As of Sept. 30, the end of its latest fiscal year, the Tennessee Valley Authority had nine coal-fired plants consisting of 39 active units, accounting for 10,995 MW of summer net capability, and 20 inactive units.
TVA noted in its Nov. 20 annual Form 10-K report that inactive units may be in three categories: retired, mothballed, or inactive reserve.
- Retired units are unavailable for service and are not expected to return to service in the future. As of Sept. 30, TVA had 13 retired units: John Sevier Fossil Plant Units 1-4, Shawnee Fossil Plant Unit 10, and Widows Creek Fossil Plant Units 1-8.
- Mothballed units are unavailable for service but can be brought back into service after some maintenance with reasonable notification, typically weeks or months. As of Sept. 30, TVA had seven mothballed units: Johnsonville Fossil Plant Units 5-10 and Colbert Fossil Plant Unit 5.
- Inactive reserve units are unavailable for service but can be brought back into service after some repairs in a relatively short time, typically days. As of Sept. 30, TVA had no units in inactive reserve. TVA refers to units which are in inactive reserve or mothballed status as idled.
In April 2011, TVA entered into two agreements (collectively, the “Environmental Agreements”) to address a dispute under the Clean Air Act. The first is a Federal Facilities Compliance Agreement with the U.S. Environmental Protection Agency. The second is with the states of Alabama, Kentucky, North Carolina, Tennessee, and also three environmental advocacy groups.
Under these agreements, TVA agreed to retire 18 of its 59 coal-fired units by the end of 2017 and was generally absolved from any liability, subject to certain limitations and exceptions, under the New Source Review (NSR) requirements of the CAA for maintenance, repair, and component replacement projects that were commenced at TVA’s coal-fired units prior to the execution of the agreements. Failure to comply with the terms of the agreements would subject TVA to penalties stipulated in the agreements.
TVA said it is confident that it has adequate capacity to meet the needs of its customers after these units are retired. Here are the actions TVA is taking under the agreements, and other coal-fired generation actions taken or to be taken by TVA.
- Allen, three affected units, existing selective catalytic reduction for NOX control on all three units, required to install SO2 scrubbers on all units or the units to be retired by the end of 2018, plan is to build gas-fired plant at the site and retire all three coal units after that replacement facility is completed.
- Bull Run, one affected unit, currently equipped with SCR and scrubber, emissions to be continously monitored with no further emissions controls or a shutdown;
- Colbert, five affected units, SCR on Unit 5, idled Unit 5 in October 2013, plan is to retire Units 1-4 by April 16, 2016, and to retire Unit 5 by Dec. 31 of this year;
- Cumberland, two affected units, scrubbers and SCRs now on both units, plan is to monitor emissions and keep them both operating;
- Gallatin, four affected units, no current scrubbers or SCR, scrubbers and SCRs on all four units to be added by the end of 2017;
- John Sevier, four affected units, no scrubbers or SCR, retired Units 1 and 2 at the end of 2012, and retired Units 3 and 4 in June 2014;
- Johnsonville, 10 affected units, idled six units in 2012-2013 period, plan is to retire Units 5-10 by the end of this year and to retire Units 1-4 by the end of 2017;
- Kingston, nine affected units, scrubbers and SCRs now on all nine, will continuously monitor emissions and keep operating;
- Paradise, three affected units, scrubbers and SCRs on all three, will build gas-fired replacement at the site for Units 1 and 2 and continue to operate Unit 3 as a coal-fired facility;
- Shawnee, 10 affected units, no current scrubbers or SCRs, retired Unit 10 in June 2014, plan is to add scrubbers and SCRs on Units 1 and 4 by the end of 2017; and
- Widows Creek, eight affected units, scrubbers and SCR now on Units 7 and 8, retired Units 3 and 5 in July 2013, retired Units 1, 2, 4 and 6 in July 2014, retired Units 7 and 8 on Sept. 30 of this year.
After TVA completes these actions, it anticipates that it will have 7,884 MW of summer net capability of coal-fired generation, a reduction of 6,689 MW from TVA’s coal-fired capacity as of Sept. 30, 2010.
In October of this year, TVA submitted a request to the EPA for an administrative order under the Clean Air Act that would allow operation of Paradise Units 1 and 2 for a year beyond the Mercury and Air Toxics Standards (MATS) extended compliance date of April 16, 2016. The additional year is necessary to allow these units to continue to operate while the new combined cycle facility is being built. Without the additional year, TVA would be forced to shut down Paradise Units 1 and 2 as of April 2016, without replacement capacity being available, which would cause adverse consequences to transmission system reliability.
To reduce SO2 emissions, TVA has installed scrubbers on 17 of its coal-fired units with scrubbers currently under construction on six additional units, and switched to lower-sulfur coal at 24 coal units. To reduce NOx emissions, TVA has installed SCRs on 20 coal units with SCRs currently under construction on six additional units, operates selective non-catalytic reduction systems on four units, installed low-NOX burners or low-NOX combustion systems on 25 units, optimized combustion on five units, and operates NOX control equipment year round when units are operating (except during start-up, shutdown, and maintenance periods). TVA has also retired or announced plans to retire 33 of 59 coal-fired units, and the remaining coal-fired units will either have scrubbers and SCRs, be repowered to renewable biomass, or be retired.
Upon the completion of natural gas-fired facilities at the Paradise site, coal-fired Units 1 and 2 at Paradise with a summer net capability of 1,230 MW will be retired. Upon the completion of a natural gas-fired facility at the Allen site, coal-fired Units 1-3 at Allen with a summer net capability of 741 MW will be retired. TVA plans to retire the Allen units before Dec. 31, 2018, Colbert Fossil Plant Unit 5 with a summer net capability of 472 MW no later than Dec. 31, 2015, and Colbert Units 1-4 with a summer net capability of 712 MW before April 16, 2016. During 2015, TVA retired Widows Creek Unit 7 and 8 with a summer net capability of 938 MW on Sept. 30, 2015, and the TVA board approved the retirement of Johnsonville Units 1-4 with a summer net capability of 428 MW by Dec. 31, 2017. Additionally, TVA plans to retire Johnsonville Units 5-10 with a summer net capability of 778 MW by Dec. 31, 2015.
During 2014, the TVA board approved the construction of two natural gas-fired facilities. One facility, with an expected capacity of approximately 1,000 MW, will be constructed at the Allen site at a cost not to exceed $975 million. The second, with an expected generation capacity of about 1,000 MW, will be constructed at the Paradise site at a cost not to exceed $1.1 billion.
Coal consumption at TVA’s facilities during 2015 and 2014 was about 28 million tons and 31 million tons, respectively. At Sept. 30, 2015, and Sept. 30, 2014, TVA had 32 days and 29 days of system-wide coal supply at full burn rate, respectively.