FERC last week approved SPP’s request to issue price corrections and resettlements for a two-week period in December 2016, stemming from Omaha Public Power District’s retirement of its Fort Calhoun nuclear plant (ER17-2495).

After OPPD deregistered Fort Calhoun from SPP’s Integrated Marketplace on Dec. 1, 2016, the RTO established a replacement settlement location to recognize previously awarded transmission congestion rights (TCRs) at the plant. However, the market software did not model the replacement location’s correct shift factors, resulting in an overstated marginal congestion component and understated TCRs. The error was not corrected until Dec. 14.

In a September 2017 filing with FERC, SPP said the error did not affect other settlement locations. It requested commission approval for the repricing because it did not notify market participants of the contemplated price correction within five calendar days of the operating day, as required by its Tariff.

SPP told FERC the modeling errors were associated with the Fort Calhoun deregistration and were “human performance anomalies that have since been corrected.” The RTO said it can recalculate the prices “with accuracy,” ensuring that market participants that “unfairly suffered” from the error will be made whole and creating only a “minor monetary impact” for other participants.

The resettlements will amount to $145,000 in net payments to TCR holders at the location, and a net charge of $400 to the virtual transactions.

— Tom Kleckner