Coconut husk for second-generation biofuel production to advance a circular economy

Abstract

The growing demand for sustainable energy alternatives has highlighted biofuel as a promising substitute for fossil fuels. Coconut husk, a byproduct of the coconut industry, remains an underused but abundant biomass resource with significant potential in biofuel production. This review provides a comprehensive overview of current technologies, challenges, and strategic opportunities in utilizing coconut husks for biofuel generation. It looks at thermochemical processes like pyrolysis, gasification, and combustion, as well as biochemical processes like anaerobic digestion, fermentation, and transesterification, focusing on how well they work, how much they can produce, and how they affect the environment. While coconut husk offers advantages in terms of biomass availability and calorific value, various technical, economic, and regulatory barriers must be addressed to unlock its full potential. Key challenges include feedstock processing, cost-effective conversion technologies, and regulatory and market limitations. Additionally, the review compares coconut husk to other biomass feedstocks, highlighting its sustainability and yield benefits. Case studies of regional programs in major coconut-producing areas provide insights into real-world applications and outcomes. The review also identifies critical research gaps in life cycle assessment, environmental impact, and policy development. Future directions emphasize technological advancements and policy measures to enhance the viability of coconut husks as biofuel sources. Overall, this review underscores coconut husk's potential as a sustainable biofuel feedstock, advocating for coordinated efforts to address existing challenges and advance renewable energy adoption.