In a previous paper, the modeling of chemical batch plants with the help of a top-down model was presented (Bieler et al. Ind. Eng. Chem. Res. 2003,42, 6135-6144). This approach was not applicable to multipurpose batch plants with highly varying production because of the high variability between products and the complexity of such plants. In the present paper, a bottom-up model is proposed, and its applicability to a multipurpose batch plant is investigated. Extensive measurements of single apparatus and unit operations were conducted, leading to simple, adaptable models for the consumption of steam, electricity, and brine. These single-apparatus and single-unit-operation models are summed according to the production schedule and the corresponding process step procedures or the production records. This leads to a bottom-up model of a complete multipurpose production plant. The energy consumption of the whole plant was modeled for 1 and 2 days, as well as for I week and 1 month. The comparison of the bottom-up modeling results with the measurements on the building level showed good agreement and demonstrated the applicability of the proposed approach. It was therefore possible to analyze the consumption of the different energy carriers in more detail on the basis of the bottom-up modeling results. The energy consumption of individual process steps, products, apparatuses, and apparatus groups was analyzed. This analysis revealed the most important saving potentials in the investigated plant and helped to focus optimization efforts. Furthermore, the bottom-up approach enables a proper allocation of energy consumption to different products in a multipurpose batch plant.