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United States Department of Agriculture

Agricultural Research Service

Research Project: SOIL CARBON CYCLING, TRACE GAS EMISSION, TILLAGE AND CROP RESIDUE MANAGEMENT

Location: Soil Management Research

Title: Sustainability: The capacity of smokeless biomass pyrolysis for energy production, global carbon capture and sequestration

Authors
item Lee, James - OAK RIDGE NATIONAL LAB
item Hawkins, Bob - EPRIDA
item Day, Danny - EPRIDA
item Reicosky, Donald

Submitted to: Energy and Environmental Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 8, 2010
Publication Date: November 1, 2010
Repository URL: http://hdl.handle.net/10113/47814
Citation: Lee, J.W., Hawkins, B., Day, D.M., Reicosky, D.C. 2010. Sustainability: The capacity of smokeless biomass pyrolysis for energy production, global carbon capture and sequestration. Energy and Environmental Science. 3(11):1695-1705.

Interpretive Summary: Application of modern smokeless biomass pyrolysis for biochar and biofuel production is potentially a revolutionary approach for global carbon capture and sequestration at large scales. A conversion of about 7% of the annual terrestrial gross photosynthetic product into a stable biomass carbon material such as biochar would be sufficient to offset the entire amount of carbon dioxide (CO2) emitted into the atmosphere annually from the use of fossil fuels. Since the char is created from pyrolysis of biomass, it is commonly called "biochar." The yield of biochar production depends on the feedstock properties and pyrolysis conditions including temperature, heating rate, pressure, moisture, and vapor-phase residence time. Currently, the world could annually harvest dry agricultural biomass. With respect to the global carbon cycle, this char-producing biomass-pyrolysis approach essentially employs existing natural green-plant photosynthesis as the first step to capture CO2 from the atmosphere; then, the pyrolysis process converts biomass materials primarily into biofuel and char, a stable form of solid carbon material. The net result is the removal of CO2 by capturing CO2 from the atmosphere and placing it into soils and/or subsoil earth layers as a stable carbon (biochar) while producing a significant amount of biofuel energy through biomass pyrolysis. Therefore, this is a "carbon negative" energy production approach. Because biochar is mostly not digestible to microorganisms, a biochar-based soil amendment could serve as a permanent carbon-sequestration agent in soils/subsoil earth layers for thousands of years. Other options, including proper creation of large biochar carbon reservoirs underground which is limitless, should also be considered. This technology makes it possible to mitigate the carbon emissions by the combination of biochar soil application and biochar reservoir creation. This information will assist scientists, engineers and policy makers in developing improved biomass methods to minimize the carbon loss and to improve soil carbon management. Farmers can develop and utilize new management techniques for enhancing soil carbon by biochar application and by changing the type and intensity of tillage.

Technical Abstract: Application of modern smokeless biomass pyrolysis for biochar and biofuel production is potentially a revolutionary approach for global carbon capture and sequestration at gigatons of carbon (GtC) scales. A conversion of about 7% of the annual terrestrial gross photosynthetic product (120 GtC y-1) into a stable biomass carbon material such as biochar would be sufficient to offset the entire amount (about 8.4 GtC y-1) of carbon dioxide (CO2) emitted into the atmosphere annually from the use of fossil fuels. Currently, the world could annually harvest more than 6.5 GtC y-1 of dry biomass. If 6.5 GtC y-1 of dry biomass could be converted to biochar and biofuel, that would offset the world’s 8.4 GtC y-1 of fossil-fuel CO2 emissions by as much as 75%. Therefore, the envisioned photosynthetic-biomass-production and biochar-producing biomass-pyrolysis approach is a significant option to solve the problem of global CO2 emission. Because biochar is mostly not digestible to microorganisms, a biochar-based soil amendment could serve as a permanent carbon-sequestration agent in soils/subsoil earth layers for thousands of years. The worldwide capacity for storing biochar carbon into agricultural soils (3,675 million acres) is calculated to be about 450 GtC, which could be a great help but still not enough to take care of all the additional CO2 emissions (4000 GtC) that are expected to be released from the burning of the remaining fossil fuel resources on earth. Other options, including proper creation of large biochar carbon reservoirs underground which is limitless, should also be considered. It is possible to mitigate all the carbon emissions (4000 GtC) by the combination of biochar soil application and biochar reservoir creation.

Last Modified: 8/22/2014
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