Converting Waste Agricultural Biomass into a Resource - UNEP

1. Introduction and Background
Globally, 140 billion metric tons of biomass 1 is generated every year from
agriculture. This volume of biomass can be converted to an enormous amount
of energy and raw materials. Equivalent to approximately 50 billion tons of oil 2 ,
agricultural biomass waste converted to energy can substantially displace
fossil fuel, reduce emissions of greenhouse gases and provide renewable
energy to some 1.6 billion people in developing countries, which still lack
access to electricity 3 . As raw materials, biomass wastes have attractive
potentials for large-scale industries and community-level enterprises.
Biomass takes the form of residual stalks, straw, leaves, roots, husk, nut or
seed shells, waste wood and animal husbandry waste. Widely available,
renewable, and virtually free, waste biomass is an important resource.
With the global campaign to combat climate change, countries are now
looking for alternative sources of energy to minimize green house gas (GHG)
emissions. Aside from being carbon neutral, the use of biomass for energy
reduces dependency on the consumption of fossil fuel; hence, contributing to
energy security and climate change mitigation.
Although there is an emerging trend on the utilization of biomass conversion
technologies -- from combustion of rice husk and sugarcane bagasse to
gasification of other agricultural residues -- biomass is still largely under
utilized and left to rot or openly burned in the fields, especially in developing
countries that do not have strong regulatory instruments to control such
pollutive practices. As a common practice, direct combustion of agricultural
residue results in air pollution thereby posing risk to human and ecological
health. Biomass is a renewable resource that causes problems when not
used. The challenge, therefore, is to convert biomass as a resource for
energy and other productive uses.
There are advantages in the use of biomass. Biomass is a renewable
resource that has a steady and abundant supply, especially those biomass
resources that are by-products of agricultural activity. Its use is carbon
neutral, can displace fossil fuels, and helps reduce GHG emissions while
closing the carbon cycle loop. As the debate on food versus fuel intensifies,
biomass can provide added income to farmers without compromising the
production of main food and even non-food crops.
1 Biomass wastes include agricultural wastes, such as corn stalks, straw, sugarcane leavings, bagasse,
nutshells, and manure from cattle, poultry, and hogs; forestry residues, such as wood chips, bark,
sawdust, timber slash, and mill scrap; municipal waste, such as waste paper and yard clippings.
2 Concept Paper, Using Agricultural Biomass Waste for Energy and Materials: Resource Conservation
and GHG Emission Reduction, A Biomass Assessment and Compendium of Technologies Project,
UNEP August 2007
3 Annan calls for greater efforts to ensure access by poor to renewable energy,
http://www.un.org/apps/news/story.asp?NewsID=15483&Cr=development&Cr1= August 19, 2005
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