Bioenergy produced from biomass is sometimes called a carbon-neutral energy source, because the same quantity of carbon released when the biomass is burned is sequestered again when the crop or forest is re-grown. Referring to bioenergy as carbon neutral or having zero net emissions may be misleading; there are emissions associated with producing biomass, such as from fossil fuel used in cultivation, harvest, processing and transport, and in manufacture and construction of fuel conversion technology. Then there are less obvious emissions, such as the fossil fuel emissions in producing fertilizer and herbicide.
Although it is clearly not a zero-emissions process, the greenhouse impact of bioenergy is much lower than that of fossil fuel energy sources.
The production, processing, transport, and conversion of fossil fuels also requires additional fossil fuel inputs; the significant difference between fossil fuels and biomass in terms of Greenhouse Gas (GHG) emissions is the ability of biomass to ‘‘recycle’’ the emissions released in fuel conversion acting as a closed loop process.
GHG emissions and removals are reported to the United Nations Framework Convention on Climate Change (UNFCCC) by sector. Fuel use is reported separately from agricultural activities and forestry removals. The emissions associated with particular forestry and agricultural operations are not explicit in national GHG inventories; nevertheless, they are reported in energy consumption figures. Recommendations for future reporting suggest that full life cycle accounting be undertaken for projects, so that credits will be earned only for net removals. Therefore policy is being formulated that will make such auxiliary emissions completely transparent.
