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Toxic Release Inventory - Generation Performance |
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The Toxic Release Inventory (TRI) is an EPA regulatory program that requires companies to report on their environmental releases of any of about 650 chemicals on a specified list. About 25,000 facilities in the United States report under this program. Dominion's fossil-fueled power stations release some of these substances during the generation of electricity. A TRI release summary for each station can be viewed for 2006, 2005, 2004, 2003, 2002, 2001 and 2000. Learn more about the TRI program and how it relates to electric utilities.
Where the Releases Come From
- By-Products: Several chemical compounds
are created as by-products during the combustion of fossil fuels — namely,
hydrochloric acid, hydrogen fluoride, sulfuric acid and low levels of dioxin.
- Trace Elements: The fossil fuels combusted
to produce energy contain trace amounts of other compounds. As a result of
combustion, some of these other compounds can be released to the environment.
Metal compound emissions (including compounds of arsenic, barium, beryllium,
chromium, cobalt, copper, lead, manganese, mercury, nickel, selenium, vanadium,
and zinc) are the result of trace elements in the fuel. Emissions of polycyclic
aromatic compounds (PACs) and benzo(g,h,i)perylene are primarily the result
of trace materials found in #6 fuel oil.
- Purchased Chemicals: In some instances, chemicals are purchased for use at our stations and can potentially be released in some way during use of the product. Chlorine is used for disinfection of water at some stations. Some of our processes require the use of hydrazine to maintain an oxygen-free environment. Ammonia is used in air pollution control equipment to reduce nitrogen oxide emissions. And, ethylene glycol is used as a heat transfer agent and to provide freeze protection at some stations.
Overview of Total Emissions
Companywide, Dominion’s total TRI air emissions have decreased from approximately 17 million pounds in 2000 to approximately 13.9 million pounds in 2006. The graph reflects releases for facilities owned by Dominion by calendar year.
The overall downward trend reflects the addition of air pollution controls at Dominion's power stations. The increase from 2004 to 2005 reflects the addition of three stations in 2005: Brayton Point, Manchester Street and Salem Harbor.
The air releases dropped from 16.9 million pounds in 2001 to 13.6 million pounds in 2002 as a result of the scrubbers at the Mt. Storm Power Station. The conversion of Possum Point units #3 and #4 from coal to gas firing also contributed to decreased air releases in 2003.
| Further air emission reductions will occur with the installation of controls to be installed to meet the requirements of the Clean Air Interstate Rule and state regulations. By 2010, it is anticipated that sulfuric acid emissions will have decreased by approximately 15 percent, that hydrochloric acid emissions will have decreased by approximately 69 percent, and that hydrogen fluoride emissions will have decreased by approximately 56 percent (as compared to 2004 air emissions). |
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TRI releases to land have, primarily in our onsite disposal areas, increased slightly from approximately 8 million pounds in 2000 to approximately 8.4 million pounds in 2006. This increase is due to the acquisition of new generating stations.
TRI releases to water, which are a very small portion of Dominion's total TRI releases, have increased slightly due to the acquisition of new generating stations.
Total Mercury Releases (reported under TRI)
Mercury is often found in trace amounts in fossil fuels. When the fossil fuels are combusted, the high combustion temperatures and the volatility of mercury and mercury compounds results in mercury being emitted in the combustion gas exhaust stream. Mercury and mercury compounds can also be found in the ash.
Dominion has reduced mercury air emissions through the installation of two additional SO2 scrubbers at the Mt. Storm Power Station and the repowering of two coal-fired boilers to cleaner-burning natural gas at the Possum Point Power Station.
Additional mercury air emission reductions are being achieved across the Dominion coal-fired generation fleet through existing particulate matter controls and advanced NOx controls.
| Further mercury air emission reductions will occur with the installation of SO2 scrubbers at the Chesterfield Power Station. Additional controls will be implemented to meet the requirements of state mercury regulations, Clean Air Interstate Rule and the Clean Air Mercury Rule across Dominion’s fleet of coal fired generating stations. It is anticipated that mercury emissions to the atmosphere will decrease by approximately 29 percent by 2010 and approximately 34 percent by 2015 (as compared to 2004 air emissions). |
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