Abstract
There is a lack of widespread interest in slow pyrolysis biochar pathways relative to other bioenergy pathways because of the perceived absence of biochar's market value when produced at a commercial scale. Thus, most refereed techno-economic analyses focus on fast pyrolysis. This study quantifies the carbon price point at which the economic feasibility of the slow-pyrolysis pathway for biochar production is equal to or greater than a fast-pyrolysis pathway for biochar and biofuel production using baseline minimum carbon prices (MCP). These factors are then modeled under uncertainty to generate stochastic cash flows for the calculation of a 20-year net present value and carbon abatement cost probability distributions. This article examines whether a slow-pyrolysis pathway is ever more financially attractive than a fast-pyrolysis pathway at realistic carbon prices. The results show fast pyrolysis to fuels and biochar achieving the lowest baseline MCP of $61.38/Mg, while the slow pyrolysis to biochar and methanol at 450 degrees C scenario yields the highest baseline MCP of $642.40/Mg. A notable result is the baseline MCP for the slow pyrolysis to biochar scenario achieving $123.48/Mg, when compared with the fast pyrolysis to fuels and electricity scenario, resulting in a baseline MCP of $182.03/Mg. The results suggest that carbon prices, when high enough, can incentivize biochar carbon sequestration produced from slow-pyrolysis pathways rather than carbon abatement with biofuels, and that slow pyrolysis to biochar and methanol scenarios require a higher baseline MCP and are less financially competitive than the other pathways. (c) 2020 Society of Chemical Industry and John Wiley & Sons, Ltd