PNNL

Abstract

The U.S. Pacific Northwest (PNW) faces increasing wildfires due to forest overcrowding and climate change, posing significant environmental and public health risks. Traditional methods of managing surplus biomass, including prescribed burning, increase air pollution and global warming. This study investigates whether producing wood pellets from the residual woody biomass from forest operations and sawmills for electricity production in Japan is truly environmentally beneficial. To achieve this, we conducted a cradle-to-grave Life Cycle Assessment (LCA) to evaluate the environmental impact of residual pellets vs coal for electricity generation. The assessment covered feedstock production, pellet processing, transportation, and combustion phases. Our findings indicate that substituting coal with PNW residual pellets can reduce the Global Warming Potential (GWP) by approximately 90%, with the highest reduction achieved using harvest slash residues due to the avoided burning benefits. Further, repurposing the otherwise burnt harvest slash residues for pellet production, results in improved local air quality through reduced PM 2.5 and smog. Based on these results, we conclude that substituting coal with residual wood pellets, particularly harvest slash residual pellets, for electricity generation, is environmentally beneficial for both PNW and Japan.