Constructing a commercial biorefinery involves significant financial and technical risks that may affect investor willingness to commit funds. Repurposing existing industrial facilities has been proposed as a means to lessen the investment risk in constructing a new biorefinery through reduced financial requirements and startup costs. This research provides a decision‐making tool for estimating the repurpose potential of existing industrial facilities considered for conversion to a biorefinery. It applies well‐established techniques for capital cost estimation of Greenfield biorefinery and pulp mill infrastructure and assets to determine their repurpose potential as a biorefinery. It demonstrates how capital cost reduction is highly dependent on the process technology present in the subject facility. A factored approach is employed to assign valuation to the major capital cost components of a Greenfield biorefinery. Existing facilities are then assessed for their compatibility through an infrastructure and asset analysis to determine an estimated capital percent savings that may be realized through repurposing into a biorefinery. Private and public databases and general facility process designs are used to determine the presence of equipment in each facility assessed. A yes/no analysis is performed to assign full cost to facility infrastructure and assets not present in the biorefinery and no cost to those that are present. This methodology provides an economic valuation tool for facility assessments as a metric for facility comparisons, and may be used to assist in decision‐making regarding the suitability of a facility for repurposing. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd