In 2021 Indonesia currently provides 58% of global crude palm oil, resulting in enormous amounts of oil palm wastes. The purpose of this research is to determine which palm oil solid waste has the potential to be used as a substrate for biogas production, and what is the optimum method and parameter to produce an economically viable source of biogas. The method used for this research was by means of literature review, in which the data used were acquired from journals, thesis, reports and research papers. This research evaluates the different energy potentials of different oil palm wastes which are; Oil Palm Fronds (OPF), Empty Fruit Bunch (EFB), Decanter Cake (DC), Oil Palm Trunk (OPT) and Mesocarp Fibre (MF). Which resulted in EFB producing the highest yield of methane (429 mL CH4/g VS) at similar operating parameters and methods. The optimization of methane yield from the substrates were studied using different methods and operating parameters resulting in the highest methane yield of 617 mL CH4/g VS from co-digestion of DC + POME. Although, considering the economic viability; it was found that OPF as the waste from bioethanol production was most preferable, not only producing biogas but also bioethanol. It produced a high methane yield of 514 ml CH4/g VS at lower operating cost.