Potential environmental benefits from increased use of bioenergy in China.

Because of its large population and rapidly growing economy, China is confronting a serious energy shortage and daunting environmental problems. An increased use of fuels derived from biomass could relieve some demand for nonrenewable sources of energy while providing environmental benefits in terms of cleaner air and reduced emissions of greenhouse gases. In 2003, China generated about 25.9 x 10(8) metric tons of industrial waste (liquid + solid), 14.7 x 10(8) metric tons/year (t/y) of manure (livestock + human), 7.1 x 10(8) t/y of crop residues and food-processing byproducts, 2 x 10(8) t/y of fuelwood and wood manufacturing residues, and 1.5 x 10(8) t/y of municipal waste. Biofuels derived from these materials could potentially displace the use of about 4.12 x 10(8) t/y of coal and 3.75 x 10(6) t/y of petroleum. An increased bioenergy use of this magnitude would help to reduce the emissions of key air pollutants: SO(2 )by 11.6 x 10(6) t/y, NO(X) by 1.48 x 10(6) t/y, CO2 by 1.07 x 10(9) t/y, and CH4 by 50 x 10(6) t/y. The reduced SO(2) emissions would be equivalent to 54% of the national emissions in 2003, whereas those for CO2 are 30%. It is important to recognize, however, that large increases in the use of biomass fuels also could result in socioeconomic and environmental problems such as less production of food and damage caused to natural habitats.