The federal district appeals court in Washington, D.C., late Friday temporarily halted a decision made last month that had taken the proposed Killingly power plant out of consideration for future power sources in New England. The operator of the New England grid, ISO-New England, which runs the auction, said in a statement on Sunday that it had considered delaying it but instead would make two calculations at its conclusion — one with Killingly and one without. It’s unclear how long the stay will remain in place and when the next court actions will occur. NTE and state officials have not responded to requests for comment. Most of Killingly’s permits are in place, and state officials have repeatedly said they have no power to simply reject it because it may not be needed or it does not meet the state’s climate change goals of a carbon-free electric grid by 2040.