This study investigates the potential of several types of agro-industrial waste and residues for biogas production. There are significant quantities of agro-industrial waste generated on the island of Lesvos (Greece) that could significantly enhance the island’s energy balance and security. In this study, anaerobic digestion is studied using a variety of feedstocks and the feasibility of generating electricity from agro-industrial waste and residues is investigated. An inclusive analysis is provided to support a large-scale application and contribute towards the decarbonization of the island of Lesvos through the reduction of fossil fuel utilization. The main objective of this study is to investigate the potential of electricity production from different renewable energy sources, such as biogas, in Lesvos Island (Greece). It has been estimated that the total power production from biomass in Lesvos could reach up to 560 GWh, however there is a strict margin for the electricity produced from renewable sources for the non-interconnected islands in Greece.