Biochar production from crop residues, its characterization and utilization for electricity generation in India

Abstract

Post COP-15, the push is to reduce coal dependence for electricity generation and GHG emissions from the national electrical grid. Phasing out coal-based thermal power plants (TPPs) does not favour India's economic and social interests. Therefore, it becomes imperative to make coal-based power plants clean. Biochar derived from crop residues has been considered a clean fuel and an economical substitute for coal. The present study investigated the biochar potential of crop residues from rice, wheat, maize and sugarcane cultivation, accounting for 89% of total agro production, for coal replacement in TPPs using primary & secondary data and ArcGIS for mapping agro-residue collection point and TPP. Results show that biochar produced from the identified agro resources in the temperature range of 400 °C–500 °C are suitable for cofiring with coal. 121 MT surplus residues of the selected crops could produce 40 MT biochar having 90 TWh electricity generation potential. Biochar produced from surplus residues is equivalent to 69 MT of coal, about 11% of coal consumed annually in Indian TPPs. Also, biochar cofiring could reduce 165 MT annual CO2 emissions from coal-burning in TPPs, about 14% of CO2 emissions by the energy sector and 7% of overall CO2 emissions by India. Techno-economic analysis showed that the infrastructure development & operation cost for the biochar conversion facility is in the range of 2–3 USD/MWh, which is significantly lower than that of the new biomass to electricity generation facility (43–53 USD/MWh). The results would provide baseline data for policy decisions to avoid net GHG emissions from TPPs, and site identification for additional infrastructure to develop alternative clean fuels for India's coal-based TPPs.