A District task force has delayed the release of long-awaited recommendations about whether the city should bury its power lines, a project that could cost $5 billion.

The committee that includes city officials, residents and Pepco's president has been meeting since August to evaluate whether such a plan was necessary or feasible. Its recommendations were due Thursday, but the group has postponed issuing its report.

"Due to the very complex nature of the issues involved, Mayor [Vincent] Gray has granted the task force additional time to deliver the final report," said Tony Robinson, a spokesman for City Administrator Allen Lew, the panel's co-chairman. "It is anticipated that the final report will be completed in February and released before the end of the month."

The delay drew immediate criticism.

"It not only annoys me, but I don't think we needed four, five or six months to do this. We didn't need a task force," said Ward 2 Councilman Jack Evans, who has previously written legislation pressing the case for undergrounding. "I don't understand what the studying is about: Pepco is going to pay for it or they're not going to pay for it."

Pepco spokeswoman Myra Oppel said the company was "fully participating in the process" and was looking forward to the panel's recommendations.

Buried lines already serve about 60 percent of the city, but District leaders began studying a broader undergrounding strategy after 64,000 customers lost electricity for days in storms last summer.

Such a plan would be expensive: Pepco has said it could add more than $200 a month

to the average residential customer's tab.

Lew has cautioned that city leaders would not allow bills to skyrocket, but he said D.C. officials were open to more creative financing options.

"A billion dollars unloaded on the consumer is outrageous," Lew said in August. "But if a portion of the costs that we're talking about was to be assigned to the consumer, along with all of the other things that we're looking at, it might allow us to move forward with this."

Lew said potential cost-reducing options would include securing federal funding and coordinating road construction projects with Pepco's schedule to tear up city streets to bury lines.