Techno-economic and environmental evaluation of decentralized bioethanol production from agricultural residues in Thailand

• Decentralized 2G bioethanol plants using mixed crop residues were evaluated. • Thailand’s bioethanol potential is estimated at 21,659 ML per year. • Ethanol gate prices range from 0.62 to 3.50 USD per liter. • Analysis identified 34 high-potential facilities for bioethanol production. • Biomass use reduces fine particulate matter formation by −168,642 DALY. Agricultural residues from sugarcane, rice, cassava, and oil palm amount to 25.0, 27.9, 21.5, and 12.2 million tonnes, respectively, based on Thailand’s crop production. This study evaluates the implementation potential of 71 previously proposed decentralized second-generation bioethanol (2G-EtOH) refineries through comprehensive techno-economic and environmental impact analyses, considering the blending of locally available crop residues at each facility. Bioethanol production capacities, simulated via thermal and enzymatic hydrolysis models, range from 2.4 to 2,633 million liters per year. Economically, 20 refineries located in northeastern Thailand and 3 in the southern region yielded positive net present values (NPV). Minimum ethanol gate prices, based on a net present value (NPV) of zero, were estimated to range between 0.62 and 3.50 USD L −1 , indicating that 47 facilities demonstrated competitiveness compared to conventional production. Despite variability in production scales and environmental impacts due to mixed feedstock use within the same regions, cross-regional analysis identified 34 high-potential facilities where human health impacts remained below 0.56 DALY/1,000 GJ, and net energy ratios (NER) exceeded 5.62, comparable to single-feedstock systems. Life cycle impact assessment revealed that the pretreatment stage contributed approximately 80 % of the total process-related impacts. Remarkably, in several regions, the reduction of fine particulate matter formation was significant when compared to open-burning practices, with a potential reduction of up to −168,642 DALY attributed to rice residue utilization. These comparative results offer valuable insights and practical options to guide the future development of Thailand’s crop residue utilization for sustainable bioethanol production.