Texas Staff Updates Estimate Of ERCOT Capacity Used For Small Fish Swim Free Rule

Staff of the Public Utility Commission of Texas have filed an updated estimate of installed generation capacity in ERCOT.

The amount of installed generation capacity is a factor in determining (1) the 20 percent limit on installed generation capacity established in PURA § 39.154 and (2) the 5 percent wholesale market power exemption established in P.U.C. Subst. R. 25.504(c).

The new capacity value for the five percent wholesale market power exemption established in 16 Texas Administrative Code (TAC) § 25.504(c) is 79,560 MW (down from 80,423 MW).

The new capacity value for 20% limit on installed generation capacity established in Public Utility Regulatory Act (PURA) § 39.154 is 89,348 MW (up from the 87,857 MW reported in the May 2018 Estimate of Installed Generation Capacity in ERCOT).

These values differ from one another because the five percent market power exemption excludes uncontrollable renewable resources and does not factor in import capability.

Staff noted in its filing the following:

• The capacity credit for wind facilities in the ERCOT Coastal region is now 58% of the nameplate capacity of the facility (decreased from 59% last year). The capacity credit for wind facilities in the ERCOT Non-Coastal region is now 15% of the nameplate capacity of the facility (increased from 14% last year). These changes were made to be consistent with the Summer Peak Average Capacity Contribution Percentages used by ERCOT in the December 2018 Capacity, Demand, and Reserves (CDR) Report.

• The capacity credit for solar facilities is now 74% of the nameplate capacity of the facility (decreased from 75% last year). This is consistent with the Summer Peak Average Capacity Contribution Percentage that ERCOT reported in the December 2018 CDR Report.

• The capacity for switchable generation facilities is reduced in accordance with 16 TAC § 25.401(e)(1)(D), which states that installed generation will include: "...generating facilities that are located on the boundary between two power regions and are able to deliver electricity directly into either power region, except that the capacity of such facility shall be allocated between the power regions based on the share of its total electric energy that the facility sold in each power region during the preceding year."

• The capacity for generating facilities with a nameplate rating of 1 MW or less is removed, consistent with 16 TAC § 25.401(e)(2), which states that, "Installed generation capacity will not include generating facilities that have a nameplate rating equal to or less than 1 megawatt (MW)."

• Any generation facilities that will be permanently retired by the date of the calculation but were not announced prior to the release of the December 2018 CDR Report have had their capacity removed from the calculation.

• The December 2018 ERCOT Generator Interconnection Status (GIS) Report, which provides the information for the New Capacity tab of the spreadsheet, stated that there were generation facilities that had achieved commercial operation since the December 2018 CDR Report was released. The capacity for those facilities was added to the calculation.

• The estimate in the calculations should not be used for purposes of resource adequacy. The definition of installed generation capacity includes capacity not currently available to the ERCOT market but could be potentially marketable, such as mothballed capacity and 'behind-the-fence' capacity.

Project 39870