ERCOT Technical Advisory Committee Briefs

Dispatch Changes won’t be Pursued

Mar 28, 2017

The ERCOT TAC declined to pursue a change in how the ISO commits and dispatches resources, and discussed principles for restarting the markets after outages.

AUSTIN, Texas — The ERCOT Technical Advisory Committee agreed last week not to pursue a change in how ISO operators commit and dispatch resources, agreeing with a Wholesale Market Subcommittee study that the software changes required would not produce sufficient production cost savings.

The TAC then asked the subcommittee to begin working on real-time co-optimization of reserves.

The ISO developed an in-house software platform to perform multi-interval real-time market (MIRTM) simulations for selected operating days from 2015 and 2016. The study found MIRTM is feasible for both fast-responding generation resources and load resources with temporal constraints. But the feasibility study concluded that “the estimated cost[s] are in excess of the measured benefits and therefore insufficient to support [moving] forward with MIRTM at this time.”

ERCOT’s real-time market dispatches and prices energy in single five-minute intervals and does not consider potential changes in system conditions more than five minutes into the future. As a result, it is unable to coordinate the commitment of combustion turbines and demand response resources that are available within 10 to 30 minutes but unable to respond within five minutes.

The study was ordered to determine whether the ISO could improve the efficiency of its short-term commitment decisions by analyzing multiple consecutive five-minute intervals to determine the most economical commitment and dispatch.

ERCOT will share the study with the Board of Directors during its April 4 meeting. If approved, the study will be filed with the Public Utility Commission of Texas.

public utility commission of texas ERCOT Technical Advisory Committee — March TAC Meeting underway | © *RTO Insider*

The WMS now finds itself freed up to take on real-time co-optimization, which shifts the responsibility for providing reserve services to online generation resources with the lowest incremental energy cost. Co-optimization has been the subject of discussion at the PUC, most recently during its last open meeting. (See Texas PUC Wary of Using ERS to Avoid Local Blackouts.)

“We’ve been waiting for [MIRTM] to clear the decks, and the decks have been cleared,” Morgan Stanley’s Clayton Greer said.

“We have an obligation at this point to explore this,” Citigroup’s Eric Goff said. “[The PUC] has given various hints that they’d like additional information. As a stakeholder body, I believe we have the obligation to make those hints and wishes reality.”

TAC Vice Chair Bob Helton, of Dynegy, agreed. With members raising concern over ERCOT’s estimate of $20 million for software changes, he directed the WMS to define a study scope and what components of co-optimization should be analyzed.

Staff Shares Draft Principles for Market Continuity

ERCOT staff shared with the TAC a draft of principles to address the ISO’s lack of guidelines on restarting its markets following outages. The principles do not change existing black start procedures.

Staff raised the issue last year with the board and conducted a workshop in May to frame the discussion around gaps in the processes.

The principles include:

Prioritizing the real-time market’s restart before other markets or activities;
Starting congestion revenue rights auctions and other functions only after the real-time and day-ahead markets are restored;
Expecting limited settlements functionality during market restoration;
Payments being made in “as timely a manner as possible;”
Relaxing credit requirements and releasing cash or other collateral to provide short-term liquidity to market participants;
Seeking emergency funding to pay resources before other alternatives are considered; and
Uplifting market restart costs on a load-ratio share basis after market recovery.

ERCOT staff is expected to build on the principles with more formal procedures.

“This is a good start. ERCOT didn’t have transparent principles before,” Direct Energy’s Read Comstock said.

Committee Approves 16 Revision Requests

The TAC also approved nine other NPRRs, three revisions to the Planning Guide (PGRRs), two revisions to the Load Profiling Guide (LPGRRs) and revisions to the Retail Market Guide (RMGRR) and Nodal Operating Guide (NOGRR).

NPRR776: Aligns protocol language with currently used verbal communication practices between transmission service providers (TSPs), qualified scheduling entities (QSEs) and generation resources. Also identifies new requirements for data TSPs provide to ERCOT, QSEs and the generators. The committee tabled NOGRR167, which aligns the Nodal Operating Guide with NPRR776.
NPRR799: Requires that TSPs and resource entities — generation and load that can reduce electricity usage or provide ancillary services — submit updates to the outage scheduler within one hour of the facility’s outage start or completion.
NPRR802: Clarifies current settlement practices and protocol language, including how reliability unit commitment resources opting out of settlement are treated in calculating real-time online reserve capacity.
NPRR804: Clarifies that ERCOT should post both a systemwide network model and a set of station one-line diagrams, and that the model posting does not disclose data about private-use networks.
NPRR808: Extends the CRR auction process into the third year forward, revises the percentages sold in the auction’s long-term sequence and aligns modifying load zones to the timetable.
NPRR809: Defines the terms “initial energization” and “initial synchronization;” adds a reference to a quarterly stability assessment for interconnecting generation resources when evaluating the need for a generic transmission constraint; and clarifies a resource’s requirements prior to initial synchronization.
NPRR810: Removes the applicability of a reliability-must-run agreement’s incentive factor to reservation and transportation costs associated with firm fuel supplies, and accordingly separates costs in the RMR standby payment equation.
NPRR812: Clarifies short-term system adequacy report language; aligns protocol language with current ERCOT practices and Public Utility Commission of Texas rules for posting resource and load information; and modifies the requirement for posting a RUC initial-conditions report to only include the process as originally intended in NPRR314.
NPRR813: Requires references to service organization controls for the annual ERCOT market settlement audits.
NOGRR166: Eliminates a redundant report of daily operational information that can be found elsewhere on the Market Information System.
PGRR052: Ensures a new generating unit’s operating limits are established by setting a timeline for stability studies following a full interconnection study (FIS), incorporating model data or transmission system changes, not known during the FIS, before a new unit is brought online.
PGRR054: Clarifies the content, review period and process for posting an FIS’ results, and establishes a process for identifying, proposing and implementing solutions to stability issues identified during the FIS.
PGRR055: Defines the process for revising the Planning Guide to first consider PGRRs at the subcommittee level.
RMGRR144: Eliminates the requirement for transmission and/or distribution service providers to maintain a secure list of retail electric provider data numbering systems for all electric service identifiers (ESI IDs) with “switch-holds” — measures to prevent customers with unpaid bills from changing retail electricity providers.
LPGRR060: Provides additional clarification to the load-profiling guide by removing “orphaned language” not captured in LPGRR057, which was approved by the TAC in October.
LPGRR061: Modifies the annual validation timelines for residential and business ESI IDs by starting the validation activities on March 30 and concluding them on Sept. 30 of each calendar year.