FERC last week approved SPP’s request to correct and resettle $13.1 million of transmission-service invoices dating back to 2009, waiving a one-year limit in the RTO’s Tariff. “The requested waiver is a one-time request related to [discrete] software issues, which SPP has resolved,” FERC said (ER15-2295).

Approximately $4.4 million of resettlements outside the one-year limitation date back to 2012, when SPP told FERC a transmission customer’s inquiry led to the discovery of miscalculations of transmission losses and reactive compensation across DC ties with ERCOT and the Western Area Power Administration. The RTO said the software error affected invoices between January 2009 and May 2013.

–Tom Kleckner