Pyrolysis activation energy, E-a, was determined using thermogravimetric analysis (TGA) for twenty Sorghum bicolor genotypes using Arrhenius-based, isoconversional kinetics formulations. lsoconversional temperatures (T-alpha) at various conversion levels, alpha from 0.05 to 1.0, were determined using TGA for separate leaf and stem tissue. E-a was then determined rising Kissinger-Akahira-Sunose and Friedman formulations. Observed E-a and predictor variables including conversion level and compositional parameters (e.g. proximate, neutral detergent fiber, lignin, cellulose, and hemicellulose content and crystallinity index, were input to a stepwise regression to build an E-a prediction model. E-a calculated using T-alpha varied with conversion indicating more complex kinetics (multiple reactions) than a single kinetic triplet can describe although averages of observed and predicted E-a were statistically equivalent at 197 and 202 kJ mol(-1), respectively. Additionally, pine wood was evaluated to assess model robustness. With no significant difference between observed and predicted E-a (217 versus 211 kJ mol(-1), respectively), the model appeared robust. (C) 2014 Elsevier B.V. All rights reserved.