Greenhouse gas emissions of local wood pellet heat from northeastern US forests

Abstract

We explored greenhouse gas (GHG) implications of locally-sourced and produced wood pellets to heat homes in the US Northern Forest region. Using data from regional pellet industries, forest inventories and harvests, we analyzed pellet GHG emissions across a range of harvest and forest product market scenarios over 50 years. We expanded an existing life cycle assessment (LCA) tool, the Forest Sector Greenhouse Gas Assessment Tool for Maine (ForGATE) to calculate GHG balances associated with the harvest, processing, and use of wood pellets for residential heating vs. alternative heating fuels. Market assumptions and feedstock mix can create diverging GHG emission profiles for pellet heat. Outcomes are predominantly influenced by biogenic carbon fluxes in the forest carbon pool. An industry-average pellet feedstock mix (50% sawmill residues, 50% pulpwood) appeared to generate heat that was at least at parity with fossil-fuel heating alternatives when harvest levels remain unchanged due to pellet production. If harvest levels increase due to pellet production, using pellet heat increased GHG emissions. If baseline harvest levels drop (e.g., following the loss of low-grade markets), GHG emissions from pellet heat would at least remain stable relative to fossil alternatives.