Oil palm plantation waste is a potential renewable energy resource in terms of energy security and carbon-neutral fuel. The wastes from the plantation sites, such as oil palm fronds (OPF) and oil palm trunks (OPT) are currently underutilised. In this work, the thermal degradation behaviour of the OPF and OPT, and evaluation on the kinetic and activation energy of the torrefied products are investigated. The samples undergo light (200°C), mild (250°C), and severe (300°C) torrefaction for 30 minutes in inert condition. Then, the samples are characterised using bomb calorimeter, FTIR, and TGA analyses. As a result, the calorific values of OPF and OPT improved to 22.46 MJ/kg and 25.48 MJ/kg from the raw samples. At mild torrefaction, the energy yield of the solid product was higher for both OPF and OPT. In conclusion, the mild condition process showed optimum characteristics for both OPT and OPF as the feedstock for energy application.