Production of Fuels from Wood Sources
Wood has been and continues to be a dominant source of energy, particularly in households in developing countries. Wood fuels consist of four main commodities: fuel wood, charcoal, black liquor and other. While fuel wood and charcoal are traditional forest products derived from the forest, wood-processing industries and recycled wooden products from society, black liquors are byproducts of the pulp and paper industry.
Woody biomass in the form of wood chips, “hog” fuel, wood pellets, and sawdust and planer shavings may be burnt to produce hot water or steam in a boiler or hot air in a furnace for distribution throughout a building or collection of buildings. Woody biomass may be distilled into biofuels such as ethanol and used as a heating and transportation fuel. Ethanol is more commonly produced from corn and other plant materials with high levels of starch that can be distilled more easily than woody biomass. Woody biomass can also be “gasified,” or heated in a controlled oxygen environment to produce a low btu-value gas (168 Btu/ft3 versus approximately 1000 Btu/ft3 for natural gas).
Forest biomass inventory is substantial and significant amounts of wood residue are generated from processing, construction, demolition, and municipal solid waste. Prospects for expanding the use of wood biomass for producing electrical power or ethanol will be enhanced by environmental needs and improvements in technology.
Technology needs include improvement of short-rotation intensive culture techniques for plantations and improvement of electrical power and ethanol production processes. These efforts can help to improve the comparative advantage of wood biomass feedstocks relative to fossil-fuel feedstocks. Key environmental concerns will constrain the supply of wood biomass from forests and plantations; particularly concern for the effects of management for wood fuel on the diversity of plants and animals and on the depletion of soil and water resources.