In November 2016, FERC issued a Notice of Proposed Rulemaking (NOPR) that would require new generating facilities to install and operate equipment that provides primary frequency response service to the grid. Based on some of the comments received on the NOPR, FERC issued a request for supplemental comments.

The reliable operation of the alternating current (AC) North American electric grid depends on maintaining a frequency near 60 Hertz (Hz). Variations from this frequency can occur due to sudden changes in the balance between generation and load on the system and cause instability. Frequency responsive power control equipment can sense changes in system frequency and autonomously adjust a generating facility’s power output.

More background on frequency response service and the NOPR may be found in the November 28, 2016 post on this blog.

FERC requested supplemental comments on two topics. The first topic is whether and when electric storage resources should be required to provide primary frequency response. The NOPR did not propose provisions specific to electric storage resources. Some commenters raised concerns that, by failing to address electric storage resources’ unique technical attributes, the new requirements could pose an unduly discriminatory burden on electric storage resources and even result in adverse impacts on those resources. In light of these concerns, FERC asks a series of detailed questions to obtain additional information regarding:

  • The performance characteristics and limitations of electric storage resources;
  • Possible ramifications of the proposed primary frequency response requirements on electric storage resources; and
  • What changes, if any, are needed to address the issues raised by commenters.

The other topic for supplemental comments is the costs associated with primary frequency response capabilities for small generating facilities. To avoid setting requirements that could be discriminatory or preferential, the NOPR proposed comparable primary frequency response requirements for both new large and small generating facilities. FERC concluded that small generating facilities can install and operate the needed equipment at low cost in a manner comparable to large generating facilities. Some commenters, however, challenged this conclusion and raised concerns that small generating facilities could face disproportionate costs to install primary frequency response capability. Accordingly, FERC requests answers to a series of questions regarding the ability of small generating facilities to comply with the proposed requirements and their potential economic impacts.

Supplemental comments are due September 14, 2017.