The application of Digital Twins for scale-up in Modular Plants is envisioned to significantly reduce the necessary time-to-process for new-to-market products and address scale-up challenges. To identify application specific requirements of a Digital Twin for scale-up in Modular Plants, expert interviews were conducted. The spectrum of identified requirements as well as plant life cycle aspects are incorporated into a workflow concept which illustrates the partial models of Digital Twins, as well as the interfaces for the exchange of information. Also presented is a roadmap illustrating the cluster-specific development pathways for Digital Twins for scale-up in Modular Plants.