FIGURE 7.8 Augmented version of Figure 7.5, with the addition of biomass power plants. These estimates, like those for other technologies, do not necessarily include all of the site-specific costs of building a plant nor all of the real-world contingencies that may be needed depending on economic conditions (see Box 7.2 for more discussion).

Source: Princeton Environmental Institute.

include direct inputs associated with tractor fuel and fertilizer, for example, as well as indirect inputs linked, say, to compensatory land clearing. To obtain net carbon inputs, these direct and indirect inputs are balanced against any buildup of carbon in soil and roots, which remove CO₂ from the atmosphere.

Values for switchgrass were taken from Argonne National Laboratory’s GREET model, Version 1.8 (Argonne National Laboratory, 2008), where fossil-carbon inputs equal 10 percent of the carbon in the switchgrass and are thereby exactly balanced by char storage. GREET also assumes that carbon buildup in soil and roots is one-thirtieth of carbon acquisition from the atmosphere by plants. Thus, the net carbon flow for the BTP-V is, by a small amount, out of the atmosphere, corresponding to the buildup of carbon in soil and roots. CO₂ emissions associated with land clearing at the site and associated land clearing elsewhere are not considered.