The study assessed the environmental impacts of landfilling, anaerobic digestion and incineration technologies and investigated the effect of the replaced source of electricity on the environmental impacts of these waste to energy (WtE) technologies. Data published in the national pollutant inventories and ReCiPe impact assessment method were employed in this study. The study showed that electricity generation through incineration had the highest impacts on human health and ecosystems, followed by landfilling. Compared to the electricity of the Australian national grid, electricity generated from all three WtE technologies have a lower environmental impact. The results revealed that global warming and fine particulate matter formation with more than 97.6% contribution were the main impact factors for human health, while terrestrial acidification, global warming and ozone formation were contributing to more than 99% of the impacts to ecosystems. Global warming was the most impactful category on human health and ecosystems from incineration with over 85% contribution to both endpoint categories. Incineration revealed significantly higher avoided global warming impacts to human health and ecosystems than landfilling from the treatment of one tonne of solid waste by replacing electricity from brown coal, black coal or the Australian power grid. The growing share of renewable energy in the Australian power grid is expected to decrease the grid GHG emissions and the effect of the avoided impacts of replaced electricity. The results revealed that if the GHG emissions from the Australian power grid (757 kg CO2 eq/MWh) decrease to break-even point (621 kg CO2 eq/MWh), incineration loses the climate advantage over landfilling.