The aim of this chapter is to present the different ways of valorizing agricultural residues for energy production. Biological and thermochemical processes can be used to produce bioenergy while reducing the quantities of agricultural residues. In addition, these processes can generate valuable products and residues that need to be valorized to ensure the sustainability of the process. However, economic, technical, or environmental barriers may limit the application of these processes. When agricultural residues are subjected to biological processes, pretreatments may be necessary to facilitate the degradation of their lignocellulose matrix and thus improve their accessibility by microorganisms. Nevertheless, it is challenging to find efficient pretreatments that have optimal energy consumption with minimal impact on the environment. This chapter will also address examples of models used in literature that are useful for first estimations of energy potential based both on process parameters (e.g., temperature) and on substrate properties (e.g., organic matter content).