U.S.-FocUSed Biochar report - BioEnergy Lists

that are in the BTV (Part 1), The final four new BBTV items A4, A5, F3 and F4 are in Part 3 of the table. Thesemajor expansion terms, none specifically considered in the BTV, are now half of the new BBTV total – the bottomhalf of Figure 5.1Below the three parts is the total BBTV. The final three lines separate out the total in a different way not shownexplicitly in the figure. These emphasize the new inclusion of idle land (A4) and converted pasture (A5), as newadditions to the agricultural land category.B-wedge Magnitudes The second table column shows the key variable of this Section: total supply of annualbiomass. The different magnitudes for the nine B-wedges range from 0.17 to 0.91.Land Requirements and Productivities. The third column gives one possible land requirement in megahectare units. The fourth column (biomass productivity in kg of carbon per m2-yr) is presented to help affirm thereasonableness of the B-wedge values and land areas of the two columns to the left. Three conversion factors arein this fourth column. A factor of 1000 converts from “megas” to “gigas”; a factor of two to convert from biomassto carbon, and a factor of ten changes from tonnes per hectare to kg/m2.5.4.3 Assumptions.The quadrupling growth factor in the forestry sector was made a little larger than the approximate tripling inagriculture. (In 2004 the forest sector supplied almost 8 times the bioenergy resource as that from agriculture)Second, the Table shows that the three extensions of Part 2 totaled much less than the Part 3 total (a 61% increasevs 161%). The four new areas now are half the total (2 B-wedges out of 4). Third, the land requirements have goneup but much less and are probably on the high side, as explained further below. Fourth, no large changes weremade in the BTV’s specified productivities.5.4.4 The BTV numbers – Part 1 - Portions A1 and F1 totaling 1.24 B-wedges.Part 1 of Table 1 gives the entries making up the 0.91 + .33 = 1.24 B-wedges of the BTV’s A1 and F1categories. Additional detail is provided in the supplementary material, but much of Part 1 can be understoodas we discuss the remaining seven B-wedge categories.5.4.5 The BBTV extensions of the BTV: Part 2 - Portions A2, A3 and F2 totaling .76 B-wedges.These are all relatively small extensions of specific items found in the BTV.A2 (Expanded Ag residues; 0.25 B-wedge) assumes that a larger portion of Ag residues can be obtainedthan is assumed in the BTV. In part, this is justified by the monetary value that will accompany their use inBiochar – a technology not included at all in the BTV. This also assumes an expanded pro-Biochar policyframework – whereas the BTV (appropriately) assumed no new policies. It is key to understand that if Biocharproduction and utilization are done effectively more carbon will be placed on agricultural land over longerperiods of time then if the residues are left in place.A3 (Expanded agri-forestry; 0.34 B-wedge) asserts that agriforestry has a larger future (by a factor of 2) thangiven in the BTV. The principal BTV author, Dr. Robert Perlack, 33 has indicated that their 2010 update willalso increase in this category – presumably justified by a change in national policy since 2005. The obviousreason for wanting this change is the large B-wedge increase that is possible with little change in land area.Here the land is assumed to be agricultural land – available as food productivity increases (due in part toBiochar) allowing conversion from food crops to energy crops. This land area assumption also could occuras more food is grown by consumers, less is lost after harvesting, land is freed up as we move away from cornethanol, and possibly a move towards a vegetarian diet.33 Private communicationBiochar GHG reduction accounting in: Potential Biochar Greenhouse Gas Reductions57