Policy makers and investors often need to consider trade-offs between alternative biomass-based energy supply options. Supply cost potentials for three bioenergy feedstocks prevalent in Canada including agricultural residues, dedicated woody crops, and forest harvest residues are summarized. Each feedstock has its own particular cost characteristics depending on the quantities involved. Importantly, this synthesis revealed significant differences in the uncertainty associated with the cost estimates, with agricultural residues having the greatest variation, followed by woody crops and postharvest forest residues, respectively. One implication of this uncertainty is that the attractiveness of each feedstock option likely depends on local market demand conditions and producer circumstances, making definitive aggregate supply estimates challenging.