A system for torrefaction of waste material comprising biogenic material and plastic material may comprise a material pre-processing system, a heating and compaction unit, a reactor system comprising a reaction portion and an extrusion portion, and a cutting unit adjacent an outlet of the reactor system. A method for operating a system for torrefaction of waste material comprising biogenic and plastic material may comprise processing the waste material to generate waste material having an aspect ratio between 0.8:1 and 1.2:1 and a largest dimension of less than 4 millimeters (mm); compressing and heating the pre-processed waste material in the heating and compaction unit; heating the compacted waste material in the reactor system to a temperature of 280° C.-500° C.; extruding material from the reactor system; and cutting the extruded material into pellets.