That brings the total shortfall to nearly $2.5 billion, according to a market notice.

"The entire energy sector failed Texas," said NRG Energy Inc Chief Executive Mauricio Gutierrez, who testified.

Those essentials include power for natural gas wells, processing plants and compressor facilities, but Texas Energy Reliability Council Chairman James Cisarik said keeping natural gas flowing to power plants requires operational water, communication and transportation infrastructure.

The outlook in the Texas oil and gas sector remains negative as most companies expect low capital spending in 2016, the Dallas Federal Reserve said.

Texas Shale Boom Could Be Nation’s Biggest Ever