The New York Public Service Commission on Tuesday petitioned a federal court again to reconsider FERC’s approval of NYISO’s proposed change to the timeline for demand curves in its installed capacity market auctions (ER21-502).

This is the third time the PSC has asked the D.C. Circuit Court of Appeals to rule on NYISO’s proposal to implement a 17-year amortization period when calculating the net annual cost of a hypothetical peaking power plant in its capacity markets and comes after FERC declined the PSC’s request for a rehearing on Monday. (See NYPSC Seeks FERC Rehearing on NYISO’s 17-Year Amortization.)

NYISO is mandated to update the assumed operational lifetime of a hypothetical fossil fuel plant in its capacity market auctions every four years, but, in response to aggressive state climate and energy legislation, the ISO proposed reducing that assumed lifetime from 20 to 17 years.

The ISO argued the 2019 Climate Leadership and Community Protection Act imposes such strict net-zero standards for fossil fuel plants that their operational use would be dramatically reduced; however, the PSC contended the adjustment to a shorter period hurts New York ratepayers and is speculative.

The PSC reiterated previous arguments when requesting the court review FERC’s decisions and its denial for a rehearing, including that a 17-year period could cost consumers $400 million, claiming FERC should have waited to rule until addressing other pending rehearing requests related to NYISO’s compliance and asserting that FERC’s decision departs from precedent.

The petition also cites a dissent submitted by Commissioner Mark Christie, who expressed concerns about the May approval of the 17-year timeframe, which reversed previous rejections by FERC. Christie opted to not elaborate, citing pending rehearing requests related to that approval order.

Despite the legal wrangling, NYISO already has implemented the 17-year amortization period as part of its demand curve reset.