Plant Optimization

ERCOT concerned about electricity demand and extreme weather

The Electric Reliability Council of Texas (ERCOT), the state grid operator and manager of the wholesale electric market, raises concerns about an increase in demand tied to extreme weather conditions and worst-case generation outages in a recently released winter assessment.

ERCOT’s winter 2011/2012 assessment is one of the first created to provide a more complete picture of near-term risks. The seasonal assessments are scheduled to be issued quarterly.

One of the concerns listed was if the ERCOT region experienced extreme weather similar to winter conditions in February that led to rolling blackouts on the electric grid.

“Our assessment indicates a concern if we experience a simultaneous occurrence of extreme weather and worst-case generation outages, much like February of this year,” said CEO Trip Doggett.  “Under normal weather conditions, the winter peak demand should be around 53,600 MW.  Available resources, based on normal generation outage rates, are approximately 64,000 MW.

“However, under extreme weather conditions, the winter peak demand could be approximately 60,000 MW.  Available resources, based on above normal generation outage rates, could dip to approximately 57,000 MW,” Doggett said.  “We believe the risk is very low of these simultaneous conditions, but the purpose of this report is to highlight such risks.”

On Feb. 10, actual peak demand reached 57, 315 MW, an al-time winter record that surpassed the 56,334 MW peak on Feb. 2, when ERCOT asked utilities to implement controlled rotating outages following the rapid loss of 8,000 MW of generation due to low temperatures and wind chill factors.

The winter assessment is the first of a new ERCOT report called the Seasonal Assessment of Resource Adequacy. The report is designed to enhance the grid operator’s assessment of near-term conditions and complement the twice-a-year capacity, demand and reserves report.

The seasonal assessments will use the most current available data on seasonal weather, the status of power plants and the impact of factors such as the economy and ongoing drought conditions in Texas.

ERCOT said it will continue to monitor drought conditions and how it is affecting capacity due to impacts on cooling water resources available for generating units.

ERCOT estimates that 11, 464 MW of generating capacity relies on water sources affected by the drought.

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