Texas REPs, Industrials: Calculation in ERCOT 4CP Report Created "False" Peak Interval

A group of commenters including several NRG retail providers, Texas Industrial Energy Consumers, Austin Energy, and CPS Energy said in comments to the Public Utility Commission of Texas that a calculation in the ERCOT 4CP report created a "false" peak interval on July 14, 2016

The joint commenters said that, in the 2016 4CP Report, ERCOT noted that the East DC Tie tripped offline at 15:50 on July 14, 2016 reducing actual imports by approximately 581 MW. Additional generation was deployed to replace this lost capacity. The joint commenters said that, as detailed in ERCOT's report, the ERCOT settlement system is designed to sum both "total generation and total scheduled DC tie imports."

The joint commenters said that they recognize that ERCOT followed applicable Nodal Protocols and Commission Rules in generating the 2016 4CP Report

However, the joint commenters noted that, as a result, for purposes of settlement of the market during the East DC Tie outage, ERCOT calculated peak demand by counting both: (1) the scheduled imports over the DC Tie (not actual), and (2) replacement generation deployed during the outage.

"This resulted in the 581 MW of lost import capacity being counted twice in the calculation of demand, which effectively created a false peak interval for that day," the joint commenters said

"Specifically, the lost import capacity was double-counted during the Interval Ending (IE) 16:00 on July 14th, so that the calculated system-wide demand during IE 16:00 appears in the Report to be higher than the actual demand during that interval," the joint commenters said

The joint commenters said ERCOT has explained that, if the DC Tie schedules (e-Tags) had been adjusted to reflect the outage during IE 16:00, then the peak interval for the month of July would have been IE 16:30 instead.

"The Joint Commenters request that for the purposes of establishing the 2017 transmission service rates the 4CP data be corrected to eliminate this 581 MW double-counting issue. This change will result in a more accurate report that reflects the true peak interval of demand for July 2016," the joint commenters said

While noting ERCOT followed protocols and PUCT rules in generating the 4CP report, the joint commenters said that, "the July 14th data has revealed an anomaly in the Settlement procedures that, inarguably, double-counts load in determining the system-wide peak based on Settlement procedures that were not necessarily designed for the purpose of establishing transmission service rates. Using scheduled e-Tag amounts may be appropriate for many Settlement procedures, but in this instance it has identified a false peak that does dot represent the actual interval with the highest system-wide demand in July, which is the relevant value needed to implement the transmission rate design calculations established by Commission rules."

"Based on conversations with ERCOT, the Joint Commenters understand that ERCOT intends to propose protocol changes to address this issue prospectively," the joint commenters said

"Joint Commenters seek only the revision of the 2016 4CP Report to support accurate setting of transmission rates and are not seeking any financial resettlement of the market by ERCOT for July 14," the joint commenters said

Docket 46604