The present study investigated the thermochemical performance of grape juice processing byproducts, namely grape pomace grits, grape pomace powder, grape seeds, and grape seed powder, using differential thermogravimetric analysis to determine kinetic parameters during thermal decomposition. Pyrolysis experiments were carried out at heating rates of 10, 20, and 30 °C to a maximum temperature of 700 °C. The mean activation energy for grape pomace powder of 29.96 kJ/mol was the most energy efficient pyrolysis among the four byproduct types. Physicochemical characterization confirmed that these pulp residues can serve as a potential feedstock for fuel and energy production. Grape seeds had a higher lignin content (49 and 52% for seeds and powder) than grape pomace (38 and 45% for grits and powder), making them an appropriate raw material for industrial applications, particularly chemical production. Moreover, their relatively high cellulose and hemicellulose contents indicate a high saccharification potential. The proposed thermal conversion technique could be used downstream from the conventional biodigesters to convert the digestates of juice processing byproducts to biochar and bioenergy. The key findings of this study target growth of sustainable circular economy in the food industry.