Biochar is a high-carbon, fine-grained residue that is produced via pyrolysis; it is the direct thermal decomposition of biomass in the absence of oxygen (preventing combustion), which produces a mixture of solids (the biochar proper), liquid (bio-oil), and gas (syngas) products.
~Wikipedia.org
Gasifiers produce most of the biochar sold in the United States.[1] The gasification process consists of four main stages: oxidation, drying, pyrolysis, and reduction.[2] Temperature during pyrolysis in gasifiers is 250–550 °C (523–823 K), 600–800 °C (873–1,073 K) in the reduction zone and 800–1,000 °C (1,070–1,270 K) in the combustion zone.[3]
Biomass burning and natural decomposition releases large amounts of carbon dioxide and methane to the Earth's atmosphere. The biochar production process also releases CO2 (up to 50% of the biomass), however, the remaining carbon content becomes indefinitely stable.[4] The biochar becomes a long term carbon storage vessel once used an agriculture or industrial application.
Biomass power plants play a critical role in woody biomass management, and can produce power rain or shine. When the biomass used for power is transformed into biochar, it provides a pathway for fixing carbon and sequestering it in soils. Interestingly, this looks a lot like a form of Biomass Energy with Carbon Capture and Storage (BECCS), listed by the International Panel on Climate Change (IPCC) as a key technology for carbon drawdown.[5]
“Biochar is one of a small set of carbon drawdown and utilization strategies identified by the Intergovernmental Panel on Climate Change (IPCC) as ready to deploy in our efforts to stabilize climate,” ~City of Boulder Senior Sustainability and Resilience Policy Analyst Brett KenCairn.