The use of lignocellulosic biomass in the production of bioenergy is escalating with time due to the increase in energy demand and ecological pollution. The purpose of this study is to examine the opportunities of biofuel production from Pennisetum purpureum which is an invasive perennial grass in Brunei Darussalam. The proximate analysis of the study showed that the proportions of moisture content (MC), volatile matter (VM), fixed carbon (FC), and ash content (AC) were 5.93%, 69.44%, 16.81%, and 7.82%, respectively. Moreover, the ratios of carbon (C), hydrogen (H), nitrogen (N), sulfur (S), and oxygen (O) provided by the ultimate analysis were 43.23%, 5.80%, 1.17%, 0.11%, and 41.76%, respectively. The low moisture content and the higher heating value (18.55 MJ/kg) marked this grass as a potential source of biomass. Fourier transform infrared spectroscopy revealed the strong bonds between O–H, C–H, C–O, C=O, and C=C in the biomass. The thermogravimetric and their derivative results depicted that the highest weight losses occurred at a temperature of 334 °C with a degradation rate of 6.56 °C/min for pyrolysis condition and at a temperature of 312 °C with a degradation rate of 7.66 °C/min in combustion conditions.