Power executives were still in the dark Wednesday about how a glitch at a substation triggered a blackout that cut power to millions across south Florida. The outage snarled traffic when traffic signals went dead, forced hospitals to scramble for generators and cut off air conditioners in the afternoon heat.
The sporadic outages Tuesday spanned 300 miles of the peninsula but appeared to be concentrated in the southeast portion of the state. Communities along the southwest coast, in the Florida Keys and as far north as Daytona Beach reported interruptions.
While the outages cut power to 2 million to 3 million people at its peak, power was quickly restored to most parts of the state and authorities said no injuries were reported. Only about 20,000 people lacked electricity during the evening commute home.
Bob Wild, a sports marketing consultant who lives in Miami's southern Kendall neighborhood, said he didn't even notice the blackout, thanks to his home's generator.
"We're a hurricane family. We've been though Hurricane Andrew and everything before and since," he said. "Our daughter called us from Washington and said she'd seen the blackouts on TV. That's when we found out."
The president of Florida Power & Light was puzzled by how the blackout happened, saying an equipment malfunction at an electrical substation should not have caused the outages.
None of the events should "have caused the kind of widespread outage that we saw," FPL President Armando Olivera said. "That's the part that we don't have an answer for yet."
Malfunction sparks fire, series of problems
At about 1 p.m. an equipment malfunction happened at a facility that transmits power in Miami, starting a sequence of events that caused power to go off in areas around the state.
The malfunction led to a fire at the facility, which in turn caused larger problems — disabling two power distribution lines between Miami and Daytona Beach, according to the power company.
Systems monitoring the power grid saw took action, automatically shutting down two nuclear plants at the Turkey Point facility south of Miami. It took just milliseconds, or seconds, but it was "quick," said FPL spokesman Dick Winn. A fossil fuel plant also went off-line.
In total, the state temporarily lost the ability to generate a total of 2,500 megawatts of power. That's about 5 percent of the total generating power Florida uses on a peak day according to Linda Campbell of the Florida Reliability Coordinating Council in Tampa, which helps oversee the state's electricity supply.
Once that amount of megawatts was not available to the grid, FPL spokesman Randy Clerihue says the system had to shut off power until it could compensate for the losses.
It was unclear how much the shutdown of the facilities at Turkey Point contributed to the loss of power. However, Florida Power & Light's web site says that the two nuclear power plants generate about 1,400 megawatts of power, or more than half of the capacity temporarily lost on Tuesday.
No threat to nuclear plant
Authorities said there were no safety concerns at the nuclear plant and the outages were not related to terrorism. The outages initially affected about a fifth of Florida's population.
Officials said Miami International Airport, the Port of Miami and the area's rail and bus transportation were working normally, although some places briefly relied on generator power.
Several Miami-area hospitals switched to backup generators when the power went out. Students left Miami-Dade schools on time, and school buses were running.
At one Starbucks Coffee Co., employees began handing out sandwiches they feared would go bad. Nelson Suarez, 35, enjoyed the free lunch. "I can't work anyway since all the power is out, so at least something good came out of this," he said.