The two nuclear reactors at the South Texas Project plant 90 miles from Houston are operating at full capacity, according to media reports.
This is despite calls from watchdogs for the facility to shut due to Tropical Storm Harvey.
A spokesman for the plant said that there was significant rain in the area but flooding had not yet been an issue.
The reactors, 44% of which are owned by NRG Energy Inc, provide 2,700 megawatts of power to 2 million customers in Texas.
The rest of the reactors are owned by the city of San Antonio’s CPS Energy utility, with 40%, and the city of Austin’s Austin Energy, with 16%.