Carbon Footprint of Biochar from Forest Harvest Residues as a Substitute for Coal during Steel Production

Abstract

Reducing industry’s reliance on coal has been a main objective in achieving short- to mid-term climate targets. Biochar, a pyrolysis byproduct, has the potential to substitute coal and can be produced using numerous feedstocks. Forest harvest residues are an abundant resource in Ontario, Canada, and have been shown to be reliable feedstocks for pyrolysis. The goal of this study was to quantify the carbon footprint of biochar from forest harvest residues for use in the steel industry. Biochar created from forest harvest residues from slash piles that were originally meant to undergo controlled burn reduced CO₂-equivalent (CO₂eq) emissions (-3.1 kgCO₂eq kg_steel^–1) immediately relative to the business-as-usual scenario. However, when using forest harvest residues from slash piles that would normally decay over time in the forest, the time to carbon neutrality was 75 years. On the other hand, time to carbon neutrality was longer than 100 years when using forest harvest residues collected from the forest floor where they are scattered during cut-to-length/tree-length harvesting.

Depending on forest management practices, biochar produced using forest harvest residues has the potential to reduce greenhouse gas emissions from the steel industry.