The biorefinery has been modeled for the production of fuel ethanol from cellulosic biomass, but it has not been integrated with cropping and animal systems. Incorporation of these systems will allow fully integrated environmental and economic analysis of biomass production, possible secondary protein products, fertilizer production and ethanol fuel production. A comparison is presented of the performance of several crop and animal simulation models, including: DAYCENT, Integrated Farm System Model (IFSM), and I-FARM. Using a grading system developed by the authors, a model is highlighted as suitable complement to existing biorefinery models for future investigation of alternative farm management strategies in conjunction with classical engineering process design. (C) 2008 Elsevier Ltd. All rights reserved.