Biomass

Posted: 27 November 2007

Wood and other vegetation (biomass) is an important source of fuel in the production of biogas, bioethanol and other biofuels. Biomass accounts for about 15 per cent of global primary energy use and 38 per cent of the primary energy use in developing countries, where it is mainly used for cooking and heating (fuelwood). The main sources of biomass include:

- domestic and industrial wastes, such as sewage gas, landfill gas or municipal wastes; - agricultural wastes, such as wood waste from forestry operations, bagasse from sugar cane, and organic wastes from animal husbandry; - residues such as straw and husks;- energy crops, such as short-rotation tree plantations, sugar cane and corn.

Biomass gasifier, Hawaii
Biomass gasifier, Hawaii
Biomass gasifier in Paia, Hawaii which uses residue from nearby sugarcane mill. Photo © NREL/Warren Gretz
  • Bioenergy projects can be as large as 100 MW power stations generating electricity and heat. About 7,000 MW of biomass-fired power generation is currently fed into the US national electricity grid.

  • Bioenergy projects can also be small enough to produce lighting and cooking energy for a single household or village.

  • Household biogas digesters, using animal dung and other farm materials, are widespread in China and India.

    Bioethanol plant
    Bioethanol plant
    Corn being unloaded from a railcar at an ethanol plant in Windsor, Colorado. The plant processes some 150 million litres of ethanol annually. Credit: NREL/Gerry Harrow
  • The largest and most successful use of energy crops are the (subsidised) US programme to produce fuel ethanol (alcohol) from corn (currently around 26 billion litres per year) and the Brazilian industry to produce ethanol from sugar cane (over 16 billion litres per year).

  • But critics suggest that the drive for bioethanol may create food shortages. See: Ethanol drives up world food prices

  • In 2006, biomass supplied nearly half of all renewable energy consumed in the United States - more than hydrolectricity.

  • Bioenergy projects can often be designed to co-generate both heat and electricity, and may also create a cost-effective solution to the disposal of wastes that may otherwise become potential environment problems.

    See Bringing biomass up to date