Texas energy company CenterPoint Energy Inc said on Tuesday that about 400,000 homes and businesses in its Houston-area service territory were without power as Tropical Storm Nicholas drenches the city.
That represents about 17% of CenterPoint's power customers in the Houston area.
Other utilities in the state reported minor outages, so far.
Separately, the South Texas nuclear plant, located near the Texas coast about 90 miles south of Houston, continued to operate at full power Tuesday morning, according to the U.S. Nuclear Regulatory Commission.