as electricity scenarios from the integrated assessment model of IMAGE. The integration in a background database ensures that all downstream processes within that database make use of the futurized cement, metal, and electricity production processes. As a result, future versions of ecoinvent are generated in five-year intervals for the period of 2020 until 2050. Using the futurized background database, we perform a case study of the future environmental impacts of wind and hydropower plants. In our scenarios, we combined several technological options like Carbon Capture and Storage (CCS) and an electrified precalciner. The scenarios imply that CCS is the best option to reduce greenhouse gases from cement production. The maximum reduction of climate change impacts of 61% is reached by combining the cement "CCS" scenario with the electricity "Mitigation" scenario. There are also reductions achieved for marine eutrophication impacts by 218 % and human toxicity impacts by 47 %. Only metal depletion impacts increase by 33 % as electricity consumption rises. Furthermore, we showed that the incorporation of cement scenarios into ecoinvent3 influences downstream consumers in Germany. The climate change impact of the electricity production from hydropower decreases by 8 %