"This is not a chamber of commerce update. This is the largest train wreck in the history of deregulated electricity," said Senator Brandon Creighton of Conroe.
"Dozens of deaths, tens of billions of dollars in insurance claims, hundreds of thousands of homes and businesses with broken pipes," said Senator Paul Bettencourt of Houston.
Chief Executive Bill Magness again conceded that despite extensive preparation for the polar vortex descending on Texas, ERCOT did not foresee the frigid conditions knocking out nearly half of the state's electrical generation capacity.
"I feel a great deal of responsibility and remorse about the event and we will continue and continue to be investigated, but I believe the operators on our team did everything they could have," said Magness.
Magness told Senators what unfolded, as demand for power outstripped supply, was a rapid succession of controlled outages, so-called "load sheds" to prevent the grid as a whole from a catastrophic, long-term collapse.
"The only way you can get back to normal is if you control the situation because blackouts aren't normal. You are not in control anymore if you go there. So what these outages did was let us hold on to the system long enough to get enough generation back to serve people," said Magness.
Magness also responded to industry allegations that ERCOT's failure to properly manage critical frequency levels during the crisis triggered multiple generators to shut down.
"They are pointing the finger directly at your agency," said Senator Charles Schwertner of Georgetown.
"I don't know what evidence they are bringing to the table. If they are right, then absolutely we have to do something because there was something going on that we weren't seeing," said Magness.
ERCOT also drew fire for not raising the weather alarm loudly enough.
With two constituents dead from the cold, Creighton demanded answers.
"How could you not know the foreseeable danger and express that danger to those who could amplify those warnings?" Creighton asked.
Senators persistently expressed concern over the current inability of Texas government to force power producers to "weatherize" their facilities against freezing cold.