What is Biochar?

Biochar is charcoal produced from biomass through pyrolysis—heating organic material (wood, crop residues, manure) in a low-oxygen environment at 300-800°C. Unlike regular burning which releases CO₂, pyrolysis converts ~50% of biomass carbon into stable solid form that persists in soil for hundreds to thousands of years.

Ancient technology meets modern climate science. Indigenous Amazonians created terra preta (dark earth) 2,500 years ago by mixing charcoal with soil. These soils still contain 70 times more carbon than surrounding areas. Today, biochar is recognized as a carbon dioxide removal (CDR) technology with co-benefits: improved soil fertility, water retention, and reduced fertilizer needs.

How it works: Plants absorb CO₂ from atmosphere through photosynthesis. When they die, decomposition releases that carbon back. But if converted to biochar before decomposition, 80-90% of carbon becomes recalcitrant (stable), effectively removing it from the fast carbon cycle. One ton of dry biomass → ~300 kg biochar → ~1,100 kg CO₂ sequestered.

Temperature matters. Low temperatures (300-400°C) produce more biochar but lower stability. High temperatures (500-700°C) yield less mass but higher carbon content and greater stability. Modern reactors optimize for both yield and quality, producing energy-dense syngas as byproduct—making process carbon-negative and energy-positive.