Abstract
This article aims to provide a systematic review of the literature on animal biomass and biogas plants through an analysis of externalities and benefits in economic, social, and environmental terms. In recent years, the spread of biogas plants has played an important role, especially in rural areas, generating benefits not only for the individual farm but for entire communities, contributing to the reduction of energy poverty and, at the same time, promoting the production of energy and organic manure. In light of the findings, the study argues that: (a) more public subsidies are needed; (b) the deployment of an appropriate policy mix would encourage the spread of small and medium-sized plants, with a reduction in road transport; and (c) targeted and diversified investments are needed on a geographic-by-geographic basis.