The carbon neutrality assumption for forest bioenergy: A case study for northwestern Ontario

Minimum break-even and carbon-neutral periods resulting from displacing coal with wood pellets for energy generation at the Atikokan Generating Station (GS) were estimated using forest resource inventory for four forest management units (FMU) in northwestern Ontario. The break-even period was defined as the time since harvest at which the combined greenhouse gas (GHG) benefit of displacing coal with wood pellets and the amount of carbon in the regenerating forest equalled the amount of carbon in the forest had it not been harvested for wood pellets. The carbon-neutral period was defined as the time since harvest at which the amount of carbon in the regenerating forest equalled the amount of carbon in the forest had it not been harvested for wood pellets. Theoretically achievable minimum break-even and carbon-neutral periods were estimated as equal to 18 and 28 years after harvest, respectively. However, for the current forest age structure in the selected FMUs, production of wood pellets required for operation of the Atikokan GS would result in a minimum break-even period of 32 years after harvest. These results must be treated as optimistic since we assumed that all forest was available for harvest for wood pellet production, applied the best post-harvest silvicultural regime, and may have underestimated merchantable volume and total carbon stocks in older stands.