AUTHOR=Granacher Julia , Schnidrig Jonas , Chuat Arthur , Lepour Dorsan , Terrier Cédric , Castro-Amoedo Rafael , Marechal Francois M. A. TITLE=Internal pricing in integrated energy system design JOURNAL=Frontiers in Energy Research VOLUME=Volume 13 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2025.1392761 DOI=10.3389/fenrg.2025.1392761 ISSN=2296-598X ABSTRACT=Environmentally sustainable and economically viable process and energy systems are imperative to a successful energy transition. Often, design configurations are derived from a global perspective, in which the individual needs and interests of actors within the system are overlooked. This work proposes an approach for designing a system considering its entire scope and acknowledging the individual actors within the system. System solutions are generated from the perspective of a universal decision-maker who is aware of the whole system, and the obtained solution space is analyzed regarding implications for the individual actors. Thereby, prices of internal exchanges between actors that would allow for the realization of the optimal integrated system solution while granting each actor their economic objectives are derived. The approach is demonstrated in three distinct case studies varying in size: a bio-based industrial site, a renewable energy community, and a national energy system. All case studies yield system configurations allowing the actors to profit from economic benefits emerging from synergies from internal cooperation. Further research must delve into diverse system settings and actor paradigms to enhance the robustness and applicability of the derived insights.