NEW LOWDOWN ON BIOCHAR

Putting U.S. Biochar Policy on the Right Track
November 2010 (Natural Resources Defense Council)

"Biochar is a term for charcoal that is formed by heating biomass at high temperatures in the absence of oxygen and then added to soil to improve its health. Biochar has generated attention as a global warming mitigation tool because of its potential to sequester large amounts of carbon dioxide…But questions about the environmental impacts of biochar’s lifecycle must be answered…

"Research should focus on biochar’s potential…In addition to sequestering carbon dioxide, biochar…protect[s] water quality through improved nutrient uptake…use[s] multiple biomass waste streams as feedstocks, and…yield[s] a variety of renewable energy resources…[These] make a more robust case for developing our understanding of biochar systems than a narrow focus on biochar’s potential to mitigate global warming…[D]evelopment of biochar systems has been hampered by the lack of market
value for most of these…[though] research has shown that biochar can reduce soil emissions of nitrous oxide and methane, both potent global warming pollutants…"

click to enlarge

"Understanding biochar’s potential starts with increased production. The performance of biochar systems depends on the feedstock…the conversion process…and the manner in which the biochar is handled, transported, and applied. Much of what is written about biochar is hypothetical or based on small-scale, laboratory demonstrations. A key barrier to understanding the performance of different biochars is the shortage of pilot and commercially operating biochar production systems…especially slow pyrolysis systems, the preferred technology…

"…An aggressive research and demonstration strategy is needed to develop a classification scheme…to answer…Which feedstocks are most promising…Which conversion systems are best…[and] How can biochar be applied to maximize soil benefits…? …There are two sets of environmental concerns…[1] the sustainable supply of biomass feedstocks and the impacts of their production, harvest, transport, and transformation….The second set of concerns deals with…emissions from the operation of different biochar systems—especially small systems…"

Schematic of slow pyrolysis (click to enlarge)

"Assessment of the impacts of any biochar system must account for the energy required to produce, collect, transport and process the feedstock and the potential for soil carbon loss during the production, harvest and application of the biochar. More research, development, and demonstration efforts are needed…Certain feedstocks and production systems may be preferable…waste biomass…is likely preferable to growing primary biomass, as it does not incur the cost in energy inputs or…land-use change emissions…Animal manures, organic municipal solid waste, and urban wood residues are the most promising feedstocks because they are most concentrated…

"Large production systems, uniform feedstocks, and tightly controlled application regimes will likely be more reliable…[S]maller systems will be much more difficult to characterize and monitor…Five to ten commercial-sized projects are needed to gather data…Demonstrations are needed on a range of technologies…slow pyrolysis is particularly important…Projects should…[access] a wide range of potential feedstocks…a representative spectrum of soil types and crop systems. Waste biomass feedstocks should be prioritized…The U.S. Department of Agriculture (USDA) should conduct a five-year program…"