Systems-Level Analysis of Energy and Greenhouse Gas Emissions for Coproducing Biobased Fuels and Chemicals: Implications for Sustainability

In light of advances in the simultaneous production of biobased fuels and chemicals, a prospective well-to-wheel lifecycle assessment (LCA) model of a two-step multistage torrefaction biorefinery is constructed to quantify both lifecycle greenhouse gas (GHG) emissions and energy return on primary fossil energy investment (EROI_fossil) for a transportation-range biofuel product. Coproductsincluding cyclopentanone (CPO), biochar, and a potential net electricity exportare handled via six coproduct scenarios, evaluated across both market-based allocation and displacement methods. Process-scale performance metrics and product distributions are compared across cases to evaluate trade-offs between process and environmental performance; carbon flows are visualized to better explain patterns of carbon yield and waste. LCA results include median GHG values spanning from −30.8 to +36.1 g CO₂e/MJ-fuel and median EROI_fossil values ranging from 1.6 to 12.8 MJ-fuel/MJ-PE_fossil. Sensitivity results for the Market CPO case under market-based allocation display a large dependence on CPO yield, hydrogen consumption and fuel and CPO prices, while exhibiting minimal dependence on liquid fuel yield. Unrealistically low lifecycle GHG and high EROI_fossil values are obtained under displacement for the maximum level of CPO production, prompting a discussion of methodological limitations, especially as they relate to the assignment of system expansion coproduct credit within existing EROI formulations