NASHVILLE, Tenn. (WKRN) — Tennessee Valley Authority described December’s arctic blast as a battle with Mother Nature.

News 2’s Mark Kelly takes a look behind the scenes at TVA to find out what it was like hour-by-hour trying to keep the power on for millions of people.

December 22. The weather was relatively mild. While many were having fun decking the halls for Christmas, Greg Henrich’s team at TVA was working hard to develop an action plan for the fast approaching chill.

“We felt like we had some conservatism built into the plan, and a really good plan going into the 23rd and 24th,” said Henrich, VP of Transmission Operations at TVA.

There plan was put to the test.

December 23rd at 2 in the morning the first domino fell. TVA’s plant in Cumberland City tripped. Then two hours later, the coal plant tripped again.

“We were concerned, but we also understood also that we had the reserves at our disposal we can then begin to utilize,” he said.

But as the sun rose, their confidence sank.

7:00 a.m., more units at natural gas plants stopped working.

“We have actually operated every single one of our plants at temperatures this low, but the difference between that and this storm is that this storm had some characteristics that we probably underestimated,” he explained.

Henrich said the winter storm was unique for three reasons: the rain leading up to the arctic air; a huge temperature drop in a short time; gale force winds that led to flash freezing.

In a snap, TVA lost 20% of its energy generation. That’s when rolling blackouts were implemented for the first time in its history.

Henrich said communication was one of their biggest challenges.

“From midnight to 9 a.m., this entire event unfolded. That’s what took the hit. We weren’t prepared to understand how do we communicate with our local power companies and the general public in that kind of time horizon,” he recalled.

During the daytime hours on Dec. 23, some warming took a little pressure of the grid. But, by nightfall, the problems were back.

That night, TVA set an all time winter record for energy use.

Dec. 24th, as many were preparing for Christmas Eve dinner, TVA alerted its 153 local power companies to being a second round of blackouts until noon.

“You understand that the situation is urgent, but you have to execute with a calm focus. That’s what we train for, that’s what we drill for,” he said.

In the month following the storm, TVA put in 200 changes to better fortify its natural gas and coal plants.

TVA admitted Mother Nature won this time, but promises to do everything they can to not lose the next battle.

“I am confident that we have the right people working on it, and the team to execute it when we do,” Henrich said.

Additionally, TVA’s board has a number of new members. Their first meeting is Thursday, Feb. 16.

A Blue Ribbon Panel is also investigating what changes TVA needs to make to prevent blackouts from becoming routine.