Biochar mines: Panacea to climate change and energy crisis?

Negative emission technology such as bioenergy with carbon capture and storage is extremely important to offset the presence of atmospheric greenhouse gases. Biochar, a solid product obtained from the thermal decomposition of biomass, is a promising pathway for the storage of solid carbon and energy applications. This article proposes the concept of artificial biochar mines as an encouraging negative emission technology through basic techno-economic analysis. Torrefaction at small-to-medium scale proves to be the preferred process for production of biochar from residual biomass with the CO2 sequestration cost in the range of 43–47 $/t. Benefits of the artificial biochar mine include negative emission with positive energy output, residual biomass management, low risk, less storage space, easy site selection, potentially beneficial applications, economically encouraging, and future energy security.