The CO2InnO project is a France-Germany cross-border living laboratory, one of its key objectives being an comprehensive assessment of H2 use in potential decentralized energy systems [1]. It involves use of H2 as a fuel for combined heat & power (CHP) plants, due to their high efficiency. The goal is to provide users (e.g. local authorities, NGO, companies, etc.) with a tool allowing to test various configurations of system components and functioning, evaluate their feasibility (technical), interest (economical), and impact (environmental). This is part of a contemporary trend to try and combine what is known as techno-economic analysis (TEA) and its environmental counterpart, the life cycle assessment (LCA) [2]. This combination is challenging due to methodological considerations, but also because there is nearly no operational tool at disposal to conduct such integrated assessments. Moreover, the most advanced propositions are based on proprietary software [3]. Our ongoing work propose a framework for such a task, while incorporating an open science approach wherever possible. It is built on a case study of the Offenburg municipality buildings energy requirements. Firstly, a simulated energy system have been developed in OpenModelica by our project partners to investigate the boundaries of technical feasibility [4]. Based on these results, we are conducting a parametric prospective LCA of every system components [5-6]. Indeed, even though the burning of H2 can be considered climate neutral if considered in the use phase only, the environmental impact during the whole life cycle is not – nor the assessment should be limited to CO2 emissions [7-8]. Disaggregated results will then be imported back into the OpenModelica simulation to allow dynamic access to LCA results, depending on simulation parameters set by users. This would act as a decision support tool helping these actors plan their local energy transition.