A comparative techno-economic assessment of biochar production from different residue streams using conventional and microwave pyrolysis

A comparative techno-economic assessment and Monte Carlo risk analysis is performed on large scale (3 tonne/h) biochar production plants for conventional (CPS) and microwave (MWP) pyrolysis using six different residue streams. Both plants are viable with minimum selling prices between € 436/tonne and € 863/tonne for CPS, and between € 564/tonne and € 979/tonne for MWP. The CPS is therefore more viable than MWP as it is a simpler and more established technology. However, a 20 % biochar price increase due to higher biochar quality makes the MWP technology more viable. Nevertheless, the discounted payback period remains higher than this of CPS due to the increased CAPEX. Biochar price is the most important determinant of a biochar production plant’s feasibility, motivating the need for economic and market research on biochar prices in function of biochar characteristics to reduce fluctuations in widely varying biochar prices.