TVA plans to replace Cumberland coal plant with another fossil fuel

In 2021 TVA announced it would shutter the Cumberland coal plant. Last week, TVA proposed to lock customers into paying for fossil gas to replace it, without fully exploring efficiency and renewable energy. TVA's decision is open to public comment through June 13.

Maggie Shober | May 2, 2022 | Coal, Fossil Gas, Tennessee, Utilities

The Tennessee Valley Authority (TVA) filed a draft Environmental Impact Statement, or DEIS, last week to analyze the potential environmental impacts of various possible replacement options for its retiring Cumberland coal plant, and pick one of the evaluated replacement options as its preferred option. Because TVA is a federal entity, it is subject to the National Environmental Policy Act or NEPA, therefore requiring it to file a DEIS, receive public comments, and publish a final EIS before moving forward with a project that has the potential to have significant environmental impacts.

Any individual, entity, or organization can submit a comment on TVA’s DEIS  between April 29 and June 13, 2022, online or via email (to [email protected]). TVA will also hold three open houses, one virtual and two at locations near the Cumberland site, where individuals can comment on TVA’s plan.

  • Virtual public open house on May 12, 2022, 6:30-8:00 PM CT. Register to attend and submit questions in advance (they are more likely to be answered than those asked during the event) by May 5.
  • In-person open houses on May 17 in Dover, TN, and May 18 in Erin, TN. No registration is necessary to attend, see TVA’s landing page for times and locations.
Cumberland Coal Plant in Steward County, Tennessee. Image source: TVA

In this DEIS, TVA proposes to retire one unit of the two units at the large coal plant in middle Tennessee between 2026 and 2030, and the other unit between 2028 and 2033. TVA claims it needs full replacement of the capacity of the Cumberland coal plant to maintain its reserve margins and meet projected load growth. However, since this is not an integrated resource planning process, there is insufficient evidence provided in the DEIS itself that what TVA presents in its alternatives is what the system needs.

TVA evaluated three options for this replacement capacity:

  • Alternative A: A large (1,450 MW) gas combined cycle (CC) power plant that would require the construction of a new gas pipeline to the Cumberland site,
  • Alternative B: Two gas combustion turbine (CT) plants (1,530 MW) at different locations, and
  • Alternative C: 3,000 MW of solar and 1,700 MW of storage.

TVA chose Alternative A, the new gas CC plant that requires a new gas pipeline, as its preferred option. The DEIS also acknowledges that the gas CC plant would only replace one of Cumberland’s retiring units, and leaves open the possibility for more gas, or a combination of gas, solar, and storage, to replace the second Cumberland unit.

Route of the new gas pipeline to serve the new gas CC plant in Alternative A. Image source: TVA DEIS

TVA proposes to lock in more fossil fuels and has already taken steps to do so

The DEIS shows that TVA chose the highest greenhouse gas (GHG) emitting alternative, yet it is touting this choice as “beneficial” on climate change because TVA compared it to the retiring coal plant instead of the other alternatives. TVA states that building a CC gas plant will have “moderate, beneficial effects” on climate change only because it is comparing the CC project to the continued operation of the coal power plant.

TVA also claims the CC gas plant can come online sooner than the other alternatives, but this is in large part because it has already set the process in motion. The actions TVA has taken to get the CC project underway have been very clear: TVA already entered into a precedent agreement with the pipeline company, which has allowed it to start the approval process at the Federal Energy Regulatory Commission (FERC).

However, despite Board approval last November that TVA could take steps to ensure all of the alternatives were an option based on timing, it does not appear that TVA took any actions to get Alternatives B or C underway. TVA could have easily requested bids for solar and storage projects to meet the requirements for Alternative C to jumpstart the process for getting those projects online as it has done for the proposed CC project.

TVA’s proposal under Alternative A – the CC gas plant – states that site preparation would begin in 2023 and construction in the fall of 2023, and the CC plant would go online in the summer of 2026. The pipeline company, Kinder Morgan, has already begun the FERC approval process under docket number PF22-2. TVA’s draft EIS states that, if approved, the pipeline will begin construction in August of 2024 and be operational by September 2025.

TVA does not need more gas and it didn’t adequately explore clean energy options like efficiency and solar to replace the Cumberland coal plant

TVA already has a large hydro fleet, which can be used to integrate variable resources like solar and wind. TVA has pulled back on energy efficiency programs that reduce energy consumption and customer bills, and therefore misses a huge opportunity to offset some of the need for new generation to replace the Cumberland coal plant. And let’s not forget, TVA is already building new gas: 2,100 MW of new gas is coming online in the next two years.

Alternatives “considered but eliminated”

TVA claims the replacement of Cumberland “must be capable of providing year-round peak capacity as well as serving large energy needs, as [Cumberland] serves an intermediate-to-baseload function.” However, a look at recent trends in generation from Cumberland shows the plant generates twice as much in summer months as winter months, a generation shape that is actually quite similar to solar in the region.

Comparison of Cumberland’s historical generation and estimated generation from 3,000 MW of solar located within TVA’s service territory. Data source: EIA and SACE.

TVA’s DEIS lists other resources considered but eliminated, such as hydro pumped storage, small modular reactors (nuclear), both in- and out-of-valley wind, energy efficiency, and demand response. The primary reasoning appears to be that most of these resources would not be available by the time TVA wants to retire the first Cumberland unit, with another reason being that these resources couldn’t meet 100% of the need to replace capacity and generation from one of the Cumberland units.

Why did TVA limit each alternative to one or two resources? TVA could add energy efficiency, demand response, and distributed solar to any one of the alternatives to reduce the total amount of large-scale capacity required. By starting these programs now, the utility could scale them until the earliest Cumberland coal plant retirement date in three years and still be able to shave some of the energy requirements from large-scale energy resources of any kind. In fact, countries in Europe are looking to quickly implement energy efficiency and electrification measures to reduce reliance on Russian gas significantly in just one year. TVA could take a lesson from what Europe is doing right now in order to retire coal and replace it, at least partially, with energy efficiency, demand response, and distributed solar. Just because these resources cannot replace 100% of the capacity and energy needs of Cumberland does not mean they are not worth investing in at all.

Let’s talk about wind specifically. TVA’s DEIS rightly states that wind can provide “dependable capacity in both summer and winter,” but that the resource was not selected due to low wind speeds for in-valley wind and high transmission costs for out-of-valley wind. Did TVA look at the latest wind technologies, which include high hub height turbines that can be effective in lower wind resource areas? It’s not clear since no details are given on what kinds of wind were evaluated. But just to the south, Georgia Power just proposed a tall wind pilot project, and TVA’s wind resources are better than Georgia’s. And let’s not forget that TVA had the option for out-of-valley wind for a total price, so including transmission, that was less than the cost of gas in a very efficient power plant. While TVA’s leadership has changed since TVA turned down $18/MWh wind from Oklahoma through Clean Line‘s Plains and Eastern transmission project, TVA’s current leadership could explore that or similar projects to replace all or some of the capacity and energy needs from coal retirements while helping get to zero emissions by 2035.

Side note: If TVA had listened to SACE and other advocates’ recommendations over the past several years to continue its effective energy efficiency and distributed solar programs, it might be able to replace 100% of the capacity and energy needs of one of these coal units with distributed resources. But instead, TVA decided to double down on its’ debunked rhetoric and go from a respectable performer in the region to a laggard on these resources that improve resiliency and reduce customer bills.

The solar and storage Alternative C (that could have been?)

The DEIS TVA only considered large-scale solar as an alternative, dismissing distributed or rooftop and small-scale solar as an option because it is assumed to cost more. However, TVA did not take into account that utility costs for distributed solar can be less than large-scale solar. The DEIS also presents solar as negatively impacting land use because TVA has chosen to only look at large-scale solar, which tends to be more land-intensive than distributed solar. For the solar and storage option, Alternative C in the DEIS, TVA says it needs 3,000 MW of new solar and 1,700 MW of new storage to replace one of the Cumberland units today.

Let’s check that math, shall we? Based on EIA data and using TVA’s assumption on the capacity factor of solar, TVA would need between 1,772-2,552 MW of solar to make up the generation from one of the Cumberland units. On storage, we have a lot less information on how TVA got to the 1,700 MW figure, except that they used a model called SERVM that we have found issues with when utilities have used it elsewhere in the Southeast.

While we understand that we need to be building as much renewable energy as possible to get off our dependence on fossil fuels, assuming too much solar and storage needs to be in place to retire this coal plant could unjustly make the cost and schedule of this alternative compare unfavorably to others. (See page 7 of our comments on TVA’s 2019 IRP for a question about how SERVM is inappropriate to use in a planning study, such as this.)

Furthermore, the DEIS contradicts itself by claiming that Alternative A, the gas plant and pipeline option, allows the Cumberland coal units to retire sooner. But the DEIS states Alternative C, the solar and storage option, has the same retirement dates as Alternative A.

Inefficient plant operation pushed TVA to retire the Cumberland Coal Plant

The Cumberland coal plant is by no means young: its units were built in 1968 and 1973, but they are among the most recently built coal units in TVA’s fleet. So why is TVA proposing to retire these units and leave older ones still operating? TVA has operated the Cumberland coal plant in ways that it was not designed to operate. Coal plants like Cumberland are highly inflexible. According to TVA’s report to the Energy Information Administration (EIA), Cumberland’s units each take more than 12 hours to start up, and likely much longer to go from zero to full capacity.

Take action

We’re glad to see TVA retiring the Cumberland plant but leery of its desire to replace fossil fuels with more fossil fuels. The utility should rebuke its intentions to double down on fossil fuels and instead pursue its “aspiration” to clean up its generation fleet and invest in renewable energy + energy efficiency.

We encourage you to submit a comment virtually, or if you are able, attend a public meeting and let TVA know the option they are clearly pursuing is unacceptable to Valley residents.

Any individual, entity, or organization can submit a comment on TVA’s DEIS  between April 29 and June 13, 2022, online or via email (to [email protected]). TVA will also hold three open houses, one virtual and two at locations near the Cumberland site, where individuals can comment on TVA’s plan.

  • Virtual public open house on May 12, 2022, 6:30-8:00 PM CT. Register to attend and submit questions in advance (they are more likely to be answered than those asked during the event) by May 5.
  • In-person open houses on May 17 in Dover, TN, and May 18 in Erin, TN. No registration is necessary to attend, see TVA’s landing page for times and locations.
Maggie Shober
Maggie Shober works to speed the clean energy transformation in the Southeast through analysis and advocacy. She has expertise in renewable energy, energy efficiency, coal retirements, energy market modeling, and…
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