Biopellets from Four Shrub Species for Co-firing in East Indonesia

The rise in industrial activity and human population has increased fossil fuel consumption. Consequently, Indonesia has promoted a decarbonization program to achieve carbon neutrality or net-zero emissions, including developing renewable energy from biomass. However, comprehensive information on the potential biomass sources for power plants remains limited. To address this, this study investigated the potential of four local shrub species (bungur, Lagerstroemia speciosa; locong, Ganophyllum falcatum; latte, Myrsine avenis; and terasa, Mischocarpus sundaicus) and bamboo (paring: Gigantochloa atter) as alternative energy sources for co-firing in power plants. These materials were processed into biopellets and evaluated according to the Indonesian National Standard 8951-2020. The results indicated that shrub and bamboo biopellets met the Indonesian National Standard requirements for density, moisture, ash, carbon, and mineral contents. Compared to bamboo, shrub biopellets exhibited superior properties, including higher density, lower moisture and ash contents, higher fixed carbon, and higher calorific value, whereas the volatile and mineral contents were similar for both. Among the shrubs, M. avenis showed the most promise for further development because it had the lowest moisture (3.2%), ash (1.5%), K2O (0.18%), and Na2O (0.0001%) contents and a relatively high calorific value (3,836 kcal/kg) compared to the other materials tested.