power generation

Texas should have enough installed generating capacity to serve peak energy demand through the winter, according to the electric grid operator that serves most of the state.

The Electric Reliability Council of Texas (ERCOT) on Wednesday issued its final seasonal assessment for this fall and the preliminary forecast for the winter season, extending from December through February. 

ERCOT manages the flow of electric power to more than 26 million Texas customers, representing about 90% of the electric load. ERCOT also manages the deregulated market for 75% of the state. 

“We study a range of normal to extreme scenarios prior to each season to determine whether there are any operational risks associated with meeting the forecasted peak demand,” said ERCOT’s Pete Warnken, who manages Resource Adequacy. “At this time, our assessments show there will be adequate generation for fall and winter.”

The peak demand forecasts for fall and winter were developed using economic data that was revised in April by Moody’s Investors Service. 

The final analysis for fall capacity, for October and November, is detailed in the the Seasonal Assessment of Resource Adequacy, or SARA. The SARA shows a 60,966 MW peak demand forecast. 

The SARA is unchanged from ERCOT’s preliminary forecast and is based on “normal weather conditions” during fall peak demand periods, from 2004-2018.

The assessment is based on generation availability and expected peak demand conditions. It takes into account expected generation outages that typically occur for routine maintenance, as well as a range of outage scenarios and weather conditions that could affect seasonal demand.

During October and November, ERCOT expects to have more than 86,000 MW of resource capacity available at the start of the season. Capacity is forecast to include 1,475 MW of planned wind and solar capacity.

ERCOT also expects to see unit outages of 14,267 MW, based on the historical average of outages for weekday peak hours in each of the last three fall seasons (2017-2019).

‘Normal’ Winter

The preliminary winter SARA includes a peak demand forecast of 57,699 MW, sharply below the record demand of 65,915 MW set on Jan. 17, 2018. The preliminary forecast is based on normal weather conditions during winter peak periods from 2004-2018.

“An additional 1,359 MW of planned winter-rated resource capacity is expected to be added between now and the start of the winter season,” according to ERCOT.

The preliminary winter SARA includes a unit outage forecast of 8,617 MW based on normal winter weather conditions. 

“For the extreme outage scenario included in the assessment, ERCOT is now using the region’s most recent cold weather event that occurred on Jan. 17, 2018, along with a three-year outage history to calculate the amount of potential outages.”

Because of the increased amount of renewables on the system, ERCOT has included a low wind output scenario in the preliminary winter SARA. Moving forward, ERCOT plans to include a low wind output scenario in all of its seasonal assessments.

The final winter SARA for 2020-21 is scheduled for release in early November.