Carbon Displacement
Carbon sequestration, the removal of carbon dioxide from the atmosphere into long-lived pools of carbon is an important mitigation option for greenhouse gas emissions. Forest carbon sequestration pools can include above-ground living biomass (trees), living biomass in soils (roots, etc.), and products created from biomass (lumber) (CSiTE 2002). Forests store carbon dioxide as a result of photosynthesis though carbon in the wood (like in fossil fuels) will be released when it is burned. Thus producing and consuming bioenergy from forest biomass represents a carbon recycling process (at right), essentially a carbon neutral process that can displace carbon dioxide emissions from burning fossil fuels. In addition to displacing fossil fuel carbon emissions, producing bioenergy from forest biomass can reduce carbon emissions from the alternate fates of the biomass itself because forest biomass left to decompose, slash burning, prescribed fire, and wildfires release greenhouse gasses. Due to data limitations, this section focuses on the cost-competitiveness of offsetting carbon dioxide emissions via generating electricity from forest biomass.
Gan and Smith (2006) estimated that about 40 million dry tons of logging residues could be recovered annually in the U.S. If this biomass were used for electricity production, the amount of carbon displaced would reach 19.4 million tons C. This is equal to approximately 3% of total current carbon emissions from the U.S. electricity sector.
The cost of carbon displacement is dependent upon the method used to calculate the production costs of logging residues. Using the marginal cost method, it would cost $60/ton C to displace carbon emissions from coal-generated electricity. Using the full cost method, the cost would rise to $70/ton C (Gan and Smith 2006) (at left).
Thus, using forest biomass, particularly logging residues, for electricity production appears to be a relatively cheap way to mitigate carbon dioxide emissions when compared with other mitigation options including agricultural practices and replacement applications. These other mitigation options can cost between $83-$164/ton C (IPCC 2001) (below).
Encyclopedia ID: p1176
