AUSTIN (KXAN) — Texas lawmakers questioned state energy regulators and leaders of major power providers on Thursday about the failures that left millions in the state without power last week during unprecedented, deadly winter storms.

The Texas House and Senate held dueling emergency hearings, which featured testimonies by representatives of the Electric Reliability Council of Texas, the Public Utility Commission, as well as the heads of power providers NRG, Vistra Corp. and Calpine.

During the joint testimony of Mauricio Guitierrez, president and CEO of NRG, and Curtis Morgan, president and CEO of Vistra Corp., state Rep. Todd Hunter of Corpus Christi demanded accountability for action, or inaction, that led to the energy disaster.

“I haven’t heard much, so, I think here’s the question folks want to ask you: who’s at fault?” Hunter said.

Guitierrez and Morgan both defended winterization efforts by their respective companies but said power providers share some of the blame. Morgan said ERCOT, the entity that manages Texas’ power grid, didn’t take the storms seriously enough.

Morgan said he has long been a proponent of the state’s deregulated energy market, but no longer knows if the system is sustainable. He said poor communication, lacking winterization efforts and a natural gas process susceptible to freezing temperatures were all factors in the blackout.

“My faith is shaken,” he said.

Over in the Senate hearing, ERCOT CEO Bill Magness was grilled about lack of communication by Sen. Brandon Creighton, a Republican representing Beaumont.

“How could you not know that it was foreseeable, very simply, to be able to warn the governor to warn the PUC, to warn the senators in this chamber, to warn the house representatives to warn the public?” Sen. Creighton questioned.

Magness said they were communicating with those who needed to be warned.

“Starting on February 8, we started providing notices to the market and all those notices we share with the commission about what we’re saying and what we’re asking the generators and the transmission owners to do,” Magness said.

He did agree that communication to the public could have been better heading into the event, but admitted that the outages were much greater than they expected because ERCOT did not accurately predict how much generation would be lost during the storm.

“What we did not anticipate was losing you know up to 48% of the generation available on Monday night, and that that is on us,” Magness explained.

He said information about how the ‘rolling’ outages were actually sustained outages should have been communicated more quickly.

“At that point, we were solving problems but I think we should have been talking more to people about what this was starting to look like,” Magness explained.

In the House, legislators said generators could have done their part in letting the public know about expected outages sooner, too.

“People don’t know who the PUC are….They don’t know who ERCOT is up until last week, but they know who the name on the bill is that they see,” Rep. Eddie Lucio, Jr. said to Morgan and Gutierrez.

The companies replied that they did not want to be the ones to sound the alarms, but representatives said that may need to change going forward.

Gov. Greg Abbott doubled down on his criticism of ERCOT on Thursday during a press conference on vaccine distribution in Corpus Christi.

Abbott said the entity was unprepared and failed to appropriately communicate with energy providers and the public about the severity of the storms.

“And then they did the equivalent of slamming on the brakes while driving on ice, and it led to a collision,” Abbott said.

State Rep. Rafael Anchia, a Dallas Democrat, attempted to shift more of the focus of the House hearing to the Public Utility Commission, which has oversight of ERCOT and regulatory authority over the energy sector in Texas.

“(PUC board members are) not elected. They have advice and consent of the Senate, but that’s the governor’s hand-picked team to regulate the market,” Anchia said.