In early innovation phases, the monetary evaluation of process innovations is a challenge for companies due to a lack of data. However, an innovation evaluation is essential in an early innovation phase to ensure that process innovations deliver economic value added (EVA) in early innovation phases and to channel technology transfer expenditures in a goal-oriented manner. This paper presents an approach for a semi-quantitative procedure for the monetary evaluation of process innovations in the early innovation phase focusing on manufacturing and material costs. Exemplarily, the approach is applied to process innovations of the Collaborative Research Center 1368 on oxygen-free production. In order to ensure the net present value orientation within the innovation evaluation, the procedure developed is based on a driver tree of the EVA. To link value drivers of the EVA and innovation-driven factors influencing EVA, the EVA driver tree is further systematized with a focus on manufacturing and material costs using a literature-based impact model. Based on the last level of the impact model, a guideline for a semi-structured expert interview is developed. Using this interview guideline, data is collected in the form of innovation-driven influencing factors, which represent the input for the final monetary innovation evaluation. An adapted weighted scoring model is used to draw a semi-quantitative conclusion regarding the EVA achieved by the process innovation. The practical application of the approach developed to process innovations in oxygen-free production has shown that, in the context of three process innovations under consideration, their implementation with the aim of achieving an EVA through reduced manufacturing and material costs at the current innovation status is not effective. However, based on the impact model developed, corresponding levers can be identified to positively influence the EVA and thus also the industrialization of the process innovation. Finally, further necessary steps are identified to evolve the presented approach into a complete method for monetary innovation evaluation in early innovation phases.