Fibres from oil palm empty fruit bunches, generated in large quantities by palm oil mills, were processed into self-adhesive carbon grains (SACG). Untreated and KOH-treated SACG were converted without binder into green monolith prior to N-2-carbonisation and CO2-activation to produce highly porous binderless carbon monolith electrodes for supercapacitor applications. Characterisation of the pore structure of the electrodes revealed a significant advantage from combining the chemical and physical activation processes. The electrochemical measurements of the supercapacitor cells fabricated using these electrodes, using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge techniques consistently found that approximately 3 h of activation time, achieved via a multi-step heating profile, produced electrodes with a high surface area of 1704 m(2) g(-1) and a total pore volume of 0.889 cm(3) g-1, corresponding to high values for the specific capacitance, specific energy and specific power of 150 F g(-1), 4.297 Wh kg(-1) and 173 W kg(-1), respectively. (C) 2013 Elsevier Ltd. All rights reserved.