On June 27, 2024, FERC issued an advance notice of proposed rulemaking (“ANOPR”) regarding potential reforms to require transmission providers to use dynamic line ratings (“DLRs”) to encourage more accurate and transparent line ratings. The Commission seeks comment on a proposed DLR framework and whether other transmission line rating reforms are needed to ensure just and reasonable and not unduly discriminatory or preferential FERC-jurisdictional rates. Initial and reply comments are due 90 and 120 days after the ANOPR’s publication in the Federal Register, respectively. After the comment period in this proceeding ends, FERC may consider issuing a formal Notice of Proposed Rulemaking, which would be a prerequisite to issuing any final rule.

Put briefly, a transmission line rating represents a transmission line’s maximum transfer capability when “taking into account the technical limitations on conductors, relevant transmission equipment, and the transmission system.” DLRs are “transmission line ratings that reflect up-to-date forecasts of weather conditions, such as ambient air temperature, wind, cloud cover, solar heating, and precipitation, in addition to transmission line conditions such as tension or sag.” In Order No. 881, the Commission adopted requirements to use ambient-adjusted ratings (“AARs”) and various other requirements aimed at encouraging more accurate and transparent line ratings. Following Order No. 881, FERC issued a Notice of Inquiry (“NOI”) in February 2022 asking a series of questions regarding potential DLR requirements, including the costs, benefits, and challenges of their implementation.

Citing the record compiled in the NOI, outreach FERC conducted after issuing the NOI, and improvements in DLR technology, the ANOPR preliminarily finds that transmission line ratings that fail to account for solar heating and wind conditions may result in unjust, unreasonable, unduly discriminatory or preferential rates. The ANOPR therefore considers reforms to require transmission providers to implement various DLR frameworks, including: (i) transmission line ratings that reflect solar heating based on the position of the sun and forecasted cloud coverage; (ii) transmission line ratings that forecasted wind speed and wind direction on certain transmission lines; and (iii) “enhance[ed] data reporting practices to identify candidate transmission lines for the wind requirement in non-RTO/ISO regions.” The ANOPR asserts that these reforms may help ensure transmission line ratings result in just and reasonable rates.

The ANOPR seeks comment on several aspects of its proposed reforms, including, inter alia:

• whether transmission line ratings that fail to reflect solar heating based on the position of the sun and up-to-date forecasted cloud coverage result in unjust and unreasonable wholesale rates;

• whether transmission line ratings that fail to reflect up-to-date forecasted wind conditions on certain transmission lines result in unjust and unreasonable wholesale rates;

• whether transparency reforms are needed to ensure accurate transmission line ratings; and

• the financial and non-financial costs and benefits of the proposed reforms.

Initial comments are due 90 days after the ANOPR’s publication in the Federal Register. Reply comments are due 30 days thereafter.

A copy of the ANOPR, issued in Docket No. RM24-6-000, is available here.