Critics say the plan isn't in the best interest of ratepayers.
But Public Service Co. of New Mexico said Monday in a filing with state regulators that rejecting the plan could jeopardize the continued operation of the San Juan Generating Station and end up costing customers more.
A hearing examiner recommended earlier this month that PNM's plan not be approved unless changes are made. He pointed to uncertainty surrounding the ownership makeup of the plant and a lack of a coal contract beyond 2017.
State regulators could make a decision in the case as soon as Wednesday.