(23d) Optimization of National and Regional Bioenergy Feedstock Supplies As Functions of Price and Biorefinery Scale

The tendency for any biorefinery is to immediately start with the lowest cost biomass source meeting their minimum requirements as the feedstock of choice, for no other reason than it is cheap. The conversion process must then contend with any stability and handling issues, compositional variability, process upsets and product yield penalties, all of which negatively impact the biorefinery’s bottom line. Most know that high quality biomass is not cheap, but many do not realize that the cheap biomass will cause these issues. Further, it is not well understood by many that mobilizing large quantities of biomass for a new use as biorefinery feedstock when there is no other significant market for that biomass leads to steeply-increasing supply cost curves and grower payments that must be high enough to provide the grower with an incentive to invest in harvesting, collecting and providing the biomass to the biorefinery.

This report summarizes the national and regional availability of three biomass feedstocks, two-pass corn stover, three-pass corn stover and logging residue, at the biorefinery gate (prior to preprocessing) as a function of delivered cost to the biorefinery gate and biorefinery size. National and regional resource assessments of the availability of three-pass corn stover, two-pass corn stover and switchgrass were performed through the use of Mixed-Integer Linear Programming. Supply data for both corn stover and logging residue were taken from the 2016 Billion Ton Report (BT16), and the assessments were conducted varying both the size of biorefinery (100,000-800,000 dry tons/year) and the delivered cost at the biorefinery gate from $50-$85/dry ton in 2014$. The quantity of biomass delivered for all feedstocks were shown to be dependent on both the delivered cost to the biorefinery gate and the biorefinery size. The maximum delivered quantities of each feedstock is delivered under the 100k dt/yr biorefinery size scenario. At 100k dt/yr a maximum of 108.4 million dry tons of three-pass corn stover, 46.6 million dry tons of switchgrass and 32.8 million dry tons of two-pass corn stover could be delivered.