Environmental Performance

Air Emissions

Mercury Emissions

Mercury is a naturally occurring metal in the Earth’s crust that is released into the environment as a result of natural and human activities. Trace amounts of mercury are present in fossil fuels such as coal and oil. Mercury is released into the atmosphere when these fuels are burned to generate electricity.

Mercury emissions from Allegheny Energy’s electric generation facilities have remained relatively constant. Annual variations in the estimated emissions are a result of the amount of coal burned and the relative trace amount of mercury in the coal.

Allegheny Energy continually evaluates mercury emissions which are periodically calculated based on the mercury content of the coal we burn and the efficiency of our emissions control equipment. Emissions control equipment already in place at our power stations helps to reduce the amount of mercury released into the air. Our mercury emissions will further decrease as additional controls are implemented under federal and state regulations.

NOTE:  Increase in 2007 and 2008 emissions is due to either higher mercury content of coal consumed and/or higher amount of coal consumption.