Mechanical and energy assessment of hybrid biofuels: Integrating agro-industrial coconut and rice husk biomass with mineral coal for sustainable energy in Córdoba, Colombia

• The 95 % biomass blend achieved the highest thermal efficiency (54.34 %), outperforming the individual fuels. • The coconut shell briquettes showed the highest mechanical strength and durability (99.88 %), which optimised their storage and transport. • Co-firing biomass with charcoal improved the calorific value and reduced dependence on fossil fuels. • Experimental analysis confirmed that the right combination of biomass and coal optimises energy efficiency and sustainability. • This study proposes a viable alternative for agro-industrial waste management and energy diversification in Córdoba, Colombia. Global dependence on fossil fuels is a major environmental and energy concern. This study investigates the potential of solid biofuels produced from blends of agro-industrial biomass (coconut husk and rice husk) and mineral coal, specifically in the context of the department of Córdoba, Colombia. The main objective is to evaluate the mechanical and energetic properties of these blends in order to optimise their performance as a sustainable alternative to conventional fuels. Through a rigorous methodological approach, drying, compaction, combustion and mechanical characterisation tests were carried out according to international technical standards. The results show that the mixture with 95 % biomass achieved the highest thermal efficiency (54.34 %) and an acceptable mechanical strength, with a durability of 93.76 % and a compressive strength exceeding 3650 kPa. In contrast, rice husk had a lower durability (83.53 %) and the lowest compressive strength (2100 kPa), while coconut husk had high mechanical properties with a durability of 99.88 % and a compressive strength of over 7000 kPa. These combinations not only improved the calorific value and combustion characteristics, but also reduced the use of mineral coal, thereby reducing its environmental impact. In conclusion, the integration of agro-industrial biomass with mineral coal offers a viable solution for the transition to more sustainable energy sources, contributing to both waste management and emissions reduction. This approach represents a significant contribution to energy diversification in agricultural regions and globally.