Santee Cooper called on its coal plants to meet power needs in the recent cold snap. That was one topic of a specially called Santee Cooper board meeting February 24.

From the Santee Cooper board session 2/24. Shows the plant difficulties.

Or a clarification – Santee Cooper tried to call on some coal units to meet the power needs in the recent cold snap. In the end the company had to purchase power from Southern Company instead.

Granted, the cold snap in the U.S., and especially in South Central and parts of the Southeast U.S., was extraordinary. There have been cold snaps before, however, with lessons learned that hopefully had been applied.

Coal 101

Time needed to ramp up for various power sources. Coal can take longer than some other sources. EIA.

Coal plants require more than half a day to reach full operation from a start-up. The time can affect the reliability and operations of the electric grid. Truer when a unit is starting from a complete stop. Steam turbines often require more time. Fuel fires up and heats water to form steam. That steam has to reach certain temperature, pressure, and moisture content before it can get to a turbine to spin the electricity generator.

Tripping Offline

Trip means that a power plant shuts down and disconnects from the power line a plant should feed. It happens fast. Circuit breakers switch off the feed because it suddenly, and usually unexpectedly, had a major issue that keeps a plant from supplying power to the transmission system.

Bottom line

Higher than expected temperatures helped Santee Cooper, and Southeast utilities in general, meet the load during the cold snap.

Having interconnections for power in the Southeast, unlike Texas, helped the Southeast.

However, to call on a plant for power when it looks like your back is against a wall and get none is an issue. That is what happened with Santee Cooper on some units.

The South Carolina Governor sent a letter to Santee Cooper, Duke, and Dominion, asking for an analysis of what happened during the freeze. That’s reasonable. That investigation ought to include a look at why Santee Cooper could not bring online well-established technology in a crunch. It ought to include more than Santee Cooper looking at the issue, too.

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Coal in the Carolinas, Florida

Santee Cooper recently announced it would begin to phase out its Winyah station near Georgetown starting in 2023 but said it could keep its Cross station near Lake Moultrie open past 2030.

Duke already shut down all of its coal plants in South Carolina, but it is still working to phase out its remaining coal stations in North Carolina. The company put forward a forecast last year showing some of its coal units being retired as early as 2022 and the remaining ones largely being shut down by 2035.

Dominion Energy told South Carolina state regulators that it does not have any plans to close any of its three coal-fired stations until after 2028. (Source)

NextEra Energy has closed all its coal plants in Florida which were under its FPL umbrella.