Experimental study of sustainable bioenergy generation from woody and agricultural residue using a downdraft fixed-bed gasifier

The surging need for sustainable clean energy has accelerated the shift toward carbon-neutral fuels. Gasification offers an effective route for harnessing biomass energy potential, significantly enhancing its utility through conversion into a combustible fuel gas. This study evaluated the performance and efficiency of four North Indian feedstocks using a 10-kW downdraft gasifier. The feedstocks are eucalyptus (Eucalyptus globulus), poplar (Populus ciliata), bagasse (Gramineae S accharum officinarum), and coconut shell (Cocos nucifera). The study assessed syngas composition, equivalence ratio (ER), calorific value (CV), carbon conversion efficiency (CCE), and cold gas efficiency (CGE). Moreover, Potential CO 2 mitigation (PCO 2 M), energy density (ED), fossil fuel equivalent (FFE), fuel ratio (FR) and thermal stability (TS) have been evaluated. The results indicate that the average CV of poplar is 5.911 MJ.m −3 , eucalyptus is 5.246 MJ.m −3 , coconut shell is 6.162 MJ.m −3 , and bagasse is 4.248 MJ.m −3 . The CGE indicated optimum efficiencies of 49.51 %, 51.34 %, 48.60 %, and 32.44 % for poplar, eucalyptus, coconut shell, and sugarcane bagasse, respectively. The CCE also demonstrated remarkable conversion rates. The energy density noted was highest for coconut shell at 11.319 GJ/m 3 , and lowest for bagasse at 4.977 GJ/m 3 . The potential CO 2 mitigation concerning petroleum is 1048.59 kg of CO 2 /m 3 of biomass for coconut shell, 916.69 kg of CO 2 /m 3 for poplar, 885.00 kg of CO 2 /m 3 for eucalyptus, and 461.07 kg of CO 2 /m 3 for bagasse. This study offers a comparative insight with published literature, revealing the strong potential of the examined feedstocks for efficient energy generation, especially in rural areas where their untapped availability often leads to environmentally harmful disposal. • A thermochemical study of four indigenous North Indian biomasses was performed using a 10-kW downdraft fixed-bed gasifier. • Gas CV ranged from 3.945 to 6.162 MJ/m³ and ED up to 11.319 GJ/m³ , affirming robust potential in all feedstocks. • Coconut shell had the highest CO₂ mitigation (1048.59 kg CO₂/m³ biomass), while poplar had peak CGE (51.34 %) and CCE (85.65 %). • Findings promote valorization of local residues for decentralized bioenergy and low-carbon rural electrification frameworks.