Economic Potential of Producing Bioethanol From Sweet Potatoes for Tropical Regions

This review presents a comprehensive techno-economic evaluation of producing bioethanol from sweet potatoes (Ipomoea batatas (L.) Lam.) in tropical regions, highlighting its agronomic, economic, environmental, and policy implications, and introducing a novel dual-role perspective that examines sweet potato simultaneously as a food and fuel crop. Sweet potato, a high-starch, drought-tolerant crop, demonstrates remarkable adaptability to low-input farming and marginal lands, traits which render it a compelling bioethanol feedstock for tropical countries grappling with food-energy nexus challenges. Drawing on a systematic qualitative literature review, the study quantifies potential ethanol yields of 4,500–10,000 L/ha/year under dual-cropping systems, benchmarked against maize, cassava, and sugarcane. A techno-economic model estimates capital expenditures, operating costs, and revenue streams, incorporating co-products like animal feed and CO₂. Financial indicators, including Levelized Cost of Ethanol ($0.50–$0.75/L), IRR (12–25%), and payback periods (3–6 years), are analysed under yield, cost, and market volatility scenarios. The study further examines GHG reduction potential (40–60% vs. gasoline), efficient land/water use, and strategies to mitigate food-vs-fuel trade-offs through marginal land use and dual-purpose cropping. Social dimensions such as rural employment and gender inclusivity are explored, especially given women’s predominant role in sweet potato cultivation. Policy and market drivers, biofuel mandates, PPPs, and regional trade are evaluated for their enabling roles. The findings advocate for the integration of sweet potato into national bioenergy portfolios as a viable pathway toward SDG-aligned climate mitigation, rural development, and energy security in tropical economies. This research closes a critical knowledge gap and positions sweet potato as a sustainable, underutilised asset in the future of biofuels.