Insights into the co-utilization of cassava industry waste and invasive woody biomass for charcoal briquettes production

• Higher LWC ratios enhanced briquette durability, density, and heating value. • Cassava peel and tuber binders reduced cost while maintaining briquette performance. • B1-TS and B1-CP showed rapid ignition and efficient water boiling performance. • B2-CP briquettes achieved prolonged heat retention and energy efficiency. The growing global demand for cleaner energy has fostered the development of bio-based fuels, particularly in agro-waste-rich regions. Therefore, this study investigated the production of charcoal briquettes using cassava rhizome (CRC) and Leucaena leucocephala wood (LWC) combined with cassava by-product binders such as tapioca starch (TS), cassava peel (CP), and cassava tuber (CT). Two charcoal blend ratios (75:25 and 50:50 CRC:LWC) were formulated and tested in six treatment combinations, with the charcoal mixtures having a fixed ratio of charcoal blend 100:binder 15:water 20. The charcoal briquettes were evaluated for moisture content, true density (TD), water resistance, shatter resistance (SR), higher heating value (HHV), burning rate (BR), specific fuel consumption (SFC), water-boiling efficiency (WBE), and water-boiling profile. The results showed that increasing the LWC proportion significantly improved TD, HHV (up to 967.55 kg m −3 and 23.13 MJ kg −1 ), and mechanical durability, while formulations with a higher CRC content in the B1 blend exhibited lower SFC (114.05 g L −1 ) and higher WBE (21.89%). In contrast, the B2 blend, particularly B2-CP, demonstrated sustained higher water temperatures and longer heat retention during boiling. Economic analysis revealed that CP and CT-based briquettes reduced production costs compared to TS, with minimum payback periods ranging from 13.46 to 18.33 tons year −1 . This study confirmed the feasibility of utilizing CRC and LWC, both underutilized or invasive biomass sources, for small-scale charcoal briquette production, thereby promoting waste valorization, forest conservation, and rural energy security.