depicts the real time temperature profiles of oil palm shell(OPS) under microwave power input of 450 W. It can be observed that OPS biomass can reach a maximum bed (T1) and surface (T2) temperature of about 122◦C and 180◦C, respectively. In case of OPF these temperatures were 95◦C and 93◦C, respectively as shown in Fig. 7. It seems that the penetration of microwaves depends on the types of materials and particle size. Fig. 6 also demonstrates the effect of particle size on the temperature profile of the biomass. The surface (T2) was much higher than the bed inside (T1) temperature when original un-grinded OPS were used (Fig. 6a). The MW was not able to penetrate the material bed due to hard and thick type of OPS biomass. While the bed inside temperature was considerably higher than surface temperature when same OPS biomass particles were grinded to small size (Fig. 6b). The height of the OPS biomass bed was approximately 5 cm, which was enough to penetrate the MW inside the bed according to the calculated penetration depth(13 cm) as shown in Section 4.4 of this paper.