FERC on Thursday denied a rehearing request by the Electric Power Supply Association (EPSA) and New England Power Generators Association (NEPGA) on a pair of commission orders issued this spring related to the recalculated cost of new entry (CONE), net CONE and performance payment rate (PPR) values used in ISO-NE’s Forward Capacity Market (FCM) (ER21-787-003).

The commission reaffirmed that ISO-NE’s proposed definition of net CONE did not violate the RTO’s tariff or the filed-rate doctrine. FERC added that it continues to find that ISO-NE estimated the values at issue in a manner consistent with tariff requirements, using “just and reasonable” inputs and methodologies.

“ISO-NE is entitled to file revised methodologies, which may include the use of updated definitions, at any time in advance of the FCA [Forward Capacity Auction],” the commission wrote. “This approach is supported by the language of the tariff, which establishes the relevant temporal limitation on the filing of new net CONE values.”

The ISO-NE tariff requires the RTO to file new values with FERC before the FCA in which they are to apply.

According to the commission, EPSA and NEPGA’s argument that the filed-rate doctrine bars the calculation and filing of new values until after a revised tariff definition takes effect “does not reasonably reflect either the authority provided to ISO-NE by the tariff or an appropriate application of the filed-rate doctrine.”

“The tariff and filed-rate doctrine do not require that the methodology underlying the calculation of net CONE be anything other than the approved methodology on file at the time the net CONE values are implemented,” FERC wrote.

Additionally, FERC said EPSA and NEPGA’s claim that the commission was departing from precedent was made “without adequate explanation.”

FERC said the situation is “analogous” to a Dec. 15, 2009, filing in which ISO-NE proposed updated values for the installed capacity requirement (ICR) for use in the final FCM configuration auction held in March 2010. That filing also included proposed amendments to the ICR methodology, which were used to derive the updated values. The commission accepted the updated values and the tariff amendments effective Feb. 15, 2010.

“Similarly, here ISO-NE used the proposed definition of net CONE to calculate its updated net CONE values for the upcoming FCA, which is allowed by the tariff,” FERC wrote. “Accordingly, we continue to find here that the commission appropriately determined that ISO-NE was entitled to base its recalculations on the definition it ‘intended to file and have in effect in advance of that FCA.’”