My ComEd power bill provides a interesting summary of the environmental impact of power usage. Apparently 88% of my electric power comes from nuclear and 9% from coal. The rest is from biomass and natural gas.
Each 1000 kWh of power usage (roughly an average month’s consumption for me) produces, on average, 189.1 lbs of carbon dioxide, 0.4 lbs each of nitrogen oxides and sulfur dioxide, 0.006 lbs of high level nuclear waste and 0.0007 cubic feet of low level nuclear waste.