State health officials said the toll could rise as they verify more deaths related to when Texas' power grid failed amid the frigid weather.
Bill Magness' ouster follows millions of people going without electricity and heat for days in subfreezing temperatures.
It’s only going to get worse with the increased demands of extreme weather triggered by climate change, he warned.
The Electric Reliability Council of Texas came within minutes of millions of people losing power "for an indeterminate amount of time," the power grid's CEO said.
How a Texas-first energy policy turned into a Texas-only energy failure.
The latest storm front was expected to bring more hardship to states that are unaccustomed to such frigid weather before moving into the Northeast on Thursday.
Dozens of fires are burning amid record-breaking temperatures, straining the state's electrical grid.
Democrats have "intentionally implemented" rolling blackouts, the president claimed.
Temperatures could creep up to nearly 100 degrees, threatening to overload the electrical grid.
Electricity is almost fully restored as of Sunday evening to Argentina, Uruguay and Paraguay, after what one leader called an "unprecedented" power failure.