Last week, the Federal Energy Regulatory Commission issued a Notice of Inquiry (NOI) seeking comment on the need for reforms regarding the provision of and compensation for primary frequency response. The NOI notes that fewer generation resources may currently be providing primary frequency response than in the past. The Commission expects this trend to continue as more Variable Energy Resources (VER), such as solar or wind generators, are integrated into the nation’s electric grid. As the Commission explained, the NOI is necessary due to the significance of primary frequency response to the reliable operation of the electric grid.
Reliable electric operations require balance between generation and load so that frequency remains within predetermined boundaries (around 60 HZ in the US). System contingencies occasionally cause frequency to deviate from those boundaries and potentially cause load shedding, additional generation tripping, or cascading outages. Some (although not all) generators deploy frequency control actions including primary frequency response to arrest and stabilize frequency deviations during disturbances. Frequency response is a measure of the ability to arrest and stabilize frequency deviations following the sudden loss of generation or load, and is affected by the collective responses of generation and load resources throughout an Interconnection. Primary frequency response is the first stage of overall frequency control and begins within seconds after the frequency changes.
The NOI points out that NERC issued an Industry Advisory in February, 2015, in which it determined that “a significant portion of generators within the Eastern Interconnection” do not fully provide primary frequency response. As a result of the evolution of the nation’s generation resource mix, as well as NERC’s concerns, FERC is taking “a proactive approach to better understand the issues related to primary frequency response performance and determine what additional actions . . . may be appropriate.”
The NOI states that the Commission is seeking comment on the need for amendments to the pro forma Interconnection Agreements for Large Generators and for Small Generators (LGIA and SGIA, respectively) to require all new generation resources to have frequency response capabilities as a precondition of interconnection. The Commission is also seeking comment on the performance of existing resources and whether primary frequency response requirements for these resources are warranted. The NOI also seeks input on the requirement to provide and compensate for primary frequency response.
In an effort to flesh out its look at the issues related to primary response, the Commission identified a number of particular questions that relate to these three topics. Some of the specific questions raised by the Commission are noted below.
Modifications to the pro forma LGIA and SGIA
The Commission is looking at whether the pro forma LGIA and SGIA should be revised to require newly interconnecting generating resources to meet specific requirements that would enable them to provide primary frequency response. In considering this question, the Commission is looking at a number of related questions, including:
- The costs associated with making a newly interconnecting generation resource capable of providing primary frequency response (e.g., what equipment or software is needed to provide primary frequency response, and what is the cost associated with that equipment or software);
- Whether the governor control settings recommended by NERC’s Primary Frequency Control Guideline are the appropriate settings to include in the pro forma LGIA and SGIA; and
- Whether physical, technical, or operational limitations to promptly providing sustained primary frequency response need to be accounted for in any new frequency response requirements.
New Primary Frequency Response Requirements for Existing Resources
The Commission is specifically looking at whether to implement primary frequency response requirements for existing generation resources. The NOI seeks comments on the appropriate means of doing so, and how transmission providers would be able to ensure that existing resources adhere to new primary frequency response requirements. Some existing generating units set frequency control dead bands wider than those recommended by NERC’s Primary Frequency Control Guideline, and some units have control settings set in a manner that result in the premature withdrawal of primary frequency response. The Commission is interested in whether these practices should be proscribed and how any restriction should be imposed. The Commission is also interested in cost issues, including costs of retrofitting existing units and specific equipment types that would be capable of providing sustained primary frequency response. As with new resources, the Commission is looking at whether there are physical, technical, or operational limitations or concerns to promptly providing sustained primary frequency response in the direction necessary to counteract under-frequency and over-frequency deviations.
Requirement to Provide Compensation for Primary Frequency Response Service
The Commission is looking for comment as to:
- Whether all resources should be required to provide minimum levels of primary frequency response capability and primary frequency response performance in real-time;
- Whether it is necessary for every generating resource to install the capability necessary to provide primary frequency response, or whether balancing authorities can identify and procure the amount of primary frequency response service that they need to ensure reliability;
- Whether compensation for primary frequency response should relate to capability, performance, or both;
- How RTOs/ISOs ensure that they have the appropriate amount of primary frequency response capability during operations;
- Whether there would be benefits to treating Frequency Response Service as a separate ancillary service; and
- Procurement requirements or compensation mechanisms that could be used for primary frequency response from stored energy resources.
Comments are due on April 25, 2016.