Texas regulators have remanded back to ERCOT a controversial protocol change attempting to regulate energy storage resources, but not before stripping out language related to state of charge (SOC) and enforcement processes.
The unanimous decision during the Public Utility Commission’s Jan. 18 open meeting is a victory, albeit temporary, for the energy storage sector, which has been battling the proposed change since last summer. As written, nodal protocol revision request (NPRR1186) sets a one-hour SOC for energy storage resources participating in two ancillary services (ERCOT contingency reserve service and non-spinning reserve). It also includes penalties of up to $25,000 per violation. (See “PUC Delays Approval of Rule Change that Penalizes Storage Resources,” Texas Public Utility Commission Briefs: Nov. 30, 2023.)
Storage developers say the new rules hold energy storage resources (ESRs) to higher standards than conventional thermal resources and could result in fines if batteries fall below SOC thresholds and still deliver the power promised.
ERCOT staff filed a report before the meeting trying to address questions raised by the PUC in November. It said with ESR capacity projected to grow from 4.4 GW to more than 20 GW by 2026, the rules are necessary to preserve reliability. The data presented showed similar failure rates for ESRs and for thermal resources involved in the ancillary service markets (54445).
Commissioner Jimmy Glotfelty, who has declared the rule change to be “discriminatory” to energy storage, was not swayed.
“They all fail. Singling out ancillary services providers of battery storage is discriminatory. Gas plants fail. Nuclear plants fail. Coal plants fail,” he said. “That’s why we over-procure ancillary services. I just cannot pass something that puts a compliance penalty on a type of service when the data from ERCOT shows that dispatchable resources fail in the same types of services.”
“It really is a big deal from a liability perspective to make sure that those ancillary services can provide the products that we need for the duration that we need them to,” Dan Woodfin, ERCOT’s vice president of system operations, told the PUC.
Commissioner Lori Cobos said ERCOT should withdraw or table NPRR1209, a directive from the Board of Directors as NPRR1186 ran into trouble. ERCOT staff said Jan. 24 the rule change was tabled in November within the stakeholder process to allow the commission to work out its issues with 1186, which also was a board priority item.
Both measures are seen as stopgaps until ERCOT deploys real-time co-optimization, currently targeted for the latter half of 2026.
The ERCOT board now will take up 1186 and the PUC’s changes for approval before they get sent back to the commission for a final review and vote.
The open meeting took place the day before Thomas Gleeson was appointed as the PUC’s chair. Gleeson was formally sworn in Jan. 23. (See Abbott Names PUC Executive Director as Chair.)
VoLL Study to Begin
The Brattle Group will open a value-of-lost load (VoLL) survey of ERCOT retail customers in March. The results will be reported back to the PUC in August as part of the grid operator’s effort to quantify VoLL (55837).
ERCOT is analyzing the frequency of load shed, but also its magnitude and duration, with an expected unserved energy metric. According to a staff filing, every 1% improvement in a plant’s weatherization reduces the needed for 175 MW of capacity.
The commission also requested comment on DC ties, such as the Southern Spirit line. Glotfelty asked PUC and ERCOT staffs to model the effect of that line had it existed Sept. 6, the last time ERCOT was in emergency operations (55984). (See ERCOT Voltage Drop Leads to EEA Level 2.)
The PUC will discuss the issue in February.
