Technical Information

Environmental Comparisons

Comparison of typical fossil-fuel-emissions levels (pounds per billion Btu of energy input)

Emission Component	Natural Gas	Oil	Coal
Carbon Dioxide	117,000	164,000	208,000
Carbon Monoxide	40	33	208
Nitrogen Oxide	92	448	457
Sulfur Dioxide	1	1,122	2,591
Particulates	7	84	2,744
Mercury	0.000	0.007	0.016

Typical emissions levels for natural gas-fired generating plants(pounds per megawatt-hour)

Plant Configuration	Carbon Dioxide	Carbon Monoxide	Nitrogen Oxides	Sulfur Oxides	Particulate Matter	Mercury
Combined-cycle	760	0.26	0.60	0.01	0.05	0.00000
Simple-cycle	1,140	0.39	0.90	0.01	0.07	0.00000

Typical emissions levels for coal and fuel-oil-fired generating plants (pounds per megawatt-hour)

Plant Configuration	Carbon Dioxide	Carbon Monoxide	Nitrogen Oxides	Sulfur Oxides	Particulate Matter	Mercury
Coal-fired/steam	2,028	2.03	4.45	25.26	26.75	0.00016
Oil-fired/ steam	1,600	0.32	4.37	10.93	0.82	0.00007

Comparison of emissions for auto engines (pounds per million Btu)

Plant Configuration	Carbon Dioxide	Carbon Monoxide	Nitrogen Oxides	Total Hydrocarbons	Particulate Matter
Natural Gas	119.6	0.409	0.082	0.193
Gasoline	160.7	1.125	0.095	0.061

Comparison of emissions for heavy-duty truck engines (pounds per million Btu)

Plant Configuration	Carbon Dioxide	Carbon Monoxide	Nitrogen Oxides	Total Hydrocarbons	Particulate Matter
Natural Gas	125.6	0.004	0.844	0.893	0.001
Diesel	166.7	0.078	1.443	0.045	0.025