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Editor’s Note: This is the first of a series with Morristown Utilities officials discussing Winter Storm Elliot’s pressure on the power grid.

The storm that hit a large portion of the United States just before Christmas, dubbed Elliot, is referred to by those who were in the thick of its utility challenges by another name.

“It was a Century event,” Morristown Utiltites General Manager/CEO Jody Wigington said on Wednesday, “covering a massive area with record cold temperatures; it had national, regional impact to the systems.”

Some 700,000 homes were without power for an extended period of time.

“In the valley, we had dodged a number of major events for years, the last being the Polar Vortex , that affected other regions but we had always escaped that. Not this time,” Wigington said during a discussion with Rotary of Morristown members.

There were several reasons for the local impact.

“It was cold. And the length of it on Friday stressed everybody’s reserves. There was not only cold, there were high winds that were factors in tripping off two major coal generation units at the Cumberland Steam Plant. It actually tripped one gas plant about 30 miles from here, the John Sevier, due to freezing conditions.

The John Sevier plant had what is referred to in utility terms as “spinning” reserves – explained by Wigington as similar to a jet engine in that they can fuel up quickly to generate load (power) – “It wouldn’t operate,” he said.

TVA had made preparations after the Polar Vortex situation, but Wigington said, “It wasn’t enough.”

TVA’s power service territory covers 80,000 square miles including most of Tennessee and parts of Alabama, Georgia, Kentucky, Mississippi, North Carolina and Virginia, providing electricity to nearly 10 million people.

The power program experienced the highest peak demand ever in the winter, the record was set on the evening of Thursday, Dec. 22, at 8 p.m. Then the record was set again on Friday.

Utilities within the Northeastern grid, located west of Denver, Colorado, purchase power from each other via contracts.

TVA had purchased two contracts to prepare for Elliott – one with a neighboring state’s utility and the other with a regional transmission organization. Both of those contracts were cancelled as the storm hit. The state utility was unable to provide enough power for its own customers and the regional organization, made up of utilities in northern states, was in the thick of the storm

“They had the right to do that,” Wigington said.

The combined contracts would have provided an estimated 6 to 7,000 megawatts worth of electricity to TVA.

“To give you a comparison, that’s like almost four nuclear units running full blast,” Wigington said.

Although TVA had done its due diligence; even with all the data, it underestimated the peak load and the time that it would be sustained.

“The peak load had been estimated at 31 gigawatts (31,000 megawatts); it went to 33.4, that’s an 8 percent miss,” Wiginton said. “TVA projected it would go down to 28 gigawatts that night. It didn’t; it stayed above 31 the entire night; that’s what resulted in the largest one day energy use in TVA history.”

To put it simply, TVA burned through its reserves … and quickly.

For example, at Raccoon Mountain, Wigington said, where water is pumped uphill to a large reservoir, the pumps ran all night – enough to drain them of power.

The Raccoon Mountain project is TVA’s largest hydroelectric facility. Water is pumped to the reservoir on top of the mountain during periods of low demand and then used to generate electricity when additional power is needed. The pumped-storage plant is located in southeast Tennessee on a site that overlooks the Tennessee River downstream of Chattanooga.

The plant works like a large storage battery: during periods of low demand, water is pumped from Nickajack Reservoir at the base of the mountain to the reservoir built at the top. It takes 28 hours to fill the upper reservoir. When demand is high, water is released from a tunnel that is drilled through the center of the mountain; the falling water drives the generators in the underground the power plant.

“When we woke up Saturday morning, TVA was not in good shape,” Wigington said. “Emails were flying back and forth starting at 4 a.m. They were short and they called for the ELC assistance.”

ELC is the power program’s Emergency Load Curtailment Program.