KC Boyce
SimonMahanGeorgia Power presented information to the Georgia PSC this morning on Winter Storm Elliott. Unlike TVA and Duke Energy, Southern Company didn't experience blackouts, so there's been little public discussion about their performance, here's a summary...🧵
GPC reported they're a vertically integrated monopoly, have coal, gas, nuclear, are connected to their neighbors, has a 26% winter reserve margin, and followed NERC standards. But the problem is...those things describe TVA/Duke, too & they had blackouts. What's different?
"We had a pretty big purchase that came in and helped." From Florida. Here's the EIA data showing all the imports/exports into the Southern Company balancing area during the week of Elliott. You can see on 12/24 large imports (negative) from Duke/TVA/FPL. https://www.eia.gov/electricity/gridmonitor/dashboard/custom/B852DFA9E82BD8CF1E3F25DD4236CB43
The EIA chart is messy, power flowing into/out of SoCo. If you net everything out, here's what it looks like. Southern Company's BA was a net importer for two days during 12/23, 12/24, the most extreme days. SoCo's BA wasn't a net help to their neighbors.
GPC said they entered into a NERC Energy Emergency Alert Level 2 on Dec. 24 - the same day TVA and Duke had rolling blackouts. By noon ET, TVA and Duke had cut off large amounts of exports to SoCo; SoCo called FPL to fill in the gap. (negative = imports)
By noon ET on 12/24, solar performance was doing great (of the solar installed). Coal seemed to have an 800 MW hiccup at 10AM. At peak, gas generation ~25 GW, but there are about 35 GW of installed gas capacity in the SoCo balancing area. Where was about 30% of the gas?
At 5AM ET on 12/24, the SoCo balancing area underestimated demand forecast by about 1 GW, similar to neighbors, and were short on generation by about 1.5 GW. Duke was providing SoCo 1.1 GW at that time. Within an hour, Duke went into rolling blackouts & still providing >500 MW.
Imports and exports aren't bad; they're vital to keeping the system low cost and reliable. But when you're a small balancing authority, like a Duke, TVA or SoCo, you're effectively an island on your own in emergencies. A lot like Texas was w/ Winter Storm Uri.
What we still don't know: what units went offline (GPC said some did)? How long? Why? How much? How much did the imports cost and how will those costs be socialized across the Southern system? How was the gas pressure in the system? Were interruptible customers cut off? How much?
These are all questions being asked by other state commissions, by state legislatures, by FERC and NERC. These were questions asked after Winter Storm Uri. If we don't know what went wrong, we can't prepare. MS and AL should follow GA's lead and ask their utilities to present.
So how was the Southern Company BA able to avoid the blackouts their neighbors TVA and Duke had? One reason is their connection with Florida. Another is their solar investments. But things were pretty serious, and we've still got a lot of questions. Video: https://www.youtube.com/live/TYktpHDPBM4?feature=share&t=596
PSC Committee Hearings - 02/02/2023
↑↑↓↓←→←→ABA̲C̲A̲B̲ 🌹@simonmahan Thanks for writing this up, I've been curious about how we managed to avoid rolling blackouts here when they were having so much trouble up in TN.