Although it is envisioned that the first Phase III or lignocellulosic biorefineries will capture the low cost or niche feedstocks, eventually a significant fraction of the feedstock potential identified by Perlack and coworkers (3) will need to be captured economically. As the biorefining industry expands, process improvements will drive biorefinery capacities up.

Therefore, the longer-term feedstock supply R&D challenge is to ensure supply systems do not limit biorefinery size or consume biorefinery profits that could be used to purchase higher-cost feedstocks (see Figure 2.10). Feedstock availability, as a function of payment to the grower (4), has shown that more than 2/3 of the feedstock potential identified by Perlack and coworkers could be made available to the biorefinery at a purchase price up to about $50/ton. Adding estimated feedstock supply system costs gives a final feedstock cost of about $70/ton.

An advanced feedstock supply system will be needed to collect the large tonnages of feedstock required for large-scale biorefineries. An efficient interface between producers and the commodity biomass system is important for large-scale feedstock supply technology development. Production, harvesting, and collection systems will be widely varied, based on biomass resources and local practices. Primary research needs include storage, preprocessing, and transportation systems suited to these varied systems.

Developing value-add feedstock preprocessing and blending technologies will provide flexibility in the biomass feedstock supply system and allow suppliers to:

1 Reformat/condition different feedstocks into a common format and quality

2 Fractionate secondary co-products for local markets

3 Produce blended, large-scale commodity biomass.

Value-added preprocessing will help create a market specification for feedstocks, which will help in the transition of biomass to a large-scale commodity and ensure that feedstocks from varied sources can supply a large-scale biorefinery without process upset.