Waste-to-energy (WTE) facilities combust both biogenic and nonbiogenic materials comprising municipal solid waste (MSW) in addition to managing waste, leading to a lack of clarity on the life cycle climate change impact (LCCCI) as an electricity generator. In order to investigate the LCCCI of this resource, a cradle-to-gate life cycle assessment (LCA) of a WTE facility in Jamesville, NY, was performed utilizing system expansion to account for avoided landfilling emissions, additional metals recycling, and the loss of potential electricity generation from landfill gas. The LCCCI of electricity from this WTE facility ranges from 0.664 to 0.951 kg CO2eq/kWh before system expansion, which reduced the impact to -0.280 to 0.593 kg CO2eq/kWh when accounting for avoided waste management emissions. Combustion is the leading contributor of GHG emissions from cradle-to-gate, and sensitivity analysis indicates that the nonbiogenic fraction of the waste most significantly influences the LCCCI before including cobenefits. The fraction of methane from landfills that is not captured is the most influential variable under system expansion. Before system expansion, the LCCCI of this system is comparable to that of electricity from fossil fuels. With system expansion, the LCCCI ranges from below that of renewable energy to comparable to natural gas based electricity. These results disagree with claims in the reviewed literature that WTE can avoid GHG emissions overall, although avoided emissions reduce the magnitude of its impact.