Texas power grid came close to rotating outages, ERCOT says
The state's biggest power grid could have been forced to implement rotating outages if one additional generator of significant size had gone off-line Monday morning amid unusually cold weather, the Electric Reliability Council of Texas said. As heating demand rose around the state, several big generators went down unexpectedly, forcing ERCOT to take steps to trim demand. Those steps included curtailments to big users that had previously agreed to reduce their consumption when necessary. That's the second stage of a three-stage emergency alert system, the third of which is rotating outages.
In a conference call with reporters, ERCOT's director of system operations, Dan Woodfin, said 3,700 megawatts of expected electricity supply was not available this morning. About half of that was due to weather-related problems at two big north central Texas generators, he said. "Both were related to freezing of instrumentation used to provide control of the plants," Woodfin said. The units were not identified.
At the same time, ERCOT took the unusual step of importing power from outside its system, which covers about 75 percent of the state's area and serves about 85 perent of its demand. ERCOT, which otherwise is self-contained, has a few ties to other power grids, and it imported about 800 megawatts from the U.S. eastern grid and about 180 megawatts from Mexico, Woodsin said. ERCOT last experienced rotating outages in February 2011, also when cold weather pushed demand higher. But that time, he said, numerous generators failed to stay online to supply power, many because of cold-related problems with instrumentation. He said the implementation of "best practices" standards for weatherization of Texas power plants were adopted in the wake of those outages, and he thought the relatively low number of generators that had issues Monday showed that the state had improved its ability to avoid cold-related problems.
Reuters reported that output at Luminant's Comanche Peak 1 nuclear reactor in in Glen Rose was reduced early Monday for repair of a heater drain pump, citing nuclear regulators. Luminant officials were not immediately available to comment on the status of the 1,209-megawatt unit. It's not clear if the issue was weather-related. Luminant is a subsidiary of Dallas-based Energy Future Holdings and is the state's largest power producer.
-- Jim Fuquay