The bioeconomy has become politically unavoidable for the transition to a carbon-free economy. It promotes the development of non-food uses of agricultural biomass. However, few methods and tools allow us—without prior fieldwork—to outline hypotheses on the bioeconomic functioning of a territory, from the stages of agricultural biomass production to its valorization. Thus, this article proposes an operational metabolic approach, based on open data, and a framework for analysis that deals with dimensions of embeddedness, autonomy, and energetic, environmental, and socioeconomic footprints. This proposal is put to the test within two territories, enabling a preliminary assessment to be made before any field application.