Stakeholders Approve Protocol Changes for Real-time Co-optimization
AUSTIN, Texas — ERCOT stakeholders endorsed several protocol changes related to the ISO’s real-time co-optimization project, keeping on track a project seen as a cornerstone for future market improvements.
Alluding to the ongoing college basketball tournaments, ERCOT’s Matt Mereness, chair of the Real-time Co-optimization and Battery Task Force (RTC+B), portrayed the protocol changes as “the road to the Final Four.” Their approval sets them up for the Board of Directors’ consideration during its April 7-8 meeting, with the goal of beginning full market trials of the software and systems May 5.
“We’re six weeks out on the first set of [market] trials starting,” Mereness told members of the Technical Advisory Committee (TAC). “Today’s approval sets the stage for more approvals and people so that we can develop the code and parameters to dial those in for our market trials. That’s the gist of it.”
The key nodal protocol revision request (NPRR1269) determines and codifies policy changes that were deferred from the original RTC-related protocols developed after the project’s inception in 2019: ramping scaling factor values, ancillary service (AS) proxy offer floor parameters, and ancillary service demand curves’ (ASDC) use in reliability unit commitment (RUC) studies.
Two other NPRRs were placed on TAC’s combination ballot, essentially a consent agenda. NPRR1268 makes changes to the ASDC as modified by the Independent Market Monitor. NPRR1270 clarifies the removal of automatic ancillary service qualification and adds details for qualifying resources that provide the services in real time.
Much of the debate during the stakeholder process centered on the proxy offer floors. ERCOT initially proposed a $0 offer floor, which was supported by the IMM, but the RTC task force pushed for a $2,000 floor. A compromise eventually was reached on the minimum of a $2,000 floor or 95% of the ASDC.
The demand curves’ use in RUC studies was another “evolving discussion,” as Mereness put it, in determining the appropriate price signals within the study tool to drive efficient commitments. The Protocol Revision Subcommittee sent NPRR1269 to TAC with its approval of the ASDC compromise, a $15 RUC ASDC floor, and a $15 floor for real-time and day-ahead market ASDCs.
TAC approved NPRR1269 22-7 with one abstention. All six members of the consumer segment opposed the measure. They were joined by AP Gas & Electric, an independent retailer in Houston. In filed comments, the consumer interests asked the ERCOT board to “exercise judicious restraint before considering” the policy change.
“There is no real harm to waiting for [RTC] to be implemented before making such a fundamental shift in its design,” they wrote. “Frankly, consumers would prefer a future where ERCOT had to justify a RUC decision in a situation like this instead of a permanent structural change in the market to avoid the possibility of hypothetical RUCs.”
“Our concern is with the underlying approach. As to why you would institute a floor without evidence that it will resolve something, we would just generally be uncomfortable with unnecessarily intervening in market outcomes,” Eric Goff said during the TAC discussion. “You have to acknowledge that this is an administratively determined curve. In general, it’s appropriate for a curve to be able to indicate a lack of value, that something is demanded. That’s kind of one of the fundamental approaches that we see to the extent that the point of this is to alleviate some potential for RUCs.”
The IMM warned that the proposed ASDC floor for the day-ahead and real-time markets could result in more than $100 million in excess costs to consumers, saying the proposal is not supported by “economic fundamentals or empirical evidence.”
It said the proxy offer floor compromise “does not reflect a competitive offer and exposes consumers to unnecessary and excessive costs,” calling for an offer cap of no more than $15. The IMM also said the ASDC floor for RUC is not necessary for the commitment process to function properly when RTC goes live in December.
Large Load Task Force to Remove ‘Flexible’
The Large Flexible Load Task Force plans to return to TAC’s April 23 meeting with charter changes that rename the group by removing “flexible” from its title.
“We could never actually define flexible when the crypto miners, where this all started, came in,” explained the task force’s vice chair, Longhorn Power’s Bob Wittmeyer. “They said that they were flexible. By that, they meant they were flexible within settlement intervals. ERCOT interpreted that to mean within milliseconds, and there was some disconnect between those two things.”
The task force’s members also proposed the group be reclassified as a working group reporting to TAC, with a sub-group focused on data centers. TAC’s leadership was open to the suggestion.
“Task forces exist when the problem is envisioned to be short term and be solvable and go away,” Wittmeyer said. “Large loads certainly appear to be here to stay, and there are operational issues with city-size loads doing things. Anytime you have a city-size load, that can all react roughly at the same time, that’s a cause for concern.”
Staff told TAC that the large-load interconnection queue contains just over 99 GW in primarily standalone projects. ERCOT says it can confirm 4,616 MW have been energized.
Market Design Discussion Postponed
A scheduled discussion on a proposed new market design framework was put off until April’s TAC meeting because of March’s “weighty agenda,” said ERCOT’s Keith Collins, vice president of commercial markets.
CEO Pablo Vegas presented the framework to the board in 2024, saying the grid operator needs a structure that allows it to evaluate changes to the market design, relative to the attributes needed to reliably operate the grid. Staff presented the framework to TAC in October and received comments from stakeholders related to resource adequacy, initiative measurement and the structure’s alignment.
The framework’s pillars, as developed by staff, are to position ERCOT as an industry leader for reliability and resilience and to strengthen the footprint’s economic competitiveness. The grid operator says that while reliability is the organization’s primary objective, “costs should always be considered” as it seeks “market outcomes and solutions that result in the most competitive wholesale power rates and retail prices without compromising reliability or resilience.”
Large Load Modeling Requirements
The committee had to endorse NPRR1234 and its associated Planning Guide revision (PGRR115) twice when a desktop edit to the PGRR inadvertently created an unachievable compliance deadline, based on the measure’s anticipated approval date. Staff then conducted a triage of the NPRR to push the compliance dates out by two months.
The two changes establish interconnection and modeling requirements for large loads, defined as one or more facilities at a single site with an aggregate peak power demand of 75 MW or more. TAC unanimously endorsed both measures. Three members of the consumer and independent generator segments abstained from the PGRR.
The committee approved the combination ballot that included four NPRRs, one PGRR, a system change request (SCR) and revisions to the Nodal Operating (NOGRR) and Settlement Metering Operating Guides (SMOGRR) that, with board approval, will:
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- NPRR1256: Changes language in adjustment period and real-time operations protocols related to must-run alternatives (MRAs), primarily in grey-boxed language from NPRR885 (Must-Run Alternative Details and Revisions Resulting from PUCT Project No. 46369, Rulemaking Relating to Reliability Must-Run Service) to align the terminology for energy storage resources (ESRs) in the single-model era. It also specifies how qualified scheduling entities representing ESR MRAs would be settled for providing MRA service.
- NPRR1268: Define the methodology for disaggregating the operating reserve demand curve into blended ancillary service demand curves.
- NPRR1270: Update requirements for load resources that are changing under RTC and were not updated in earlier revisions; remove language associated with group assignments in the day-ahead market; eliminate the automatic qualification of all resources to provide on-line non-spinning reserve and SCED-dispatchable ERCOT contingency reserve service, among other changes. Resources will be required to undergo a qualification test to provide each of these services.
- NPRR1273: Modify ESRs’ capacity to the amount sustained for 45 minutes included in the physical responsive capability’s calculation.
- NOGRR274: Conforms the guide to NPRR1217’s (Remove Verbal Dispatch Instruction Requirement for Deployment and Recall of Load Resources and Emergency Response Service Resources) protocol changes.
- PGRR119: Codify that a reliability margin will be used when limits associated with a stability constraint are modeled in the Regional Transmission Plan’s reliability and economic base cases.
- SCR829: Add an application programming interface to upload and download unit testing data from the net dependable capability and reactive capability application.
- SMOGRR028: Give guidance for allowing loss compensation for current limiting reactors.