Assessing industrial waste heat potential: Insights from a comparison of methods at the city level. A case study from Hamburg

Abstract

It is often claimed that industrial waste heat can significantly reduce primary energy demands. In order for waste heat potentials to be utilized, they need to be made known, in location and quality. Estimating waste heat potentials proves difficult because of the heterogeneity of waste heat sources. Industrial processes differ in the amounts, temperature levels and temporal availability of their waste heat. The thesis compares different methods of estimating waste heat potentials based on German emissions data and international literature. Based on national statistics of energy carriers in the Manufacturing Sector, the thesis first identifies the amount of process heat in different temperature ranges. This analysis can be done for geographical regions (country, federal state, city), economic sectors (Industry, Households, Commerce) or facilities. On a more detailed level, a case study from Hamburg describes two methods for waste heat estimation within the Manufacturing Sector. Waste Heat Factors and Carnot Factor are applied to local data and the outcomes at the city and company level are compared. The thesis outlines the importance of first understanding the estimation method itself and the results it can provide. Furthermore, the purpose of the analysis and the availability of waste heat specific data drive the choice of the estimation procedure. The case study shows that both two methods applied at the city level lead to an overestimation of waste heat potential in comparison to a company-specific evaluation. The properties of waste heat are essential for the accuracy of results and therefore, the author recommends what further information would facilitate the estimation of waste heat potential. Ultimately, from an urban planning perspective, the magnitude of waste heat, as well as the characteristics and location of the source can influence the development of energy systems for waste heat storage and reutilization.