Waste Heat Utilisation in Automotive Factories

The decarbonisation of industrial heat supply requires a realistic assessment of how waste heat can contribute to factory-level energy systems and where applicable, to external heat networks. This paper analyses temperature-specific waste heat potentials in automotive factories, distinguishing between vehicle assembly and component production. Waste heat sources are classified according to their integration feasibility, differentiating between directly usable heat and lower-temperature heat requiring upgrading via heat pumps. Using real-world operational data from eight automotive factories, waste heat potentials are quantified relative to site-specific heat demand. The results show that vehicle assembly factories exhibit relatively homogeneous shares of directly usable waste heat, while indirectly usable potentials vary strongly across sites, particularly in component manufacturing. To capture temporal utilisation constraints, a time-resolved case study is conducted for one vehicle assembly factory, combining hourly waste heat availability, internal heat demand and the load of an external district heating network. The dynamic analysis indicates that a substantial share of available waste heat can be utilised internally over the year, including periods of full internal heat coverage, while only limited surpluses remain available for external use. Overall, the findings underline the importance of factory-level, time-resolved analyses for identifying realistically utilisable waste heat shares and for supporting site-specific planning of waste heat integration under realistic constraints, thereby supporting the decarbonisation of industrial and urban thermal energy systems.