Committed to improving air quality

Exelon’s investment in, and commitment to, clean technologies keeps our air emission rates well below industry averages. We continue to work with regulators and communities to achieve positive program results.

Nuclear generation constitutes the majority of our generating capacity and is the main driver behind Exelon’s low-emission rates. Other factors contributing to our low-emission rates include:

• Non-emitting Conowingo Hydroelectric power plant
• New and existing advanced pollution controls at many of our fossil power plants
• Uprate and efficiency programs that provide additional generating capacity at Exelon’s nuclear and hydroelectric power plants
• Industry-leading capacity factors at Exelon’s nuclear plants
• Retirement of older less efficient fossil plants

Reducing Carbon Dioxide (CO2) Emissions

The direct CO2 emissions from fossil-fuel electric power generation represent more than 90% of Exelon Corporation’s total 2010 GHG emission inventory of all six major GHGs from all operating companies and emission sources.  Exelon is required to report GHG emissions from 8 of our generating facilities under the EPA’s Mandatory GHG Reporting Rule (40 CFR Part 98) finalized in December 2010. 

In 2010, Exelon Generation’s  output from fossil generation increased by 6.4% as a result of increased market demand and weather conditions.  Consequentially, carbon dioxide (CO2) emissions from all owned fossil generation also increased 5.8% due to the added run time for fossil generation versus 2009.  Additional details on CO2 emissions and emissions of other GHGs can be found under Climate Change. 

Reducing Nitrogen Oxide (NOx) Emissions

Exelon continued to operate post-combustion NOx controls at some generating units on an annual, rather than ozone season-only, basis to support compliance with Clean Air Interstate Rule (CAIR) NOx requirements that took effect in 2009. However, increased fossil generation and low NOx emission allowance prices combined to result in a net NOx emission increase in 2010 versus the prior year. Despite these economic and market factors, annual NOx emissions were still 19% lower in 2010 versus 2008 (the year before the CAIR program took effect). 

Managing Sulfur Dioxide (SO2) Emissions

All coal-fired units in which Exelon has an ownership interest now have scrubbers for SO2 removal.

The first full year of operation for new wet limestone scrubbers at the coal-fired Keystone Station, in which Exelon is a 20.99% owner, was 2010. These new scrubbers were the primary driver behind reduced SO2 emissions in 2010. The scrubbers have a 98% SO2 removal capability. Actual removal is dependent on a number of factors, including sulfur content of coal burned, emission allowance prices and permit requirements. Exelon’s share of the new scrubber capital costs was in excess of $140 million. With the completion of the Keystone scrubbers, all seven coal-fired units in which Exelon has an ownership interest are scrubbed. All Exelon Power-operated coal units have been SO2 scrubbed since the early 1980s.

Toxics Release Inventory (TRI) Emissions

Exelon’s Toxics Release Inventory (TRI) report represents data from Exelon Power facilities that are required to report, including our shares of Keystone and Conemaugh. Overall, TRI emissions were reduced by 20% in 2009.  TRI data for 2010 will be reported to EPA by July 1, 2011.

• The majority of decreased TRI emissions in 2009, versus 2008, relate to a 4.3% reduction in fossil megawatt-hour output in 2009, in addition to co-benefit TRI emission reductions resulting from the new SO2 scrubbers at the Keystone plant that began operating in late 2009.
• Portfolio hydrochloric acid emissions were reduced by 26% and hydrogen flouride emissions reduced by 28%. Similarly, a 28% reduction in mercury emissions was achieved versus the prior year.
• Exelon expects to see a further significant reductions in its 2010 TRI data as a result of the Keystone scrubbers having a full year of operation in 2010 versus only a few months at the end of 2009.
• Additional reductions in TRI releases will occur in 2011 and 2012 as Exelon Power retires the Cromby Generating Station and the two coal-fired units at the Eddystone plant.

Changes in our aggregate TRI emissions are generally related to year to-year variations in generation output at our individual generating plants and to the intricacies of the reporting requirements. For example, TRI reports are not required for facilities that only utilize natural gas to generate electric power for sale during any given calendar year. Some Exelon Power facilities have dual-fuel capability and can use oil or gas. Variability can also occur since facilities may not exceed the 25,000-pound reporting threshold for TRI substances in any given year.  For further information on TRI emissions, please visit EPA’s Web site: www.epa.gov/tri

Compliance Performance

Air Notices of Violation

Exelon has set a goal of zero air notices of violation (NOV) and permit non-compliances for company operations. NOVs are issued by a regulatory agency when a company is believed to have violated a permit condition or regulatory requirement.  Exelon self-reports violations of regulations and regulatory agency-specified environmental permit conditions when they are identified.

Exelon received one air Notice of Violation (NOVs) in 2010.  This NOV was a low level, administrative NOV, not related to operational compliance, for late filing of an optional request to use DERCs (Discrete Energy Reduction Credits) Power holds for Mountain Creek.  The use of the DERCs, however, was granted by the TCEQ (Texas Commission Environmental Quality).

Air Permit Non-compliances

Exelon self-reports violations of regulations and regulatory agency-specified environmental permit conditions when they are identified.  There were no such non-compliances identifed in 2010.