U.S.-FocUSed Biochar report - BioEnergy Lists

the sustainability of biochar production reflect concerns that pressures from the other spheres, particularly theeconomic sphere, will exert too much influence over choices and practices related to biochar. Thus, the environmentand certain elements of society, particularly the rural poor, will be unduly impacted, i.e. be renderedunsustainable.Biomass OverviewBiomass, ecologically speaking, is the aggregation of all living organisms, from microbes to plants to animals,present in an ecosystem and part of the active carbon cycle. Fossil fuels, although derived from biomass, are nolonger characterized as such due to extensive mineralization and their long absence from the active carbon cycle.At the most fundamental level, biomass is created by the conversion of the sun’s energy to matter by cells capableof photosynthesis, i.e. plants. Plants, by performing this critical function, become purveyors of energy to animalshigher up the food chain. The levels of the food chain, called trophic levels, concentrate energy into less and lessbiomass. For example, a plant-eating mammal, like a cow, may need 16 pounds of grain to create one pound ofmeat. Simply, the most abundant form of biomass is found at the first or primary producer level. One measure ofthe first level of biomass production is net primary production (NPP).For convenience of discussion and in considering sustainability guidelines for biomass-to-energy and biocharproduction, biomass can be divided into three sources. Plants - living or recently living – and their by-productsare the primary source of abundant biomass. Secondary sources are found after humans have processed plants,in whole or part, into other materials and uses (lumber, paper, palm oil, food stuffs, animal bedding, etc.). Thebiomass available for conversion to energy may be either production waste or materials that have been used andare ready for disposal, thus both are commonly found in the waste stream.Tertiary biomass sources come from higher trophic levels: animals and their by-products. Although possible,these are seldom used for biomass-to-energy, because of the scarcity of supply, high content of non-energy producingmatter especially water, and social concerns over practices like incineration of carcasses and humanwaste. (Note that this discussion does not extend to by-products of biomass byproducts such as methane gasfrom manure and landfills.)Because biomass removal and utilization are viewed mainly as economic activities, biomass sources are identifiedby recognizable economic sectors within the context of the environments in which the biomass is produced.The sectors are agricultural, forest and municipal solid waste. Examples of biomass sources in each sector are:Agriculture – Primary• biomass crops (planted to create harvestable biomass),• dual purpose crops (grown for food/feed and biomass),• biomass removal from land in the Conservation Reserve Program (CRP),• material from fallow fields, buffer strips and riparian areas adjacent to cultivated fields,– Secondary» crop residuals (utilizing materials that are currently burned off, composted, tilled-in or hauled off-site),» animal bedding (e.g. chicken litter)» food processing residuals–Tertiary› manure› offalForest – Primary• trees harvested for biomass (dead and live),• low value logs cut as part of stand management (usually sold for pulp)Biochar sustainability in: Biochar and Sustainable Practices41