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• interstate transport • mercury • New Source Review • ozone • particulate matter • regional haze • Toxics Release Inventory

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Ozone & the Electric Utility Industry

Background

Ground-level ozone is created by chemical reactions between emissions of nitrogen oxides (NO_x) and volatile organic compounds (VOCs) in the presence of sunlight. Emissions from motor vehicles, industrial facilities, electric utilities, construction equipment, locomotives, ships, gasoline vapors, and chemical solvents are some of the major sources of NO_x and VOCs.   Currently, electric utilities emit only about 10 percent of the nation’s combined emissions of NO_x and VOCs, and this percentage is expected to decrease upon implementation of existing rules federal air quality regulations

The Clean Air Act (CAA) requires the U.S. Environmental Protection Agency (EPA) to establish national ambient air quality standards (NAAQS) – at levels that are protective of public health with an adequate margin of safety – for six pollutants, including ozone.  Breathing elevated ozone concentrations can trigger adverse health effects, such as respiratory inflammation, particularly for sensitive groups like asthmatics.  Ground-level ozone also can reduce crop yields and tree growth. 

EPA reviewed its ozone standards in 1997 and set a limit of 0.08 parts per million (ppm) for 8-hour average ground-level ozone concentrations (with rounding, the standard actually is 0.084).  The CAA requires EPA to complete a review of each ambient air quality standard, including ozone, at five-year intervals and make any necessary revisions.  EPA in March 2008 tightened the standard to 0.075 ppm.

What are electric utilities doing to help reduce ozone?

The electric power industry nationally has reduced its NO_x emissions, even as demand for electricity has increased, by almost 50 percent since 1980.  Electric generators emit virtually no VOCs, the other primary ingredient in the formation of ozone. Since 1980, NO_x reductions from electric utilities have been required to meet the CAA’s Acid Rain Program requirements and the “NO_x SIP Call.” 

Under the Acid Rain Program, coal-fired boilers were required to reduce annual NOx emissions in the United States by over 2 million tons per year beginning in 2000.  In addition, EPA’s NO_x SIP Call to address long range transport of ozone across 22 eastern states and the District of Columbia, reduced summer season NO_x emissions by approximately 1 million tons per year beginning in 2004.  To comply with the NO_x SIP Call, electric utilities invested approximately $10 billion to install emission control technology and hundreds of millions of dollars each year to operate the equipment.  As a result, the electric power sector will reduce emissions of NO_x by 80-90 percent throughout most of the eastern U.S. during the summer ozone season (May-September).  In fact, during the 2004 ozone season, power industry NO_x emissions in the eastern U.S. were about:

• 30 percent lower than in 2003, when a limited number of states were subject to NO_x SIP Call requirements;
• 50 percent lower than in 2000, before the NO_x SIP Call was implemented; and
• 70 percent lower than in 1990, before implementation of the Acid Rain Program.[1]

The electric power sector has done all of this despite a steady climb in electricity demand, and without sacrificing the reliability and affordability of the electricity that we produce.   For example, between 1980 and 2004 electric generation increased 73 percent. 

According to EPA, air quality has improved dramatically as a result of these ongoing investments in emission reductions from the electric power sector plus those of other industries.  In 2004, EPA reported that ozone levels in 2003 were at their lowest level nationwide since 1980.[2]

Despite all of the progress that has been made, EPA recognizes that some areas of the country do not consistently meet the ozone standard and recently finalized several regulations, such as the Clean Air Interstate Rule (CAIR) and the Clean Air Diesel Rule, to reduce interstate transport of NO_x emissions that contribute to the formation of ozone (and particulate matter). 

CAIR creates EPA-administered cap and trade programs for NO_x. The CAIR NO_x program covers 25 States and the District of Columbia.  In 2009, CAIR will reduce NO_x emissions from electric utilities by 1.7 million tons or 53% from 2003 levels.   By 2015, CAIR will reduce power plant NO_x emissions by 2 million tons, achieving a regional emissions level of 1.3 million tons, a 61% reduction from 2003 levels.   EPA estimates the cost for the electric power sector to comply with CAIR (as well as the Clean Air Mercury Rule and Clean Air Visibility Rule) at $47.8 billion, and a portion of that cost will be for additional NO_x emission controls.[3]

Many sectors across the economy will be forced to cumulatively invest tens to hundreds of billions of dollars to reduce emissions to try to meet the tighter March 2008 ozone standard.

Find out more at EPA’s ozone website.

© 2008 Edison Electric Institute