BIOMASS

The world's energy markets rely heavily on the fossil fuels coal, petroleum crude oil, and natural gas as sources of energy, fuels, and chemicals. Since millions of years are required to form fossil fuels in the earth, their reserves are finite and subject to depletion as they are consumed. The only other naturally-occurring, energy-containing carbon resource known that is large enough to be used as a substitute for fossil fuels is biomass.

Biomass is all non-fossil organic materials that have an intrinsic chemical energy content. They include all water and land-based vegetation and trees, or virgin biomass, and all waste biomass such as municipal solid waste (MSW), municipal bio solids (sewage) and animal wastes (manures), forestry and agricultural residues, and certain types of industrial wastes. Unlike fossil fuels, biomass is renewable in the sense that only a short period of time is needed to replace what is used as an energy resource.

The idea of using renewable biomass as a substitute for fossil fuels is not new. In the mid-1800s, biomass, principally woody biomass, supplied over 90% of USA energy and fuel needs. As fossil fuels became the preferred energy resource, biomass energy usage began to decrease. We know that there is only a finite amount of fossil fuel resources on earth, which will eventually run out - estimates place this occurrence at between 2020 and 2060. This knowledge, together with the adverse impact of their use on the environment, is expected to be the driving force which will stimulate the transformation of biomass into one of the dominant energy resources.

Virgin biomass and any waste biomass that results from the processing or consumption of virgin biomass can be transformed into energy, fuels, or chemicals:

• Wood-fuelled power plants in which wood and wood wastes are combusted for the production of steam, which is passed through a steam turbine to generate electric power

• Gasification of rice hulls by partial oxidation to yield a low-calorific-value fuel gas which drives a gas turbine to generate electric power

• Thermal decomposition of MSW to yield liquid fuel oils and chemicals

• Anaerobic digestion of bio solids to yield a relatively high methane-content fuel

Liquid fuels and products can also be produced by growing certain species of biomass:

• Extraction of triglyceride oil co-products from soya beans which is then converted to high-cetane biodiesel fuels

• Tapping of certain species of tropical trees to obtain liquid hydrocarbons suitable for use as diesel fuel without having to harvest the tree

• Extraction of terpene hydrocarbons from coniferous trees for conversion to chemicals