Technoeconomic and life-cycle assessment of multi-product and single-product lignocellulosic biorefineries

This study compares technoeconomic analysis (TEA) and life-cycle assessment (LCA) for single-product and multi-product biorefineries producing ethanol, butanol, itaconic acid (IA), and 3-hydroxypropionic acid (3-HP) from brewer's spent grain. Single-product biorefineries had minimum selling prices (MSPs) of $1.26 kg^-1 for ethanol, $2.41 kg^-1 for butanol, $2.74 kg^-1 for IA, and $5.46 kg^-1 for 3-HP. In the 8,000 MT/day multi-product biorefinery, butanol had a lower MSP ($2.32 kg^-1), while ethanol had a higher MSP ($1.74 kg^-1). The MSP for 3-HP also increased to $7.07 kg^-1. A feedstock-constrained 2,000 MT/day multi-product scenario further increased MSPs, indicating the importance of economies of scale. Sensitivity and Monte Carlo analyses indicate that MSP is mainly governed by product conversion efficiency and plant production capacity. Global warming potentials (GWPs) ranged from 5.50 kg CO₂-eq kg^-1 for butanol to 9.07 kg CO₂-eq kg^-1 for 3-HP. Enzyme production dominated life-cycle GWP, with biogenic carbon uptake providing partial offset. These findings indicate that multi-product biorefineries do not consistently enhance economic or environmental performance, as the outcomes depend on the product properties, production scale, and separation requirements.