Traditional sources -- dung, crop and forest residues, fuelwood, and human and animal energy -- make up a very significant amount of the energy used in developing countries. Estimates of how much traditional fuels are used vary, largely because of the difficulty in measuring non-commercial fuel use. Recent estimates indicate that in Asia these fuels account for about 65% of total energy use, in Africa, about 85%, and in Latin America, about 20%. This masks an enormous variation both between and within countries.
Biomass offers many advantages for the environment compared to deriving energy from non-renewable fossil fuels. Energy taken from biomass generally adds far less carbon to the atmosphere, thus reducing the contribution to climate change. If new plant material is grown to replace that taken to produce the energy, the little carbon that is released will be reabsorbed, thereby completing the cycle. The low sulphur content of most biomass presents another advantage. Producing energy from fossil fuels, especially coal, is associated with heavy sulphur dioxide emissions, which can lead to acid rain and other problems.