A comprehensive study was conducted on the fuel feasibility of forest-based biomass-pine bark pellets (BPs) and their pyrolyzed biochar pellets (BP800) using molten hydroxide direct carbon fuel cells (MH-DCFCs). The polarization behaviors of MH-DCFCs fed with BP and BP800 were Ohmic resistance-controlled in the low current density region, while mass-transfer-controlled polarization behavior was dominant in the high current density region. The achieved maximum current density and peak power density were 74.5 mA/cm(2) and 30.8 mW/cm(2) at 450 degrees C for BP and 110.4 mA/cm(2) and 45.0 mW/cm(2) at 450 degrees C for BP800, respectively. The fuel availability test revealed that the batch lives of BP- and BP800-fed cells are similar to 19.0 and similar to 15.7 h and the energy conversion efficiencies are 39.0 and 45.9%, respectively, indicating that the fuel performance of BP is comparable with that of the pyrolyzed biochar (BP800) thereof with regard to energy conversion efficiency and cell stability. The characterizations suggest that this can be largely attributed to the inherent ash components in BP and the water formation during the BP-fed cells' operation, which can suppress the carbonate ion accumulation at the anode. In conclusion, direct utilization of raw BP as the fuel is feasible to feed MH-DCFCs, and the thermal pretreatment might not be required for biomass to run MH-DCFCs.