Last winter was the “longest sustained cold spell in 25 years,” for the American southwest, this document says and the break in gas flow “to the region was unprecedented.”

Though FERC just opened an new investigation into last week’s SDG&E blackout in southern California, Arizona and northern Mexico, on Thursday it held a meeting to publicly review this document, results of an investigation into a different debilitating blackout, six months ago, which affected New Mexico, Arizona and Texas.

A FERC task force already found that there exist no regulations on winterizing power plants. The August 18 task force report held back on full-scale recommendations and instead called for state level investigation on whether requirements for power companies to winterize their facilities are necessary. Read more: How To Solve A Regional Winter Blackout.

Although the report found that other failures occurred at the time, the majority that were weather-related failures ultimately tripped the plants offline and prevented natural gas from flowing through the pipelines to customers.

“The balancing authorities could have been better prepared for this event by, among other things, requiring accurate information about temperature design limits from generators, not allowing planned outages requested when extreme weather is expected, raising reserve levels when extreme weather is expected, and having procedures that would allow them to order some units to warm up (and be compensated) before extreme weather hits,” the report says.

The report also recommends that better communication be a must during extreme weather conditions. According to Thomas Pinkston of the Office of Enforcement who was among those who presented the report to FERC, the grid operators should have had better access to weather forecasting tools to foresee the extreme weather and plan adequately.

“These outages could have minimized,” he said. Among his suggestions: heating up the gas units beforehand.

FERC Commissioner Marc Spitzer noted that abundant gas storage units could have also prevented the shortages during the blackout.

And even though some might say hindsight is 20/20, the commissioners noted that in 1989 a similar winter freeze occurred in the area and lessons were not learned. FERC Commissioner John Norris emphasized that this time, the lesson would be learned.

This document, Outages and Curtailments: Southwest Cold Weather Event: February 1 – 5, was compiled by Loye Hull of the Office of Electric Reliability and Kathryn Kuhlen, James Meade, Heather Polzin and Thomas Pinkston of the Office of Enforcement.