Commissioner James Danly Statement
September 22, 2023
Docket No. ER22-2341-000

I dissent in part from today’s issuance[1] to the extent that it concludes that Alabama Power Company, Georgia Power Company, and Mississippi Power Company (collectively, Southern Companies) would not be in compliance with the requirements of Order No. 881[2] if they implement ambient-adjusted ratings (AARs) that use the same solar heating assumptions (i.e., the same zero value) for both daytime and nighttime AARs.[3]  I agree Order No. 881 requires separate values for daytime and nighttime periods.[4]  What Order No. 881 does not say is that such values must be different.  It simply requires that the nighttime period value be zero.  This is to prevent “the worst-case solar heating assumptions in every hour, even at night when there is no solar heating of transmission lines at all.”[5]  The majority correctly notes that Order No. 881 does not specify what the solar heating assumptions must be for daytime AARs.[6] 

Southern Companies explain they do not include solar heating in their nighttime AAR calculations (i.e., they use a zero value), as required by Order No. 881 explicitly.[7]  Likewise, they explain they do not include solar heating in their daytime AAR calculations (i.e., also a zero value), consistent with their vendor specifications which do not require solar heating.[8]  Southern Companies further aver that having a different solar heating value in their daytime AARs would result in a significant reduction in the amount of transmission capacity available on their system, thereby increasing costs and reducing system flexibility.[9]  Telling Southern Companies they could make additional revisions to their transmission line rating methods is hardly required by Order No. 881, given Southern Companies’ explanation that neither their historic operations, nor success using a zero value consistent with vendor specifications, counsels for making a change.[10]  Why break something that is fixed, especially when Order No. 881 does not, by its plain terms, require a particular or different value for daytime periods?

For these reasons, I respectfully dissent in part.




[1] Ala. Power Co., 184 FERC ¶ 61,173 (2023).

[2] Managing Transmission Line Ratings, 177 FERC ¶ 61,179 (2021) (Order No. 881), order on reh’g & clarification, 179 FERC ¶ 61,125 (2022) (Order No. 881-A).

[3] See Ala. Power Co., 184 FERC ¶ 61,173 at P 18.

[4] See Order No. 881, 177 FERC ¶ 61,179 at P 147.

[5] Id.

[6] Ala. Power Co., 184 FERC ¶ 61,173 at P 19 (citation omitted).

[7] See id. P 16 (citing Filing, Transmittal Letter at 4).

[8] Id.

[9] Id.

[10] See id. P 19.

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