Stranded Peaker Units and Coal Capacity in the Southeast

Thanks for the info and the link. I agree that many utilities are slow to find capacity replacements for old coal plants - that are obviously not economical. I call these "zombie plants" and there are many of them all across the country. That may change over the next few years as storage becomes more prevalent.

What's needed before a coal plant retires...

 - most coal plants drop below 50% CF in the years before closure announcement

 - there needs to be replacement generation available or planned

 - in most cases there needs to be new replacement capacity

Let's take a look at the three states you mentioned.  Note: I've included a chart at bottom that shows Top 30 coal states and their generation so far this year.

Georgia 

"Southern has no plans to close any of its larger units, though it has begun discussing the future of two units at Bowen"

There are 3 major plants left in GA. Scherer(3,440MW), Bowen(3,232) and Wansley(1,744MW) - for a total of 8.4GW.

In 2019, Georgia retired about 1GW of coal plants. Another 3GW of coal plants were retired/converted in mid 2010s.

You can see on the chart that Georgia has had the steepest drop of any state when it comes to coal generation in 2020. One of the reasons for this is a drop to basically zero generation for the Wansley plant - it is now a zombie plant. So my guess is that the retirement of Wansley will be announced within the next year - assuming that Vogtle does not fall substantially behind schedule and Wansley will close in 2022.

Scherer and Bowen have also seen substantial drops in 2020.  

Unit 4 of Scherer(892MW) which is co-owned by Jacksonville and FPL will close in 2022. So in 2022 - 2,604 MW of coal will retire in Georgia - leaving 5.8GW remaining.

Once the second unit at Vogtle goes live Southern will announce the retirement of one of the two remaining plants. I think Bowen is more likely because it is older. That will leave only the remaining 2,580MW at Scherer. Solar/storage will eventually replace this and all coal will be gone from Georgia.

North Carolina

"Duke’s Roxboro plant will shut down two of its four units in 2028 and another two in 2033 under the company’s current plans. "

North Carolina is definitely a mess - still has 10GW of coal capacity left although coal generation is declining pretty quickly as can be seen in chart below. The current "zombie" plant in NC is the GG Allen (1.1GW) plant. This is scheduled to be retired in 2024/2028. There is no reason this can't be retired earlier - assuming Duke starts to implement some storage capacity.

In order to shutdown remaining coal NC will need to triple solar generation, add a bunch of storage and perhaps add some offshore wind and/or small nuclear.

Tennessee

"And TVA is not considering a retirement date at present for Cumberland."

TN has 5,700 MW of coal and Cumberland is about 2,450MW of this total. The obvious zombies on the TN coal list would be the 1.4GW Kingston coal plants and the 870MW Bull run plant - both of which will have a CF below 15% this year. Both of those should close first.

Next in-line would be the 976MW Gallatin plant and finally Cumberland. 

Kingston and Bull Run could easily be closed with additional solar/storage.

In order to close Gallatin and Cumberland a lot more capacity will need to be developed - more storage, more NG, or small nuclear.