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

Abstract

Smokeless biomass pyrolysis for biochar and biofuel production is a possible arsenal for global carbon capture and sequestration at gigatons of carbon (GtC) scales. The United States can annually harvest over 1.3 Gt (gigaton) of dry biomass. Use of the smokeless (clean and efficient) biomass-pyrolysis technology would enable the United States to converts its 1.3 Gt of annually harvestable biomass to biochar products equivalent to 325 million tons of stable carbon plus significant amount of biofuels including syngas and bio-oils. Currently, the world could annually harvest more than 6.5 GtC y⁻¹ of biomass. The 6.5 GtC y⁻¹ of biomass could be converted to biochar (3.25 GtC y⁻¹) and biofuels (with heating value equivalent to that of 6500 million barrels of crude oil). 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. By storing 3.25 GtC y⁻¹ of biochar (equivalent to 11.9 Gt of CO₂ per year) into soil and/or underground reservoirs alone, it would offset the world's 8.67 GtC y⁻¹ of fossil fuel CO₂ emissions by about 38%. The worldwide maximum capacity for storing biochar carbon into agricultural soils (1411 million hectares) is estimated to be about 428 GtC. It may be also possible to provide a global carbon “thermostat” mechanism by creating biochar carbon energy storage reserves. This biomass-pyrolysis “carbon-negative” energy approach merits serious research and development worldwide to help provide clean energy and control global warming for a sustainable future of human civilization on Earth.