Strategies for a low carbon building stock in Germany

Abstract

The German building sector is currently responsible for one third of the CO2 emissions and more than 40% of final energy consumption. Moreover, the German Federal Government's Energy Concept has set a target for Germany's building stock to be nearly climate-neutral by 2050. In order to achieve this ambitious target, a long-term road map for energy upgrades is necessary.We analyzed different strategies for reducing primary energy demand and CO2 emissions from residential building stock up to the year 2050. These strategies comprise the Federal Government´s energy concept measures on the one hand, and alternative paths and options using more renewable gases and innovative heating systems on the other. The calculations are based on the dynamic simulation model JEMS-BTS. The model simulates the effects of various energy efficiency measures such as thermal insulation and improvements to heating systems. The "business as usual" scenario represents measures which have already been implemented. Based on this scenario, we explored the energy concept scenario by applying stringent improvements to building codes and assuming large reductions in the energy use of existing buildings through energy renovations. In contrast, we analyzed an increased use of renewable gases, an early exchange of heating systems, and a forced use of low carbon heating systems in an alternative scenario.The results show that the primary energy demand and the CO2 emissions within the energy concept and the alternative scenarios could be reduced by more than 80% by 2050 and would lead to a climate-neutral building stock. The costs (Net present value) of the alternative scenario are much lower than in the energy concept scenario, resulting in much lower CO2 avoidance costs. Sensitivity analysis underlines the robustness of these results.