Sustainable fuel production from water hyacinth: evaluation for cooking applications and resource mapping

Water hyacinth (WH), scientifically known as Eichhornia crassipes, is an invasive free-floating perennial hydrophyte that poses a significant threat to the environment and the economy. This study aims to systematically address the management challenges associated with WH by conversion into a potential solid fuel specifically targeted for rural cooking energy applications and estimate the potential of WH waste in India using GIS analysis. WH was collected, and various physical pre-treatment approaches were explored. Four shaping methods (unprocessed, chopping, roll pressing, and roll pressing + chopping) and four drying methods (open sun, multi-tray solar-small, multi-tray solar-large, and solar still) were attempted to identify the most efficient approach for rapid drying. The dried WH samples were pelletised, and characterized for calorific value ultimate analysis, proximate analysis, and heavy-metal content. The pellets, when utilised with a forced-draft cookstove, adhered to the BIS IS:13152 cookstove testing limits for thermal efficiency and emissions of PM_2.5 and CO. The blending of WH with locally available agricultural waste (sawdust, cotton straw, and bagasse) in different ratios improved the calorific value by 10–15% while reducing ash content to below 6–8%. GIS analysis showed the estimate of WH cover over India to be around 60.15 million hectares. This translates to nearly 22,540–35,284 Terajoules of energy potential after adjusting for water content. Our analysis demonstrates the viability of effective and sustainable WH waste-to-fuel management, prompting exploration into water retrieval mechanisms for effective and sustainable management of WH.