The energy intensity of production processes is generally defined as energy consumption per unit of added value. This thesis enables the quantification of energy intensities in industry, based on a literature study and by analyzing the documents of the "Best Available Technology". The evaluated data is compared with values of existing companies. The analyse is focused on the industry sectors of iron- and steelproduction, ferrousmetal processing, and pulp- and paperproduction. The energy use in these production processes is presented, analyzed and compared by defining common system boundaries and the creation of energy flow diagrams using the stock flow analyse software, STAN. Comparing different industrial sectors and production processes promotes research in the energy sector by monitoring of potentials for further improvements, new structures, approaches and evidences. The results of the thesis provide ranges for low energy-intensive, energy-intensive and highly energy-intensive processes. Furthermore a benchmark to compare different industry sectors is discussed and proposed.