Energy efficiency in the German residential sector: A bottom-up building-stock-model-based analysis in the context of energy-political targets

This paper assesses the practicability of meeting the German federal government’s energy-political targets for the residential sector by analysing the potential future development of this sector in an aggregated bottom-up model. The domestic building stock is considered in terms of the likely developments in the housing market, as well as the energetic characteristics of current and future buildings. The employed method is based on deterministic projections of demand floor space and demolition/refurbishment rates.
The key novelty lies in the focus on developments in this sector in Germany; existing studies have not had this focus and have therefore employed a more rudimentary methodology, for example with static refurbishment rates, shorter time horizons or no spatial differentiation. The total resulting final heating demand of domestic buildings of about 500 TWh lies above that of other studies in 2050, which is mainly due to the conservative assumptions regarding renovation activity and new build made in the present case. Hence in the reference scenario the target for 2020 is not met, suggesting that further political intervention is required. In another scenario, it is shown that a drastic increase of the renovation rate is required in order to meet the 2020 target, especially amongst existing single family buildings. The supply side is only indirectly considered due to the aggregated nature of the model, which could be improved for further work, but the presented method nevertheless represents a good compromise between using solely freely available data and obtaining superior degree of precision to previous studies