Most Oklahoma electric utilities had planned outages across their systems Tuesday morning after the region’s grid operator reported a shortage of generating capacity.
The outages were by circuit and came with little notice from a customer’s utility.
Oklahoma Gas & Electric Co. announced early Tuesday on Twitter it had initiated “temporary service interruptions” as directed by the Southwest Power Pool in parts of Oklahoma City, Muskogee, Tishomingo, Norman, Edmond, Paul’s Valley, Enid, Woodward, Glenpool, Yukon, Ardmore, Kingston, Guthrie and Fort Smith, Ark.
“The estimated duration of the interruptions is two hours,” the OG&E statement said.
In the Tulsa area, which is served by Public Service Co. of Oklahoma, rolling outages came to thousands of homes.
By mid-morning, both PSO and OG&E said they were suspending planned outages after the latest update from the Southwest Power Pool, which controls generation and transmission in a 14-state area including Oklahoma. But they told customers that more outages may be necessary as the power demand fluctuates amid historically cold temperatures.
The grid operator said its system fell below its generating capacity of 42 gigawatts early Tuesday morning. The shortfall was due to extreme cold and a drop in supplies of natural gas.
It’s been so cold that some natural gas wellheads froze, limiting or stopping their expected production. Some gas processing plants that collect and process the natural gas had some equipment freeze, limiting their ability to fill the pipelines at adequate pressures. Meanwhile, some companies or utilities that didn’t have firm contracts were forced to go out to the spot natural gas market, where prices were going very high.
Coal generation has helped make up some of the shortfall in generation capacity, but the Southwest Power Pool has been moving to more natural gas and wind generation in the past decade, making natural gas supply issues more pronounced in periods of extreme cold weather. The grid operator doesn’t generally count on much wind generation in the coldest winter months, although some turbines in the region froze and had to be idled to protect their equipment.
The National Weather Service said the official Oklahoma City temperatures at Will Rogers World Airport at 7:12 a.m. Tuesday fell to minus-14 — the coldest official OKC temperature recorded since February 12, 1899.
Grid and state officials encouraged customers to conserve electricity by lowering temperatures on thermostats as safely as they can bear and unplug any unnecessary devices. The SPP briefly entered Level 3, its highest emergency level, on Monday but pulled back after about an hour.