NEW ORLEANS -- Many area residents, including residents of New Orleans, started returning to their homes Wednesday and Thursday after evacuating in advance of Hurricane Gustav's landfall.

Many area residents returned home from their Hurricane Gustav evacuation Wednesday to find no one left the lights on. There were still nearly 1.2 million homes and businesses in Louisiana without power, including about 77,000 in New Orleans. For many returning residents it means a number of things: no lights, no air conditioning and no refrigeration.

While the number of service disruptions are down from the immediate aftermath of the storm, the main transmission lines into southern Louisiana are crippled. The state said it would be as long a month, during the dank heat of the Louisiana summer, before the air conditioning returns for all.

Nearly 750,000 Entergy customers remained without power two days after the Category 2 hurricane slammed into Louisiana, knocking out power to about 850,000 customers by Tuesday.

As of Tuesday afternoon, nearly 170,000 Cleco customers still were without power, mostly in St. Tammany Parish, and power remained out for more than 9,000 WST customers.

Entergy officials said the outage was the second largest in the company’s 95-year history, behind only Hurricane Katrina, but elected officials wondered why so little progress had been made.

"There is no excuse for the delay. We absolutely need to quicken the pace at which power is restored," said Gov. Bobby Jindal. "I cannot emphasize it enough, it is the No. 1 obstacle."

After flying over flooded fields and downed trees on a tour of the state's hard-hit areas, President George W. Bush said the response to Gustav has been "excellent" while cautioning there was more work to be done.

"One of the key things that needs to happen is that they've got to get electricity up here in Louisiana," Bush said. "There's a lot of folks from the states that are working hard to restring the lines."

New Orleans Mayor Ray Nagin and Mississippi Gov. Haley Barbour and received a briefing from David Paulison, director of the Federal Emergency Management Agency.

"Baton Rouge got hit pretty hard," Paulison told reporters on the plane. "They got hit worse than New Orleans did. There's obviously no power. A lot of trees are down, windows blown out in buildings, roofs gone."

Paulison warned residents against returning to their homes before city services are up and running.

Torrential rains and the threat of tornadoes continued to cause new outages Wednesday as crews worked to restore power, utility officials said, and some supplemental crews have been sent from Louisiana to Arkansas, where about 22,000 customers are without power.

Additional utility workers have responded from 26 states and the District of Columbia, but officials said some customers still might not have power restored for up to three weeks in some areas.

Crews restored connection lines Tuesday night linking southeast Louisiana’s transmission system to the east and west, and 13 of 14 transmission lines serving the New Orleans metropolitan area remain out of service.

Even as Mayor Ray Nagin reluctantly reopened New Orleans to returning evacuees, most neighborhoods still did not have power, hospitals were running on generators and most businesses remained shuttered.

The lack of power was holding back the other critical needs, including gasoline and hospital care, confronting the nearly 2 million people returning to coastal Louisiana after heeding the call to flee from Gustav.

Without electricity, gas station can't pump their fresh stocks of fuel. Hospitals running on generators, some of which had already moved patients who they feared would suffer without air conditioning, were running low on fuel and could be forced to close entirely.

The public hospital in Baton Rouge was being partially evacuated because of power problems, with patients sent to Texas and Mississippi facilities, Jindal said.

Some places never lost power, including the Superdome, where the Saints planned to open their regular football season Sunday.

In Jefferson Parish, which reopened to all residents Wednesday, officials reported that most of their sewage stations were out of service because there was no power. The parish urged residents not to flush toilets, wash clothes or dishes, or even take showers, worried that an overwhelmed system will backup and send sewage overflowing in home and businesses.

"This is a bit of concern," parish spokeswoman Patricia Borne said. "We don't know how many people will be coming in."

Power remained out across Saint John Parish, where the hospital and some businesses were open, and officials warned residents that power might not be restored for several days.

Almost all customers remained without power in St. Tammany Parish, where Cleco officials still have not scheduled an estimated completion for repairs.

Widespread power outages also were reported in Lafourche, Plaquemines, St. Bernard, St. John and Terrebonne parishes, which provided widely varying estimates for power restoration.

For example, most customers in Plaquemines Parish should have their power restored by the end of the week while customers in Terrebonne Parishes might be asked to wait four weeks for service.