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TRI National Analysis

Electric Utilities Mercury Releases in the 2016 TRI National Analysis

Coal and fuel oil contain trace amounts of mercury. When coal or oil is burned by power plants to produce energy, mercury can be emitted to air in the form of stack emissions unless removed by pollution control devices. Examining the trend in mercury emissions shows that the sector’s releases dropped by 46% (68 thousand pounds) since 2006:

  • The considerable decrease in mercury releases was driven by an 86% (79 thousand pounds) decrease in mercury air emissions. This drop was offset somewhat by increased releases of mercury to land.

While decreased use of coal to generate electricity does play a role, mercury releases per gigawatt-hour (GWh) of electricity generated dropped even more dramatically.

  • Since 2006, net electricity generation from coal decreased by 38%, while the rate of release of mercury to air per GWh of electricity generated from coal dropped 77%.
  • In 2016, over three times as much mercury (in coal ash) was disposed of on land compared to mercury released to air. In 2006, the amount of mercury disposed on land was less than half that released to air. This shift in the release trend reflects higher rates of mercury capture and disposal due to improved air emissions controls, such as activated carbon injection systems installed at electric utilities.
  • The recent rise in installations of equipment to control mercury air emissions at coal-fired power plants to meet regulatory requirements is detailed in a data analysis by the U.S. Energy Information Administration.

This page was published in January 2018 and uses the 2016 TRI National Analysis dataset made public in TRI Explorer in October 2017.

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