Rio, Pablo delPablo delRioKiefer, Christoph P.Christoph P.KieferCarrillo-Hermosilla, JavierJavierCarrillo-HermosillaKönnölä, TottiTottiKönnölä2022-03-062022-03-062021https://publica.fraunhofer.de/handle/publica/26836310.1007/978-3-030-74792-3_3This chapter provides a thorough literature review on existing definitions, classifications and taxonomies of the CE. This is a necessary exercise, as most researchers and practitioners recognize that the CE is an ""umbrella concept"". There are different approaches to circularity, and a commonly agreed definition of the CE currently does not exist. Precisely determining the concept is a difficult task.enenergy managementenergy resourceliterature reviewTaxonomy303600book article