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In Nebraska, the first of the rolling electrical outages came at 12:07 p.m. Feb. 15. Over the course of the next two days, 38 breakers were purposely disconnected from the grid for varied periods of time, in order to keep the power grid in the 14-state Southwest Power Pool — of which Nebraska is a member — from crashing.
The culprit was extreme cold. Valentine, Neb., saw the thermometer dip to minus 33 degrees F in the early-morning hours Feb. 15. The next day was even worse, with temperatures sliding to at least 30 below all the way south to Beatrice, Neb., with similar readings across the state.
According to Mark Becker, media services supervisor for the Nebraska Public Power District, across the SPP area, the first outage on Monday lasted 51 minutes and affected 1.5% of the 14-state region. Tuesday’s blackouts were longer, lasting up to three-and-a-half hours and affecting 6.5% of that same region.
Rural customers, farmers and ranchers, and others felt the sting of the controlled outages. Trying to keep livestock fed, watered and warm was a tough task during blackouts. Fortunately, these kinds of outages because of an excessive load to the SPP system are rare in Nebraska.
At a media briefing Feb. 16, Tom Kent, NPPD president and CEO, noted that he could not recall another time that the state had experienced controlled rolling blackouts in the winter because of excessive load.
“The only other time I know of when this has happened was during the extreme drought and heat of the summer of 2012,” Kent said.
At the briefing, Kent gave a snapshot of the situation at that moment, noting, “If you look at our energy mix right now, we are generating for our customers and for the footprint about 2,400 megawatts of electricity. Our current load is a little under 2,000 MW. Of the 2,400 MW, 33% of that is coming from our nuclear plant, roughly 57% of it is from our coal plants, and we’re getting about 6.5% of our energy right now from wind resources.”
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Kent noted that SPP saw the problem coming. “They saw that the wind forecasts were going to be less,” he said. In the southern part of the SPP footprint, wind generators suffered from icing issues.
“They also saw the issues coming with regards to natural gas supply, and they started implementing their emergency planning,” Kent said. “Computers monitor the conditions on the system for SPP, but the decisions to make these actions to set these emergency levels to call for load control are based on human engineers and operators in the control centers of utilities and in the control center of SPP, who are looking at the situation” around the clock.
On Feb. 14, a news release from NPPD asked electric customers to conserve energy to reduce usage during the extreme cold, taking measures such as turning down thermostats in the home, closing shades and blinds to reduce heat loss from windows, and unplugging unnecessary appliances. For businesses and farms, NPPD asked customers to minimize use of electric lighting and electricity-consuming equipment.
By Feb. 16, SPP had notified NPPD system operators that they could stop the rolling service interruptions. Although emergency levels tipped back and forth over the next several days, as temperatures moderated and electricity use declined, no further interruptions took place because of the high loads.
Kent said that over the 14-state area covered by SPP, there was a need to interrupt service loads in order to bring things back into balance, so use and demand could balance out. “These actions were taken to prevent a larger outage from occurring,” he said. “When the decision came out, we worked with our customers to share with them what was happening.”
He defended the multistate electric grid, saying it was easier to manage challenges such as the extreme cold at a lower cost and with less risk for everyone. “We are working together to help each other and keep the lights on,” Kent said.
To learn more, visit nppd.com.