Jun. 26--A widespread power outage at 9:15 p.m. Sunday knocked out electricity all over Southcentral Alaska, with reports of blackouts from the Mat-Su Borough to Homer.

Utility company officials still didn't know what had caused the outage almost two hours after it hit. However, at press time, the companies said they were restoring power, phasing it back a piece at a time to keep the system stable.

"It's all good news at this point," said Phil Steyer from Chugach Electric Association at 11 p.m. He expected all power would be restored before morning.

"I still don't know about the cause," he said. "Frankly, we may not for a day or two."

The regional intertie -- the grid system that Southcentral utility companies are connected to -- took "some sort of hit," said Gary Fife, spokesman for Municipal Light and Power. He wouldn't speculate what that was.

Electricity around Anchorage was spotty; some major streets such as Tudor Road and Bragaw Street had power on one side and not on the other.

Fife said ML&P had turned off some neighborhoods when trouble struck to keep power running to "priority" customers, such as hospitals. Late Sunday, Providence Alaska Medical Center and Alaska Regional Hospital had power, but Regional reported a short outage.

Steyer, from Chugach Electric, said 80 percent of Chugach customers had lost power. Chugach supplies Matanuska Electric Association with power, he said, and Homer and Seward also buy power from Chugach.

Steyer said Golden Valley, the utility in Fairbanks, maintained power to supply the Interior.

Alaska State Troopers dispatchers in Soldotna said they heard reports of outages in Nikiski, Anchor Point and Clam Gulch. Residents from the Mat-Su area also reported outages.

Reports of fire alarms flooded public safety scanners, but dispatchers attributed most to power outages.