Hydrogen and electricity potential generation from rice husks and persiculture biomass in Rio Grande do Sul, Brazil

The Southern region of Brazil has the highest grain and fruit production at a national level. Therefore, the biomass waste from rice and peach harvest in the Rio Grande do Sul (RS) state represents a promising source of available clean energy. This study seeks to demonstrate the average potential for biohydrogen and energy production by utilizing residues from peach cultivation rice straw and husks from 2014 to 2021. The findings reveal that an average of 2.89E+06 m³.year−1 of bioH2 theoretically obtained from the dark fermentation of rice husks and straw, with a biogas production of 1.49E+06 m³.year−1, derived from the anaerobic digestion of peach residues. After the purification process, the biogas yields an average of 4.73E+05 kg year−1 of H2, resulting in a total of up to 2.26E+08 kg year−1 when combined with the bioH2 obtained from the dark fermentation of rice residues. The results indicate an average energy of 8.50E+06 GJ year−1 potentially obtained by burning rice husks. Furthermore, for peach and rice biomass, the average energy potential is 3.37E+04 GJ year−1. Besides, considering using 2% of the bioH2 theoretically produced for green ammonia generation, the results show an amount of approximately 2.55E+04 tons. Therefore, this study is relevant since highlights the region's potential to produce clean energy from agricultural residues while presenting viable solutions to mitigate the negative environmental impacts caused by improper disposal of these materials. Moreover, these residues used for clean energy production contribute to the sustainable energy transition, reduce dependence on fossil fuels, decrease the need for nitrogenous fertilizer imports, and promote the implementation of the Circular Economy.