Biomass-to-Bioenergy Conversion Technologies: An Exploratory Review from a Circular Economy Perspective

Biomass conversion can support the circular economy when energy production is linked to the recovery of value from organic waste and residual biomass. This exploratory review examines how recent research has approached this relationship, with particular attention to the practical conditions that influence the use of biomass-to-bioenergy systems. A literature search was performed in Scopus to identify relevant scientific articles and reviews, which were afterwards analyzed through a critical thematic synthesis within the scope of an exploratory review. The literature covers a broad range of feedstocks and conversion routes, including anaerobic digestion, pyrolysis, hydrothermal processing and integrated biorefinery systems. The findings show that the circular value of these technologies depends not only on energy production but also on how recovered products are used and whether the process can operate under realistic conditions. Feedstock availability, scale, logistics and access to suitable markets remain important constraints. Further progress will depend on evidence from longer-term operation and on assessments that better reflect the conditions in which these systems are implemented.