The D.C. Circuit Court of Appeals signaled Friday that it may take another look at the court’s order voiding the Federal Energy Regulatory Commission’s authority over demand response compensation.

A three-judge panel of the D.C. Circuit ruled May 23 that FERC Order 745 violates state ratemaking authority. (See Court Throws Out Demand Response Rule.) FERC asked the circuit on July 7 to conduct an en banc review of the 2-1 ruling.

In a one-page order Friday, the court told the Order 745 challengers — the Electric Power Supply Association, American Public Power Association, National Rural Electric Cooperative Association, Old Dominion Electric Cooperative and Edison Electric Institute — to file a joint response to FERC’s petition within 15 days.

In its petition for review by the full D.C. Circuit, FERC acknowledged the rarity of rehearing. It noted that the commission has sought such a rehearing only once in the last 18 years — a case in which the Supreme Court reversed the circuit’s original decision.

Order 745 requires PJM and other RTOs to pay DR providers full locational marginal prices.

FERC said a review was warranted because the May 23 ruling “severely departs” from previous rulings on FERC’s jurisdiction under the Federal Power Act. A broad reading of the ruling could potentially invalidate DR participation in any wholesale market — energy, capacity or ancillary services — FERC said.

PJM joined FERC in seeking a review of the ruling, saying the loss of DR would be disruptive to operations. PJM General Counsel Vince Duane acknowledged that the court grants less than 1% of the rehearing requests it receives but said the odds were better in this case because of the implications of the ruling.