Life cycle assessment of thermal energy production from short-rotation willow biomass in Southern Ontario, Canada

•Environmental impacts of thermal energy from combustion of willow were evaluated.•Biomass combustion resulted in ∼85% reduction of GWP relative to fossil fuels.•Willow biomass production contributed to most of the life cycle impacts.•Increasing yields and better management will improve willow energy performance.•Cleaner combustion technologies will improve willow bioenergy performance.