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.