Are all the U.S. biomass energy sources green?

Whether biomass energy should be regarded as a clean energy or not is still a contentious issue in the literature. Biomass energy comes from different sources, each having the possibility to affect the environment differently. Accounting for this heterogeneity to avoid any aggregation bias, this study examines the impact of biomass energy on environmental quality in the U.S. from the standpoints of consumption and production, different biomass sources, asymmetric changes, and threshold effects. We find that the adverse environmental impact of biomass energy production is higher than its consumption. Moreover, except in the long-run where the impact of negative changes in biomass energy consumption overshadows its positive changes, positive changes in biomass energy consumption and production degrade the environment more than negative changes in biomass energy consumption. The threshold analysis further reveals that the production and consumption of biomass energy beyond some levels reduces environmental quality, unlike when they are minimal. Finally, wood is the most environmentally unfriendly biomass energy source, whereas biodiesel is the most environmentally friendly. The policy implications of these findings are crucial for environmental sustainability, climate change mitigation, and efficient production and use of biomass.