It may take as long as three weeks to restore electricity in typhoon-stricken areas in Luzon, energy authorities said Sunday.

Power in Metro Manila is expected to be fully back on by Tuesday, six days after Typhoon “Milenyo” roared through the region.

Energy Secretary Raphael Lotilla said efforts to restore power is were taking longer than expected because there were too many fallen posts and downed lines.

The Manila Electric Co. (Meralco) said that in Metro Manila, 660 of its distribution circuits were damaged and 570 posts were blown down by Milenyo.

“It is really very difficult to predict but we are targeting to normalize the supply of power in Metro Manila by Tuesday. By Monday, we are coordinating with the Metro Manila Development Authority to fast-track giving power to major thoroughfares so traffic flow will not be affected,” Meralco’s President Jesus Francisco said.

Restoring power to other regions, including Bicol, may take longer.

A report from the National Transmission Corp. (Transco) and the National Electrification Agency (NEA), said power may be fully restored in the Bicol region and portions of Cavite, Quezon and Batangas in the next three weeks as Transco completes the repairs of its transmission lines.

The Dasmariñas-Rosario line, which serves the towns of Rosario, Gen. Trias and the export processing zone in Cavite, is expected to be repaired on Wednesday.

On Sunday, power was back on in Naga City and nearby towns following the energi­zation of the transmission line linking the Tiwi Geothermal Plant and the Naga Substation.

Transco also expects to light up Daraga, Tabaco and Legazpi City Sunday night with power from the Tiwi Geothermal Plant.

In Sorsogon, where more than 60 poles need to be repaired, the blackout could last until October 18.

In Quezon, 21 percent of its average daily load of 38MW is already being served. Transco will be installing emergency restoration system (ERS) structures or temporary tower structures to connect the Tayabas substation to the Labo Substation, to bring in more power to Quezon and Bicol.

Transco expects to provide additional power to most of Meralco’s Cavite franchise area when the Dasmariñas-Lakeview and Dasmariñas-Tagaytay lines are put back on Sunday night and the Dasmariñas-Ternate line by Monday.

Transco President Arthur Aguilar said about 40 transmission towers were severely damaged by Milenyo, including the 230-kilovolt Naga-Tayabas line and the Kalayaan-Gumaca line.

Transco would start its evaluation on the value of the damages beginning Monday, Agui­lar said.

As of 2 p.m. Sunday, Transco said power has been restored in 72 percent of the entire Luzon grid, equivalent to a demand of 3,408 megawatts (MW). The remaining 28 percent will be restored in the next three weeks, but Transco, NEA and Meralco all agreed that there would still be isolated areas, which would have no electricity because of the difficulty in repairing the electricity distribution system.

Despite the seemingly slow restoration work, Lotilla said that present efforts “are much faster” compared to the typhoon-induced Luzon-wide blackout in 1995.

“The response is more organized now compared in the past,” he said.

Power restoration efforts, Lotilla said are hampered by the billboards, which brought down poles and lines.

He said the government is considering regulations on setting up billboards that may endanger major infrastructure such as power transmission and distribution systems.

Lotilla said they are also studying the possibility of minimizing the number of overhead wires in Metro Manila.

Meralco recommended pruning or trimming overgrown trees within its franchise area to minimize outages brought about by strong typhoons.