1. Introduction
Our dependence on oil brings with it concerns for long-term environmental impacts, energy security, and rising costs of living. There is an opportunity to replace fossil fuels like petroleum and coal-based products with bio-based products and biofuels from biomass. In general, agricultural and forestry biomass are widely used to generate electricity, supply heat and steam power, and heat homes. A recent joint study by the USA, Departments of Energy (DOE) and Department of Agriculture concluded that there is more than a billion tons of biomass in the USA, which can replace about 30% of its current petroleum consumption (Perlack et al., 2005).