According to comments filed on August 26 with the Federal Energy Regulatory Commission (FERC) by the American Public Power Association (APPA), the Edison Electric Institute, the National Rural Electric Cooperative Association, the Large Public Power Council, and the Transmission Access Policy Study Group, the North American Electric Reliability Corp. (NERC) must be given flexibility for any revisions made to an existing reliability standard to address reliability concerns related to transmission system planning for extreme heat and cold weather events impacting the reliable operations of the bulk electric system.

The group’s comments were filed in response to a pending FERC notice of proposed rulemaking (NOPR) proposing to direct NERC to revise mandatory reliability standard TPL-001-5.1 (Transmission System Planning Performance Requirements) to address reliability concerns related to transmission planning for extreme heat and cold weather events.

According to the groups, while they support addressing the planning for extreme heat and cold weather events in NERC reliability standards, “the variation in extreme weather events between regions and the highly varied system topologies of registered entities call for the Commission to vest NERC and the standard drafting team with flexibility in determining how to address the issues identified by the Commission, including potential corrective actions.”

The groups noted that they share FERC’s desire to better address and respond to extreme heat and cold weather events, and they also support efforts to improve system planning specifically for these extreme heat and cold weather events. However, the groups noted, “The manner and process required to achieve these goals is complex, requiring flexibility and multiple tools, if this effort is to be fully effective.”

The groups noted that the purpose of the TPL standard is to establish transmission system planning performance requirements over a broad spectrum of system conditions, including extreme events, based upon operating experience that may result in wide-area disturbances and following a wide range of probable contingencies. “Including extreme heat and cold weather as described by the Commission potentially could require adding numerous elements and specifics to a planning analysis,” said the group members in their comments to FERC.

Because of the wide set of issues and corresponding circumstances that a new or modified standard must entail, the groups recommended that FERC “defer to the technical competence of the subject matter experts on a standard drafting team in order to develop a risk-based approach to the myriad issues raised in the NOPR.”

The groups also said that addressing challenges to electric system reliability posed by extreme heat and cold weather should be informed by the highly varied nature of risks and potential consequences to the electric system posed by these events. “Different parts of the country face different risks, in terms of both type and severity of weather events,” said the groups. “The risks faced by, and appropriate measures for, an entity in Florida may look very different from those of an entity in Texas, Wisconsin, or California; the risks may, moreover, change over time.”

Entities also vary in terms of the scope of their facilities. For example, some NERC-registered transmission owners own only one or two bulk electric system transmission lines, while others own extensive transmission systems covering a wide range of varying topography. “The flexible approach proposed by the NOPR is thus imperative to help ensure that threats are assessed accurately and that selected corrective actions are suited to the region, system topography, and affected entities,” said the APPA in a press release.

The groups suggested to FERC that the standard drafting team “should determine the best possible approach for addressing a continent-wide extreme heat and cold weather planning standard that accounts for geographic, system topology, and other variations, as well as the best approach to accommodating such variations or determining if regional variances are necessary.”