The increasing need for simulation-based analysis along the life-cycle of modern process plants introduces new requirements and limitations in the development of simulation models. In the context of modular plants, according to VDI 2776, the distributed knowledge arises as a challenge in enabling system simulations. Co-simulation can enable a provider-independent simulation of chemical processes, but the co-simulation interfaces need further standardization to be efficiently integrated in the modular plant life-cycle. This paper works toward the usability of process models for co-simulation to support standardization efforts and make simulation models more usable and re-usable. To increase the usability of co-simulation in the process industry by working towards a common standard, two co-simulation standards, namely the Functional Mock-Up Interface and the CAPE-OPEN standard, are semantically linked. A use-case for a co-simulation-based operability analysis of a heterogeneous electrolysis plant is presented and necessary model requirements and interfaces are defined. Criteria to assess the compatibility of the model interfaces as a first step of a usability analysis are collected and presented. With the available requirements and interface specifications Functional Mock-Up Units can be created and the shown use-case can be carried out. Challenges regarding the potential integration of varying thermophysical properties have been pointed out and methods to overcome these challenges in the context of usability have been outlined.