Brazos Electric, the largest power cooperative in Texas, filed for Chapter 11 bankruptcy protection Monday, citing a nearly $2 billion bill from the state’s electricity grid operator as a result of last month’s freezing weather that left millions of people without power for days.

Brazos pays the grid operator, the Electric Reliability Council of Texas, to get electricity to hundreds of thousands of Texans. ERCOT is in charge of regulating supply and demand on the grid.

“They’re like a toll road for the electricity system,” said Costa Samaras, associate professor of civil and environmental engineering at Carnegie Mellon University.

In the February deep freeze, Brazos Electric ran up bills many times higher than normal.

“The prices are allowed, through the Texas electricity system, to rise when demand is really high and supply is low,” Samaras said. “That’s kind of the theory of all this” — the theory behind the state’s largely deregulated market, a system that many are now questioning.

“In fairness, I don’t know that anyone ever anticipated an event like this when they were designing that system,” said David Spence, professor of business, government and society at the University of Texas School of Law. “This seems like a ‘black swan’ event in that sense.”

But a similar event did hit Texas 10 years ago, and lawmakers decided not to winterize the system. 

Emily Grubert, assistant professor of environmental engineering at Georgia Tech, said there’s an opportunity, again, to rethink infrastructure more generally.

“I think we need to be really, really thoughtful about when it is actually logical to spend a little bit more money here to make sure that these systems actually do what we want them to do for the next several decades,” Grubert said.

Brazos Electric said that before the freeze, it was financially robust. Its bankruptcy filing could be an ominous sign as other Texas power providers assess the storm’s damage.