Biofuels in Perspective

Sustainable Production of Cellulosic Feedstock 33
downstream in adding value (upstream from the biorefinery), hydrolyzing the cellulose
completes the cellulosic conversion to sugars at the storage site. Depending on the local
situation, the use of dilute fermentation sugars may be limited. Concentrating the sugars
from 30 % to 80 % solids would likely make them fungible, opening up a broader market
to supply other biorefineries. Concentrated fermentation sugars reduce feedstock risk,
removing a major concern when considering debt financing.
2.15 Looking Upstream
Farmers can work with crop science companies – such as Monsanto, Pioneer and Syngenta
for corn and soybeans or Ceres and Mendel Biotechnology for perennial grasses – to obtain
new cropping systems with traits that are desirable for increasing the margins from the
crops and achieve sustainable production.
Companies looking at plants as sources for chemicals and plastics, like Metabolix,
ADM, National Starch and Allylix have a potential partner for growing the desired crops,
recovering the expressed ‘value added’ material and processing the remainder.
2.16 Logistics
Transporting and delivering liquids to biorefineries like dry mill ethanol plants eases the
logistic problem. The liquids can be delivered via truck or rail, but pipelines to transport
the liquids – similar to the pattern used for oil wells to collect fossil fuels – avoid traffic
disruption and have an economic advantage in most places.
Expanding the fermentation and downstream processing operations of existing ethanol
plants permits capacity growth without going beyond their present corn buying area and
increases their competitive position – benefiting from economies of scale.
A gasifier using some of the biomass as a feedstock can provide the process energy
source. As markets develop for lignin products beyond fuels, selecting plants with the
desired lignin properties and recovering lignin as a co-product can provide additional value
added.
Providing fermentation sugars and lignin feedstocks in lieu of crop residues positions
the farmer for benefiting from Greenhouse gas offset credits when carbon trading becomes
a standard way of doing business. The economic value is expected to be 5–10 times the
$2–$4 per ton of CO2 now being offered to US farmers for carbons offsets.
The engineering and biotech tools are available to make this happen. When the economics
work, we can expect the farmers will be a huge player in the future – the carbohydrate
version of OPEC, as they control the feedstock.
2.17 Conclusions
Higher and more unstable prices of petroleum and natural gas, along with the desire to
produce more energy domestically, are making agricultural feedstocks a more attractive
alternative for the transportation fuel, chemicals, and plastics industries. With ongoing