Biochar projects are a carbon-removal project type within the engineered & geological segment of the carbon market. They involve carbon-rich solid material produced from biomass and stored in a durable application pathway. In practice, the CO2 originally removed from the atmosphere by biomass growth is converted into a more durable carbon form and stored. Common project configurations include Pyrolysis of agricultural residues or other sustainable biomass feedstocks to produce and store biochar.

Biochar is often discussed as a more durable biomass-based removal because pyrolysis converts part of the biogenic carbon into a relatively stable solid form. This segment is generally aimed at more durable carbon storage and is often attractive to buyers seeking high permanence, but lifecycle emissions, measurement precision, and storage durability remain the decisive quality questions. For buyers and program designers, the most important diligence questions are: Is feedstock sustainable? Is the carbon-storage fraction robust? Are end-use, contamination, and emissions from processing accounted for?