Supplying renewable energy for Canadian cement production: Life cycle assessment of bioenergy from forest harvest residues using mobile fast pyrolysis units

Cement production contributes over 5% of global greenhouse gas (GHG) emissions. Heavy manufacturing industries like cement production continue to rely primarily on fossil fuels for primary energy production and have limited renewable energy options. This study used life cycle assessment (LCA) to quantify the potential environmental benefits of substituting bio oil and biochar from mobile fast pyrolysis of forest harvest residues for fossil fuels in an average cement plant in Québec, Canada. Bioenergy Pathways for cement production showed reductions in non-biogenic GHG emissions as high as 50% relative to the Reference Pathway for energy provision in the plant. The use of bio oil and biochar from mobile pyrolysis units increased the share of renewable energy in the cement plant energy mix from just under 15% in the Reference Pathway up to 47% and 73% in the Bioenergy Pathways, depending on the scale of fuel substitution. Bioenergy Pathways also led to decreases in potential acidification, ozone depletion, respiratory effects, and eutrophication impacts, with slightly higher contributions to smog-forming emissions. The environmental and socioeconomic sustainability of fast pyrolysis units are strongly linked to the availability of, and proximity to, sufficient forest harvest residues, such that regional-level analysis of feedstock availability is needed prior to wide-scale deployment of these systems.