The Federal Energy Regulatory Commission on Feb. 15 revised its regulations for the provision of primary frequency response, which FERC said is an essential service in ensuring the reliability and resilience of the North American bulk power system.
At its monthly open meeting, the commission approved a final rule that reforms the Commission’s rules and regulations and adopts requirements to ensure that interconnecting generating facilities are capable of providing primary frequency response.
Primary frequency response is the initial action that arrests abnormal frequency deviations. Primary Response comes from generator governor response, load response (motors) and other devices that provide immediate response based on local (device- level) control. Further frequency response beyond the initial primary response is not included in the rule.
Notice of inquiry
In February 2016, the Commission issued a notice of inquiry on the need for reforms to FERC’s regulations related to primary frequency response.
In November of that year, the Commission issued a Notice of Proposed Rulemaking, or NOPR, that proposed revisions to FERC’s standard, or “pro forma” large and small generator interconnection agreements.
“These revisions were designed to address the potential reliability impact of the evolving generation resource mix, and to ensure that the relevant provisions of the pro forma interconnection agreements are just, reasonable, and not unduly discriminatory,” said Jomo Richardson of FERC’s Office of Electric Reliability, in a presentation at the meeting.
In the NOI, the Commission “explained that in recent years, the nation’s electric supply portfolio has transformed to a point where fewer resources may now be providing primary frequency response than when the Commission considered this issue in other relevant proceedings,” Richardson said.
“In addition to the concerns associated with the nature and operational characteristics of the evolving resource mix is the uncertainty of whether a resource configured to provide primary frequency response is willing and able to offer such a service when called upon to do so,” he said. “While almost all existing synchronous resources and some non-synchronous resources have governors or equivalent control equipment capable of providing primary frequency response, generator owners and operators can independently decide whether generating units provide primary frequency response.”
Association filed comments
In response to the NOI, the American Public Power Association was joined by the Large Public Power Council and the Transmission Access Policy Study Group in filing comments.
“The NOI rightly puts the spotlight on the growing concern that the changing generation mix is both increasing the need for, and reducing the capability to provide, primary frequency response,” the Association, the LPPC and TAPS said in their April 2016 comments.
Among other things, the groups said at the time that it would be appropriate to begin a rulemaking process to modify the pro forma Large Generator Interconnection Agreement and Small Generator Interconnection Agreement to require all new generators interconnecting under those agreements, including non-synchronous generators, to install primary frequency capability.
At the same time, they said it would be inappropriate “to impose significant new obligations on existing generators at this time. Requiring existing generators to retrofit equipment to provide primary frequency response capability could be very costly. While we recognize that the changing generation mix may create future frequency response challenges, there does not appear to be any evidence that such a burdensome and costly change to the frequency response obligations of existing generators is now needed,” the Association, LPPC and TAPS said.
Final rule adopts core proposals in NOPR
The final rule approved by FERC adopts the core proposals of the NOPR by amending the pro forma large and small generator interconnection agreements to require newly interconnecting generating facilities, both synchronous and non-synchronous, to install, maintain, and operate equipment capable of providing primary frequency response as a condition of interconnection to the transmission grid.
In addition, the final rule establishes certain minimum, uniform operating requirements in the pro forma large and small generator interconnection agreements.
The reforms in the final rule address the Commission’s concerns related to the decline of interconnection frequency response as well as concerns that the frequency response provisions in the existing pro forma large generator interconnection agreement are too limited because they apply only to synchronous generating facilities, Richardson noted in his presentation.
“The reforms also account for recent technological advancements enabling new non-synchronous generating facilities to have primary frequency response capabilities. Further, the reforms adopted here address potentially unduly discriminatory and preferential impacts by revising both the pro forma large and small generator interconnection agreements to impose comparable requirements on both new large and small generating facilities,” he said.
The requirements will apply to newly interconnecting generating facilities that execute, or request the unexecuted filing of a large or small generator interconnection agreement on or after the effective date of the final rule, which FERC said would be 70 days after the final rule is published in the Federal Register.
While generally excluded from the requirements of the final rule, existing generating facilities will become subject to the new requirements by taking any action that requires the submission of a new interconnection request that results in the filing of an executed or unexecuted interconnection agreement on or after the effective date.
Final rule addresses unique characteristics of storage resources
The final rule also “addresses the unique physical and operational characteristics of electric storage resources by requiring transmission providers to include in their pro forma large and small generator interconnection agreements specific accommodations and limitations on when electric storage resources will be required to provide primary frequency response,” Richardson said.
In particular, newly interconnecting electric storage resources will be required to specify an operating range representing the minimum and maximum state of charge over which the resource will provide primary frequency response.
The commission is not imposing a headroom requirement, nor is it mandating compensation for compliance with the requirements of the final rule.
The final rule does not apply to a subset of combined heat and power facilities and also exempts generating facilities regulated by the Nuclear Regulatory Commission.
FERC chairman asks about grid resilience
FERC Chairman Kevin McIntyre said he believes the order will encourage the provision of an essential service that will help support the reliability and resilience of the country’s bulk power system “in the face of an evolving generation resource mix.”
At the meeting, McIntyre asked FERC staff to comment on how the final rule on primary frequency response could be a contributor toward the strengthening and fostering of resilience on the grid.
Richardson said the reforms in the final rule “address the commission’s concerns regarding the reliability impact of the decline of interconnection frequency response, as well as changes in the generation resource mix by requiring newly interconnecting generating facilities to have primary frequency response capability.”
Richardson said the requirements in the final rule will contribute to the reliability and resilience of the bulk power system by helping to ensure that each interconnection can stabilize frequency deviations following an unexpected loss of generation or load.
“The ability to stabilize these deviations will help to minimize the impact of the loss of generation or load and rapidly return system frequency to an acceptable state,” he said.
FERC Commissioner Cheryl LaFleur noted that in her recent separate statement on the Department of Energy resilience proposal, she observed that the Commission should work to sustain the reliability and resilience of the grid while adapting to the changing resource mix “and the grid of the future and I think that’s exactly what today’s final rule is about.”
She said that changes in the nation’s resource mix, particularly the lower percentage of synchronous generation, “have contributed to declining frequency response performance in both the Eastern and the Western interconnection.”
LaFleur said she supports the decision in the rule not to require compensation “right now – not to require the markets to price this – and also not to direct a mandatory reliability standard on this at this time as there already is in the Texas interconnection.”
LaFleur also said she thinks “we should monitor the impact of today’s rule and monitor frequency response performance going forward and consider additional actions – whether it’s market pricing of frequency response or additional reliability actions, if and as appropriate, as we move forward.”
