Puerto Rico may not have the majority of its power generation back until January or February, U.S. Army Corps of Engineers commander Lt. Gen. Todd Semonite said Friday during a briefing on hurricane relief efforts.

“The governor has made a milestone of trying to get 30 percent of the Puerto Rican load up by the end of October, and then 50 percent by the end of November,” Semonite said. “I personally think those are stretch goals, but we‘re very, very committed to trying to meet where the governor’s at. ... I personally think it’s going to go into January and February to get the majority of the backup running.”

In addition to the Army Corps of Engineers, the Defense Department has responded with roughly 13,000 personnel to hurricane-ravaged Puerto Rico and the U.S. Virgin Islands, according to a media update released Friday. The USNS Comfort, a Mercy-class hospital ship, is also conducting medical support operations near Aguadilla, Puerto Rico, and 64 of 67 hospitals on the island are now open, according to the statement.

Additionally, the Defense Department has sent 74 rotary wing aircraft and 16 fixed-wing aircraft to assist in operations, according to the statement. The Defense Logistics Agency is planning to continue delivering 2.5 million meals a day through Nov. 5.

The U.S. Army Corps of Engineers’ strategy has been anchored around first providing 400 to 500 temporary generators in Puerto Rico, Semonite said. Normally they would provide 40 to 50 generators for hurricane relief, but Puerto Rico requires a massive rebuild of the energy grid, he said.

“We are going all out to put in as many generators as we can,” Semonite said. “This is not a generator like you would buy at a hardware store downtown; this is a generator pulled behind an 18-wheeler.”

The Army received a list from Puerto Rico Gov. Ricardo Rosselló outlining priorities for electricity, Semonite said. Hospitals are at the top of the list, followed by public utilities like water facilities, wastewater treatment plants, cell phone towers and schools, he said.

“The goal is to get 100 percent of power back to everybody on Puerto Rico. ... Some of these generators could be there for months on end,” he said.

The Army also is working to bring power plants back online for long-term power generation, Semonite said.

“This is where we have our work cut out for us,” Semonite said. “Right now, we've got about 21.6 percent of that [power] up ... that’s 579 megawatts.”

However, most of the big power plants on Puerto Rico are in the south of the island, while most of the demand for power is up in the north, Semonite said. Getting power generation back up to normal capacity will require probably three new power lines from south to north, over a mountain, to “put enough electricity up in San Juan,” he said.

“So, the challenge is how do you get that electricity from south to north? Even if all of the power plants are up and running, we would have a generation shortfall,” he said.

To assist with that shortfall, a company was contracted to build a temporary power plant in San Juan, Semonite said.

“That power plant is being built today and will be up by the end of October. That will put another 50 megawatts into the grid,” he said.

Semonite cited a 2016 report by an independent firm that warned of the frailty of the power generators on Puerto Rico.

“One of the power plants up in San Juan was actually shut down seven weeks before the storm because it had massive maintenance challenges,” he said.

Even bringing the power generation back to pre-hurricane levels will require a longer term plan for the island, Semonite said.

The terrain on the island, and the remote housing of its inhabitants could mean 100 percent power to everyone on the island isn’t restored until May, he said.

“We are doing everything we can to shorten those timelines,” Semonite said. “I certainly hope that I am wrong and we can go a lot faster, but what I don’t think it’s smart to do is give false hope to those people in remote locations that the power is going to be on week.”