Item E-1 | News Release & Fact Sheet

Good morning Chairman Phillips and Commissioners,

Item E-1 is a draft Advance Notice of Proposed Rulemaking, or ANOPR, to consider  potential requirements for transmission providers to use dynamic line ratings to improve the accuracy of transmission line ratings.

Dynamic line ratings, or DLRs, are transmission line ratings that reflect up-to-date forecasts of weather conditions, such as ambient air temperature, wind, and solar heating.  

Today’s draft ANOPR builds on Order No. 881.  In that order, the Commission revised its pro forma Open Access Transmission Tariff and its regulations to improve the accuracy and transparency of transmission line ratings by requiring, among other things, transmission providers to adopt “ambient-adjusted line ratings”, or AARs, that reflect ambient air temperature.

Shortly after issuing Order No. 881, the Commission issued a Notice of Inquiry, or NOI, on DLRs.  In the NOI, the Commission asked questions to further build the record about criteria for potential DLR requirements and the benefits, costs, and challenges of implementing DLRs.

Based on the record in both the Order No. 881 and the NOI proceedings, and on information gathered in subsequent outreach and further research, the draft ANOPR explores potential reforms to further enhance transmission line rating accuracy.  The draft ANOPR preliminarily proposes a framework of DLR reforms that would require transmission line ratings to reflect solar heating based on the sun’s position and solar heating based on forecastable cloud cover.  The proposed framework would also require transmission line ratings to reflect forecasts of wind speed and of wind direction for certain transmission lines in windy and congested areas.  In order to identify candidate transmission lines for a DLR requirement related to wind, the draft ANOPR proposes metrics to measure congestion both in RTO/ISO regions and in non-RTO/ISO regions. 

Overall, the draft ANOPR preliminarily finds that transmission line ratings that incorporate dynamic line ratings – those that better reflect solar heating and, where appropriate, wind conditions – would result in more accurate system transfer capability, thereby resulting in just and reasonable rates. 

The draft ANOPR seeks comment on both the need for a DLR requirement and on the proposed framework of DLR reforms.  Initial comments are due 90 days after publication in the Federal Register, with reply comments due 30 days later.

Thank you, this concludes our presentation.  We are happy to address any questions.

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This page was last updated on June 28, 2024