ERCOT Files Updated Analysis On Rayburn Integration
May 21,2018
ERCOT has filed an update to an analysis of the impacts of the proposed transition of the remaining portion of the Rayburn Country Electric Cooperative, Inc. (RCEC) load that is currently served by the Southwest Power Pool (SPP) into the ERCOT Region
On May 1, 2018, ERCOT had filed with the Public Utility Commission of Texas the ERCOT-SPP Coordinated RCEC Integration Analysis-Addendum (Modified Alternative Option Integration Analysis). That report detailed ERCOT's analysis of the impacts of the proposed transition of the remaining portion of the Rayburn Country Electric Cooperative, Inc. (RCEC) load that is currently served by the Southwest Power Pool (SPP) into the ERCOT Region using a transmission option deemed the "Modified Alternative Option."
The Modified Alternative Option Integration Analysis also compared the impact of integrating RCEC's load using the Modified Alternative Option against the impact of using a different transmission option, deemed "Option 2," which had been the subject of a report filed by ERCOT on March 1, 2018. After conducting this comparison, ERCOT recommended that the Modified Alternative Option be used to integrate RCEC's load because it was found to be the lowest-cost reliable option.
Subsequent to filing the Modified Alternative Option Integration Analysis, ERCOT staff discovered an inaccuracy with respect to Option 2. More specifically, the previously-filed reports did not reflect the fact that a minor component of the Option 2 transmission option proposed by Lone Star Transmission, LLC -- specifically, the Elkton—Tyler Switch line upgrade -- was not necessary for reliability. Accordingly, that specific component should not have been included in ERCOT's analysis of the Option 2 transmission option.
In order to correct this discrepancy, ERCOT has revised the Modified Alternative Option Integration Analysis to remove the Elkton—Tyler Switch line upgrade from Option 2 for purposes of comparing Option 2 to the Modified Alternative Option.
As a result of this revision, the estimated capital cost of Option 2 has decreased by $2.1 million. The removal of the Elkton—Tyler Switch line upgrade from Option 2 had no other significant impacts on ERCOT's previously-reported results with respect to Option 2, ERCOT said
Despite this revision, ERCOT said that ERCOT's prior recommendation in this matter -- i.e., that the Modified Alternative Option be used for the integration -- remains unchanged. As reflected in the revised report, the Modified Alternative Option remains the lowest-cost reliable option for integration of RCEC's load, ERCOT said