Technoeconomic assessment of a small scale, decentralized torrefaction unit for sustainable utilization of British Columbia Forestry residual biomass

In British Columbia forestry, biomass residues are burned as a method of disposal, releasing greenhouse gas emissions and posing significant wildfire risk. An emerging method of disposal is the thermochemical conversion of these residues via controlled pyrolysis to produce biochar – a carbon-rich material with promising applications for carbon removal, soil enhancement and renewable energy. However, the economic viability of large-scale biochar production has been contested due to large transport distances to a centralized facility and loose, wet, and bulky biomass feedstock. A start-up company, Takachar, has developed a small-scale, decentralized reactor that operates at the site of the residues, greatly reducing transport costs. Increasing revenue opportunities such as grants and carbon credits also make biochar production more economically favourable. The present study provides a technoeconomic assessment complete with a sensitivity analysis to compare the economic and environmental outcomes in a BC setting for two scenarios: (1) continue with slash burning, and (2) produce biochar with the Takachar reactor. A discounted cash flow analysis was used for a 5-year project life to process 4320 tonnes/year of biomass. The levelized production costs on a feedstock basis were found to be 7. 55 t⁻¹ and 292 t⁻¹, for scenarios 1 and 2, respectively. In the biochar production scenario, the net present value was 316, 414, with a minimum selling price (MSP) for biochar of 941 t⁻¹. The MSP of carbon credits was 139 t⁻¹ CO₂e. Key sensitivity factors to profitability were feedstock moisture, production schedule, capital cost, and equipment fuel consumption. CO₂ emissions were reduced by 125% in the biochar scenario compared to slash burning, corresponding to a net carbon removal of 9. 29 kt year⁻¹ between the two scenarios. Thus, the decentralized biochar system offers a more environmentally sustainable alternative to slash burning and may be economically viable if cost-reduction measures are effectively implemented.