U.S.-FocUSed Biochar report - BioEnergy Lists

and commercial installations, thereby developing the necessary basis to evaluate their potential if proposed forlarge-scale applications.Calculating the impact on Carbon Dioxide EmissionsUnique to this analysis is the valuation of the solid residue from any biomass conversion process as “Biochar”.Biochar, when utilized in agriculture, is carbon-negative, since it contains carbon atoms that were removed ascarbon dioxide from the atmosphere as the biomass grew and now securely reside in the soil. As will be seen, allbiomass conversion processes invariably generate additional energy co-product streams. The carbon in these energyco-product streams is carbon-neutral, having come from the atmosphere, and offers the potential to replacefossil fuels in many applications. When carbon-neutral biomass energy co-products displace carbon-positive fossilfuel in an existing application, the net effect is considered carbon-negative, by virtue of avoiding that portionof carbon-positive fuel consumption. If the energy co-product is not used to displace fossil fuels, then that portionof the biomass conversion process is carbon-neutral.For example, suppose a biomass conversion process produces 30 tons of biochar, 20 tons of bio-oil and 50 tonsof combustible vapors that are either used within the biomass conversion process or flared (combusted to carbondioxide and water vapor and discharged). The 30 tons of biochar would be carbon-negative in the soil bythe amount of elemental carbon in the biochar that is calculated and predicted to be stable in the soil, convertedto the carbon dioxide equivalent (CO 2 e). If the biochar were used to substitute for a fossil fuel, typically coal, itwould be carbon-negative by the amount of carbon dioxide emissions avoided by not using the fossil fuel. The 20tons of bio-oil would be used to displace a fossil fuel application, perhaps industrial fuel oil, and would be carbonnegativeby the amount of fossil fuel carbon dioxide emissions avoided, which depends on the specifics of thefossil fuel displaced. The 50 tons of combustible vapors, as used in this case, would be carbon-neutral upon beingreturned to the atmosphere. If some of the combustible vapors were diverted to a local generator and electricalpower sent offsite, then the combustible vapors would be carbon-negative by the amount of fossil fuel displacedby the electrical power exported to the “Grid”.How accurate is “semi-quantitative”This analysis will seek to establish clear distinctions wherever possible, with semi-quantitative trends and predictionsat all times. Quantitative accuracy can become the enemy of clarity when drawing conclusions. As such,calculations will be accurate to within about 10 percent and numbers will be rounded by similar amounts toclarify the parallels. English units will be used most of the time and approximate metric equivalents provided inparentheses. For example, within 6%, one (1) million British Thermal Units equals one (1) gigajoule (exactly 1.055GJ), which would be depicted as 1 MMBtu (1 GJ) in the text. One very accurate equivalence is 1 GJ / metric tonne* 0.43 = 1 thousand Btu / pound.Valuing Energy Co-productsFundamentally, all biomass conversion processes start with some form of biomass, and likely either supplementalair or thermal energy, and discharge a solid, which is designated the “char”, and one or more vapor streams,which are the potential Energy Co-products. The objective for Energy Co-products is to utilize the chemical andthermal energy contained in the vapors that exit the biomass conversion process. The exiting char representsanother product from the biomass conversion process, and the valuation of that solid will be taken up next.The vapors created during biomass conversion are a combination of non-condensable gases and condensableliquids that can be isolated by lowering the vapor stream temperature. Biomass conversion processes distinguishthemselves by the manner that they partition and recover the vapor stream(s) into one or more product streams16U.S.-Focused Biochar Report:Assessment of Biochar’s Benefits for the United States of America