Investigating biochar as a net-negative emissions strategy in Colombia: Potentials, costs, and barriers

Biochar is identified as a land-based mitigation technology (LMT) and a net-negative emissions technology (NET) with significant potential for mitigating climate change and providing co-benefits. Transforming residual biomass into biochar can potentially avoid CO2 emissions to be rapidly released to the atmosphere. This study aims to assess the sustainability of biochar production in Colombia as a NET. The research consists of five steps, literature review, expert elicitation, estimation of agricultural residues for biochar production, evaluation of biochar's CO2 mitigation potential, and techno-economic analysis of biochar under different biomass availability and technologies scenarios. Our findings indicate that approximately 10% of agricultural residual biomass can be transformed into biochar and reintegrated into the soil. Over a 100-year period, each tonne of biochar in the soil has the potential to avoid emissions of 1 to 2.2 t of CO2eq. Cost-wise, biochar production cost structure depends on the pyrolysis technology used. The cost structure of biochar production depends on the pyrolysis technology used. We find that raw feedstock represents the main cost component, ranging from 64% to 74% of total costs for artisan-made equipment, and 33% to 34% for specialized pyrolysis equipment. Capital investments, fixed costs, and raw feedstock account for the remaining costs. Our results highlight that the net present value (NPV) is most sensitive to biomass transport distance, biomass price and biomass humidity. Our findings can be used internationally for navigating the production, mitigation potentials, costs, and barriers of biochar, and devising deployment and market creation strategies.