As an agricultural country, the Philippines produces large undetermined amounts of biomass wastes from onion production. The utilization of these resources as feedstock for energy generation is one of the possible solutions to sustain the constantly-increasing energy demands of the country. However, relevant information on their production, availability, and distribution are the main reasons for hindering the development of bio-energy conversion technologies. This paper aimed to assess and analyze the available energy potential of onion leaves produced in Bongabon, Nueva Ecija. The onion production map of the municipality was generated through image processing of downloaded satellite images using ArcGIS. The map created was used to determine and calculate the total area planted with onions. Other important data were acquired through field sampling and with the use of mathematical equations, the computed available energy potential of onion leaves in Bongabon, Nueva Ecija was 48,265,466.48 MJ or 13,407,084.75 Kilowatt-Hours (kWh) given that the residues were 100% available and fully collected. This will be the amount of energy that the onion leaves can provide annually in the municipality. Considering the amount of energy computed, this may provide a significant contribution to the municipality’s energy supply.