Tennessee Valley Authority
2004 Environmental Performance Update
The 2004 Environmental Performance Update is a summary of TVA’s environmental performance for the calendar year. It is expressed through a series of 20 indicators against which TVA measures its environmental progress and a brief mention of key developments related to environmental activities. TVA is committed to improving its environmental performance and reducing the impact of its operations on the Tennessee Valley.
Climate Change and Global Warming
Air Quality Research and Development Initiatives
Air Quality and Emissions
In 2004, one year ahead of schedule, TVA met its commitment to reduce ozone-season nitrogen oxide (NOx) emissions by 75 percent below 1995 levels, and continued on track toward reducing sulfur dioxide (SO2) emissions 80 to 85 percent below 1977 levels. We did this by starting up 10 new selective catalytic reduction (SCR) systems in addition to the eight that have been operating in previous years, placing a total of 18 of the advanced NOx control systems in operation. We also continued construction on the SO2 scrubber at Paradise Unit 3, which is expected to operate in 2006, and began engineering and planning studies for the three scrubbers at Kingston and Colbert fossil plants, as well as for the installation of advanced NOx control equipment at John Sevier Plant in east Tennessee. Construction of the scrubber at Bull Run started in May 2005.
TVA's Clean Air Progress
TVA’s emissions of SO2 and NOx in 2004 were the lowest on record since measurements began after passage of the Clean Air Act in the early 1970s, while we supplied the sixth-highest amount of coal-fired generation in TVA’s history. Currently, 30 percent of TVA’s coal-fired capacity is equipped with scrubbers and 57 percent of the coal capacity is equipped with SCRs, making the TVA emissions control program one of the most aggressive in the nation. (See charts on SO2 emissions, NOx emissions and NOx ozone season emissions for 2004.) By the end of the decade, TVA will have spent about $5.6 billion on air quality improvements. TVA’s total outlay for emissions controls may be even higher, however, because of two new Environmental Protection Agency (EPA) rules passed in 2005 that may add another $4 billion to $5 billion in costs over the next 10 years.
In 2004, nearly 40 percent of the electricity that TVA generated came from non-air-emitting sources (nuclear, hydro, and renewables). TVA continued to work toward the restart of Browns Ferry Nuclear Plant Unit 1, the uprates of Units 2 and 3 at Browns Ferry, and completion of the hydro-plant power-train modernization program. When completed, those three projects will add almost 2,000 megawatts of nonemitting generation to the system. In addition, in 2004 TVA began purchasing 27 megawatts of additional wind generating capacity at Buffalo Mountain in Tennessee. TVA also joined with other electric industry trade associations in completing a memorandum of understanding with the Department of Energy (DOE) to reduce the greenhouse gas intensity of the U.S. electric sector by the equivalent of 3 to 5 percent by 2012, in support of the President’s Climate Vision Initiative.
Climate Change and Global Warming
TVA has been one of the utility industry’s leaders in taking voluntary actions to reduce greenhouse gas (GHG) emissions. This includes being the first utility to support Climate Challenge, an agreement with DOE that started in 1995. Under this agreement, TVA reduced, sequestered, or avoided producing more than 260 million tons of carbon dioxide (CO2). TVA will continue this effort under a new agreement with DOE called Climate Vision. Under this agreement, TVA has committed to take action to help achieve the President’s goal of reducing the intensity of GHG emissions by 18 percent from 2002 to 2012. TVA expects to do this in part by continuing to add more emissions-free capacity to its system. This includes restarting TVA’s Browns Ferry Nuclear Plant Unit 1 by 2007, which will provide a low-cost supply of energy but produce no greenhouse gases. See chart on CO2 emissions for 2004.
Carbon Dioxide Litigation
In July 2004, five utilities, including TVA, were sued in New York by the attorneys general of a number of states. They alleged that the CO2 emissions from the utilities’ plants constitute a nuisance and should be reduced. TVA and the other companies have asked the court to dismiss the lawsuit on various grounds. The emission of CO2 and other greenhouse gases and their contribution to global warming are policy issues being debated by Congress and the Administration. It is TVA’s position that those are the forums for addressing the global warming issue, not the courts.
New Source Review
The Eleventh Circuit Court of Appeals declared “legally inconsequential” an administrative order that the Environmental Protection Agency issued to TVA. In this order, EPA alleged that repair projects at 14 of TVA's fossil generating units had violated New Source Review (NSR) requirements of the Clean Air Act. The court found that the process used by EPA to do this was unfair to TVA and said that TVA could ignore the order. EPA also sued a number of other utilities in court on similar alleged NSR violations for repair projects at those utilities. Several of these cases have been settled, and EPA has prevailed in two and lost one.
Mercury Research
TVA’s mercury research focus in 2004 was primarily in four areas: determining the effect of the SCR system on the process by which mercury changes form in the flue gas; participating in highly leveraged projects to test injection systems for mercury removal; working with the Electric Power Research Institute (EPRI) to prove the QuickSEMs mercury measuring technology; and measuring mercury emissions from TVA’s coal-fired power plants. TVA has been working closely with EPRI, DOE, and other electric utilities to leverage our research funds to evaluate these important issues.
The SCR systems being installed have shown an ability to convert the relatively inert elemental mercury into an oxidized form that can be removed in a downstream flue gas desulfurization (FGD), or scrubber, system. Using existing emissions-control equipment to remove sufficient mercury to achieve compliance with the new mercury regulations would save TVA enormous future compliance costs. Short-term (several days) research completed in 2004 at Paradise Unit 1 and Cumberland Unit 1 indicated that the emissions control equipment already installed on both of these units will allow compliance with EPA’s mercury-emissions regulation without installing any additional mercury-specific, end-of-pipe controls.
TVA is participating with EPRI, DOE, and other electric utilities in a number of full-scale demonstrations of activated carbon injection (ACI) systems for mercury removal. Through our participation in EPRI, TVA has leveraged small investments into larger demonstration projects to gain insights regarding the advantages, disadvantages, and costs of installing ACI systems.
TVA’s work with the EPRI-developed QuickSEMs technology is designed to provide a lower-cost option for measuring total mercury emissions from coal-fired power plants using a relatively simple carbon trap. In addition to its relative simplicity and low cost, QuickSEMs offers the opportunity, if perfected, to eliminate many of the challenges associated with measuring very low mercury concentrations in the flue gas at the stack. In contrast, existing continuous emissions monitoring systems have yet to demonstrate the accuracy, reliability, and cost-effectiveness that will be required for measuring mercury in utility applications.
Finally, TVA has taken baseline mercury emissions measurements at several of its coal-fired power plants. The purpose is to understand current mercury emissions at units that are not slated for additional emission controls, while simultaneously testing mercury measurement techniques.
Air Quality Research and Development Initiatives
The Great Smoky Mountains National Park is one of the most beautiful areas in the United States, with a diversity of wildlife and vegetation unsurpassed anywhere east of the Mississippi. The issues of air quality in the Park have been studied extensively throughout the past decades. TVA is concerned with air quality issues in the Park because of the proximity of its fossil plants and its responsibility as a steward of natural resources. For these reasons, research activities related to the Park are a substantial element of TVA’s environmental research and development. Numerous stakeholders cooperate in TVA’s research efforts, including the National Park Service and the Environmental Protection Agency.
TVA is monitoring an air quality “supersite” at Look Rock in the Great Smoky Mountains. This site is operated to determine the sources, levels, and visibility impacts of fine particles in the most visited Class I Area in the Eastern United States. In addition to routine monitoring, two major research efforts were conducted at the site during 2004: the organic fraction of fine particulate matter (FPM) was collected and analyzed to determine the relative contribution and source(s) of these particles; and TVA installed instrumentation to enable continuous fine-particle measurements. These two activities provided information that will be used in assessing additional strategies for improving visibility in the Park beyond reductions at TVA plants.
Research to improve the models used to develop emissions strategies for regional air quality was also conducted. These efforts will help determine the contribution of various emissions sources to air quality degradation. In addition, with the reduction in sulfur emissions over the past decade, a proportional reduction in sulfate deposition has not been as evident in the areas near the Park as in other areas of the eastern U.S. Research is under way to determine the causes of this phenomenon.
Fine Particulate Matter - ARIES
EPA has established national clean air standards for fine particles because of their potential to adversely impact human health and visibility. (These particles are 2.5 microns in diameter or less, which is 1/30 the diameter of a human hair, and are referred to as PM2.5). While some fine particles, such as soot, are emitted directly from sources, a large portion are formed in the atmosphere as sulfur dioxide converts to sulfates, nitrogen oxides to nitrates, and volatile organic compounds to organic particles. TVA continues to support the Aerosol Research Inhalation Epidemiological Study (ARIES), a key health-impacts study conducted by EPRI.
This study has concluded that many of the adverse health effects related to air pollution are associated with exposure to carbon monoxide, nitrogen dioxide, and carbon-containing fine particles. These pollutants are primarily associated with transportation source emissions. Current efforts to reduce the levels of fine particles, on the other hand, are directed in large part toward fossil plant emissions of sulfur dioxide, which were not a major source of these pollutants. The findings in the ARIES study demonstrate the importance of particle composition in estimating health impacts. However, although additional control of sulfur dioxide will reduce the amount of fine particles in the air and improve visibility, it is uncertain whether this reduction will have a positive effect on public health.
See also next.