Technical Potential for CO2 Drawdown Using Biochar in Washington State

This technical assessment evaluates the long-term carbon drawdown potential of biochar production across Washington state using agricultural crop residues, forestry harvest residues, and municipal solid waste wood. Using an adapted version of the Biochar Global Response Assessment Model (BGRAM), the analysis integrates county-level biomass supply, soil carbon stocks, crop productivity, and technology adoption scenarios at high spatial resolution.

Across multiple biomass and processing scenarios, biochar production over 100 years could generate between 6.6 and 381 million metric tons of biochar carbon, with immediate greenhouse gas offsets ranging from 8.5 to 430 million metric tons CO₂-equivalent. At peak production, biochar could offset 8–19% of Washington state’s annual greenhouse gas emissions (based on 2018 levels). The study also compares biochar production to direct bioenergy use, finding biochar provides roughly 2.5 times greater climate mitigation benefits under Washington’s low-carbon electricity mix.

Results highlight both the promise of large-scale biochar deployment and the importance of storage capacity, transport logistics, and long-term soil carbon dynamics.