On the other side, there is currently no sustainable potential for
agricultural biomass, such as energy crops, crop residues and grass.
On the other hand, there is a substantial potential from woody
biomass, manure and waste biomass. The main constraints that
limit the sustainable biomass potential are competing material
utilizations, economic factors. The most prominent examples are
the competition between food, feed, and energetic utilizations of
biomass from agriculture and organic wastes [51]. Biofuels are expected
to reduce dependence on imported petroleum with associated
political and economic vulnerability, reduce greenhouse gas
emissions and other pollutants, and revitalize the economy by
increasing demand and prices for agricultural products [21].